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HomeMy WebLinkAboutErosion Management Plan Nov 95 revised Jan 96 TOWN OF SOUTHOLD EROSION MANAGEMENT PLAN Prepared for: Prepared by: Revised by: November 1995 Revised January 1996 Town of $outhold Allee King Rosen & Fleming, Inc. Moffatt & Nichol, Engineers The Saratoga Associates NTS Department of State, Divison of Coastal Resources Town of Southold SOUTHOLD EROSION M~qAGEMENT PLAN TABLE OF COlvr~2~rS ACKNOWLEDGMENTS EXECUTIVE SUMMARY Pa~e Number i S-1 CHAPTER I. COASTAL PROCESSES AND SHORELINE EVOLUTION A. COASTAL GEOMORPHOLOGY COASTAL PROCESSES Winds Waves Water Levels Astronomical Tides Storm Surges Sea Level Rise Currents Sediment Characteristics and Supply Storms Human Activity and Land Use Introduction Hardened Structures Sof~ Engineering Solutions Land Use Flood-Prone Areas C. SUMMARY I-1 I-1 14 I-4 1-5 I-7 I-7 I-8 I-9 I-I0 1-10 1-11 1-13 1-13 1-15 1-21 1-22 1-22 1-22 CltAPTER II. INVENTORY OF SOUTItOLD BY REACII A. LONG ISLAND SOUND SIDE OF THE TOWN OF SOUTHOLD B. REACH 1: TOWN LINE TO DUCK POND POINT C. REACH 2: DUCK POND POINT TO HORTON POINT D. REACH 3: HORTON POINT TO ROCKY POINT E. REACH 4: ROCKY POINT TO ORIENT POINT F. REACH 5: ORIENT POINT TO YOUNGS POINT (GREENPORT) H-1 II-1 II-1 II-2 II-2 1I-2 II-3 G. REACH 6: FANNING POINT TO FOUNDERS LANDING H. REACH 7: FOUNDERS LANDING TO INDIAN NECK I. REACH 8: INDIAN NECK TO DOWNS CREEK J. REACH 9: DOWNS CREEK TO THE TOWN LINE K. REACH 10: FISHERS ISLAND 11-4 II-4 II-5 II-6 II-7 CHAPTER HI. COMMON MANAGEMENT UNITS A. INTRODUCTION LONG ISLAND SOUND COAST Jetty Areas Areas of Low Bluffs and Dunes Areas of High Bluffs PECONIC BAY SIDE OF SOUTHOLD Cre~k Mouths Exposed Shores Protected Shores Flood-Prone Areas III-1 11I-1 III- 1 111-1 111-2 111-2 111-3 11I-3 111-3 111-4 m4 CHAPTER IV. PROPOSED EROSION MANAGEIVII~NT POLICIES A. PREAMBLE POLICY STANDARDS Standard Setting Priorities for Erosion Control Structures and Reflecting Stat~ laws Standard on Natural Protective Features Standard to Protect Public and Public Trust Lands Standard on Management of Navigation Structures Standard Expenditure of Public Funds for Flooding and Erosion Control Standard on Sea Level Rise IV-1 IV-I IV-3 IV-3 IV-5 IV-5 IV-7 A. V. POST-STORM RECOVERY POLICIF_~ POST-STORM RECOVERY Introduction Post-Storm Recovery Goals by Common Management Unit Long Island Sound Side Jetly Areas Low Bluffs and Dunes V-1 V-1 V-1 V-1 V-I V-1 V-2 Areas of High Bluffs Peconic Bay Side Emergency Permits V-2 V-3 V-3 CHAPTER VI. IMPLEMENTATION OPTIONS IMPLEMENTATION OPTIONS Studies Capital Projects Long-Term Coordination Government Agencies Private Foundations VI-I VI-1 VI-1 VI-2 VI-2 VI-2 GLOSSARY APPENDIX A: LONG ISLAND SOUND EROSION MANAGEMENT POLICY G-1 A-1 SOUTHOLD EROSION MANAGEMENT PLAN LIST OF TABLES I-1 Long Island Extreme Wind Velocity Records I-2 Southold Area Fetch Distances I-3 Southold Tidal Ranges 1-4 Historical Storms Affecting the New York Coast I-5 Summary of the Volumes of the Sand Removed From the Area West of Jetties of the Mattituck Inlet: 1960-1975 I-6 Summary of Town of Southold Dredging Projects Paee Number I-6 I-7 I-8 1-12 I~14 1-15 Chapter I I-1 I-2 I-3 I-4 I-5 I-6 SOLeI~OLD EROSION MANAGEMENT PLAN LL~I~ OF HGURES Typical Bluff-Backed Beach Profile Typical Spit and Tombolo Formations Storm-Induced Profile Erosion Schematic Wave Height Estimates Wave Period Estimates High Tide Frequency - New London, Connecticut Preceeding Pa~e Number I-2 I-4 I-6 I-6 I-6 1-10 Chapter II Il-1 II-2 H-3 II-4 II-5 H-6 II-7 II-8 Southold Reaches Geographic N~nes Deduced Direction of Littoral Drift Natural Shoreline Features Environmental Sensitivity Structural Shoreline Protection Land Use Mattituck Inlet Chapter III HI-1 Common Management Units II-2 H-2 H-2 II-2 H-2 II-2 H-2 II-2 HI-2 ACKNOWLI~T~GMENTS The following report was initially prepared by Mr. Philh'p C. Sears of Allee, King, Rosen, and Fleming, Inc., Environmental and Planning Consultants, 117 East 29th St., New York, NY 10016 in November 1995, under contract to the Town of Southold. The Town of Southold received an Environmental Protection Fund Grant from the New York State, Department of State to prepare an initial Local Erosion Management Plan. The report was revised in January 1996 by the New York State Department of State, Division of Coastal Resources, and the Town of Southold, to incorporate additional information and enhance the final plan. Report copies are available from the Town of Southold. This report is the synthesis of input and support from a large number of people. Ruth Oliva, Town Deputy Supervisor, has spent long hours chairing meetings with elected officials, agency personnel, and local citizens. Ruth has been the main force behind producing this report and has been very supportive throughout the process. Town employees Vaiarie Scopaz, Town Planner, and Jim McMahon, Community Development Director, have provided valuable reaources in developing the information base. They have collected information from numerous sources, scouted out reports and other data, and guided us on field trips. Steve Ridler, Fred Anders, and John Novak of New York State Department of State have provided teehnicai guidance throughout our work and have provided many insights on statewide policy concerns. The Local Waterfront Advisory Committee has given their insight into local concerns. A number of Southold residents have given of their time and shared their knowledge with us. Many have submitted reports, photographs, and written records of their observations and comments on the effects of coastal processes in Southoid. Their help supplied the local knowledge that is vital to this type of analysis. They include Donald Stanton, Reach 2; Whitney Booth, Reaches 2 and 3 (Horton Point); David S. Corwin, Reach 3; Louis Emmanuele, Reach 4; William W. Wetmore, Jr., Reach 6 (Con/ding Point); Judith Phiney, Reach 7 (Town and Jockey Creeks); Ronnie Wacker, Reach 8 (Nassau Point); Joe MacKay, Reach 8; Joe Gold, Reach 8; Harry p. Taylor, Reach 9 (Deep Hole and Downs Creeks); and Norman Wamback, Rick Curcio, and Eugene Bozzo, Reach 9 (James Creek). We thank each of them for their help. EXECUr~v-E SUMMARY CAUSES OF EROSION The Long Island Sound Shoreline The primary cause of erosion on Southold's Long Island Sound side is littoral drift caused by wave action. When waves break on Southold's shore at an angle, water moves in the direction of the wave angle, taking sand with it in a natural ongoing process called littoral drift. In Southold, the predominate direction of littoral drift is eastward, but major storms - which can generate waves higher than 6 feet - often move the sand from east to west. Generally, annual cycles of beach building and erosion take place. Over long periods of low wind and wave action, when the sand moves slowly west to east, a gently sloping beach builds up. During large winter storms, sand moves quickly from east to west and off-shore. These storms can remove sand and leave behind a stone and cobble beach. As long as the bluffs remain in a natural condition, beaches heal themselves over the summer and Southnld's shoreline erodes slowly over time. Points form around the areas with large rocks and cemented bluff sands. Areas with low bluffs and clayey soils become embayments. Although Southold's Long Island Sound shoreline is eroding slowly, over the short-term it is dynamically stable. However, jetties to keep inlets open and groins and bulkheads to keep bluffs from eroding have, in pieces, taken the system out of equilibrium. Because of the bluffs, coastal flooding is localized along this shoreline. Very high tides rise to the bluff toe, but houses are not flooded. In certain low-lying areas, such as the east side of Mattltuck Inlet, localized flooding does occur. The Peeonic Bays Shoreline Causes of erosion on Southold's Peconic Bays are complex. Littoral drift dominates in areas exposed to waves. Going from west to east, bays become smaller, and therefore bay waves are smaller. Shoreline on either side of James Creek is fully exposed to waves from Great Peconic Bay, where waves can theoretically reach a height of almost 5 feet. Robins Island affords some protection to Cutchogue Harbor and the west side of Nassau Point, but the east side of Nassau Point is exposed to Little Peconic and Hog Neck Bays. Southold Bay and its waves are smaller. At the far east end of Southold, Hallock Bay is almost totally enclosed. However, the Peconic shore, unlike the Long Island Sound side, has few high bluffs. Therefore, when a storm causes erosion, fur an equivalent wave conditions, shoreline L,~a. eat is greater and recovery is slower. In addition, flooding is common along the shore. To protect these low flat shores, over the years property owners have built many groins to hold beaches and bulkheads to raise ground level. S-1 Currents are the second cause of erosion on the Peconic shores. Baymen report eddies in many bays, indicating that water flows constantly in one direction, no matter whether the tide is flooding or ebbing. These currents contribute to formation of elongated features, such as Nassau Point. Compared with the two inlets on the Long Island Sound side of Southold, at least 25 inlets, depending on how they are counted, are found on the Pecoulc side. Tidal currents flowing through these inlets move and deposit sand, both inside and outside of the inlet's mouth. Under natural conditions, each inlet maintains a shallow channel and forms shoals around its mouth. However, these inlets are dredged for boat navigation. The resulting deeper channels have changed the currents, which leads to different erosion patterns. The interaction of waves, offshore currents, tidal flows through inlets, and human construction leads to a series of complex erosion and deposition systems that change seasonally and yearly in response to weather. CONDITION OF SOU'I~OI~'S SHOI~RL~W.,S The Long Island Sound Shoreline This shoreline has two inlets, both protected by jetties - Mattituck Inlet and Goldsmith Inlet. Mattituck Inlet is heavily used by recreational and commercial boaters. It is a maritime center of statewide significance whose uses are an important aspect of Southold's character. Shoreline west of the inlet (updriff side) has generally accreeted seaward as a result of the jetties, but shoreline east of the jetties has severely eroded. It has eroded close to the jetties, and the low bluffs and dunes cannot provide sufficient sand to resupply the shoreline, resulting in a prominent shoreline offset. Goldsmith Inlet is not navigable and is not used by boats. A single jetty stabilizes inlet location. The inlet is actually an outlet to a coastal pond, and water flow is unidirectional toward the Sound. It is periodically dredged by the Town and sand is used for off-site construction purposes. It is unclear what role dredging plays, if any, in keeping the inlet open. However, review of historical maps and photos back to the 1870's shows the inlet open at each date examined. Like Mattituck Inlet, the west side (updrift) has accumulated sand while the east side has eroded, resulting in a prominent shoreline offset. During the past five years, shoreline open to the northeast has been heavily eroded by a series of storms, some of which had characteristics approaching the 100-year storm. Over the previous $0 years, the same areas eroded at a much slower rate. The rate of erosion during the past five years seems to be anomalously high (this is supported by a study conducted in Nissequogue). The level of shore protection construction is evidence of the long-term lower rate of erosion. Only a few thousand feet of bulkhead and less than 100 groins have been built over the 39 miles of Southold's Long Island Sound shoreline. Long-term shoreline erosion is slow, because the bluffs have been able to resupply some of the sand lost to the system. Long-term shoreline erosion averages less than 1 foot per year based on independent studies by Davies et al, 1971, and the Department of Environmental Conservation for the Coastal Erosion Hazard Areas Act. Exceptions occur east of Mattituck Inlet and east of Goldsmiths Inlet (2.5 + ft/yr erosion). S-2 The Peconic Bays Shoreline The Peconic shores have been subjected to many erosion control structures to prevent landward migration. Over it~ 136 mile~ of tidally influenced shoreline, more than a thousand groins have been built. Groins are prominent along the 35+ miles of sandy shoreline. Where houses have been eon- structed, about 50 percent of the shoreline is bulkheaded. Most of the more than 25 inleta are protected by jetties. In 27 separate areas, the Town has uudertaken almost 150 dredging projecta since the 1960's. Suffolk County has dredged at least five creeks yearly since the 1950's. This heavy investment has main- rained the shoreline, and few, if any, houses have been lost to erosion. However, several areas still flood regularly, leading to property damage. A high level of investment will continue to be necessary in the future to prevent loss of property and minimize damage. RECOMlVlENDATIONS FOR ACTIONS The Long Island Sound Shoreline The Board of Trustees should closely examine each permit application for shore protection to determine if the proposed structure ia necassary. A proposed shore protection structure's potential effects on neighboring property during the next few years and the long-term must be analyzed. Will the struc- ture cause downdrift erosion? Will it reduce the supply of sand to public beaches and underwater lands and private propertias over time? These kinds of questions must be answered before granting a permit. The same requirements should apply in a post-storm situation when a property owner applies to rebuild a structure. Only those properties that are in imminent danger should qualify for a permit. Several zoning mechanisms should be used to reduce potential damages to new buildings. For new lots, a shoreline setback should be instituted. The New York State Coastal Erosion Hazard Areas Act provides a minimum 25 f~ setback from the bluff edge, however, this may not be adequate for all areas of Southold. Further study is needed to establish a variable setback distance from reach to reach based on rate of erosion. However, a 150-foot setback including a 50-foot natural vegetation buffer, measured from the high water line or the bluff toe, could be a reasonable starting point. Setback creation requires an assessment of lot sizes to determine impact on public and private property. The Peconic Bays Shoreline The beach and nearshore morphology ia highly dependent on human activity, including dredging and a multitude of shore protection structures. Radical change from current shore protection practice might lead to loss of public and private property, and some of these losses could occur quickly. Therefore, permit review does not need to be as detailed as for permits required on the Long Island Sound side. However, in areas where structures do not dominate, such as Hallock Bay, shore protection structures should be discouraged, and avoidance measures encouraged. Likewise, in the aftermath of a severe coastal storm, when broad areas of coastal structures are destroyed, there may be opportunity for natural shoreline restoration. Use of dredged materials ia very important to the health of this shoreline. Unfortunately, current S-3 practices do not recognize this. Decisions about where and how the dredged materials are used are not subject to rigorous review. Dredged materials should be used to build beaches, dunes, and other types of natural protective features. Currently, these materials are often just piled out of the zone of interaction with coastal processes, and, in one observed case, used for filling in wetlands. Instead, this material should be placed on eroding beaches below the mean high water line. Concerned government agencies - the Board of Trustees, Suffolk County DPW, and New York State Department of Environmental Conservation and Department of State - should meet to generally review placement options given regulatory concerns, erosion trends, and available scientific information. Thereal~er, the Trustees, Suffolk County DPW, and the Department of Environmental Conservation should meet regularly to jointly decide where and how the dredged material is placed. Decisions must be reviewed annually in light of weather and level of erosion over the past winter season. Dredged material must be viewed as a valuable resource which cannot be squandered without detrimental consequences to beaches. Townwide Actions Southold should include shore protection structures in its building code. The type and size of the structure and building materials used to construct it can be restricted by the building code. Existing groins vary widely in height, length, and spacing. Casual observation suggests some are effective in trapping enough sand to maintain a modest beach, while bypassing some sand to downdrift beaches. However, some groins are so high and long that they trap all sand, and bypass none to downd- rit~ beaches, effectively causing erosion. Others are totally ineffective, either because of design flaws or lack of maintenance, and thus serve only to reduce public uses and aesthetic quality of the shore. A Townwide building code could prevent new problems and rectify some existing ones in post-storm situations. The building code should set the top elevation and the downward slope of groins in order to retain sufficient sand to protect property while not completely blocking flow to downdriff properties. In addition, the length of individual groins and spacing between them should be regulated. These are two interrelated factors. Development and enforcement of a shore protection building code would bring order and reason to the current variety of shoreline sUm~ctures, some of which are in conflict with each another. Coastal processes can be confusing to people who are not used to living by the sea. Many newcomers (and some long-time residents) do not understand erosion and its causes. Meetings that the Town of Southold has held are a meaningful beginning to the process of educating the public, but they must be continued. Informative beoldets and pamphlets - such as those published by the East End Economic and Environmental Institute, Inc. - are additional important tools. The public must be made aware of dangers in siting a house on the water's edge. S-4 CHAPTER I, COASTAL PROCESSES AND SHO~I~.I.INE EVOLUTION This chapter summarizes and is an introduction to coastal processes and their interaction with Southold's shoreline. The intent of this chapter is to present an overview of the coastal processes affecting Southold. Chapter II contains the detailed, reach-by-reach description of Sonthold. As an introduction to the physical processes governing the evolution of the coastal environment and their complexity, the following is from the U.S. Army Corps of Engineers' Shore Protection Manual (1984): .... The beach and nearshore zone of a coast is the region where the forces of the sea react against the land. The physical system within this region is composed primarily of the motion of the sea, which supplies energy to the system, and the shore, which absorbs this energy. Because the shoreline is the intersection of the air, land, and water, the physical interactions which occur in this region are unique, very complex, and difficult to fully understand. As a consequence, a large part of the understanding of the beach and nearshore physical system is simply descriptive in nature. A general discussion describing the physical coast with emphasis on the Sonthold region is presented below. Included 'are the evolution of Long Island, the forces that act on the shore, and its reaction to these forces. The chapter is divided into three sections: 1) Coastal Geomorphology - development of Long Island and existing coastal landforms; 2) Coastal Processes - forces affecting shoreline change; and 3) Southold Coastal Conditions - response to normal and storm-induced conditions along the project shoreline (e.g., flooding and beach and bluff erosion). A glossary of pertinent coastal engineering and coastal geology-related terms is included for further reference. Primary references used throughout this document include: Governor's Coastal Erosion Task Force, Final Report, Volume H, Long-Term Strategy (GTFH 1994); o Shore Protection Manual, U.S. Army Corps of Engineers CLISACE 1984); O North Shore of Long Island, Suffolk County, New York, Beach Erosion Control and Interim Hurricane Study (Survey) (USACE 1969); and 0 Erosion of the North Shore of Long Island by Davies, Axelrod, and O'Connor (Davies et al., 1973). A. COASTAL GEOMORPHOLOGY The marine coastline of the Town of Southold includes the shorelines along the northern shore of Long Island from the western Town boundary (Mat~ituck Hills) to Orient Point; the southern coastal areas fronting Gardiners Bay, Orient Harbor, Shelter Island Sound, Hog Neck Bay, the Peconies (Little Pecunic and Great Peconic Bays), and Flanders Bay; and Fishers Island in Block Island Sound. Southold's shoreffont features include beaches, bluffs, dunes, wetlands, and barrier landforms. Topographic character and sediment composition of the area determine the manner in which these landforms interact with the marine environment, thus affecting coastal erosion and flooding. This section summarizes the development of the Long Island coastal complex, including the evolution of the shoreline and its I-I landforms to the current configuration. To fully understand the physical environment and its dynamic character, its development must be examined historically. The following paragraphs, from G"I'I,'II (1994), discuss the area's geologic history. .... Glacial advance during the Pleistocene epoch generally ended at the ap- proximate centerline of what is now Long Island (Fuller 1914). Seaward of the glaciers, extensive outwash plains of sand and gravel were deposited on top of pre-existing sediments and the gently seaward sloping Atlantic Coastal Plain. Glacial termination along an east-west front resulted in the present east- west orientation of the south shore. Outwash glaciation resulted in sand depo- sition on the adjacent continental shelf. .... gently seaward sloping rocks of the Atlantic Coastal Plain are buried beneath more recent semi-consolidated and unconsolidated sediment. Pleistocene sediment deposited over the last 2 million years was greatly modified during the last glacial episode. Surficial sediment of Long Island is composed of a variety of loosely consolidated glacial material deposited primarily as moraine or outwash. Further modification by rising seas over the past 15,000 years has resulted in the present geomorphic landforms. About 20,000 years ago, the final period of glaciation, known as the Wisconsian, glaciers stopped extending southward and started to retreat. This was not a smooth, one-way process, but involved several advances and retreats. Along Southold's Long Island Sound shore, a ridge of glacial materials - eom- prising clay, sand, cobbles, and boulders - was deposited. This landform is called a recessional moraine, and the Harbor Hill recessional moraine forms the bluffs of the current shoreline. This recessional moraine contains highly variable sediments that cause the changes in beach character along Southold's Long Island Sound shoreline. Coastal areas are typically described both in profile and plan. A schematic beach profile is depicted in Figure I-1 (refer to the glossary for definitions of specific terms). This profile is valid for almost all of the Long Island Sound side of Southold. On the Peconic Bay side, it is valid without the bluff for shoreline away from the creek mouths. Specific landforms common along the Southold coastal region include beaches, dunes, bluffs, spits, tombolos, inlets, and tidal and non-tidal wetlands. These landforms are defined in the glossary included at the end of this report section,, and are summarized below. Beache4. Along the seashore and acted on by waves, tides, and currents, the zone of unconsolidated material that extends landward from the low water line to the place where there is a marked change in material or physiographic form, or to the line of permanent vegetation. Figure I-1 depicts the interaction of the sea with a typical beach profile backed by bluffs. Beaches are found along the whole langth of Southold's Long Island Sound shore. 0 Dunes. Ridges or mounds of loose, unconsolidated sand, that back the beach, providing added protection against wave at'ack and flooding during storm events. Dunes are found adjacent to Mattitock and Goldsmith inlets and at Horwn Lane Beach. I-2 6,9S Coati ~J~, Beach ar shore Bluff or Beach flockshore Hqa~ore zone (deflnel oreo of neorihorl currentl Inshore or ehorerace (exJends throuoh breaker zone Surf Zone Nigh weler leveL.. ~Gffshore Plunge point Bottom Source: U.S. Army Corps of En§h~ee~'s, Shore Pfolecll()n Man.al, Fi~,.re I- 1 l~each Profile and l~efinitions Bluffs. A high steep bank or cliff. Deposited during glacial movement, these coastal landforms are highly susceptible to erosion and collapse because of their steep seaward slope. Bluffs line much of Southold's Long Island Sound shore and the east side of Little Hog Neck. O Shits. Formed when the dominant waves and currents carry sediment into an elongated subaerial depositional feature, extending away from a headland. Generally oriented parallel to the shoreline, with sediments transported along the trunk of the spit to its end in deeper water, thus permitting the spit to grow longer. Spits grow in a variety of shapes depending on local bathymetry, sediment supply, tidal conditions, and wave climate. Spit growth often forms shoreline features, such as cuspate bars and baymouth barriers. These are commonly found on the Peconic Bay side of Southold. Typical examples are the mouths of Town and Mill Creeks, as well as the elongation of Nassau Point. Inlets. A short narrow waterway connecting a bay, lagoon, or similar body of water with a large parent body of water. Inlets are highly dynamic with natural tendencies toward movement and closure, and subsequent openings of more efficient inlets. They are often stabilized for navigation requirements. The Peconlc Bay shore of Southold has many inlets, while only Mattituck and Goldsmith inlets exist on Southold's Long Island Sound shore. Tidal and non-tidal w~tlsnd~. Tidal and non-tidal wetlands are low-lying areas subject to frequent inundation by tidal flows or storm tides, or merely having a relatively high water content. These areas are established in locations with little wave energy, allowing vege- tation to establish itself away fi'om destructive wave energy. Along Long Beach Bay, for instance, the protected shorelines have allowed the establishment of extensive wetland areas. Shorelines fronting Long Island Sound are characterized by nearly continuous bluffs composed of loosely consolidated glacial outwash (primarily sand) and moraine material, which is a mix of clay, silt, cobble, and boulder. The glacials expanded from the north, carrying this mixture of sediments with it. When the climate warmed, the advance of the glacier slowed, then stopped with back-and-forth shudders. During this process, the morainal materials were deposited in a long ridge shape along the face of the glacier. As the glacier retreated with the warming climate, sand was deposited in outwash plaim. This stopping and retreating formed what later became Southold's bluffs, dunes, and beaches. Material eroded from the bluffs enter the littoral system, contributing to beaches of varying width, slope, and sediment character. Beaches fronting Southold consist of sediments ranging from sand to cobble, with widths ranging from 25 to 100 feet. Portions of the coast are backed by dunes (e.g., east of Goldsmith's Inlet) and tidal wetlands, while some locations represent low-lying coastal barriers (e.g., Truman Beach). Shorelines fronting the Peconics are irregular and indented by numerous inlets and bays. Coastal areas east of Shelter Island fronted by Gardiners Bay are exposed to a moderate wave climate, while those west of Shelter Island and along Long Beach Bay have minimal wave energy. The wave energy becomes greater in Little Peconlc Bay and greater still in Great Peconic. However, the fetches (length of open water where wind waves can form) are longer in Gardiners Bay than the Peconlcs. Beaches are generally narrow and sandy and predominate along the eastern shoreline, with the exception of the wetland areas along Long Beach Bay. Bluffs are relatively low and infrequent along the Peconlcs. Shorelines backed by dunes are limited and specific to Orient Point State Park, which is a spit f~rmation. Tidal wetlands predominate along the western Iow-energy shorelines, which are the result of the presence of Shelter Island. Numerous barrier spits and shoals exist along the entire bayfront region. I-3 B. COASTAL PROCESSF, S Shoreline configuration is constantly changing as a result of varying hydrodynamic (water motion, water level, and other forces) and sediment processes. The evolution of a shoreline can be discussed both in the across-the-beach profile and along the beach, which is often called longshore. This evolution occurs during both normal low wave conditions and storms. During the storms, the more spectacular changes occur, but the normal weather conditions act over longer periods of time and are important in understanding beach evolution. The movement of a beach in response to waves is referred to as littoral transport, defined as the alongshore movement of sediments in the nearshore zone by waves and currents. Transport direction is mostly determined by wave steepness, sediment characteristics, and beach slope. Longshore transport of sediments results from the initiation of sediment motion by incoming waves and continued movement due to longshore currents. The magnitude and direction of longshore transport is dictated by the angle of wave approach to the shoreline, sediment characteristics and supply, and available wave energy. Direction and magnitude of longshore sediment transport is highly variable from day to day. Differences in longshore transport result in either accretion or erosion of the shoreline, and are responsible for many of the current erosion hazards along the project coast. Interruption of this longshore movement - e.g. headlands, inlets, and shore protection structures - can result in significant impacts on shoreline position. At Mattituck Inlet, for example, jetty construction and channel dredging to reduce shoaling of the inlet channel resulted in erosion on the east as the sediment supply was interrupted. The across-the-beach profile (Figure I-1) continually adjusts to dissipate the incoming wave energy. Beach response during normal conditions is subtle, as .wave energy is easily dissipated by the beach's natural protective features. The beach will accrote sand from the litwral transport and become wider and higher. At the end of a summer, a beach will normally have stored a large volume of sand. During storm conditions, however, the coast responds to Increased amounts of wave energy, often leading to the loss of significant quantities of beach, dune, and/or bluff material. Figure I-2 illustrates a beach response to wave attache during a storm. The foreshore is eroded and the backshore is often lost. During large storms, the dune system or bluffs are also eroded. The beach slopes become flatter. Some of the eroded sand is deposited in an offshore bar, and much can be lost offshore. These losses are sometimes (but not always) temporary, except in the case of bluff erosion, which is a permanent change to the coastal configuration. Winds Winds over coastal regions result in coastal changes through three primary mechanisms: 1) wind- generated waves, 2) wind-induced storm surges, and 3) aeolian (wind-induced) sediment transport. Generation of wind waves depends on the fetch (the distance over water that the wind blows without interruption) and wind conditions (duration and speed). During storm events when extreme wind speeds persist, water elevations at coastal sites may increase ss water piles up against the coastline. This effect is a component of sWrm surge, which often causes flooding and extreme wave attack damages. Aeolian sediment transport is a primary mechanism responsible for either the growth or deflation of coastal dunes. Strong winds (generally exceeding 1S miles per hour) must be present to cause significant sediment tuovement by aeolian transport. The magnitude of aeolian transport is highly dependent on the presence of vegetation and/or moisture, both of which reduce the movement of sediment. A wide beach I-4 ~ ~ '~ ! ~:':'-'.'-~- ~.7:: :'.:. :..'.~.~ ~: ::::.!.~.../8~rm ~ , -.W .~. -~ '.?? ~ ". '~:'..~.~-. ?: ..~.:~'~.'~:'.:..::~ :...~-..~. · ~ ~.-~.. ..... Profile 8 ~lniliol oltoc~ of storm ,,- - ,~.-~;~:~. :~ ..- ~~~'Profile l ~----~ Sierra Tide ~ ....... Crest ~~. .. .. ?~..'~.:. Profile 0 - After storm w~ve aHack, ~cc~ Profile A Source: U ~. Army Corps of En$in .eers, Shore Pmtec~on Manua/, r~n o~ Southold Figure I-2 Beach Response During a Storm is also necessary for dune formation. Dunes are found in the vicinity of Mattituck and Goldsmith Inlets, but the Town does not have the large dune systems that are found on Long Island's Atlantic shore. Wind data for long periods of record are available from observations at the Brookhaven National Laboratory at Upton, the Suffolk County Department of Public Works and Highways at Westhampton Beach, and the U.S. Weather Bureau at La Guardia Airport for New York City. Short-term data are also available from the U.S. Weather Bureau at Calverton Airport. Average wind conditions for the northeast, southeast, northwest, and southwest quadrants were estimated from the records at the four wind stations. With minor exceptions for the station located at La Guardia, the wind direction distribution for Long Island can be summarized as northeast, 120 percent; southeast, 17 percent; northwest, 30 percent; and southwest, 33 percent. (Wind directions refer to the direction from which the wind is blowing.) Winds from the northern quadrant dominate during the winter, and winds from the southern quadrant dominate during the summer. The wind velocity and storm duration during the winter tend to be higher than during the summer. In the summer, the percentage of calm conditions is over 10 percent, while calm conditions drop to under 3 percent during the winter. These values summarize wind conditions in the Long Island vicinity, but may not be directly applicable to Southold because of their distance (La Guardia Airport) and different topographic settings (Upton and Westhampton). Because wind data are not available for coastal areas along the north shore of Long Island, these data must be considered representative. In addition to long-term wind records, wind observations during storm events are important for evaluating coastal changes. Data obtained during storms were available for several locations, including Montauk Point, Block Island, and La Guardia Airport. Table I-1 contains the pertinent maximum re- corded wind velocities for some major storm events. The fastest mile and S-minute average data are typically used to conduct wave estimates. The most applicable information for Southold are records from nearby open-coast weather stations. Block Island and Montauk Point data, therefore, are suggested for use at $outhold; La Guardia wind data are used to augment the records. Waves Waves are created by wind blowing across the water with energy transferred to the water surface. This energy transfer creates perturbations in the water surface commonly referred to as wind waves (see Figure I-3 for a definition of wave characteristics). The waves then travel across water until reaching land, where they expend the/r remaining energy on the shore. Waves generated by local winds blowing on shore typically reach the shore as steep (i.e., wave length to wave height ratio is small) erosive waves called seas. Waves generated at great distances (hundreds to thousands of miles) prior to reaching the shore will decay into long low waves referred to as swell. The height, length, and period of wind waves at a coastal site are determined by the fetch, wind characteristics, decay distance, and water depth. In general, increases in fetch, wind speed, and duration result in larger wind waves. Water depth, if shallow enough compared with the wave height and period, will affect wave characteristics, with wave breaking beginning when the wave height is roughly 80 percent of the water depth. Waves generated by wind are characterized by many combinations of beight, period, and direction. This combination of waves is referred to as the wave spectrum, which is often characterized by representative wave parameters (wave height and period). Wave conditions at any given I-5 LONG ISLAND ~ocatfo~ Block Island Block Island Eastern End of Long Island Block Island Block Island La Guardia Airport Block Island Block Island Block Island Block Island Montauk Point Montauk Point Montauk Point Table I-1 ~"fl{~W.L~ V~OCI~CO~)S Velocity Date (mph) 21 September 1938 82 21 September 1938 91 21 September 1938 96 14 September 1944 88 14 September 1944 100+ 25 November 1950 94 6-7 November 1953 95 6-7 November 1953 98 31 August 1954 105 31 August 1954 135 12 September 1960 105 12 September 1960 120 6-8 March 1962 68 Ty~e of Record 5-minute average Gust US Weather Bureau wind pattern Fastest mile Gust Gust Fastest mile Gust Fastest mile Gust 5-minute average Gust Gust location over a period of time can be described through use of a wave spectrum, where characteristic wave conditions are referred to as the wave climate. Wave data for the north shore of Long Island have never been rigorously collected. Waves that affect the shore are generated by local winds, as Long Island and Block Island stop ocean swells from entering Long Island Sound (Davies et al., 1973). Given the orientation of the Southold Long Island Sound shoreline, winds from the northern quadrant and the west are primarily responsible for wind waves along the coast. In the Pecoulcs, the fetch is limited compared with the Long Island Sound side, but waves large enough to cause erosion can occur except within the creeks. Fishers Island is somewhat exposed to ocean wave conditions from the southeast; however, waves traveling from the ocean are affected by Montauk Point and Block Island. In general, the wave climate at shorelines along Long Island Sound (Fishers Island) are moderate, whereas shorelines along the Peconics and the majority of Gardiners Bay are less energetic. USACE (1969) summarized fetch distances for the Long Island Sound coast, that were augmented with approximations for the Peconics and Fishers Island. Estimates for these locations are for the maximum single fetch distance rather than the average 'distances used in wave calculations. The fetch distance for Fishers Island corresponds to the breadth of Block Island Sound, and excludes the narrow opening to the open ocean. These fetch distances are somrnarized in Table I-2. Wave heights and periods for shallow water waves (waves interacting with local bathymet~]) were hindcast using techniques given in the Shore Protection Manual (1984). Information used for these computations included water depths of 50 (no symbol) and 100 feet (with symbols), fetch distances from 10 to 70 miles, and wind speeds from i0 to 120 mph. The results are shown in Figures I-4 and I-5. While these results are not applicable to any particular location along the project shoreline, they are representative of the relationships between various wave generation parameters. I-6 6o9S Wave Cresl --,.s-~l ~ Cresl Leng Reoion Ocean EJollom L: Wavelenglh Direclion of Wove Travel = Wove Height ~ Wovej Trough r Ilwoler Level oh Len01h ' i Region d: Depth Source: U.S. Army Corps of Engineers, SI)nm I)rolecllon Man:iai, 19/J4 Town of Sn.thold Figure 1-3 Wave Characteristics 35 ~5 15 0 I0 WIND VELOCITY (mph) ...... 70 redes -- · -- 40 redes Figure I-4 Estimated Wave Hei~,hts 6,95 II I0 9 8 10 813 ~0 100 1 I0 120 WIND VELOCITY (mph) Town of So,,thl~Jll Fi~,.re I-$ Estimated Wave Period Table 'F-2 Location Wildwood Mattituck Inlet Hashamomuck Beach Orient Point Fishers Island* Bast Shelter Island Little Peconic Great Peconic $OoTaOLD AUrA FETCH DISTANCES Fetch Distance (miles) Northwest Northeast Southwest Southeast 27 30 50 20 49 14 17 11 45 6 10 20 Fetch (miles) 30 50 49 17 20 45 6 10 * To the Race that restricts short period wind waves but not swells Water Levels Elevation of the water surface can be considered as a long-term average dependent on the volume of water contained in glacial form or as a short-term change in water elevations as a result of astronomi- cal tides, storm impacts, and precipitation and ice melt (for rivers and small bays). The fluctuations resulting fi.om the combined effects of astronomical tides and storm surges, and the effect of sea level rise on global ocean levels are of primary importance for this report. Astronomical Tides Tides are created by the gravitational forces exerted by the moon and, to a lesser extent, the sun. These forces of attraction - coupled with the fact that the sun, moon, and earth are always in motion relative to one another - cause oceans to be set in motion. These tidal motions are very long period waves, and result in the periodic rise and fall of water levels along the coast. The phasing of high and low tides is variable and important to the level of wave attack along the shoreline. High tides in con- junction with strong onshore winds, for example, cause increased shoreline erosion as large waves break closer to shore in deeper water, thus exerting greater forces on the shoreline. Tides in Long Island Sound are semi-diurnal (occurring twice a day), and the height increases fi.om east to west due to the narrowing of the Sound, as the area of the Sound lessens and the volume of water remains unchanged. Tidal ranges for points within Southold are shown in Table I-3. Tides are given as spring and mean fide for each location. The mean tide is the average tidal range, and the spring tide is the tide that occurs at or near the time of the new or full moon, which rises the highest and falls the lowest from mean sea level. I-7 Table I-3 SOo'£aOLD TII~L uXUGF~ ~ida~anse _ (~eet) Loca~ion Heart Sprin~ Mattituek Inlet 5.0 5.8 Horton Point 4.0 4.6 Truman Beach 3.4 3.9 Orient Point 2.5 3.0 Southold 2.3 2.7 New Suffolk 2.6 3.1 Hurricanes and tropical' storms are large wind fields, driven by central low pressures and temperature gradients. These storms cause the water elevation at the shoreline to rise and flood the land. Several factors are involved: wind stress, wave setup, barometric pressure reduction, and the Coriolis force. In response to the earth's rotation, the Coriolis force causes water currents to deflect to the right in the northern hemisphere. These factors have caused increases in water elevations in excess of 13 feet above normal in Long Island Sound. Wind stress and barometric tide are of primary importance to the magnitude of storm surge. Height of the wind stress depends on wind speed and direction, fetch, bathymetry, and nearshore slope. Basically, the wind drives the water into the shore faster than it can return to open water. Either the water piles up until the wind reduces in force, or the water reaches such height that gravity forces it to return to open water. The barometric tide is the increase in water surface elevation within the storm's low-pressure system. The higher barometric pressure outside of the storm forces water in toward the lower barometric pressure at the center of the storm. A Coriolis water level rise occurs when the storm forces currents to flow along the shoreline. This component of storm surge occurs in Long Island Sound, but is not particularly large. However, it can also reduce the storm surge when the current direction causes the Coriolis force to be directed toward Connecticut. The final component is the wave set-up, which occurs in the surf zone when wave momentum transfers from the waves to the water column. This component is important for large storm waves where wave set-up may be as much as 20 percent of the breaking wave height. Factors that eventually determine the magnitude of the storm surge are the stage of the astronomical tide (storm surge is superimposed on top of the tide level), storm intensity, forward storm speed, and angle of storm track to the shoreline. Shoreline configuration is also important in determining surge elevations, much as shoreline configuration affects astronomical tides. This effect is simply the funneling of water that occurs when there is a constriction between two land masses. This occurs in Long Island Sound, causing water levels in the western portion of the Sound to exceed those in the eastern section. Increased fetch distances for wind setup also contribute to this effect. I-8 Storm surge frequency relationships, available for many locations, are either compiled and estimated from historical data or obtained through predictive techniques. These frequency relationships describe the annual probability of occurrence for any particular water level event. The highest tidal height ever observed was 13.3 feet above Mean Sea Level (MSL) at Willets Point during the hurricane on September 21, 1938. At Port Jefferson Harbor during the hurricane of August 31, 1954, a water surface elevation of 9.45 feet above MSL was recorded. No extreme water level predictions have been prepared for the Town of Southold, but extreme water level predictions for London, Connecticut are considered to be representative for the Long Island Sound shore of Southold. This is shown in Figure I-6. The highest predicted water level is 14 feet above MSL, close to the physical maximum that can occur. The more commonly used 100-year flood level is 10.7 feet above MSL. Although this is called the 100-year flood, it is a statistical measure, and that water level has never been measured in Southold. Additionally, if it does occur, water could rise to this level more than once in a given year. Having this storm surge once does not mean that it will not occur for another 100 years. Sea Level Rise Sea level rise can be separated into two categories: 1) eustatic rise (change in ocean elevation) and 2) relative rise (change in ocean level relative to adjacent land). Relative rise includes changes in both ocean and land levels, thus including eustatic sea level changes. Causes of sea level rise include changes in sea floor spreading, ocean and land area changes, tectonic plate movement changes, thermal effects, ocean sedimentation, glacial characteristics, hydro-isostasy, sediment isostasy and compaction/subsidence, ocean surface topography and temperature/salinity effects, changes in the geoid, geological faulting, and climatic effects (GTFII 1994). Scientific evidence suggests that water levels during the peak of the ice age were at least 450 feet lower than they are now, because of water contained in glaciers. As the glaciers melted, sea levels rose about 0.3 inches per year. Along the New York coastal region, the relative sea level rise over the last 100 years (accounting for land rebound and sediment accumulation) is estinmted to have been from 0.04 to 0.14 inches per year. Historical sea level rise rates are anticipated to continue, but there is much uncertainty about the possibility of an increase. The effect of excess fossil fuel emissions, which leads to global warming, would be to accelerate glacial melting. Past estimates have been for sea level increases from 2 to ? feet in the next century; more recently, these estimates have been revised to less than 2 feet. Further research is required to refine these estimates; thus, use of non-historical sea level rise rates is highly subjective. Despite the difficulties associated with predicting sea level rise, especially accelerated rates, it is an important factor in determining future erosion patterns. As sea levels increase, low-lying areas become more subject to flooding; magnitude of wave attack on previously protected shoreline locations increases; and wetland areas could become inundated, exposing current inland locations. These conditions are important in the Southold region for several reasons. First, the bases of bluffs are particularly susceptible to sea level increases, as current protective beaches would be rendered ineffective in protecting against wave attack. Once bluffs are exposed to more direct wave attack, bluff recession would proceed at a relatively rapid rate. Therefore, the rate of bluff erosion and shoreward migration along Southold's Long Island Sound shore is likely to increase in the future. In addition, development in low-lying areas along the Town shoreline, such as Fishermans Beach, would be subject to increased flooding and landward movement or destruction of coastal beach and dune systems. Finally, current protective measures - e.g. bulkheads, revetments, and groins - would be destroyed or at least rendered less effective, and current Federal Emergency Management Agency Flood Insurance Rate Map boundaries would be affected. 1-9 CulTent~ Nearshore currents play an important role in the evolution of coastal environments. Currents are driven by four mechanisms: 1) spatial differences in water surface elevations, 2) wind, 3) angled wave approach to the shoreline, and 4) river discharge. Significant currents can be generated by tides at inlets to bays or lagoons or at entrances to harbors. Currents at these constricted entrances flow inland when the tide is rising (flood tide), and flow outward as the tide falls (ebb tide). USACE (1969) reports that maximum currents along the north shore of Long Island typically range from 0.5 to 3.5 knots during floodtide and 0.6 to 4.3 knots on the ebbtide. Average currents along Southold were reported as 1) Terry Point -- 2.7 knots (flood) and 3.2 knots (ebb); 2) Mulford Point - 1.9 knots (flood) and 2.3 knots (ebb); and 3) Plum Gut - 3.5 knots (flood) and 4.3 knots (ebb). High fiver discharges or strong winds can alter these velocities, which can be seen in Long Island Sound when strong winds from the west slow the ebb tide and allow the flood tide to bring additional water and subsequent extreme water surface elevations into the Sound. Currents are created as wind blows over the water's surface, and stress on the surface initiates movement in the direction of the wind. When the surface current reaches a barrier, such as a coast, water piles up against the land. This piling up of water, which is called wind setup and is a component of storm surge, can create significant increases in water elevation when it occurs during storms. Another important mechanism in the nearshore region is the generation of alongshore currents caused by waves approaching the shoreline at an angle. This results in a gradient in nearshore surface elevations and induced currents, which tend to dominate during calm periods. Tidal current velocities rapidly decrease as the shoreline is approached, and therefore, any littoral movement is usually the result of wave action. This holds true for Long Island Sound shorelines east of Port Jefferson, whereas the western areas are subject to increased tidal ranges, which cause higher tidal current velocities. Sediment Characteristics and Supply Shoreline condition, in general, is affected by the amount of sediment entering and leaving an area. Sediment supply is a major factor in determining whether a coastal region is eroding, accreting, or stable. Along the Southold coastal front, the primary sediment source is the glacial bluffs. Sediments on most beaches range from fine sands to cobbles, with occasional large boulders. Wave erosion of these bluffs - along with the impacts of surface drainage, rainfall, ground water seepage, and vegetative cover, and subsequent bluff failure - introduces large amounts of sediment to the littoral environment. This material is then transported alongshore to other shoreline reaches at a rate referred to as the longshore sediment transport. The direction of longshore transport can often be deduced from the study of existing landform. As sediment is transported in the nearshore and beach, human structures can interrupt this flow. Sediment is deposited on the updriff side, and the downdriff side suffers a loss of sediment. Sand can also be lost offshore into deeper water because of these human structures. On the Long Island Sound shore of Southold, the predominant direction of longshore transport is toward the emt. The jettiea at Mattituck. and Goldsmith Inlets interrupt this flow, leading to accretion on the west side of the inlets and erosion on the east side. Along the rest of the Long Island Sound shoreline, the headlands and points interrupt the flow during low wave periods, forming cells between the points. During storms, longshore transport occurs around the points, primarily from west to east. This storm movement is thought to be the I-I0 6*95 FREQUENCY IN DESIGN HURRICANE T1DE EL 14.0 YEARS 38 ADJUSTED PROM A 225 yEAR PERIOD TO A 146 YEAR PERIOD ~ 19~4 ADJUSTED FROM A 225 YEAR PERIOD TO A 146 YEAR PERIOD j ~ i HIGH SPRING TID~= MEAN SPRING HIGH WATER Mu. R'GH WATER MEAN SEA LEVEL MEAN LOW WATER j ~ PERCENT CHANCE OF OCCURRENCE PER YEAR Z lo 0 > 2 Elevation Based on Recording Tide Cage Reading or High Water Marks Referred to a 225 Year Period, July 1938-December 7 960, Inclusive Elevation Based on High Water Marks Referred to a 746 Year Period, 7875-7960, IncJusive Cu~e prepared by New England Division, Coq~s of Engineers ~'lgwn of Southold Figure I-6 Extreme Water Level Predictions dominant force in determining the direction of longshore transport on Southold's Long Island Sound shoreline. On the Peconic Bay shoreline, the direction of longshore transport varies greatly. The orientation of the shoreline differs by up to 180°. Therefore, one storm causes longshore transport in two or more different directions on the Peconic Bay shore. Additionally, the many inlets, with and without jetties, interrupt the longshore transport. The Peconic Bay shore has many small coils for longshore transport, and cannot be described in general as the Long Island Sound shore can. The volume of sediment transported is an important parameter, and its analysis requires a large amount of data. The problem needs to be studied in ali three dimensions to determine how many cubic yards of sediment are contained in a foot of beach. Several seasons are needed over which to obtain these data beach profiles. The profiles can be supplemented with aerial photographs to determine changes in form, but the photographs do not show elevation changes. Without collecting and analyzing these data, only the most general estimates of sediment volume and change in the longshore transport can be made. Storrns Shoreline changes result from both day-m-day coastal processes and storm-induced coastal processes. It is not certain which of these change mechanisms is most important over the long term; however, it is clear that both play an important role in coastal conditions. While shoreline changes under normal condi- tions are nearly imperceptible, those that take place during a storm event are otten distinct. As discussed earlier, storm winds typically generate high, steep waves in conju=¢tion with the storm surge. Increasing water levels expose higher portions of the beach to wave attack, and allow large waves to pass over the nearshore without breaking. At the point where the breaking occurs, which is often close to shore, the remaining surf zone is insufficient to dissipate the increased wave energy. This excess energy then causes erosion of the beach, berm, dune, or bluff. The eroded material is carried offshore in large quantities and is deposited in a bar formation that grows to the point where the large storm waves break farther offshore, spending their energy in the surf zone. Ultimately, these storm-inducod processes establish an offshore bar that provides protection from storm wave energy. Eroded beach material will often return to the beach berm during normal conditions when waves assume an accretional character. This stage is referred to as post-storm recovery. This recovery is fairly slow in Long Island Sound because there are few long period swells to move sand from deeper water onto the beach. Erosion of dunes is more severe, requiring re-establishment through aeolian processes. Bluff erosion is most problematic because it is permanent - no post-storm recovery is possible. Although post- storm recovery does take place, each storm removes some amount of beach material, decrensing its protective capabilities. Finally, storm waves and water levels can also dsmA~e coastal structures and flood low-lying areas. Although damage resulting from these mechanisms is more immediately evident and financially harmful, erosion of the coastal region is the avenue through which other storm-induced damages are initiated. Along the coastline of New York State, two types of storm events are of signifieanco: 1) tropical storms (originating in the tropics) typically affect the New York area from July to October, and 2) ex- tratropical storms (originating outside of the tropics), which are primarily less intense winter storms. Hurricanes are the most powerful tropical storms to reach the New York area, with wind speeds in excess of 74 mph. Historically, New York has been hit by a number of hurricanes; 24 storms have been I-Il recorded in the New York coastal region. Table 1-4 lists several hurricanes. Because of the cold water in the New York region, hurricanes move faster in the forward direction, which increases the apparent wind speed. Many meteorologists also believe that it is improbable that the New York area could be sub- ject to a hurricane more powerful than Class 4 (winds from 131 to 155 mph~. Damage from this class of hurricane, coupled with high forward speeds, would be tremendous. Alternatively, the high forward speeds and relatively limited size of hurricanes reduce damages as a smaller area is impacted and storm duration is limited. Furthermore, storm damage magnitudes can be traced to the concurrence of high astronomical tides and the storm surge, which act together to allow large waves to penetrate farther inland, resulting in extreme erosion and flooding. The relatively short duration of hurricanes often results in reduced damages, as water levels are reduced by storm impact at a low tidal level. Recent hurricanes along the New York coastal region have not resulted in significant erosion and flooding because maxi- mum storm surges have coincided with low tide, as opposed to recent extratropical storms that have occurred with high tides. Extratropical storms originate outside of the tropics, usually in the mid- to upper-latitudes during winter months. More conunonly referred to as northeasters, these storms are less inte~e than hurricanes but have localized winds that often reach hurricane strength. Extratropical storms cover large areas and are slow moving; typical storm durations last for a period of days. USACE (1969) states that 65 moderate to severe northeasters have impacted the New York coastal region over the 100-year period before 1965. More recently, a series of severe northeasters has impacted the New York coastal region in October 199t, December 1992, March 1993, and December 1994. Table 1-4 lists the severe extratropical storms that have had significant impacts on the New York coastlines. Table HISTOF,.ICAL STORW~ A~e~CTIN~ '£~ ~w YOllK COAST Date Storm Type Name September 14, 1904 Hurricane -- September 8, 1934 Hurricane September 21, 1938 Hurricane September 14, 1944 Hurricane -- August 31', 1954 Hurricane Carol September 12, 1960 Hurricane Donna August 6, 1976 Hurricane Belle September 27, 1985 Hurricane Gloria August 19, 1991 Hurricane Bob March 3, 1931 Extratropical -- November 17, 1935 Extratropical -- November 25, 1950 Extratropical November 6, 1953 Extratropical -- March 6, 1962 Extratropical -- February 6, 1978 Extratropical -- March 28, 1984 Extratropical October 30, 1991 Extratropical -- December 11, 1992 Extratropical -- 1-12 Northeasters are similar to hurricanes in that damage to coastal areas occurs from erosion and flooding stemming from high winds, large waves, and increased water levels. Although wava heights and storm surges from extratropical storms are less severe than from hurricanes, erosion and flooding can equal or exceed hurricane-induced levels. Increased storm duration is the primary factor that causes large coastal damages during northeasters. Because they last days rather than hours, northeastors persist over numerous tidal cycles, continually attacking coastal areas with several peak water elevations. In addition, continued strong winds can trap much of the ebb tidal flow within Long Island Sound, allowing flooding tides to augment existing high water and cause extreme water elevations. Damage from hurricanes and northeasters is highly dependent on storm intensity and duration. However, the location of a storm relative to Long Island's north shore is another major factor. Storm location is linked to storm characteristics that determine where, relative to the storm movement, the most severe conditions exist. Tropical cyclones are characterized as small fast-moving storms consisting of a counter-clockwise spiral about the center (the "eye") of the storm. This forward speed increases the apparent wind speed. Winds to the right of the eye are most severe and are parallel to and reinforced by the forward storm speed. Therefore, since tropical storms travel in a general northerly direction, south-facing coastlines are usually subject to the greatest hurricane forces. North-facing coastlines, however, are somewhat protected from the strongest storm impacts. Similarly, extratropical storms are characterized by a counter-clockwise spiral directed toward a central low pressure center. Wind direction and velocity at a given coastal location depend on the relative location of the storm track. The course of a northeaster to the east of the Sound is the most important factor for the north shore of Long Island, where winds blow initially from the northeast. Wind direction changes with storm movement to north-northwest winds as the storm passes, and produces large wave heights and wind setup along the north shore. Northeasters, with winds from the east occurring through numerous tidal cycles, have historically had the greatest effect on the Long Island Sound coastal region because of their long duration. Human Activity and Land Use Introduction Construction of shoreline structures and dredging operations are a major factor affecting coastal erosion and flooding. Engineered structures -- e:g. groins, jetties, bulkheads, breakwaters, and seawalls - can halt, slow, or exacerbate coastal erosion. Structures introduced to the coastal environment to alleviate one problem often cause more severe problems, because the structures may have multiple influences on coastal processes. Other efforts, including beach nourishment and dredged material placement, can be undertaken to augment the coastal system by introducing additional littoral materials to the coastal system without adversely affecting other locations. As beach erosion and accretion, inlet opening and closing, bluff erosion, bay and wetland environmental changes, and other changes to the coastal regime are natural and ongoing processes, any alteration to the natural system will affect its dy- namic stability. To show the amount of effort and money expended to maintain an engineered approach, Table I-5 presents the dredging that has been performed at Mattituck Inlet. Much of the dredged sand was removed and used by the town. Human intervention in the coastal environment - for the prevention of flooding and erosion, reduction of inlet shoaling, or land development - is a short-term attempt to engineer a solution to a problematic coastal condition. These interventions are often poorly engineered and fail to accommodate the dynamic nature of the coastal environment. 1-13 Table T-5 SUIdMAR.Y Og TIIK VO~ OF THE SAND REHOvAb FROH 1960-1975 Yards Yea~. Removed 1975 3,965 1974 364 1973 3,356 1972 9,502 1971 8,532 1970 7,208 1969 6,482 1968 15,914 1967 24,914 1966 25,808 1965 26,534 1964 20,032 1963 36,098 1962 14,734 1961 17,694 1960 23,214 244,351 source: New York Sea Grant. Construction of eiiher hardened coastal structures (e.g. bulkheads, groins, jetties, or seawalls) or vegetation, or dune buildin§) are ai~.empts w s~abilize beaches, bluffs, soft methods (beach nourishmentl;lacement of hardened structures requk, es .pe. rio~ic_m~_..ai~%oa~siefn and inlets, or barrier inndforms, and mitigation, and often results in significant negalive impacts. These can mcmoe aownut,,, loss of sediment offshore. Navigational needs also lead to large disturbance of natural systems. Table I-6 lists the number of projects and dredging volume performed out by the Town of Southold in Gold- smith Inlet and on the peconic Bay side· system - may requke frequent maiD~ance Soft structures - which have less ~mpact on the natural . and could provide less protection against the problem in question. These soft solutions ~o e~:os~on may not be feasible for individuals, as large conslxuction may be requked for proper p~ormance. Although feasible and practical engineering of the coastal environment is possible, construction must eousider the range of impacts resulting from such solutions. As discussed below, placement of dredged materials on adjacent beaches is an important soft engineering approach in Southold. 1-14 Hardened Structures Bulkheads, revetments, and seawalls are common along the coast of New York, especially the northern shorelines of Long Island. The function of these shore-parallel structures is to retard erosion of the upland while sacrificing the beach and nearshore are. aa. The potential for negative impacts from these structures is apparent at many locations. However, placement at sites with adequate sediment supplies can mitigate these impacts. The jetties at Mattituck Inlet have caused severe erosion on the east side, which has lessened aa sediment has either bypaa,~ed the inlet or was transported from further east and deposited behind the east jetty. To illustrate possible negative impacts, a shore parallel structure placed at a location that experi- ences chronic long-term erosion is analyzed here. The structure essentially removes the upland sediments from the coastal regime, thereby pinning the shoreline to a given location. Under natural conditions, the upland would provide the sediment necessary to maintain a protective beach, but would result in perma- nent loss of the upland. The structure pins the shoreline position but does not alleviate the erosional condition. Nature often finds an alternative sediment source, which results in accelerated erosion of the beach directly in front of and adjacent to the structure. Following or prior to the loss of protective beach, beach nourishment is necessary as a mitigation effort. Should the situation not be mitigated, the beach might totally disappear, resulting in direct wave attacks on the structure. This condition often leads to structural failure and severe erosion of the upland that can even exceed that which would have occurred had no protective measures been constructed. Table ~-6 SEnn(any OF TO~i OF SOu'£uOLD Dn~ngllqG I~.O,TECTS Cubic Dates Yards Reach Prolect Name l~red~ed Dredged i Mattituck Creekd 1955 1,595,400 1 Long Creek (part of Matti- tuck Creek) 2 Goldsmith Inleth S~total 2 North Sea 5 Gull Pond Subtotal 1967 13,000 1977 4,000 1980 3,700 1982 6,000 1985 2,640 1987 4,800 16,340 1992 12,980 1959 177,200 1960 28,500 1970 29,000 1979 23,300 1983 1,000 259,000 ]~thod of Soil Displacement Upland site of Matti- tuck Creek and Long Creek Beach nourishment Beach nourishment be- tween Gull Pond and Sterling Basin Types of ~ater Dependent Facilities 3 marinas and park district boat slips and ramp Matt-A-Mar Marina is at intersection None Town beach, docking and boat ramps 1-15 Table [-& (Continued) ~]~OfARy OF TO~N OF SOu'.I:B. OL,D D~KP~Z~G Reach 5 6 7 Cubic DaCes Yards Prolecc Name Dredged Dredged Sterling Basind 1959 163,900 1963 129,200 1976 12,000 1992 4,490 Subtotal 305,590 Mill Creek 1963 66,300 1968 2,700 1975 6,000 1979 4,000 1981 4,500 Subtotal 83,500 Town Creek/Harbor: 1959 23,200 1959 93,400 1976 9,000 Het~od of Soil Displacement Formerly used wetlands by cemetery, now use back side of inlet for beach nourishment Upland on island to the west Beach nourishment to the west 7 Subtotal Jockey Creekc Subtotal Goose Greekb Subtotal Cedar Beach Subtotal 125,600 1959 23,200 1959 93,400 1976 9,000 125,600 1959 46,700 1967 75,200 1968 11,100 1976 6,000 139,000 1979 12,400 1980 1,900 1981 9,700 1982 1,700 1983 1,700 1984 1,900 1985 1,440 1986 2,880 1987 1,920 35,540 Beach nourishment to the west Formerly upland by Bay- view Avenue, now beach nourishment Beach nourishment to the west Ty~es of Eater Dependent Facilities 4 marinas and a sailing club 3 marinas Marina near mouth of creek and town ramp on bay Marina Ramp Marine Tech- nology Dept. of Suffolk County Commu- nity College 1-16 Reach 7 7 Table I-6 (Continued) SIDO~ARy OF TO~N OF SOu'£HOLD DREDCINC PROJECTS Project Name Corey Creekb Subtotal Richmond Creek Subtotal Broadwater Covea Cubic Dates Yards DredKed Dredged 1963-64 345,600 1967 23,900 1972 7,600 1981 10,200 1983 800 1984 3,500 1986 18,600 1987 5,040 315,240 1959 123,000 1964 82,800 1967 25,100 1972 5,500 1983 15,300 1995 20,000 271,700 1966 434,400 1976 11,000 1982 10,200 Subtotal 455,600 Little Creekb 1967 51,000 1968 3,700 1975 5,000 1976 40,000 1978 4,000 1979 5,000 1980 2,400 1981 2,400 1981 5,500 1982 7,000 1983 2,400 1983 2,300 1984 2,400 1984 6,000 1985 3,120 1986 5,760 1987 8,400 1991 4,000 1992 4,740 1993 5,000 Subtotal 170,120 Hethod of Soil Displacement Formerly upland and now Ramp beach nourishment Beach nourishment on both sides of inlet Upland disposal adja- cent to creek Formerly upland on 2 sites, now beach nour- ishment to the west of inlet Beach nourishment on both sides of inlet ~j~es of ~ater Dependent Facilities None Marina Ramp/Moorings 1-17 Reach 8 8 9 Table I-6 (Continued) SUNNARy OF TO~IN OF SOu'_ruOLD D~CrNG F~Od~CTS Pro~ect Name Mud Creeka Subtotal East Creeka Subtotal Wickham Creek Subtotal Schoolhouse Creek New Suffolk Subtotal West Creekb $~btotal Halls Creek¢ Subtotal Cubic Dates Yards DredRed l~edKed 1966 434,400 1976 11,000 1982 10,200 1987 6,600 1992 2,910 465,110 1966 434,400 1976 11,000 1982 10,200 455,600 1966 48,300 1972 10,000 1979 3,600 1981 1,700 1982 2,200 1983 1,900 1984 1,400 1985 1,440 1986 2,640 1987 2,640 1992 1,500 77,320 1976 12,000 1977 4,000 1979 1,500 1980 1,0OO 1981 2,000 1982 3,300 1983 1,000 1984 1,800 1985 2,500 1986 1,250 1987 1,500 1993 2,000 21,850 1966 92,500 1976 9,000 1982 2,800 101,800 1979 17,400 1980 4,200 21,600 Hethod of $otl Displacement Formerly upland on 2 sites, no beach nour- ishment to the west of inlet Formerly upland on 2 sites, now beach nour- ishment to the west of inlet Beach nourishment to the west Types of ~ater Dependent Facilities None None Marina Beach nourishment Marina Beach nourishment on Boat ramp town beach to the south Beach nourishment on both sides of inlet Ramp Beach nourishment to None the east 1-18 Reach 9 10 Table I-6 (Continued) ~mwsuy OF TOW OF SOu'£uOLD DU~ING PHOJEOTS Project Name Deep Hole Creek Subtotal James Creek Subtotal Brushs Creek Subtotal West Harbor (Fishers Island, channel connect- ing to federal project) Wunneweta L~goon Subtotal Cubic Dates Yards DredKed Dredged 1964-65 243,500 1972 21,100 1975 4,000 1976 14,000 1980 5,000 1980 10,000 1982 8,800 1983 6,300 1987 7,680 1991 4,600 1993 10,600 335,580 · 1964-65 272,500 1979 3,000 1980 6,700 1983 9,400 1985 5,250 1986 1,570 298,420 1966 86,400 1975 7,500 1979 5,000 1980 1,900 1981 5,800 1983 1,500 1984 4,800 1985 6,750 1986 3,000 1991 3,000 1992 1,530 127,180 1971 43,100 1991 2,700 1993 1,000 46,800 Method of Soil Displacement Beach nourishment on both sides of inlet Formerly upland to the east, now beach nour- ishment on both sides of inlet Beach nourishment on both sides of inlet Dumped at sea TOTAL 5,875,470 Types of Hater Dependent Factlitie~ None 2 marinas Marina 1-19 Broadwater Cove, Mud Creek, and East Creek were dredged as one project in 1966, 1976, and 1982. The Suffolk County Department of Health Services has determined that dredging Goldsmith Inlet was necessary in 1985 to protect the public health. Jockey Creek and Town Creek/Harbor were dredged as one project in 1959 and 1976. Mattituck Creek and Sterling Basin are federally authorized projects. Analysis of Dredging and Spoil Disposal Activity Conducted by Suffolk County, County of Suffolk, New York, Historical Perspective.and a Look co the Future, Suffolk County Planning Department, October 1985; Annual Environmental Report, Office of the Suffolk County Executive, 1987, 1988, 1992, 1993, 1994. Breakwaters are hard structures that are offshore and parallel to the shoreline and that act to reduce the wave energy behind the breakwater before it reaches the coast. By reducing the wave energy, breakwaters allow littoral materials to deposit, which leads to the formation of a protective beach. Accumulation of beach material behind the breakwater reduces the littoral material available fur other shoreline reaches unless beach nourishment or other mitigation measures are undertaken. The very large rocks that can be fuund on Southold's beaches or just offshore serve as breakwaters on a very small scale. Accretion occurs just behind them. Shore-connected and perpendicular structures, called groins, are used along many shorelines. These structures intercept littoral material, which results in the accumulation of a beach updrii~ of the groin. Downdrift of the groin, however, the littoral material is reduced, which ot~en leads to erosion. As with other coastal structures, beach nourishment can mitigate this impact. One mitigation method is a series of groins, with beach nourishment filling in the groin compa~craents. Since the groin comparUnents are at capacity, longshore sediments can bypass to downdrift beaches, thus minimizing negative impacts on the littoral supply. However, the groins must not be constructed in such a way that the sand is transported offshore and lost from the littoral system. This distance offshore is related to the width of the surf zone under normal conditions, which - in an area like both sides of Southold - can strictly limit the allowable groin length. The groins on the Peconlc Bay shore of Southold provide illustrations of every type of groin field imaginable. Stone, concrete, steel, and wood have all been used as construction materials. The length, height, and spacing of the groins have varied from very short, low, and closely spaced, to a single high groin sticking out into the middle of the bay. These groin fields are described in the next chapter, where their effectiveness is [partially] assessed. However, each set of groins would have to be individually studied to accurately estimate their usefulness and their effect on neighbors. Setties are another shore-perpendicular structure used to stabilize inlet positions and reduce channel shoaling. Littoral material is intercepted by jetties in a manner similar to groins. However, the negative effects of jetties on the downdrif~ shorelines relative to natural inlets and frequent channel dredging are of greater magnitude. Jetty-stabilized inlets intercept a great deal of sand, and a series of jetties increases this effect, decreasing the volume of sand traveling in the downdrift direction. Inlet stabilization also appears to deposit larger volumes of sediments in ebb and flood tidal shoals compared with natural inlets. In natural inlets, sand is distributed along the ocean and bay shorelines as the inlet migrates alongshore, which reduces the volume of material trapped by the inlet. Natural inlets allow more material to bypass to downdrif~ sections; therefore, whether jetties are present or maintenance dredging alone is used, inlet maintenance leads to downdritt sand deficits. Many jetties have been built at the mouths of the inlets on the Peconlc Bay shore. These jetties ~ described in the next chapter, where some assessment of their effectiveness is given. However, each inlet needs to be individually studied to accurately estimate its effects. 1-20 Soft En~ineerinu Solutions Soft structures are often preferable to hardened structures, and represent an attempt to work with the natural system by augmenting its natural defenses. Soft engineering solutions include beach nourishment (placement of beach sediments to create a larger protective beach and dune system), beach shaping, sand fencing (to help the dune-building process), and vegetation (to stabilize existing dunes or trap additional wind-blown sand). These soft engineering solutions are often combined very successfully with hard engineering solutions. Beach nourish- ment is accomplished by dalivering sand to the beach or dune from either an offshore or upland site. This is a temporary solution to erosion and flooding problems, since the placed material is sacrificial and only offsets ex- isting erosion problems. Although this method requires frequent maintenance, it has few detrimental envi- ronmental consequences. Large-scale beach nourishment is often augmented with coastal structures, when there is severe long-term erosion (greater than 3 feet per year, typically). Beach nourishment is usually less expensive than hardened structures; however, should insufficient material sources be unavailable or projects be undertaken by local interests, costs may increase. Beach nourishment is an effective mitigation technique, whether or not combined with coastal structures or inlet dredging and stabilization. At inlets, bypassing of materials from either updrift beaches or channel dredging operations to downdrift beaches is an effective and feasible solution to reduc- ing downdrift erosion. Beach nourishment - combined with breakwaters, bulkheads, or groins - often improves the effectiveness of these structures by introducing additional material to the littoral system. Placement of sand or dredged materials on a beach requires a permit from the New York State Department of Environmental Conservation (DEC), who have been hesitant to issue these permits. DEC is concerned about the loss of productive wetlands if the materials are not placed carefully. In the past, they have required upland placement of the materials. As discussed in Chapter VI, "Implementation Options," the Town needs to have ongoing coordination with DEC and Suffolk County to determine the best location to place dredged materials. A long-term relationship with DEC could allay their concerns about loss of wetlands and allow the dredged materials to be returned to the coastal system. Beach scraping augments dune profiles and beach berm widths to provide additional recreational beaches and protection against flooding. The technique consists of removing sand from the nearshore and scraping it up on either the berm or dune. It has been questioned whether beach scraping is an effective means of preventing erosion. Although increasing the volume of the dune profile is a practical way to creatu additional flood protection, the steepening of the beach face may actually increase erosion and loss of beach material during storms. Beach scraping has also been described as an effective tool for dune building that, when properly conducted, leads to no significant negative impacts. However, it introduces no additional beach material to the system, and its effectiveness in providing protection in eroding areas is therefore limited. Sand fencing and establishment of vegetation are other techniques used to provide additional flood protection by increasing dune volumes. These attempts at dune restoration use wind-driven sediment transport to capture necessary sediments. This approach seems to have bean successful at New Suffolk. Since this is an environmentally sound and low-coat effort, many communities undertake dune restoration projects. Increased dune volume protects upland areas from flooding during storm events and reduces beach erosion by acting as reservoirs of additional beach material. Because of frequent erosion of the dune during storm events, the success of dune building projects depends on continued effort and vigilance. A sof~ engineering solution that is often in conjunction with jetties is sand bypassing. As sand accumulates on the updrift side of the jetty, it is periodically dredged or mined and then placed on the downdritt side of the jetty. Sand bypassing prevents erosion on the downdrifr side and large accumulation of sand on the updrif~ side. The littoral system, if the bypassing is done correctly, stays in equilibrium. 1-21 Land Use Human activity brings additional forces into the coastal 'area that often cause erosion. At its simplest, dunes that store sand are stabilized by shallow-rooted vegetation. People walking across the dunes break the root systems, weakening the plants and leading to their destruction. Without the vegetation, the dune is easily eroded and the sand is lost to the beach system. A public beach draws a large number of people who require parking and amenities, such as changing rooms and food supply. These requirements mandate that the shoreline must be managed and not allowed to vary greatly in its width or position. This management can range from restricting times of year when the beach is open to constructing large-scale, hard structures, including groins and break- waters. Beach nourishment using sand from other areas is an intermediate approach that is often used. Unless large buffer distance is available, residential use creates the same situation. If the shoreline erodes, improvements on a lot, such as houses, become endangered. Some type of shoreline stabilization is demanded to protect homes. Because home owners usually have limited financial resources, stabilization projects taken on by individuals tend to be small. Public use includes roadways, which have public investment and are needed for public safety and emergency services. Therefore, large, he.aW structures are built to protect the road. These often disrupt the beach system and lead to further erosion which leads to further construction. Commercial activities, such as motels and restaurants, make similar demands and their approach tends to be an intermediate one, between private residential, uses and public facilities. Boating, with its need for vertical bulkheads and deep water next to the shore, also affects erosion. In Southold, the marinas' private moorings are in inlets where erosion is not a major concern. However, inlets naturally shoal, close, and change position, none of which are acceptable to boaters and marina owners. Boating leads to the demand for dredging, which has been discussed above. Flood-Prone Areas The danger from large storms is not limited to erosion from wave action; flooding from elevated water levels damages properties, some far inland. As discussed earlier, the maximum water level expected in the Long Island Sound shore of Southold is about 14 feet above MSL, and the 100-year flood level is about 10.7 feet. These levels are lower on the Peconi¢ Bay side. Because of the bluffs, most of the inhabited areas of the Long Island Sound shore are above these elevations. The four exceptions are the mouth of Mattituck Inlet, Goldsmith Inlet to Kenneys Road Beach, Hashamomuck Beach, and Truman Beach. On the Puconic Bay side, much of the shoreline and inlets is subject to flooding. There are fewer areas above flood elevations than areas that are sub- ject to flooding. With the exception of Little Hog Neck, almost all of the shoreline is just about or slightly more than 10 feet above MSL. While most houses do not flood regularly, such areas as Fishermaus Beach and Marratooka Point flood several times a year. C. SUMMARY This report describes the evolution of existing coastal landforms and the specific processes that govern the continuous landform changes. Where explanations were necessary, the processes were presented in cause-and- effect relationships - e.g. the relationship between wind and waves and erosion of beaches. The section provides a concise frame of beach and water interactions and the physical problems that apply to Southold, as well as the reasons for problem areas. In summary, the primary concerns within the Southold area include long-term and storm-induced beach/dune and bluff erosion, and the flooding and erosion of low-lying areas associated with 1-22 storm even~. Beaches are composed of loosely compacted sediments, usually sand or gravel. The beach profile shape depends on the incident wave energy and sediment size. Beaches are dynamic; most change annually due to vary- lng wave climates. During the summer months, relatively long-period waves of Iow height persist, causing the subaerial (above-water) beach to be at its maximum width. As winter approaches, waves become steeper and tend to move material to an offshore bar that reduces wave energy on the beach face. This offshore movement reduces the subaerial beach width, yet represents an equilibrium with the winter storm climate. The cycle is repetitive, as summer approaches with the onshore movement of beach material from the offshore bar. A noteworthy feature of this cycle is the change in beach composition from season to season as the finer beach material is more readily transported, which causes a sandy summertime beach to be primarily cobble during winter months. During storm events, especially on open coasts, this cycle is amplified as larger waves erode the beach face and carry more sediment to an offshore bar. With the attendant increased water levels, waves attack and erode dunes and bluffs, and deposit material offshore. The growing bar in turn reduces the magnitude of wave attack on the beach face, dunes, and bluffs, thus providing a natural defense system. After the storm, the normal wave climate moves material onshore to the beach and re-establishes the normal seasonal profile. Problems occur when eroded bluff and dune materials are not returned to their pre-storm locations, but only reach elevations of maximum wave uprnsh on the subaerial beach. During severe storms, beach material is moved beyond the point of sediment motion under normal conditions, which effectively removes the material from the nearshore coastal environment. Dune and bluff erosion occur through these processes, requiring human intervention to mitigate the losses. Glacial bluffs are a prominent feature along the Long Island Sound shoreline; understanding the processes that cause bluff recession is critical. These bluffs, which can approach 100 feet, are composed of unconsolidated sediment -- principally cobbles, sand, clay, and, on the top of the bluff, loam. In certain areas, primarily Pettys Cove, the bluff is composed of clay alone.. Roughly 75 percent of these bluffs are vegetated (stable), while the remainder are uncovered and actively eroding (Tanski, 1980). Some bluff areas are estimated to erode at rates as high as 6 feet per year. Erosional sections are musfly storm related and are caused by undercutting of the bluff by waves or tidal currents. Groundwater seepage, overland runoff, vegetation density, and bluff geometry and composition are other factors that affect bluff erosion. Once bluff erosion is initiated, the bluff steepens beyond a stable value, which is subsequently followed by slope failure and marked recession. Although bluff erosion is complex and difficult to predict, it is easily monitored and readily stabilized through engineered means. These stabilization efforts, however, often fall to recognize the importance of maintaining the bluffs as a component in the littoral environment. In addition, they are expensive to construct and maintain. Bluff erosion is particularly noteworthy along the Southold shorelines, where a high percentage of the total coast is fronted by glacial bluffs. Erosion processes are different from beach and dune erosion because bluffs serve as the major reservoir of sediment along the shoreline. As beaches are inundated and move landward, bluff material is introduced to the liRoral environment. This material is then transported alongshore or offshore, resulting in further erosion of the bluff. The continuous process is a natural equilibrium in which the bluff sacrifices a volume of material to the beach to prevent further beach erosion. Unfortunately, bluff erosion (unlike dunes) is permanent, which leads to efforts to stabilize bluff faces against further erosion. The flooding of low-lying areas that results from overtopping of beaches, dunes, and coastal structures occurs along the Peconic Bay shoreline. Although the water elevations can be higher on the Long Island Sound side of Southold than on the Peconic side, more damage usually results on the Peconlc side. This is caused by the low elevation of the land on the Peconic Bays. More of the Long Island Sound side is above flood elevations, except 1-23 for the area immediately around the two inlets and Hashamomuck Beach. Fiooding alone causes a significant amount of damage to coastal communities, but also results in the loss of beach material as flood waters carry large volumes of sediments to back. shore areas. This problem is particularly severe on barrier beaches and islands, and represents the natural tendency for these systems to move onshore. The continued alongshore movement of sand that is dependent on wave direction and height is superimposed ou cross-shore movement of sand on the beach. Gradients in this alongshore movement erode or accrete beaches. Long-term erosion up to 2 feet per year and annual accretion rates of nearly 2 feet have been estimated along the Long Island Sound shoreline in Southold (Davies et al., 1973). In general, the shoreline is erosive with sparse accretional shoreline sections. Significant problems occur when liuoral material is intercepted by coastal structures or inlets - e.g., at Goldsmith's and Mattituck Inlets. At Mattituck Inlet, for example, annual updrift shoreline changes reflect roughly 3 feet per year of accretion, and downdrif~ erosion rates exceed 1 foot per year. Erosion rates of 6 to 10 feet horizontally have been reported at Goldsmiths Inlet. Downdrift erosion is a particular problem of stabilized inlets and groins and results in steep narrow beaches that are unable to provide necessary storm protection. 1-24 CHAPTER H. INVENTORY OF SOUTHOLD BY REACH This chapter provides a general reach-by-reach description of coastal processes and landforms. It is intended to give some insight to existing conditions. Each reach needs a detailed study to provide specific lot recommendations in an area. The inventory is summarized in seven figures that provide an overview of existing conditions in Southold. Figure IL1 shows shoreline reaches and general configuratinn. Geographic names used in the narrative are presented in Figure II-2. Figures II-3 through 1I-5 indicate major natural considerations, including deduced littoral drift, natural features, and environmental sensitivity. Results of human activities are featured in Figures II-6 and II-7. A. LONG ISLAND SOUND SIDE OF TIlE TOWN OF SOUTHOLD This side of the Town of Southold is exposed Long Island Sound waves. Wave fetch varies from 9 to more than 20 miles, generating waves from 6 to more than 9 feet in 75 mile-per-hour winds. Wind- generated waves are the primary cause of coastal erosion; certain individual areas are greatly affected by their orientation toward the waves. During the 1990's, shoreline facing northeast have been heavily eroded by four major storms: IIurrieane Bob, the Halloween storm, and the storms of December 12, 1993, and December 24, 1994. Shorelines with a more northerly exposure have not been as affected in the 1990's. Bluff composition and height are also very important factors in erosion levels. Silty-clayey sediments in Pettys Bight have been heavily eroded while rocky points, such as Horton Point, have resisted erosion forces more successfully. IIigh sandy bluffs, such as those east of Mattituck Inlet, have supplied large volumes of sand to the shoreline. Low bluffs and dunes do not provide the necessary volume of sand, and adjacent downdrift shorelines are usually eroding. B. REACH 1: TOWN LINE TO DUCK POND POINT Coastal erosion processes in Reach 1 are dominated by the jetties at Mattituck Inlet (see Figure 11-8), which block littoral drift. Because of this blockage, shoreline morphology has changed over a period of tirae. Predominate drift direction is from west to east, but waves from large storms often come from the northeast and move sand from east to west. Reach 1 west of Mattimck Inlet appears to relatively stable due to the jetties. The area next to the west jetty has filled with sand, which could be migrating around the end of the jetty into the channel. Disposition of sand entering the channel is unknown. The shoreline from the town line to the west jetty is very regular. The east side of Mattituck Inlet does not appear to have stabilized. Just east of the inlet, the beach is eroding and the low dunes have not been able to supply sufficient sand to replenish the volume blocked by the jetties. The bluff, which rises to between 80 to 100 feet at Oregon IIills, has been attacked at the toe and has slumped in a number of locations, perhaps due to the shadow effect of the jetties. These slumps have been supplying sand along this reach. Because of erosion, the foundations of a hotel constructed on the beach at the end of Duck Pond Road have been undermined. II-1 C. REACH 2: DUCK POND POINT TO HORTON POINT The bluff is 40 to 60 feet high east of Duck Pond Point for about 7,500 feet. About 2,000 feet of various bulkheads have been built along the stretch. The bluff then drops to about 20 to 40 feet high, and turns inland just west of Goldsmith Inlet. The stretch of shoreline known as Keunys Beach is probably a baymouth barrier landform which formed during the Hnlocene across the embayment between Duck Pond Point and Horton Point headlands. A single jetty was built at Goldsmith Inlet in 1964 by New York State and Suffolk County. It was part of a Suffolk County plan for a marina in the pond, but the marina was never built and the inlet is not navigable. In fact, it is not a true inlet where tidal flow in two direaions can be observed, but rather an outlet from the pond directly to the Sound. Although it has been suggested it would probably close except that the Town dredges it yearly for the sand, examination of historical maps and photos suggests it remained open prior to jetty construction. Furthermore, given Goldsmith's pond appears to be slightly higher than the Sound, the head difference should be sufficient to maintain the outlet. The shoreline west of the jetties has accreted sand to the jetty tip. It is unknown if sand is now bypassing to the downdrift shoreline or if it is deflected offshore by the jetty. The shoreline to the east does not receive sufficient sand and is eroding, despite construction of several groin~ and bulkheads. The problem is most severe between the Inlet and Kennys Beach, where oversized groins further disrupt the littoral drift and may cause the sand to be lost offshore. The low dune~ in this reach do not store sufficient sand to compensate for the aceelersted erosion. The easternmost stretch has not experienced much erosion; according to long-time residents, it has actually acereted sand. Horton Point protrudes far enough into Long Island Sound to provide protection from most storms. The angle of Horton Point makes waves diffract around it, weakening their energy before they break on the neighboring shoreline. D. REACH 3: HORTON POINT TO ROCKY POINT Conditions along Reach 3 are variable. While portions of the shoreline are dynamically stable, others remain unstable, causing damage to several houses. At Horton Point, the bluff is high, and the shoreline has smoothed out over the past 60 years. Although some erosion has occurred, there has been no property damage. After about 4,500 f~et, there are protective shoreline structures even though the high bluff continues for about another 3,000 feet. Various types of structure and building materials have been used in this 3,000-foot length of shoreline west of Town Beach, but observation suggests they have either been ineffectual or increased erosion. Town Beach has been eroding; to the east, the shoreline has experienced severe erosion. The December 1994 storm led to condemnation of two houses, and County Road 48 is threatened in several areas. Erosion may have been aggravated by the groin on the west. About 7,000 feet east of Town Beach, the bluffs reemerge and the shoreline is generally stable through Inlet Point. Because Inlet Pond sits between the bluffs and Long Island Sound, exceptionally high tides can result in water overwashing the beach at Inlet Point. From Horton Point to Inlet Point, the predomi- nate drift direction is from west to east. The bluffs are very steep from Inlet Point to Rocky Point, and the beaches are generally stable and very rocky. E. REACH 4: ROCKY POINT TO ORIIO/T POINT The first 4,000 feet of Reach 4 extends almost due east-west and has a steep bluff. This very rocky area has been fairly stable. Bluffs give way to a smooth embayment that includes Truman Beach; 1I-2 10'95 SCALE ,,., )?r.Y~_)'_ ~,.'~ FISHERS ~ NEW SUFFOLK [] Reach Number LITTLE PECONIC NORTH SEA LONG/SLAND SOUND ORIENT PLUM ISLAND SMELTER ISLAND NOYACK EPRINGS 0 2 MILES ECALE Figure II- 1 Southold Reaches 11'95 SCALE FISHERS ISLAND IIORTON LANE REACll BAY MATrlTUCK NEW SUFFOLK GREAT PECONIC BAY CREEK CREEl{ ROBINS ~ iSLAND [] Reach N,mber Town of Soulhold LONG ISLAND SOUND TERRY PT IIORTON POINT HARBOR pT. PLUM ISLAND ISLAND RICIIMOND COREY GOOSE CIIEEK CREEK CREEK INR~AN NECK KROADWATER COVE MUD CREEK LITTLE PECONIC BAY NOYACK NORTH SEA SCALE £igure 11-2 Geographic Names 7*95 LONG ISLAND SOUND ORIENT 5~ HARBOR SHELTER ISLAND PLUM ISLAND iioQ NECK MATmUCK LITTLE PECONIC ~.~ Naw SUFFOLK ~ BAY I ~ flOBlfl9 / ~NOYACK· : · NOR~ SEA Reach Number Deduced direction SAG HARBOR SCALE N Figure 11-3 Deduced Direction of Littoral Drift 7*95 r'~.ANDERS BAY MATrlTUCK [~]. GREA r PECONIC BAY NEW SUFFOLK ROBINS IgLAND LITTLE PECONIC BAY NORTH SEA [] Reach Number .T. own of Soulhold ............. High bhlffs ...................... Low bluffs BAY LONG ISLAND SOUND ORIENT 5~ H4RBOR PLUM ISLAND SHELTER ISLAND NOYACK SPRINGS 0 2 MILES SCALE Figure 11-4 Natural Shoreline Features SCALE ~ ,,o~ 1,1../vI ~ ~ FISHERS LONG ISLAND SOUND ORIENT SI ISLAND PLUM ISLAND MATTITUCI~ FL~NDER$ BAY [] Reacb Number Town of Southold LITTLE PECONIC *.~u., NEW SUFFOLK ,.x~c~ BAY ROBIN8 18LAN~ NOYACK Mar~h SPRING8 0 2 MILES SCALE Figure 11-5 Environmental Sensitivity 7.95 MATrlTUCI~ FLANDERS BAY [] Reacb Number Town o~ Snuthold PECONIC BAY LITTLE PECONIC BAY LONG ISLAND SOUND PLUM ISLAND SHELTER ISLAND NORTH SEA NOYACK BAD HARBOR Heavily structural Light or non-struch~ral 0 2 MILES SCALE Figure 11-6 Structural Shoreline Protection 7.95 0 I MILE SCALE LONG ISLAND SOUND ORIENT 5~ HARBOR SHELTER ISLAND PLUM ISLAND MATrlTUCK ..,~o~r NEW SUFFOLK FLANDERS BAY [] Reacl~ Number -' Small lois Town o[ Sonll~91d GREAT PECONIC BAY ......... Public uses ROBINS ISLAND LITTLE PECONIC BAY NOYACK SAG HARBOR SPRINGS 0 2 MILES SCALE N Figure 11-7 Land Use m SOUNL)INC;S - (eot I~elow Murat Luw Walur $.urce: Nnli.n,~l ( )cunnic and ^h,.)Sld~Hc Adminislrali~.~ CONTOUK - I'eet above Mean I Il§h Waler Town of. Sou. thold Fi~,.re II-fl ~Hattituck Inlet East Marion Orient Park -- an area that has eroded over the years - is to the east. From Terry Point to Mulford Point, the shoreline is rocky and backed by a steep bluff. The area from Mulford Point to Orient Point, known as Pettys Bight, has recently experienced severe erosion. Although no erosion problems were reported for 30 to 40 years, the five major storms in the 1990's have caused large-scale erosion. The area around Orient Point also narrowed during these storms. F. REACH 5: ORIENT POINT TO YOUNGS POINT (G~.k'NPORT) Like all of the Bay side shoreline, Reach 5 has a wide range of erosion potential and causes. Orient Point is fully open to Gardiners Bay and experiences waves similar to those on the Long Island Sound shoreline. The beach is all stone and cobbles, with three rock groins between the Orient Point ferry slips and Orient Point. Orient and Long Beaches, west of the ferries, are also fully exposed to Gardiners Bay. They form a long spit extending west-southwest. The roadway was damaged on several occasions during storms, and breached during the December 14, 1994 storm, and now lies in pieces under water. The roadway has since been rebuilt north of its old location. The beach is a mixture of rock and sand, except at the public bathing areas, where it is all sand. There are about 10 groins in various state of repair along the beach, where predominate direction of littoral drift is from east to west. Long Beach Point is reported to change its orientation from season to season. The spit protects Long Beach Bay, which is lined with intertidal marshes. Long Beach Bay is not exposed to wave-generated erosion, but some tidal currents have affected the shoreline. A channel was dredged and then lined with bricks to give access around Peters Neck and Browns Point. Although it has changed the circulation pattern, it does not seem to have caused erosion. Orient Harbor is an open bay, protected by Long Beach on the southeast and Shelter Island on the southwest from waves of Gardiners Bay. Between the end of King Street and Peters Neck Point, there are almost 20 groins along the beach, where the predominatn direction of littoral drift is south. Predom- inate drift direction changes to the north near King Street. A number of groins, bulkheads, and the Orient Yacht Club pier line the shoreline up to the tidal marshes at the head of Orient Bay; the shoreline is then armored with stone to protect the road. Land is less than 1,000 feet wide in this area. At Dam Pond, there are only two thin strands of land, Truman Beach and Main Road. Shoreline from Dam Pond to Spring Pond is lined with more than 20 groins and many bulkheads; predominate direction of littoral drift is from northeast to southwest. The mouth of Spring Pond is kept open by a pair of jetties. Shore- line from Gull Pond to Cleaves Point contains many erosion-control structures. Gull Pond Inlet was first dredged in 1959, when 177,200 cubic yards of sand were removed. It is dredged about every 10 years; about 20,000 to 25,000 cubic yards of sand are removed. It's position is stabilized by jetties. Overall, Orient Harbor is heavily protected by structures. Although Orient Harbor is only a little wider than 2 miles, wave action is sufficient to be the main cause of erosion and beach movement. Tidal currents are important in shaping shoreline around Peters Neck and Long Beach Points. The stretch of coast from Cleaves Point past Gull Pond to Youngs Point is well protected by Shelter Island and does not experience high wave action. However, the shoreline is heavily protected with structures of various types. Direction of sand movement seems to be from east to west, but can be highly variable. At the mouth of Gull Inlet, tidal currents result in the formation of shoals, both inside and just outside the inlet. These shoals act as a sink for sand, removing it from the beach system. 1I-3 G. REACH 6: FANNING POINT TO FOUNDEI~ LANDING Pipes Cove spans Fanning Point to Conk, ling Point. Tucked behind Shelter Island, the cove is about 5,000 feet wide. The two sides of the cove are protected by structures, and the head is the mouth of two creeks, Moores Drain and drainage for Arshamonaque. There are tidal wetlands at the mouth of the creeks and freshwater wetlands farther inland. The beeches have been fairly stable, overwashing during storms but building back fairly rapidly. The highly developed land along the east side of Conlding Point is protected by bulkheads for its whole length, and almost 20 groins have been built along this shoreline. Because of the bulkheads and limited wave fetch, movement of sand is predominantly controlled by currentS, although storms move sand depending on the wind direction. The general direction of drift is north on the north half of the shoreline and south on the south half. Conkling Point itself has been accreting sand and has expanded southwest. The west side of Conk. ling Point, facing Brick Cove, is also heavily bulkheaded with more than 15 groins. At the northwest end, the shoreline turns toward an east-west orientation. There are basins near the turn, which were initially dredged in 1959 (163,900 cubic yards) and re-dredged in 1963 (129,200 cubic yards). They are protected by stone and metal jetties, lust west of these basins, Mill Creek - the entrance to Hashamomuck Pond and currently the entrance to the Port of Egypt marina - has been dredged regularly since 1963. The old entrance on the west side of the marina at Budds Pond has been closed off, and the channel through the offshore bar in front of Port of Egypt is maintained by dredging. This area is open to waves from the south across Southold Bay, which has a 10,000 foot fetch, allowing for waves as high as 3 or 4 feet. Storm waves and tidal currents at the inlets have led to erosion, but structures and dredging have been the major forces in shaping the current shoreline. At Budds Pond, the shoreline has a north-south orientation, predominate direction of littoral drift is south, and the shore is open to waves from the east. These waves can reach 3 to 4 feet in height. The shoreline is heavily bulkheaded with almost 20 groins, and Biexedon Creek mouth is protected by two large jetties. H. REACH 7: FOUNDERS LANDING TO INDIAN NECK The confluence of Town and lockey Creekz at Harpers Point has complex tidal currents and is complicating the situation. A barrier spit l~as pro~ecu~ m on the east end. The spit is connected to the shore just north of Goose Creek, which is part of the tidal complex. Several groins were constructed at the east end of the spit to prevent sand from depositing in the channel and to hold the spit in place. The groins have deteriorated over time and have not been replaced. In the past, erosion of the spit was mitigated by placement of dredged material from the channel, however, lack of sand placement in the past decade has left the spit in a severely eroded condition. As the spit erodes, Harpers Point is exposed to increasing wave action. A channel into lockey Creek has been dredged immediately along the lee side of the spit, and when waves overtop the shoal, sand is carried landward into the channel. As this sand is removed by dredging it is disposed off-site thus preventing self maintenance of the spit through natural processes. Shape of the shoreline is controlled to a large degree by dredging and tidal currents, but east winds, which cause westward traveling waves, contribute to erosion of the area. The north shore of Great Hog Neck is open to waves from a north and northeast storm. The I1-4 shoreline is heavily bulkheaded. Small boat basins have been dredged into Great Hog Neck. The predominant direction of littoral drift appears to be to the east. According to bayman, tidal currents run east during both the flood and ebb. This could be caused by a tidal gyre setting up in Southold Bay. Tidal currents appear to be causing elongation of Paradise Point. Between Paradise and Cedar Beach Points, Cedar Beach is open to waves across Shelter Island Sound. The shoreline is bulkheaded and has about 20 groins protecting it. The shoreline appears to be eroding due to wave action. However, some accretion is occurring around Cedar Beach Point, and tidal currents at Cedar Beach Creek form shoals around its mouth. The south shore of Great Hog Neck is open to waves from the south across Little Peconic Bay, a distance of 30,000 feet. Although winds from the south typically blow in the summer and are usually low speed, occasionally a storm can cause high winds from the south. The shoreline is bulk, headed and has more than 40 groins, especially towards the east end of this stretch. Corey Creek ends the south side of Great Hog Neck, and Richmond Creek is at the head of Hog Neck Bay. These form the apex of the bay, which is open to waves traveling towards the northwest. Similar to waves that affect Cedar Beach, these are normally small, but storms can generate erosion-caus- ing waves. Corey Creek was first dredged in 1963-1964 (345,600 cubic yards) and has been maintenance dredged regularly since. Richmond Creek was first dredged in 1959 (123,000 cubic yards) and is regularly dredged. Dredged materials have been used for various purposes and placed in different locations. In January 1995, about 20,000 cubic yards was dredged and mounded on the beach at Emerson Park. The dredged material was bulldozed into surrounding vegetated areas to smooth it out. Bars at the creek mouths overwash during storms, but normally rebuild quickly. Tidal currents form shoals inside and outside of the creek mouths. Dredging, storm waves, and tidal currents are the major forces shaping the shoreline. I. REACH 8: INDIAN NECK TO DOWNS The shoreline curves around Indian Neck to a north/south orientation along Little Hog Neck. This curve is interrupted by one inlet at Little Creek that is dredged yearly. Shoreline from the public beach south to Nassau Point is bulkheaded along its whole length with many groins. This shoreline is backed by a very steep bluff that quickly rises to more than 50 feet. This bluff has eroded in places from groundwater seeps that are not associated with coastal erosion. Fetch across Hog Neck Bay to Jesup Neck is about 20,000 feet, and waves come directly from the east. Direcxiun of littoral drift is very sensitive to wave direction and can reverse many times during a year. According to baymen, the tidal current along this shoreline always sets towards the south. Nassau Point seems to be elongating in response to littoral drift and the tidal current. The west side of Little Hog Neck is punctuated by two natural inlets for Hog Creek and one dredged basin. The shoreline is not as steep and high as the east side. South of the Hog Creek inlets, the land rises to about 20 feet. From the inlets north, the land is low lying. The shore is open to waves from the southwest, but Robins Island provides shelter. The coast is protected by a number of bulkheads and groins. Meadow Beach, which is a Nature Conservancy preserve, is a small blunt spit enhanced by placement of dredged materials. The small boat channel between Meadow Beach and Little Hog Neck was dredged, but has generally maintained its depth without additional dredging. According to local residents, Meadow Beach has not eroded for at least the past thirty years. 11-5 North of Meadow Beach spit, an inlet serves as the mouth of three creeks, East Creek, Mud Creek, and Baywater/Broadwater Coves. This inlet was first dredged in 1966 (434,000 cubic yards) and now is maintenance dredged every one to two years. The beach on the west side lengthens to the east and into the channel, requiring dredging. The channel used to run in front of Fishermans Beach, but now runs straight out from the inlet. A large shoal, not attached to the shoreline, has formed on the west side of the channel, and a smaller shoal, attached to Fishermans Beach, is forming. Beaches on either side of the inlet regularly overwash and houses flood. Observation suggests the beaches have eroded back about 20 feet in the past 20 years. Fleets Neck shoreline is exposed to waves traveling wast/northwest from little Peconic Bay. It is bulkheaded, and the beach is primarily fashioned from placement of dredged materials. Bluffs behind the beach rise to about 50 feet. Wickham Creek was first dredged in 1966 (48,300 cubic yards) and is now dredged regularly. Between Wickham Creek and Schoolhouse Creek, the shoreline is partially bulkheaded with heavier bulk, heading towards Wickham Creek. This shoreline is open to waves coming from the east across Cutchoque Harbor. Schoolhouse Creek is dredged occasionally. Sand accretes in the vicinity of New Suffolk Marina and Robbins Island ferry slip, which is dredged yearly. The groin for the New Suffolk point was recently rebuilt, and the New York State Department of Environmental Conservation has installed a sand trapping system. Town Beach is open to waves from the south coming across Great Peconic Bay, a distance of about 37,000 feet. According to local residents, however, the beach has not eroded, but has been stable. The shoreline is backed by a low bluff. Based on the spit at Kimogener Point, littoral drift is generally from east to west. West Creek was dredged in 1966 (92,500 cubic yards) and is dredged regularly. At least since the 1950's, the shoreline from West Creek to Downs Creek has been eroding except when dredged materials have been placed on it. Several deteriorating groins are located along this beach. J. REACH 9: DOWNS CI~k'~.K TO ~ TOWN LINE The reach is fully open to Great Peconic Bay, and the shoreline is shaped by two large embayments or bights (gentle concave curve between two points). The first bight is between Kimogener and Marratooka Points, a distance of about 6,000 feet, and the second between Marratooka and Brnshs Points, a distance of about 16,000 feet. Based on an open water fetch of 32,500 feet across Great Pecenic Bay, a hurricane force wind (75 miles per hour) can generate waves up to 4 to 5 feet high. This wave height is limited because the bay is only 20 to 25 feet deep. Shallow water retards wave growth. Downs Creek is not regularly dredged and shoals form at its mouth. Placement of dredged materials from Halls and Deep Hole Creeks provide sand, that is shifted by wave and current action. Since the 1950's, six groins have been built between Downs and Halls Creeks. Bnlkheading started in the 1920's, and the shoreline is now heavily bulkheaded. Halls Creek was first privately dredged in the 1920's. In 1965, deep channels were dredged from Halls and Deep Hole Creeks (243,000 cubic yards) to a joint channel about ~A-mile offshore. The channels are maintenance dredged regularly with the sand placed on the beaches. The spit in front .of Deep Hole Creek is accreting towards the east, indicating a west to east general littoral drift. Between the two creeks, two deteriorated groins do not prevent erosion of the shoreline. Shoreline between Deep Hole and James Creeks is heavily bulkheaded with many groins. Predominate direction of littoral drift is west to east. The mouth of James Creek is protected by jetties, 11-6 with the west jetty built in the 1940's. When the channel was first dredged in the 1940's, a layer of cohesive peat and clay acted as a jetty on the east side of the channel to a certain extent. This layer has been eroded, and a shoal formed in the channel, about 300 feet into the creek. During the 1950's when no eastern jetty existed, the eastern shore eroded back about 1,000 feet. In 1964 two jetties were built on the east side to stabilize the channel and shoreline. As a result, the western shoreline at the mouth of James Creek extends about 1,000 feet bayward, more than the eastern shoreline. The channel is dredged about every three years, and dredged material is normally placed on the eastern shoreline. The western jetty is usually filled with sand. Between James and Brnshs Creeks, the shoreline is heavily bulkheaded with about 70 groins. Brnshs Creek was first dredged in 1966 (86,400 cubic yards) and is maintenance dredged regularly. The dredged material is placed on either side of the inlet depending on erosion. Shoreline between Brnshs Creek and the town line is heavily bulkheaded and has about 10 groins. K. REACH 10: FISHERS ISLAND Because of its location, land use patterns, and geology, erosion at Fishers Island is very different from the rest of Southold. The island is mostly elevated and rocky, having been part of the Harbor Hill recessional moraine. Very few erosion protective structures have been built along the shoreline, although in a few locations unusual methods have been tried, such as insitu cementing of beach cobbles. The south side of the island is exposed to Block Island Sound, although the narrow opening at the Race acts as a constriction on the wave energy striking the island. The bluffs have been eroded and adjacent beaches reflect the composition of the glacial material after wave action winnows out the finer particles. The beaches are made up mostly of cobble to boulder size material (approximately 3 inches or larger in size), with a veneer of sand covering coarser materials during summer months. This situation has minimized ongoing erosion. The houses have been built on the bluffs and set back from the edge. Erosion of the bluff is a problem on the Navy property. Likewise, bluff erosion is a problem in other locations where houses have been sited too close to the edge and/or surface drainage has accelerated bluff erosion. For most of the south side of the island erosion is not a problem. The north side of Fishers Island faces Connecticut, approximately 2~A miles across Fishers Island Sound. This side experiences much lower wave energy and high elevations so that houses are not endangered by erosion. However, several houses in West Harbor have been built in a Iow-lying area, and home owners have built groins for protection. These structures appear to have had some success. CHAPTER HI. COMMON MANAGEMENT UNITS A. INTRODUCTION Although the Town of Southold's shoreline is highly variable because various coastal processes are shaping different glacial landforms, certain commonalities emerge. Natural common elements relate to wave exposure, proximity to tidal inlets, bluff height and stability, and flooding. Human elements include land use, lot size and shape, marine-related activity supported in the area, and already constructed erosion measures. When these factors are combined, they form common management units where certain coastal processes are dominant, and certain erosion protection policies are most applicable. Figure III-1 presents the common management units. On the Peconic Bay shoreline, these units overlap, and joint policies need to be considered. On both shorelines, particularly on the Peconic Bay side of Southold, the boundaries are not definitive, and further study is required to precisely characterize the unit and define its boundaries. B. LONG ISLAND SOUND COAST Three common management units make up the Long Island Sound coast of Southold; these are: areas directly affected by jetties, areas of low bluffs and dunes, and areas of high bluffs. These features are shown in Figure II-3 and II-4. Jetty Areas Jetties at Mattituck and Goldsmiths Inlets dominate coastal processes and responses in the area. Although it does not affect coastal processes, the fact that Mattituck Inlet is navigable is an important policy consideration. Mattituck Inlet supports a strong, thriving maritime community dependent on navigating the inlet. Goldsmiths Inlet is not navigable and does not support any type of human activity. From field observations and map studies, direct effects of Mattituck Inlet are felt at least 1 mile west and ~ of a mile east. On the west, sand has been trapped by the jetty, and the shoreline has built seaward. The west jetty appears close to completely full, and sand is being lost, either offshore or into the channel. As long as the jetty is functioning, the west side of Mattituck Inlct will be protected from erosion. However, sand that would help erosion on the east side of the jetty is being lost into the channel and offshore. The east side of the jetty has experienced severe erosion and loss of dunes. As discussed in Chapter I, these dunes act as sand "b~nks;H during severe storms; sand is excavated by waves and depositod on the beach to help it recover. However, dunes east of the jetty are now much reduced in size and far landward of the beach. They may no longer act as "banks. H The two jetties and channel intercept the flow of littoral drift and hold sand on the west side of the inlet. The major factor limiting the extent of downdrift erosion is the presence of Oregon Hills, which act as a large sand source feeding beaches further downdrift (east). Maps do not indicate a large degree of erosion of Oregon Hills. The beach between the east jetty and Oregon Hills has eroded because of the lack of sand. Some sand has been added to the beach, both by natural by-passing and human activity. Maps show that the 111-1 beach has responded by flattening its slope. This means that added sand has not moved the normal high water line further seaward, but the added sand is being redeposited offshore, creating a shallow beach. This process will not rebuild dunes until sand in the shadow of the jetty is exposed to air where wind can blow sand landward. The single jetty at Goldsmiths Inlet does not have an updrift (west) effect as large as at Mattituck because it is shorter. Updrift influence is evident for about ~A mile. Downdrift (east) effects are more apparent because of the low elevation of the land. Unlike the high bluffs of Oregon Hills, Horton Lane Beach and the adjacent upland is low lying; typical of a barrier landform. The effects of Goldsmiths Inlet jetty is observable for more than 1 ~h miles downdrift. Hot'ton Lane Beach regularly erodes and requires replenishment. Erosion protection policies are discussed in the next chapter, but the major factor in applying them in vicinity of the jetties is downdrift erosion. Methods should be applied whe~ever possible to have sand bypass the jetties. Bypassing has the double advantage of preventing sand from being lost offshore and supplying it immediately to an area prone to erosion. Areas of Low Bluffs and Dunes Areas of low bluffs and dunes include Horton Lane Beach (discussed above), Hashamomuck Beach. and Pettys Bight. These areas are characterized by lack of high bluffs. High bluffs on the Long Island shore of Southold tend to be more than 40 feet high, while low bluffs are typically less than 20 feet high. Some dunes may be found behind the beach. In Pettys Bight, the bluff is generally less than 20 feet high. To a certain degree, these areas also coincide with small building lots. These lots tend to be narrow and deep, allowing houses to be set back from erosion danger. Dunes around the inlets and near Hashamomuck Beach are the only place on Southold's Long Island Sound coast where flooding occurs landward of the shoreline. Excluding jetties at the two inlets, few shore protection structures are found on Southold's Long Island Sound coast, but they are found along these areas. Each structure has been built to protect a single lot or small area, and no overall plan has been developed. Along low bluffs and dunes, structures should only be allowed when a house on a beach is in danger, and no other alternative will save the house. One alternative to be considered entails moving the house. The policy recommendatious in the next chapter for set backs and native seaside vegetative plantings are especially applicable in these areas. Areas of High Bluffs High bluffs constitute much of Southold's Long Island Sound coast. The bluffs are from 40 feet to nearly 100 feet high and consist of unconsolidated sediment. The sediment ranges from clay to sand and gravel to huge boulders. These bluffs are the source of sand and gravel that form Southold's beac- hes. They are very important in determining the shoreline erosion rate. Few erosion protection structures are found in areas of high bluffs. Lack of strectures has allowed the shoreline to erode very slowly. If hard structures are built in these areas, this dynamic would change. The hard structures would cause an overall increase in the rate of erosion as the shoreline tries to come into equilibrium with the loss of sand source. IH-2 LONG ISLAND SOUND ORIENT HARBOR PLUM ISLAND $OUTH(XO BAY SHELTER ISLAND Town of Sottthold GREAT PECONIC BAY LITTLE .., PECONIC h NEW SUFFOL~Km .~lc[~.. BAY J) ROBIN8 OYACKe Loog Islaod Sound Pecooic Bay ,,-,..-,,,. High I~lu[[ ..... ,. ............. . Low ........... gXl~;serl Area ............ Florwl ?mae SPRINGS SCALE Figure III- 1 Common Management Unit Presence of clay lenses within a bluff can be a problem. The only area with large clay lenses is Pettys Bight (a low bluff area), but some are also found in high bluffs. Clay layers can accelerate bluff erosion. Clay tends to be impervious to water, and water migrates along its upper surface. If a large source of water, such as a septic system for a restaurant, is located above the clay, water will flow out to the bluff face. This creates a wet area where internal water pressure can be greater than friction holding sediment together. When this happens, the sediment slips causing a bluff slump. C. PECONIC BAY SIDE OF SOUTHOLD Coastal dynamics of the Peconie Bay side of Southold are more varied than the Long Island Sound side. As described more fully in Chapter II, many inlets, marshes, varying wave exposures, and opposing tidal currents characterize the shoreline. Generally four common management units emerge: creek mouths; wave exposed shorelines; wave protected shorelines; and flood prone areas. Certain locations may have two of these characteristics, and therefore policy decisions will involve weighing management objectives. An example is Fishermans Beach, which floods regularly and is at the outlet of three creeks. Creek Mouths Creek mouths act as a funnel for tidal currents, speeding water flow and carrying sediment in and out of the creeks. When the current reaches wider areas inside and outside of the mouth, the current slows down and sediment is deposited. These deposits form shoals around the creek. Almost all of the creeks are used for navigation, and the shoals need to be dredged to provide sufficient navigation depth. Use of dredged materials is the key management objective in these areas. This dredged sand is a valuable resources that needs to be used wisely to prevent erosion and to build beaches. The most beneficial use of sand varies from inlet to inlet, and will vary at the same inlet in different years. Each decision concerning where to place sand will depend on the history of storms that most recently affected the inlet. Within this management unit, the length of jetties to stabilize the inlets is important. At James Creek, the west jetty is 200 feet long while the east jetty is 50 feet long. This length has stabilized an offset inlet with the west side seaward of the east side. The east side erodes and requires periodic beach fill while the west side has trapped sand. When jetties are proposed or reconstructed, careful thought about relative length and placement is required. Exposed Shores The Peconic Bay Side of Southold has several shores exposed to waves coming across Great Peconic Bay, Hog Neck Bay, and Gardiners Bay. For the most part, these shorelines have been heavily protected with bulkheads and groins (see Figure II-6). The low lying nature of some shoreline and easily eroded sediment in the bluffs led to early use of erosion protection structures. Because so much of these shores have been protected by erosion-control structures, the few remaining unprotected lots are eroding. Therefore, it would be very difficult to refuse permission to one homeowner to protect property when all the surrounding houses have bulkheads. However, standard designs can be developed that will minimize effects on updrift and downdriff properties. Groins are particularly common and should be thought of as groin fields, not as individual groins. As an example, an eight-groin field had been LII-3 installed and worked well. When a ninth groin - longer and 2 feet higher than the existing groins - was installed, erosion ensued and the groin field no longer functioned properly. When a groin field is designed as a whole, specific lengths, heights, angles, and spacing can be developed so that all groins act as a unit and provide the most benefit to all property owners. Protected Shores Protected shores include Hallock Bay, Pipes Cove, Conkling Point, and parts of Southold Bay and Cutchoque Harbor. These areas are also heavily protected with bulkheads and some groins. Flooding has led to most of the bulkhead construction. A bulkhead with backfill allows a house to be raised above the flood plain. In these areas, granting of permits should not be automatic, especially for groins. Wave action is the major cause of erosion, but groins can exacerbate wave effects. Therefore, the use of non- structural measures should be analyzed first. In many cases, beach filling can solve or at least ameliorate the problem. To accomplish this, cooperation among neighbors and with DEC will be required. People most affected would have to jointly allow beach filling across all of their properties. If one neighbor objected and did not allow new sand to be placed on their property, beach filling may not function as well as it could. In addition, DEC and the Corps of Engineers will need to allow the beach filling project. Long-term coordination among the Town, DEC, and Suffolk County is required so that dredged material is reintroduced into the littoral system and used to ameliorate erosion problems. If non-structural solutions are not feasible, a structural solution to problems should be considered provided it is clearly defined how the structure will mitigate the problem and what its potential impacts are. The problem that the structure would solve should be clearly defined. Flood-Prone Areas Many areas on the Peconic Bay side of Southold are flood-prone. The problem with flooding is not the physical process itself, which is an inconvenience, but the damage to houses and property. The traditional method of preventing damage has been to protect property and houses with bulkheads. With backfill behind the bulkheads, this approach raises the ground out of lite floodplain. Another method used in other areas, and recommended by the National Flood Insurance Program (N-FIP), consists of building the house on piles with the 1st floor above flood level. When a flood occurs, the water goes under the house but does not damage it. Installing breakaway walls below, flood level is an important component. Limiting the number of stories in a house could satisfy building appearance concerns. While this method would not work for existing houses already protected by bulkheads (unless those bulkheads are not sufficient to prevent damage from the 100 year flood), it would work for new houses. It is recommended that all property owners in areas subject to flooding purchase NFIP flood insurance and that Southold participate in the Community Rating System to reduce homeowner premiums. I11-4 CHAPTER IV. PROPOSED EROSION MANAG~ POLICIES A. PREAMBLE Southold's shoreline is more than 26 linear miles long, and when the embayments, inlets, and spits are included, the coast stretches to approximately 175 miles. This diverse shoreline attracts a wide variety of human and natural activities. Almost 1,000 acres of protected tidal wetlands and more than 1,400 acres of shellfish beds are encompassed in this coastal area. Miles of beaches and shore parkland attract visitors and residents. Homes and summer houses line the shore. Marine businesses, including fishing, shell fishing, transportation, recreational boating, and construction, are vital to the economic well being of Southold and its residents. To stabilize and protect these shores for personal and public uses, myriad structures have been built over a period spanning many years. These include groins, jetties, bulkheads, and revetments. To improve navigation for both business and pleasure, channels have been dredged through the inlets, and dredged materials used to make new land. Each construction project took place with a view to achieving its own goals, whether protection of one landowner's beach and upland property or the creation of a nav- igable channel for a particular marina. These projects were often undertaken without regard to overall effects on coastal processes. Dredging and building of jetties at Mattituck Inlet have served the marina businesses and boaters well, but have led to loss of beach east of the inlet. In other instances, shore protection structures have protected one property owner, but have damaged neighbors' properties. One of the main purposes of the coastal erosion policies is to ensure that consequences of building an erosion control structure are understood before construction. Erosion control structures often contribute to erosion both on- and off-site due to poor design and siting. Increased erosion, aesthetic impairments, loss of public recreational resources, loss of habitats, and water quality degradation can result from poorly placed or designed erosion control structures. Cumulative impact of a number of individual structures can be even more damaging. Therefore, the purpose and function of erosion control structures must be defined, and the consequences and potential impacts, both on- and off-site, need to be analyz~.~d, before permission is granted for building a structure. As discussed earlier, the number and type of erosion control structures differ greatly between Long Island Sound and Peconic Bay shores. On the Long Island Sound shore, few structures have been built and bluffs back almost all of its length, preventing flooding. The Peconic Bay coast has been hardened by many structures, and long lengths of it are low in elevation and prone to flooding. Therefore, proposals for erosion control structures on these two shores of Southold need to be evaluated separately. The Long Island Sound shoreline generally has few structures and houses are well above flooding elevation. Hard engineering solutions should be minimized whenever feasible, and where erosion has recently become a problem, such as Pettys Bight, a soft solution should be encouraged. Soft solutions include setbacks from the top of bluff or high-water-line, relocation of existing structures whenever possible, creation of natural vegetative buffers, and beach restoration. However, in certain situations, combined hard and soft solutions may be required where houses or public properties are in imminent danger and soft solutions cannot be applied. In areas of high public use, such as Hot'ton Lane Beach, beach filling should be used to maintain recreation values. If erosion threatens property downdrift of the two sets of jetties, sand bypassing or off-shore wining of sand should be considered to nourish downdrift beaches. With existing heavy construction along the Peconic Bay shore, rebuilding existing structures and building of new structures will be required into the foreseeable future. Unprotected properties adjacent to hard structures could erode and be subjected to damaging floods. However, permits should not be granted automatically. Before granting a permit, sound engineering analysis of the effects of the individual structure within the surrounding structures, such as whole groin fields, is necessary. Soft solutions, such as use of dredged materials for beach fill, should be the preferred approach and always included as an alternative. The soft solutions' inability to achieve acceptable erosion mitigation goals must be demonstrated before granting permission for the structure. Very often, a combined solution will work best. For example, under the right circumstances installation of a carefully designed groin field using dredged materials to fill between groins could provide a very satisfactory solution that functions well for a number of years. For both shores of Southold, whole reach or length of similar processes' analyses should be required. Consideration must go beyond a single structure or a single piece of property, and the effect updrift and downdrift on properties should be evaluated. Because such an evaluation covers multiple pieces of property, the burden of the study cannot fall onto an individual property owner; it is the responsibility of organi2ed groups of property owners and the Town and the Board of Trustees. As discussed in Chapter V, removing and rebuilding whole groin fields should be considered. This approach would go beyond ameliorating a single person's problem. Further, by considering whole shoreline reaches at a time, an entire community's problem could be addressed. Appendix A contains text of Policy 5 Minimize loss of hfe, structures, and natural resources from flooding and erosion from the Long Island Sound Coastal Management Plan. Proposed Policy 5 of Southold's Local Waterfront Revitalization Plan follows the same format. The following section discusses each policy standard specifically for Southold and how to apply each standard. These standards address Southold's specific conditions including erosion hazards, flood prone areas, and existing site conditions. The application cites existing regulations and recommends changes in regulations to meet standards in the Long Island Sound Coastal Management Plan, where applicable, for the Town of Southold. B. POLICY STANDARDS Standard Setting Priorities for Erosion Control Structures and Reflecting State Laws. 5.1 Minimize losses of human life and structures from flooding and erosion b~-~rds by using the following management measures which are presented in order of priority: A. Minimize potential loss and damage by locating development and structures away from flooding and erosion hazards. B. Use vegetative non-structural measures which have an reasonable probability of managing flooding and erosion based on shoreline characteristics including exposure, geometry, and sediment composition. Use vegetative measures to increase protective capacities of natural protective features at every opportunity. C. Enhance existing natural protective features and processes and use non-structural measures which have a reasonable probability of managing erosion. D. Use hard structural erosion protection measures for control of erosion only where: 1. Avoidance of the hazard is not appropriate because a s~ructure is: functionally dependent on a location on or in coastal waters; located in an area of extensive public investment; or reinforces the role of Maritime Centers or Areas for Concentrated Development. 2. Vegetative approaches to controlling erosion are not effective. 3. Enhancement of natural protective features would not prove practical in providing erosion protection. 4. Construction of a hard structure is the only practical design consideration and is essential to protecting the principal use. 5. The proposed hard structural erosion protection measures are: a. limited to the minimum scale necessary b. based on sound engineering practices 6. Practical vegetative methods have been included in the project design and implementation. 7. Adequate mitigation is provided and maintained to ensure that there is no adverse impact to adjacent property or to natural coastal processes and natural resources and, if undertaken by a private property owner, does not incur significant direct or indirect public costs. The purpose of these standards is to establish a hierarchy of approaches to erosion protection and to incorporate New York State laws and regulations into local codes. The Town of Southold has already incorporated requirements of the Coastal Erosion Hazard Area (Chapter 37 of the Town Code) and the Floodplain Management Acts (Chapter 46 of the Town Code) into its local codes. These amendments allow no permanent structures in the coastal hazard area where housing would be destroyed and lives endangered by wave action and high water levels. These areas are located primarily along the low bluffs and dunes on Southold's Long Island Sound coast. Flood plain management requires that habitable space be located above the 100 year floodplain. On the Peconic side it is recommended that the code specific- ally include building on piles rather than using bulkheads. For the prope~y owner, raising the building rather than the ground would be less expensive. A bulkhead that could affect nearby neighbors would not be required. The hierarchy to erosion control measures given above has not been officially adopted, and it is recommended that it be included in the application requirements for a waterfront construction permit. Each applicant would have to demonstrate why the structure (building) cannot be located or relocated outside of a flooding or erosion area; why vegetative or other non-structural measures would not protect the applicant's structure; why natural protective features are not sufficient protection, before a permit could be granted for a groin or bulkhead. These measures should be included in both the Board of Trustees by-laws and in the Town of Southold Building Code. As discussed in Chapter III, using this hierarchy is particularly important on Southold's Long Island Sound high bluff areas and needs to be seriously considered everywhere. Specifically, Section 100-239.4 of the Town Code should be amended so that the set back be 150 feet from the top of bluff or mean high water, whichever is more landward, on the Long Island Sound side. The same distance should be used on the Peconic Bay side where the shore has not been bulkheaded. Additionally, vegetation that retains soils cannot be removed beyond 75 feet from the top of bluff or mean high water, whichever is more landward. The only exceptions include accessory structures for changing clothing, of less than 100 square feet that could be located between the 75-foot vegetative buffer and the 150-foot setback. Many of the residences and buildings on the Peconic Bay side of Southold are subject of water damage and flooding. The Town's building code recognizes these dangers and has incorporated the applicable standards from the Federal Emergency Management Agency and the Uniform Building Code. These standards need to be vigorously enforced. As discussed above, the use of pile supported structures, rather than building bulkheads, could limit structural damage without the drawbacks of bulkheads. In addition, the amount of debris that can break loose during a storm needs to be limited. The Town Code should have a requirement for recovering and cleaning up debris after a storm. This includes walkways, docks, piers, and other structures that were dislodged during the storm. These materials could cause further damage to other buildings, especially if a second storm closely follows the first. The requirement would include posting a bond when the structure is built. Marinas and other water-dependent users tend to locate in the protected creeks on the Peconic Bay side and in the two inlets on the Long Island Sound side of Southold. On the Long Island Sound side, three sites are zoned resort/residential and one site zoned MIL The MU site is no longer used and an undermined ramp reroain~ from a fishing station. On the Peconic Bay side, Orient Point is zoned MI1 for the ferries. Areas zoned as marinas are located in Orient Harbor, Cleves Point, Mills Creek area (2), Town Creek, and New Suffolk. Four areas zoned resort/residential are also found on the Peconic Bay side. Fishers Island contains two MII zones, and the rest of its shoreline is zoned residential. The marine-zoned areas should allow only water-dependent usas, such as marinas, fishing stations, and boat repair yards. The areas zoned resort/residential should be encouraged to develop as commercial ventures with public access. Non-water-dependent uses in these zones, such as restaurants, should be sited to allow the maximum possible use of the waterfront by the water-dependent uses. Siting the non-water- dependent uses near the road and sharing parking with the water-dependent uses will help accomplish the maximlzationofwater-dependent uses. Residentialuse prevents public access, and many resorttype uses, such as conference centers and restaurants, provide water-enhanced experiences for the users. IV-4 Standard on Natural Protective Features 5.2 Preserve and restore natural protective features. A. Maximize the protective capabilities of natural protective features by: 1. avoiding alteration or interference with shorelines in a natural condition 2. enhancing existing natural protective features 3. restoring the condition of impaired natural protective features wherever practical 4. using practical vegetative approaches to stabilize natural shoreline features 5. managing activities to limit damnge to, or reverse danmge which has diminished, the protective capacities of the natural shoreline 6. providing relevant signage or other educational or interpretive material to increase public awareness of the importance of natural protective features B. Minimize interference with natural coastal processes. Natural protective features, such as bluffs and dunes, are found throughout the Town and must be protected to minimize erosion and flooding. The Town of Southold should adopt the same definition of natural protective features found in New York State regulations. They specifically include the nearshore area, beaches, bluffs, primary and secondary dunes, wetlands, and natural vegetation. Alteration of natural protective features ".might reduce or destroy the protection afforded other lands against erosion or high water, or lower the reserves of sand or other natural materials available to replenish storm losses through natural processes.' It is recommended that these be added to the zoning code, along with a prohibition on removing or lessening natural protective features' effectiveness, without a permit from the Town. Standard to Protect Public and Public Trust Lands 5.3 Protect public lands and public trust lands and use of these lands when undertaking all erosion or flood control projects. A. Retain ownership of public trust lands which have become upland areas due to fill or accretion resulting from erosion control projects. B. Avoid losses or likely losses of public trust lands or use of these lands, including public access along the shore, which can be reasonably attributed to or anticipated to result from erosion protection structures. C. Provide and maintain compensatory mi~gation of unavoidable impacts to ensure that there is no adverse impact to a4jacent property, to natural coastal processes and natural resources, or to public trust lands and their use. Portions of Southold's shoreline above Mean High Water (MHW) are in public ownership, and all lands below MHW are in public trust and administered by the Board of Trustees. This public trust dates back to the Andros Patent. A key responsibility of the Board of Trustees is to ensure that these lands are available and usable by the public. To accomplish this goal of access and availability, the Board must issue a permit for any construction below MHW. The Board must review each proposal and make a determination that the proposal will not result in the loss of these lands due to erosion. This review includes not only the land which would be protected by the structure, but also updrift and downdrit~ property. If the Board determines that the structure is vital to protect the property but would lead to loss of other public trust land, then compensatory mitigation must be developed. This mitigation could be land banked before or could involve the Trust for Public Land, discussed under "Long-Term Coordination" in Chapter VI. Standard on Management of Navigation Structures 5.4 Manage navigation infra~isacture to limit adverse impacts on coastal processes. A. Manage navigation channels to limit adverse impactS on coastal processes. B. Manage stabilized inletS tu limit adverse impacts on coastal processes. All inlets in Southold need improved management. In particular, sand trapped in the inlets should be considered a valuable resource vital to the long-term health of adjacent coastal systems. Accordingly, every effort should be made to ensure that dredged materials are placed on adjacent beaches in the zone of active sand movement. At those inlets stabilized by jetties, sand bypassing should be considered to restore natural longshore sand transport and natural beach conditions. Sand bypassing could be as simple as routine dredging and placement of sad on downdrift beaches, or shortening of existing jetties, to more complex floating or fixed bypassing plants working routinely at the inlet. The need for bypassing is particularly evident on Long Island Sound inlets. Standard on Expenditure of Public Funds for Flooding and Erosion Control 5.5 Expend public funds for management or control of flooding or erosion only in areas of the coast which will result in proportionate public benefit. A. Give priority in expenditure of public funds to actions which protect public health and safety, mitigate past flooding and erosion caused by previons human intervention, protect areas of intemive development, and protect substantial public inve~hiie~t (land, infrastructure, facilities). B. Expenditure of public funds for flooding or erosion control projects: 1. is limited to those ciro,m~tances where public benefitS exceed public costs 2. is prohibited for the exclusive purpose of flooding or erosion protection for private development, with the exception of work done by an erosion control district. C. Factors to be used In determining public benefit attributable to the proposed flood or erosion control measure include: protection of public infrastructure and investment 1. economic benefitS derived from and protection of water-dependent commerce, or 2. protection of significant natural resources and maintenance or restoration of coastal pro~esses~ or 3. integrity of natural protective features, or 4. extent of public infrastructure investment, or 5. extent of existing or potential public use. Although most propert~ threatened by erosion is privately owned, protection of that property can IV-6 be in the public's interest under some circumstances. Loss of private property could signal loss of lands in the public trust below MHW. However, public benefits must be carefully weighed when considering expenditure of public funds. At Mattituck Inlet the federal government is making large expenditures to protect navigation for fishing and commercial fleets, as well as for some recreational boating. The U.S. Army Corps of Engineers has made detailed benefit cost analyses and has found that benefits outweigh costs. However, use of dredged materials and cost of installing a sand bypass system need to be investi- gated. A sand bypass system could speed beach recovery on the east side of the inlet, leading to more public use of the area with its tourist benefits. A sand bypass system would also reduce the cost of dredging because sand would no longer move around the end of the jetty and deposit in the channel; it would be bypassed and deposited on the beach. Goldsmiths Inlet is not navigable and does not provide the benefits that Mattituck Inlet provides. The analyses for Goldsmiths should give careful consideration to jetty removal. While jetW removal could reduce downdrift erosion, it could cause erosion of the accretion fillet on the west side of the jetty. These issues would need to be addressed. On the Peconic Bay side, the same analyses should be done for dredged materials from creek mouths. Suffolk County bears the cost of this dredging, and the greatest public benefit should be derived from that expenditure. The analyses to date have focused on navigational aspects, and erosion and erosion protection benefits have not been fully included. On exposed areas, the cost of developing the approach to groin field design would bring public benefits. Existing erosion problems could be ameliorated, and future problems minimized. When required, groin fields covering whole lengths of shoreline could be laid out and their height, length, and spacing specified. Areas between groins would have to be filled, and the source of material identified. Groin field development projects should be combined with dredging projects. The dredged materials could be placed between groins, providing the benefits of both soft and hard solutions. By specifying placement of sand between groins, DEC should be more amenable and not require upland disposal. This approach would benefit all owners sharing a given part of the shoreline, not just one property owner. Standard on Sea Level Rise 5.6 Consider sea level rise in the siting and design of projects involving substantial public expenditure. Given the potential for accelerated sea level rise in the future, and the significant consequences which could result from a rise in sea level, wise coastal management requires that sea level rise be at least considered in the planning of projects requiring substantial public funding. CHAPTER V. POST-STORM RECOVERY POLICrg-q A. POST-STORM RECOVERY Introduction A common tendency after a damaging storm is to return to the same condition as before the storm, whether or not that situation was desirable. Instead, post-storm rebuilding should be aimed at preventing and minimizing future erosion end flooding. The approach will vary by type of damage inflicted by the storm end by the goals of each common management unit. In addition, the permitting procedures may constrain or delay certain rebuilding actions. This chapter discusses the approach to be taken in each of the common menagement units, and how existing permitting procedures may be used to achieve unit goals~ Post-Storm Recovery Goals by Conunon Management Unit Long Island Sound Side On Southold's Long Islend Sound coast, the major cause of damage during a swrm is wave action leading to bluff erosion end dune loss. A storm could also seriously damage jetties at Mattituck end Goldsmiths Inlets. Inundation of large inlend areas does not typically occur. letw Areas At Mattituck, a storm could flank the jetties, causing the inlet to migrate out of its present channel. In this case, the flanked area should be filled so the protected channel is returned. A migrating channel could lead to erosion of property end inlet instability. A storm could seriously damage or destroy the jetties. If Mattituck Inlet jetties are destroyed, they should be rebuilt. The economic hardship on businesses in Mattituck Inlet would be unbearable, end they would either relocate or close. In either case, Southold would lose jobs from its economic base and part of its maritime tradition. Therefore, rebuilding of the jetties to protect the inlet end its uses should be done quickly. The U.S. Army Corps of Engineers has studied different solutions for the stabilization of Mattituck Inlet end has found that maintaining the channel by dredging end rebuilding the existing jetties provide the best solution. However, careful consideration should be given to new jetty dimensions which would permit greater bypassing while still maintaining the navigation channel. For Goldsmiths Inlet, the decision is different. The original purpose of the jetties - a public park - is no longer envisioned, end the jetty is causing erosion along Horton Lane Beach, which is heavily used by the public. Serious consideration should be given to removal of the jetty if it is destroyed or damaged during a storm. Effects on adjacent beaches need to be analyzed prior to making this decision. The final situation around the jetties is severe erosion of downdrift beaches end loss of dunes. In both areas, the beach should be refilled with send, from the updrift side of the jetties. These beaches are V-I valuable and heavily used by the public. At Mattituck Inlet, beach erosion could cause a breach, and the inlet would migrate outside of the current channel. The new channel would probably not be navigable by fishing boats and could cause additional erosion. Low Bluffs and Dune During large storms, waves erode bluffs at their toe, which leads to slumping. Slumping brings new sediment to the beaches. Damage is normally loss of bluff, which can include encroachment into a yard area. This excludes those cases where the principal residences are endangered, as is discussed below under Emergency Procedures. In dune areas, flooding often occurs during the storm, eroding dunes and causing water damage to personal property. The management objective in low bluffs and dunes common management areas is to protect public resources by reducing the number of hard erosion protection structures and encouraging soft approaches, such as vegetative cover. However, since existing structures that are either grandfathered or permitted can be rebuilt as-of-right some erosion protective structures will undoubtedly be rebuilt almost immediately. The Town and Board of Trustees' focus should not be on rebuilding everything immediately, including erosion protection structures, but on how the current damage to homes can be corrected while minimizing future damage. Applications for new structures should be carefully reviewed rather than granted quickly. Effects of new structures on surrounding properties must be shown by the applicant. If a permit is granted, conditions should include meeting setback requirements for the principal structure and full width of native vegetation planting. Construction work, if permitted, would have to include meeting these requirements prior to completion. In many cases, a homeowner will have funds from flood insurance to pay for reconstruction and moving a house beyond the setback limit. Therefore, requiring the homeowner to meet these requirements would not cause a financial hardship, as long as the property has flood insurance. As part of rebuilding, the Buildings Department needs, to examine the condition of each house and its likelihood of being damaged again in the next storm before issuing its permit. If a house could be damaged in the next storm, the owner should be required to rebuild it so that damage would not occur again. This could include moving the house further away from the shoreline on a new foundation. In a dune area, raising the house above the flood area could be appropriate. Areas of Hi h Bluff The toe of high bluffs is eroded during a storm resulting in a bluff slump because of lack of support. Slumping of high bluffs supplies large volumes of sand and gravel to beaches. Each linear foot of a 50-foot-high bluff supplies about 2 cubic yards of sediment for each landward foot of erosion. Bluffs are of great importance in maintaining beaches and protecting areas of low bluffs and dunes, which are more susceptible to landward erosion. The management objective of this common management unit is to minimize building of groins and erosion protection structures to the extent possible, without causing loss of dwellings. Therefore, the post-storm recovery approach should be the same as during the normal permitting process; the overwhelming need for an erosion protection structure mUSt be demonstrated by the applicant before a permit is issued. For rebuilding damaged structures or building new erosion con- trol structures, the Board should consider storm intensity that would likely cause more damage. In Florida, a homeowner receives a permit only if a storm with a return period of 15 years or less mused V-2 damage. Emotional appeals of property owners who feel their lands are in danger can be persuasive, but the overall public needs of the shoreline must be considered first. Measures, such as planting vegetation along the shoreline, must be analyzed first, and the permit for erosion protection will be issued only when such methods are shown to be infeasible. Peconic Ba¥Side On the Peconic Bay side of Southold, much of the shoreline is beavily protected, the focus of post- storm recovery policy application is reach long. analysis, rather than on individual structures. Ifa whole length of similar shoreline is considered as one, solutions that protect all property owners can be developed and implemented. Aggregate cost for protecting a whole length of shoreline will probably be less than the sum totals that individual property owners would pay. The Town should consider setting up special taxing districts to pay for the study, design, and construction of shore protection. However, this could be prove to be administratively burdensome. Alternatively, homeowners could consider setting up their own special fund similar to a homeowners' association. While the Town and Board of Trustees do not have direct power to cause a group of properties to act in concert, the post-storm review process can lend itself to this approach. If a group of neighbors submitted a joint application, effects of proposed structures on neighbors would already have been dem- onstrated, whereas if a single property owner submits an application, effects of the proposed structure on neighbors would still need to be demonstrated. Using this group approach would help achieve the management objectives in all common management units on the Peconic Bay shoreline, except for flood- prone areas. These areas have an additional goal of preventing further flood damage. Therefore, the Buildings Department should not issue permits unless flood-proofing can be demonstrated. As discussed above, raising the building on piles rather than raising the land behind a bulkhead may be a preferable approach. Emereenc¥ Permits The above recommendations apply when a structure is not in imminent danger of collapse or significant structural damage. Certain storms will cause damage that must be repaired under emergency conditions. Homes and principal residences must sometimes be immediately repaired or they will collapse or become permanently damaged. This can be caused by falling trees, trucks striking the house, and coastal erosion. An emergency situation for a house or principal residence is often defined as when 25 percent of the floor area is close to collapse or permanent structural damage as certified by a professional engineer or licensed architect. This is a situation that is handled by the Buildings Department, and they have proper procedures in place. Shore protection structures can generally be mended temporarily while a decision on the type and extent of the final restoration is being made. The heavy construction materials and type of structural supports make this delay possible. According to existing state regulations, an existing erosion protection structure that is properly permitted or grandfathered can be repaired without a permit. However, many groin fields, especially on the Pecouic Bay shoreline, are not truly functioning structures. Therefore, if erosion control structures are being emergency repaired, the building inspector or an independent should inspect the site and certify that it was a functioning structure. If the structure was not functional, the work should be halted. As discussed in Chapter VI, 'Implementation Options,' an inventory of functioning structures should be mapped and photographed in the future. Trying to determine if a V-3 structure was functioning afxer having been. damaged is likely to lead u) disputes. This inventory would address that issue. ..... public The only true emergency situation that would requ~ro a discreuonary penmt ~s wheu the sole access to a group of houses is about to be destroyed or wheu a vital public utility, such as water or electricity, is about to be severed. Then, the only ways to protect the sole access or utility from the next storm would be to move it or build an erosion control sunscua~. In cases such as this, the State Environmental Quality Review Act (SEQRA) lists the action as exempt, and the New York State Department of Environmental Conservation (DEC) has emergency procedures for permitting under its regulations. The Corps of Engineers has similar procedures. Therefore, an emergency permit should only be issued for protection of sole access ways and vital utilities, and existing regulatory eme~ency procedures should be used. ¥-4 CHA/'FER VI. IMPLEMENTATION OPTIONS A. IMPI,F. MENTATION OPTIONS Studies Because of the breadth and variety of Southold's shoreline, recommendations contained in this report are general in nature. To fully implement these recommendations, detailed study of each reach and common management unit is recommended. An important task that can be done almost immediately is to develop an inventory of erosion protection structures. It will be important in implementation of this post-storm recovery policy. In addition, this data base can be used to determine effects of structures on coastal erosion. Functioning coastal erosion structures that are damaged in a storm can be repaired without a permit. As part of the post-storm recovery approach, restrictions on rebuilding erosion control structures have been recommended. These data could refine the design of existing shore protection so that they protect structures and do not cause erosion elsewhere. At the current time, no inventory of functioning structures exists, and disputes could arise if post- storm judgements are made on the functionality of structures. This inventory should include maps, photographs, and videotapes. The jetties at Mattituck Inlet have caused downdrift erosion and have threatened dunes between the inlet and Oregon Hills. However, commercial and recreational uses in Mattituck Inlet are an essential part of the character and economic life of Southold, and the jetties are helpful in maintaining navigation. Sand bypassing could address erosion problems and reduce the expense of channel dredging. A study of the feasibility and cost of sand bypassing is recommended. In Chapter V, "Post-Storm Recovery Policies," rebuilding the jetty at Goldsmiths Inlet if it were damaged in a storm was discussed. The jetty has led to erosion at heavily used public beaches. The effect of removing the jetty should be considered prior to a damaging storm, forcing a decision without sufficient study. Capital Projects Without the studies discussed above, no capital projects can be recommended at this time. Prior to committing to capital development, public benefits need to be more firmly established and costs estimated in detail. Southold could implement several demonstration projects with its own resources. These include a natural vegetation nursery to determine which plantings do well and provide the best erosion protection. The Town could erect sand fencing, such as the New York State Department of Environmental Conservation (DEC) is doing at New Suffolk, on public dune areas. VI-1 Lone-Term Coordination Government Aeencies Coordination with the state level of government will benefit the Town of Southold. First, current coordination with the Division of Coastal Resources and Waterfront Revitalization in the Department of State should be continued. This division has been providing important guidance and funding to Southold for development and protection of the coastal area. This relationship should continue. Second, long-term coordination is needed with Suffolk County and DEC for the use and placement of dredged materials. Thousands of cubic yards of sand are dredged every year on the Peconic Bay shore, and Southold has had little, if any, input into placement of sand. Dredged material is a very important resource that can address erosion problems in creek mouths and along exposed shoreline. A committee comprising the Town of Southold, Suffolk County, and DEC should be set up to review the upcoming dredging projects and decide where to place sand. These decisions will have to made yearly because erosion patterns change based on direction and severity of storms. This committee could be the most important tool available to Southold for alleviating its erosion problems along the Peconic Bay shores. The final part is internal to the Town of Southold. One aspect is the Building and Zoning Codes. The Building Code specifies flood protection and structural requirements. These requirements can be strengthened, especially in flood-prone management units. The Zoning Code can provide for setbacks and soil-retaining plants. The second important area is enforcement of the codes. The Building Inspector should become familiar with coastal erosion and methods of minimizing erosion. With its long coastal expanse, this area of expertise is as important as knowledge of structural systems in the Town of Southold. Private Foundations Parts of Southold's shoreline are in public ownership and other parts, such as Meadow Beach Preserve are held by the Trust for Public Lands (Trust), a private organization that holds and protects ecologically valuable land. Those areas of shoreline in public ownership must be kept for use of Town residents and visitors. The Town should work with the Trust to preserve valuable natural lands, such as marshes and wetlands. The Trust will often set up trades where a developer will deed a valuable natural site to them in return for another site that would be easier to develop. This private sector entity can raise funds to protect natural protective features and ecologically significant sites, where the Town could not. By working with the Trust, the Town would have an instrument to direct development and protect sites on a smaller scale than can normally be achieved through zoning or other regulation. VI-2 COASTAL ENGINF. F~RING GLOSSARY (FROM SHORE PROTECTION MANUAL, 1984) AGCKETION. Buildup of land on a beach either by action of the forces of nature or an act of man. ~ItOT-T~,N S~I}S. Sediment of sand size or smaller that have been transported by winds. aLCHGSHOII~. Parallel to and near the shoreline (LCH~ISHOIm). alll{Oll, lllqll. Relatively large quarrystone or concrete shape that is used for wave protection struc- tures. A'~E~H~A'~TON. The lessening of the amplitude of a wave with distance from the origin or through structural or landform interference. BAC~.SHOR~. Zone of the shore or beach lying between the foreshore and coastline. Acted on by waves only during extreme storm events. BAR. Submerged or emerged embankment of sand, gravel, or other unconsolidated material built on the sea floor in shallow water by waves and currents. BARRIER BEACH. A bar parallel to the shore, the crest of which is above normal high water level. IlalIRIER LaC, OOlq. A bay separated from the open ocean by barrier islands. BA'raxtlZlXY. The measurement of depths of water in oceans, seas, and lakes. ~aY~lou'm m~R. A bar extending partly or entirely across the mouth of a bay. BRaGH. The zone of unconsolidated material that extends landward from the Iow water line to the place where there is a marked change in material of physiographic form, or to the line of perma- nent vegetation. Consists of a ltOR~SHORII and ~gKSHORE. BF, ACH Bl~lll[ Nearly horizontal part of a beach or backshore formed by the deposition of material by wave action. BF_.ACH EROSlOI~. The removal of beach materials by wave action, tidal currents, littoral currents, or winds. BF_.ACH FILL (~ooRI~rn'r). Material placed on a beach to renourish an eroding beach, or the act of beach replenishment either naturally or artificially. BEAGH I~ROFII_~. The intersection of the ground surface with a vertical plane; may extend from the top of the dune line to a seaward limit of sand movement. IIEAGIt SCARP. An almost vertical slope along the beach caused by erosion due to wave action. IIF.&GH WIIIYII. The horizontal dimension of the beach measured normal to the shoreline. G-1 Bl,u~,t, (ES~). A high steep bank or cliff. B~. A wave breaking on a shore, over a reef, etc. laR~_ak-~a.~.~t. A structure protecting a shore area, harbor, anchorage, or basin from waves. BUL~x~-An. A structure that retains or prevents sliding of the land, and protects the upland from wave action. I~YPA-~SIlqC, S,~'~ID. Hydraulic or mechanical movement of sand from the accreting updrift side to the eroding downdrift side of an inlet or harbor entrance. cgAn'r (TII)~/,) I)A'rUK The plane or level to which soundings, elevations, or tide heights are re- ferred. CO.~S'r. A strip of land of indefinite width that extends from the shoreline inland to the first major change in terrain features. CO.~STLII~. Line separating the coast and the shore; more commonly, the boundary between land and water. CUEREI~. A flow of water, typically generated by wave action, tidal fluctuations, or winds. cusPA'rg BAIl.. A crescent-shaped bar uniting with the shore at each end. DECAY OF ~'AVE$. The change waves undergo after leaving a generating area and passing through a calm or region of lighter winds. DEEP ~'A'£,'r.s.. Water deep enough that waves are not affected by the ocean bottom. DEFI~'rIOS. The removal of loose material from a beach or other land surface by wind action. DgP'nt. The vertical distance from a specified tidal datum to the sea floor. D'rFFR~CTIDS. The phenomenon by which energy is transmiued laterally along a wave crest. In a coastal sense, it occurs when a wave train is interrupted by a smacture or seafloor elevations differences in such a way that waves are propagated into the sheltered region of the structure. DIURli~L 'rIDE. A period or cycle of approximately one tidal day. DOmmKIF'r. The direction of predominant movement of littoral materials. DUllS. Ridges or mounds of loose, unconsolidated material, usually sand. ~m~,I,l~lq'r. An indentation into the shoreline forming an open bay. ESC,~ll/,m,.~'~'. A line of cliffs or steep slopes facing in one general direction that are caused by erosion or faulting. G-2 V-S'~ARY. Portion of river that is affected by tides or region of a river mouth in which fresh and salt water mix. ga'£V, AI'ROI'ICatL S'rOgU. Storms that develop in the mid-latitudes in response to the interaction of warm and cool air masses, commonly referred to as northeasters. I~TCH. The area in which seas are generated by wind having a fairly constant direction and speed. The horizontal distance (in the direction of the wind) over which a wind generates seas. FOI~SltOILg. The part of the shore lying between the crest of the seaward berm and the ordinary low- water mark. GgOI~ORFIiOLOg¥. That branch of both physiography and geology that deals with the form of the earth, the general configuration of its surface, and the changes that take place in the evolution of landform. GRal)im~rr. Rate of change with respect to winds, currents, or wave heights. ~ROII~. A shore protection structure built perpendicular to the shore to trap littoral material or retard erosion of the shore. m~.snLal~. A high steep-faced promontory extending into the sea. TII)i; (ltI~;lI l/~.£~.u). Maximum elevation reached by each rising tide. ltI(:-m~.~ llI~;lt wA'£1~.l~. The higher of the two high waters of any tidal day. ~tIS~C~sTIlqc, W,~VE. The use of historic synoptic wind charts to calculate characteristics of waves that occurred at some past time. tml~tCalgg. An intense tropical cyclone in which winds tend to spiral inward toward a core of low pressure. Maximum surface wind velocities equal or exceed 75 miles per hour for several min- utes or longer at some point. Ili-l,g~. A short narrow waterway connecting a bay, lagoon, or similar body of water with a large parent body of water. J~'rx'~e. On open seacoasts, a structure extending into a body of water that is designed to prevent shoaling of a channel by littoral materials. I~GOO~q. A shallow body of water usually connected to the sea. LI~rrORikL. Of or pertaining to a shore, especially of the sea. LI'I~ORAI, l~gl,~'rA~r. (I~RII~). The sedimentary material moved in the littoral zone under the influ- ence of waves, and currents. LITTOIL*I'. TRANSPORT. The movement of littoral drift in the littoral zone by waves and currents. G-3 LI'I~OR~L 'I~ASSI'OR~ RAT~. Rate of ~poR of ~imen~ materi~ eider p~lel or pe~endicu- 1~ to ~e shore. ~g~o~ ~. A cu~ent mov~g ~gmi~ly p~lel to ~e shore, usu~ly generat~ by wav~ brewing at ~ ~gle to ~e shoreline. ~X~g (~ ~a~). M~imum elevation r~h~ by each f~ling tide. ~ ~x~ ~e lower of ~e ~o low watem of ~y tid~ day. s~ ~vgC. ~e average height of ~e su~a~ of ~e sea for ~1 stag~ of ~e tide over a 19- ye~ period. high, low, lower low) waters over a 19-ye~ ~riod. ~o~. A ridge, mound, or i~e~l~ m~s of boulders, gravel, s~d, ~d clay, c~i~ in or on a glacier. A deposit of such a ma~ri~ le~ on ~e ~ound by a glacier. ~o~ Zoo. An indefinite ~ne exmnd~g sow~d ~om ~e shoreline well beyond ~e brewer ~c~. A n~ow s~ip of l~d co~g a ped~ula wi~ ~e m~d. o~sao~. ~e comp~atively fiat ~ne of v~i~le wide, exmnd~g from ~e brewer ~ne to ~e seaw~d ~ge of ~e Con~en~ Shelf. o~Sao~/o~sao~ ~'x. A cu~ent dir~ o~hore/o~hore of ~e shore. ~. A fac~g of stone, co~, ~-, bu~t w prot~ erosion by wave action or cu~enm. S~. Wav~ caus~ by w~d at ~e pl~e ~d ~e of obse~ation. s~.~. A s~re sep~at~g l~d ~d w~r ~, ~ic~ly d~i~ w prevent erosion or o~er d~age due W wave ~ion. S~iU~ ~- A tide wi~ ~o hi~ md ~o low w~rs in a tid~ day. S~V vl~ Water of such dep~ ~a sud~e wav~ ae noti~ly ~ by bonom topogra- phy. ~o~. ~ A de~h~ elevation of s~ bosom, ~m~s~ of ~y mamri~ except rock or corg, ~at may end~g~ sud~ navigation. ~ To b~me sh~low ~adu~ly or w pr~ from a ~eat- er to a lesser dep~ of wa~r. 13-4 SHOREFACE (INSHORE ZOI~E). The narrow zone seaward from the low tide S~O~.~m~-, covered by water, over which the beach sands and gravels actively oscillate with changing wave conditions. SHOaELIUE. The intersection of a specified plane of water with the shore or beach (typically taken as mean high water or mean higher high water). SOIL C.T.n~SIFICA'rlOIq. An arbitrary division of a continuous scale of grain sizes. -~I'IT. A small point of land or a narrow shoal projecting into a body of water from the shore. STOI~! slm. gE. A rise above normal water level on the open coast due to the action of wind stress on the water surface or atmospheric pressure differentials associated with storm events. SlYlY' ZONE. The area of breaking waves. SI/ELL. Wind-generated waves that have traveled out of their generating area. 'rII)AL DAY. The time of the rotation of the earth with respect to the moon, or the interval between two successive upper transits of the moon over the meridian of a place, approximately 24.84 solar days. 'fII)AI, RANG~-. The difference in height between consecutive high and low waters. 'fI~E. The periodic rising and failing of the water that results from the gravitational attraction of the moon and sun and other astronomical bodies acting on the rotating earth. · folls0LO. A bar or spit that connects an island to the mainland or to another island. 'rOPOi;RAi'HY. The configuration of a surface, including its relief and the positions of its streams, roads, buildings, etc. 'rRoP'tC, AI, s'rOlm. A tropical cyclone with maximum winds less than 75 miles per hour. ue~)~xF'r. The direction opposite that of the predominant movement of littoral materials. ways cr.mt,'ng. The combination of waves of different heights, periods, and directions. ~Avlz caXs'~. The highest point on a wave. ~aW I)XRgC~TON. The direction from which a wave approaches. W&VE m~:.Xgl~. The vertical distance between a crest and the preceding trough. gAVl~ I.I~¢'11t. The horizontal distance between similar points on two suecasaive waves measured perpendicular to the wave crests. ~AVg l'gRIOl~. The time for a wave crest to traverse a distance equal to one wave length. G-5 WAV~ p~Op&~ATION. The transmission of waves through water. ~'&V~ R~IzP~.C'~ION. The process by which the direction of a wave moving in shallow water is altered as the part of the wave advancing in shallower water moves more slowly, causing the wave crest to bend toward the shallower water. series of waves from the same direction. ~I-~ql~ ~'&VE. Wave~ being formed and built up by the wind. G-6 APPENDIX A: LONG ISLAND SOUND EROSION MANAGEMENT POLICY Policy 5 Minimize loss of life, structures, and natural resources from flooding and erosion. Within the Long Island Sound coastal area, there are presently more than 8,200 buildings and other structures located in special flood hazard areas, and over 1,200 buildings and other struc- tures seaward of the present coastal erosion hazard area boundary. In response to existing or perceived erosion and flood hazards, many landowners have constructed erosion control structures. Approximately 50 percent of the Sound shoreline has been armored with erosion control struc- tures, and the trend is continuing. In Suffolk County, for example, only 8.96 miles of the 132.5 miles of the Sound shoreline was engineered with riprap, bulkheads, or seawalls in 1969. Today, 43.7 miles of the county's shoreline are hardened. This significant increase in the miles of hard- ened shoreline is not associated with water-dependent uses in Maritime Centers, but rather for uses that do not have a functional relationship to coastal waters. While some erosion control structures are necessary to protect development, there are many erosion control structures located along the Long Island Sound shore that are not necessary for erosion protection. Erosion control structures often contribute to erosion both on and off the site due to poor design and siting and lack of downdrift remediation. Increased erosion, aesthetic impairments, loss of public recreational resources, loss of habitats, and water quality degradation can result from indi- vidual hardening of the shoreline. The cumulative impact of these structures is potentially large. Before a permit is granted to allow construction of hard erosion control structures, the purpose, function, impact, and alternatives to the project need to be carefully evaluated to determine that the structures are necessary and to avoid adverse impacts. Although the Long Island Sound shoreline has been heavily fortified, there are significant stretches of the coast that remain in a natural state. The natural shoreline has an inherent natural, social, and economic value that should be respected to ensure continuing benefits to the state and the region. Consequently, those portions of the Sound shoreline that are not fortified should generally remain in a natural condition to respond to coastal processes. Where feasible and appropriate, portions of the shoreline that have been hardened should be returned to a natural condition. Development and redevelopment in ba?ard areas needs to be managed to reduce exposure to coast- al hazards. Hardening of the shoreline is to be avoided except when alternative means, such as soft engineering alternatives, beach nourishment, revegetation, offshore bar building, or inlet sand bypassing, are impractical to protect principal structures or extensive public investment (land, infrastructure, facilities). Areas of extensive public investment include City Island and the Throgs Neck in the Bronx, the Cross Island Parkway section of Queens, Bayville, the Asharoken tombolo, Sunken Meadow State Park, Wildwood State Park, portions of the identified Areas for Concentrat- ed Development, and the ten Maritime Centers. Barrier landforms that protect significant public investment or natural resources should be main- tained. Soft structural protection methods are to be used to conform with the natural coastal pro- cesses. Barrier beach landforms should be maintained by using clean, compatible dredge material, when feasible, for beach nourishment, offshore bar building, or marsh creation projects. In suitable locations and where appropriate, interpretive materials could be considered to enhance the public's understanding of natural coastal processes. A-1 This policy seeks to protect life, structures, and natural resources from flooding and erosion haz- ards throughout the Long Island Sound coastal area. The policy reflects state flooding and erosion regulations and provides measures for reduction of hazards and protection of resources. 5.1 Minimize losses of human life and structures from flooding and erosion hazards by using the following management meosures which are presented in order of priority: Coastal Barrier Resource Area is any one of the designated and mapped areas under the Coastal Barrier Resources Act of 1982, (P.L. 97-348), and any areas designated and mapped under the Coastal Barrier Improvement Act of 1990 (P.L. 101-591), as administered by the U.S. Fish and Wildlife Service, and any future designations that may occur through amendments to these laws. Coastal Hazard Area is any coastal area incltuted within the Erosion Hazard Area as designated by the New York State Department of Environmental Conservation pursuant to the Coastal Erosion Hazard Areas Act off981 (Article 34 of the Environmental Conservation Law), and any coastal area included within a V-zone as designated on Flood Insurance Rate Maps prepared by the Fed- eral Emergency Management Agency pursuant to the National Flood Insurance Act of 1968 (P.L. 90-448) and the Flood Disaster Protection Act of 1973 (P.L. 93-234). Natural protective features are beaches, dunes, shoals, bars, spits, barrier islandz, bluffs, and wetlands; and associated natural vegetation. A. Minimize potential loss and damage by locating development and structures away from flooding and erosion hazards. 1. No development is permitted in natural protective feature areas (nearshore, beaches, bluffs, primary dunes, and wetlands as defined under 6 NYCRR Part 505), except as specifically allowed under the relevant portions of 6 NYCRR Part 505.8. 2. Avoid developing new structures and uses or reconstruction of structures damaged by 50 percent or more of their value in areas which are likely to be exposed to hazards unless: a. the structure or use functionally requires a location on the coast or in coastal waters, or b. the new development would be located in an area of substantial public invest- ment, or c. the new structure or use is necessary for shoreline development which: (1) reinforces the role of Maritime Centers and Areas for Concentrated De- velopment in concentrating water-dependent uses and other development, and (2) would not result in impairment of natural resources 3. Locate new structures which are not functionally dependent on a location on or in coastal waters, are not in areas of substantial public investment, or do not reinforce the role of a Maritime Center or an Area for Concenuated Development, as far away from flooding and erosion hazards as possible. a. Locate new development away from coastal hazards associated with inlet areas. b. Avoid hazards by siting structures to maximize the distance from Coastal Ero- sion Hazard Areas. c. Provide sufficient lot depth to allow relocation of structures and maintenance of A-2 required setbacks over a period of thirty years. Where practical, moving existing structures and development which are exposed to hazards away from the hazard is preferred over maintaining structures and develop- ment in place. Maintaining existing development and structures in hazard areas may be warranted for: a. structures which functionally require a location on tho coast or in coastal wa- ters, or b. water-dependent uses which, by the nature of the use, cannot avoid exposure to hazards, or c. sites in areas with extensive public investment, public infrastructure, or major public facilities Provide public infrastructure in or near identified high velocity flood zones, structural hazard areas, or natural protective features only if the infrastructure: a. will not promote new development or expansion of existing development in: a Coastal Barrier Resource Area, except as provided in the Coastal Barrier Re- source System Act; a Coastal Erosion l-Ia?~rd Area; or a V-zone. b. is designed in a manner which will not impair protective capacities of natural protective features, and c. is designed to avoid or withstand damage from flooding and erosion Manage development in floodplains outside of coastal haTard areas so as to avoid adverse environmental effects and minimize the use of structural flood protection measures. Comply with the provisions of the Environmental Conservation Law, section 36, Participation in Flood Insurance Programs; 6 NYCRR Part 500; and any local flood protection program. Use vegetative non-structural measures which have a reasonable probability of manag- ing flooding and erosion based on shoreline characteristics including exposure, geome- try, and sediment composition. Use vegetative measures to Increase protective capaci- ties of natural protective features at every opportunity. Enhance existing natural protective features and processes and use non-structural mea- sures which have a reasonable probability of managing erosion. 1. Enhance the protective capabilities of beaches by using fill, artificial nourishment, dredge disposal, or by restoring coastal processes. a. Use only clean sand or gravel with a grain size equivalent to or slightly larger than the native material at the project site. b. Design criteria for enhancing the protective capabilities of beaches should not exceed the level necessary to achieve protection from a 30-year storm, except where there is an overriding public benefit. c. Provide for sand by-passing at engineered inlets or other shore protection struc- tures to maintain coastal processes and protective capabilities of beaches. 2. Protect and enhance existing dunes or create new dunes using fill, artificial nourish- ment, or entrapment of windborne sand. a. Use only clean sand with a grain size equivalent or slightly larger than native dune material. b. Design criteria for created dunes should not exceed the overtopping height defmed by the 30-year storm, except where there is an overriding public bene- A-3 fit. c. Enhance existing or created dunes using snow fencing and dune vegetation. d. Construct and provide for use of walkovers to prevent pedestrian damage to existing and enhanced dunes. Increase protective capacity of natural protective features using practical vegetative measures in association with all other enhancement efforts. D. Use hard structural erosion protection measures for control of erosion only where: 5.2 A. 1. Avoidance of the hazard is not appropriate because a structure is: functionally depen- dent on a location on or in coastal waters; located in an area of extensive public in- vestment; or reinforces the role of Maritime Centers or Areas for Concentrated Devel- opment. 2. Vegetative approaches to controlling erosion are not effective. 3. Enhancement of natural protective features would not prove practical in providing erosion protection. 4. Construction of a hard structure is the only practical design consideration and is es- sential to protecting the principal use. 5. The proposed'hard structural erosion protection measures are: a. limited to the minimum scale necessary b. based on sound engineering practices 6. Practical vegetative methods have been included in the project design and implementa- tion. 7. Adequate mitigation is provided and maintained to ensure that there is no adverse impact to adjacent property or to natural coastal processes and natural resources and, if undertaken by a private property owner, does not incur significant direct or indirect public costs. Preserve and restore natural protective features. Maximize the protective capabilities of natural protective features by: 1. avoiding alteration or interference with shorelines in a natural condition 2. enhancing existing natural protective features 3. restoring the condition of impaired natural protective features wherever practical 4. using practical vegetative approaches to stabilize natural shoreline features 5. managing activities to limit damage to, or reverse damage which has diminished, the protective capacities of the natural shoreline 6. providing relevant signage or other educational or interpretive material to increase public awareness of the importance of natural protective features B. Minimize interference with natural coastal processes. Provide for natural supply and movement of unconsolidated materials a/Id for water and wind transport. Limit intrusion of structures into coastal waters. Limited interference with coastal process~ may be allowed where the principal pur- pose of the structure is necessary to: A-4 5.3 5.4 A. a. simulate natural processes where existing structures have altered the coast, or b. provide necessary public benefits for flooding and erosion protection, or c. provide for the efficient operation of water-dependent uses Limited interference is to be mitigated to ensure that there is no adverse impact to adjacent property, to natural coastal processes and natural resources, and, if undertak- en by a private property owner, does not incur significant direct or indirect public costs. Protect public lands and public trust lands and use of these lands when undertaking all erosion or flood control projects. Retain ownership of public trust lands which have become upland areas due to fill or accretion resulting from erosion control projects. Avoid losses or likely losses of public trust lands or use of these lands, including public access along the shore, which can be reasonably attributed to or anticipated to result from erosion protection structures. Provide and maintain compensatory mitigation of unavoidable impacts to ensure that there is no adverse impact to adjacent property, to natural coastal processes and natu- ral resources, or to public trust lands and their use. Manage navigation infrastructure to limit adverse impacts on coastal processes. Manage navigation channels to limit adverse impacts on coastal processes. 1. Design channel construction and maintenance to protect and enhance natural protective features and prevent destabilization of adjacent areas by: a. using dredging setbacks from established channel edges and designing finished slopes to ensure their stability b. locating channels away from erodible features, where feasible c. preventing adverse alteration of basin hydrology d. including by-passing methods to maintain navigability and reduce frequency of dredging 2. Use clean dredged material as beach nourishment whenever the grain size of the dredged material is suitable for that purpose. B. Manage stabilized inlets to limit adverse impacts on coastal processes. 1. Include sand bypassing at all engineered or stabilized inlets which interrupt littoral processes. 2. Manage flood and ebb tidal deltas to simulate natural processes. 3. Avoid extending jetties when it will increase disruption of coastal processes. A-5 5.5 Ensure that expenditure of public funds for flooding and erosion control projects re- suits in a public benefit. Give priority in expenditure of public funds to actions which protect public health and safety, mitigate past flooding and erosion caused by previous human intervention, protect areas of intensive development, and protect substantial public investment (land, infrastructure, facilities). B. Expenditure of public funds for flooding or erosion control projects: 5.6 1. is limited to those circumstances where public benefits exceed public costs 2. is prohibited for the exclusive purpose of floeding or erosion protection for private development, with the exception of work done by an erosion control district Factors to be used in determining public benefit attributable to the proposed flood or erosion control measure include: 1. economic benefits derived from protection of public infrastructure and investment and protection of Water-dependent commerce, or 2. protection of significant natural resources and maintenance or restoration of coastal processes, or 3. integrity of natural protective features, or 4. extent of public infrastructure investment, or 5. extem of existing or potential public use Application of these factors indicate that public expend#ure for erosion and flood control projects may be warranted in: City Island and the Throgs Neck in the Bronx, the Cross Island Parkway section of Queens, Bayville, the Asharok~n tombolo, Sunken Meadow State Park, Wildwood State Park, portions of the identified Areas for Concentrated Development, and the Maritime Centers of Port (7tester, Mamaroneck Harbor, New Rochelle-Echo Bay, City Island, Port Washington-Manorhaven, Glen Cove, Huntington Harbor, Northport Har- bor, Port Jefferson, and Mattituck Inlet. Consider sea level rise in the siting and design of projects involving substantial public expenditure. A-6