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HomeMy WebLinkAboutMattituck Creek Watershed Study Phase I 1981 MATTITUCK CREEK WATERSHED STUDY PHASE I INVENTORY OF EXISTING CONDITIONS AND IDENTIFICATION OF DEVELOPHENT OPPORTUNITIES 30 April 1981 Suffolk County Department of Planning Dr. Lee E. Koppelman Director Suffolk County Department of Planning MATTITUCK CREEK WATERSHED STUDY PHASE I INVENTORY OF EXISTING CONDITIONS AND IDENTIFICATION OF DEVELOPMENT OPPORTUNITIES Tabie of Contents Letter of Transmittal ....... Section 1 Section 2 Section 3 - Section 4 - Section 5 - Section 6 - Section 7 - Section 8 Section 9 - Section 10 - Section 11 - Land Management.. Section 12 - Results of Phase I - Findings .... - Opportunities.. · 'Introduction ........ Development Issues and Problems. Watershed Analysis ..... Zoning ...... · · Popu}ation Analysis ..... Land Available for Development . Dredging History . Marine Water Quality . Natural Resources. Groundwater.. Appendix A - Appendtk B - Special Exception ~es ...... Management Strategy for Control of Off-Road Vehicles in Coastal Areas ........ Bibiliography .............. 1 3 6 7 g 13 15 19 29 31 35 · 38 38 41 B-1 C-1 ! ! ' III ii ii Iii ii ii Section 1 - Introduction The Mattituck Inlet Advisory Com~ittee a~ting bn behalf of the'Town of $outhold, requested assistance from the Suffolk County Dept. of ~lanning. in preparing alternative design proposals for areas located on Mattituck Creek. The Director of the Planning Dept. responded to this request by letter dated 10/24/80, describing the type of assistance to be rendere~ by · the Dept. This assistance was to include the preparation of conceptual plan layouts for the use of the Com~itte~ in its formulation of a plan for the management and future development of Mattituck Creek. It was decided that the study would consist of two phases. This re- port covers the work undertaken in Phase I - Inventory of Existing Condi- tions and Identification of Development Opportunities. The report summarizes the analysis of natural resources at the study site, the identification of problems,.and the analysis of the suitability of various areas for the accomo- dation of different uses. Phase I concludes with a report of the findings, recommendations and the identification of site planning and management oppor- tunities. These are to be the subject of a review by the Committee and others. Upon receipt of the Committee's recommendations, Phase II - Design Alternatives, will be initiated. In Phase II, site plans will be prepared for a limited number of key sites and uses recommended by the Committee. The Committee has assisted the Dept. by providing natural resource in- ventory data and descriptions of various development problems in the study area. The Co~ittee also organized a day-long field trip to the site on 1/21/81. The trip enabled the Dept. staff to familiarize itself with site conditions and to.interact with various officials and interested parties. The scope of this study is limited to the Mattituck Creek watershed area 1 as delineated on the maps that accompany this report. The watershed in- cludes the primary areas that contribute runoff to Mattituck Creek. The total land area in the waterghed is approximately 2,000 acres; the surface area of ~attituck Creek is about 150 acres. References in this report are made to the following eight maps: Watershed Analysis Zoning Land Available for Development Natural Resources Aldicarb Contamination Land Management Opportunities A set of color slides and color photographs of the maps will be provided to the Connnittee under separate cover fo~ its use. 2 Section 2 - Development Issues and Problems The major development issues and problems in the Mattituck Creek water-.~ shed are summarized on the map entitled "Issues." The malor issues focus on the area adjacent to the inlet of the creek. Erosion problems are en- countered on both sides of the inlet along the Long Island Sound shoreline. The Mattituck Park District property on both sides of the inlet has been adversely affected. The Park District property on the east side of the inlet is not an, officially recognized beach, and as such, does not have sanitar~ or ocher facilities, although it is used by a limited number of people. creased usage of the public beach in this area would require significant investment in beach facilities and construction of a new road for improved access. The industrial ar~a on the west side of the mouth of the creek is occupied by abandoned oil, gas, and asphalt storage tanks, and is strewn with constructin materials and rubble. Continued use of this area by North- ville Industries' to store its maintenance barge and other equipment will pro- bably be required. Tidal wetlands abut the south side of the Park District property on the east side of Mattituck Creek. The New York State Department of Environmental Conservation intends to purchase approximately 30 acres of tidal wetland ex- tending from the Park District property to East Mill Rd. This proposed pur- chase was recently placed on a high priority list, and it is anticipated that the State will obtain title early in 1982. These wetlands are part of a site that has been proposed for residential and marine recreational development. The proposed development, known as Seb stian's Cove, was to p.roceed in three sections with a boatel/marina planned for the wetland portion. State purchase of this tidal wetland would preclude development of this section. The Town of Southold holds title to the road right-of-way at the terminus 3 of East Mill Rd. The parcel requires certain safety improvements if public access to the creek is to be maintained at'thiS location. Long Creek has been modified to some extent because of Suffolk County bridge construction activities, and dredging/drainage imProvements' An old spoil site is located at the head of Long Creek. The old bridge abutments remain, on Long Creek and have been a source of complaints from local resi- dents who report that the abutments tend to trap debris. The marina near Long Creek, now known as Matt-A-Mar Marina, has been expanded to include boat storage and maintenance activities, giving rise to concern about oil, grease, and paint residue entering the creek via runoff. Boat anchorage is provided at the head of Mattituck Creek for residen~ and transient vessels. It is ~uspected that the release of vessel sanitary waste during su~mmer contributes to water quality degradation at this location. An equipment storage yard is located at the terminus of Ba~view Avenue. This collection of abandoned vehicles is not only an eyesore, but also a potential source of oil contamination into the creek. In addition, a number of storm drains that discharge directly into Mattttuck Creek are believed to be significant contributors to surface water quality degradation in the area. Mattituck Creek is closed to shellfishing from the south shore of Howard's Creek southward to the head of the creek. Double docking appears to be a navigation safety problem in the vicinity of the Mattituck Inlet Marina. A bulkhead line could be established at this location to alleviate additional problems in the future. There has been significant subdivision activity involving lands within the watershed in the recent past. Six proposed subdivisions'in the Mattituck watershed have received approval or conditional approval from the Suffolk County Dept. of Planning. Plans for three proposed subdivisions were returned to the town for local determinatinon. Preliminary plans have been re- viewed for the "Sebastian's Cove" subdivision, which encompasses a signifi- cant portion of the creek's remaining undeveloped shoreline. No formal action has been taken on this subdivision. Six of the proposed subdivisions are "minor" subdivisions, i.e., subdivisions having four lots or less. All the proposed subdivisions contain lots of at least one acre. The following subdivisions, which are numberically illustrated on the "Issues" map, have been proposed: 1. Honeysuckle Hills Conditional Approval 19 lots 2. Minor Subdivision Conditional Approval, 2 lots Inlet East Estates Approved 14 lots f? Sebastian's Cove Review. of Preliminary Map 3 Sections Proposed for Development Minor Subdivision Conditional Approval 2 lots Mi~or SubdiviSion Conditional Approval 3 lots 7. Minor Subdivisio~ Local Determination 3 lots 8. Minor Subdivision Local Determination 4 lots Heritage Harbor Conditional Approval 10 lots 10. Minor subdivision Local Determination 3 lots Section 3 - Watershed Analysis ~.~ '~ A topographic map of the Mattituck Creek area with a contour interval of .5 ft. and a scale of 1 inch'~ 400 ft. was used to delineate the boundary of the creek watershed and to analyze drainage charactertisties. This information is shown on the Watershed Analysis map. The watershed boundary was delineated on the basis of the slope of the land, direction of groundwater flow and natural surface drainage systems. The land area within the watershed boundary is approx~mmtely 2,000 acres; this area serves as the focus of this study. Stormwater runoff from developed areas reaches Mattituck Creek either by storm sewer systems, paved right-of-ways, or by overland flow. The ~irection of flow is indicated by blue arrows on the map. Stormwater drain outlets to the creek are also indicated. The critical watershed for Mattituck Creek is indicated on the map in yellow-green and green. The yellow-green areas indicate tidal wetlands, in~lud- lng intertidal marsh, low marsh, high marsh, and formerly-connected tidal wet- lands. The critical watershed area also contains the major swales leading to the creek, streams and stream channels, the 100-year floodplain boundary, areas :of high stormwater runoff and sedimentation from upland sites, and specific priority sites where stormwater biofiltration sites and recharge basins could be located. These areas are shown in green. The areas where such best management practices for stormwater treatment are suitable are shown circled in blue. Susceptibility to water pollution and the potential future adverse environmenta,~impacts were also major factors in the determination of the critical watershed boundary. Section 4 - Zonin~ The map entitled "Zoning" shows the zoning classification of all uplandg' located in the Mattituck Creek wate~hed. Zoning information was obtained from Chapter 100 of the Code of the Town of Southold, (1978). The overwhelming majority (approximately 95%) of the acreage con'tained within the Mattituck Creek watershed is zoned "A" Residential and Agricultural. The permitted uses within this zone include one-family detached dwellings, not to exceed one dwelling on each lot containing a minimum area of 40,000 square. feet; commercial agricultural operations, and buildings, structures and uses owned and operated by the Tow~ of Southold. Uses permitted by special excep- tion by the Town of Southold Board of Appeals within this zone and the busi- ness and industrial zones discussed below are listed in Appendix A. The "B" Light Business District within the Mattituck Creek watershed is . ~limited to two areas located at (1) the head of Mattituck Creek, and (2) the intersection of C.R. 27 and Cox's Neck Rd. Approximately 1.5% of the land area within the Mattituck Creek watershed is zoned "B" Light Business. The permitted · uses within this zone include: 1. commercial agriculture operations 2. buildings, structures and uses owned or operated by Town of Southold 3. boarding and tourist houses 4. business, professional and governmental offices 5. banks and financial institutions 6. retail stores, including retail shopping centers 7. restaurants 8. bakeshops (for on-premises sale at retail) 9. laundromats and similar establishments 10o personal service stores and shops 11. marinas for the docking, mooring'and accommodation of noncommericai boats, including the sale of fuel and oil primarily for the use of boats accommodated in such marinas. Areas zoned "B-l" General Business within the' Mattituck Creek watershed represent approximately 1% of the total land area and are located along (1) C.R. 27 near the head of Mattituck Creek, and (2) Mill Rd. adjacent to Mattituck Creek. Although permitted uses within this zone are the same as those permitted in the "B" Light Business District, more uses are permitted by special exception by the Board of Appeals in this district than in the~ i"B" Light Business District. Areas zoned "C't Light Industrial within the Mattituck Creek watershed account for less than 1'% of the land area and are located (1) on the west side of Mattituck Creek south of }~ill Rd. ~d (2) adjacent to the LIRR tracks. The permitted uses within this zone include commercial agricultural operations, and buildings, structures and uses owned and operated by the Town of Southold. The Only area zoned "C-l" General Industrial within the Mattituck Creek watershed is located near the mouth of Mattituck Creek and represents approxi- mately 1% of the land area within the watershed; in the "C-i" District, build- ings and premises may be used for any lawful purpose, except that no building and/or premises shall be used for dwelling, boarding and tourist home, hotel, motel or tourist camp purposes. Section 5 - Population Analysis Estimates of 1980 population and of saturation population were prepared '~ by means of a land use analysis. The number of existing and potential dwelling units was calculated using a 1980 large scale aerial photograph that permitted identification of developed and vacant parcels and facilitated comparison of these parcels with existing zoning designations. Once the number of existing · and potential dwelling units was determined, an average household size factor was applied to the dwelling unit count in order to estimate the existing popula- tion and the additional population that could be accommodated in new units. This potential population increment together with the population that could be accom- modated in currently existing vacancies was added to the estimated 1980 peak population figures. The following paragraphs describe the step-by-step procedure used in the population analysis. Step 1. Step 2. Step 3. 1980 Population Estimates The ~atershed boundary, U.S. census tract (C.T.) and enumeration district (E.D.) boundaries, and Town of Southold zoning designations were superimposed on a 1980 aerial photograph for study purposes. The entire area lies within E.D.s 342T, 343T and 343U, in C.T. 1700.01. Since, however, the census tract and enumeration district boundaries were.not contiguous with the ~atershed boundaries, the Census data could not be utilized to calculate population estimates. Using tax map information, developed residential parcels were identi- fied and tabu.lated. ,..?~ In order to estimate the number of vacant and occupied households, the, 1980 Census vacancy rate, including units "vacant for sale or rent" but not seasonal or "held for occasional use," was applied to the Step 4. Step A. total number of residentially developed parcels. By subtracting the vacant units thus derived,from the total potential units, number of occupied 'and seasonal units was calculated. the Housing unit counts were multiplied by the appropriate 1980 pre- liminary Census count average household sizes to obtain the i980 population estimates. Saturation Population Utilizing the information in Step 1 described above, vacant residential and agricultural land parcels were identified. 'Step B. A factor of one unit per 40,000 square feet, as required for Residential ~.~ "3." in the present zoning ordinance, was used to calculate t'~e potential dwelling units which could be accommodated on the vacant one to three ~ acre parcels. The computation of the potential yield of unsubdivided ].and parcels greater than three acres in size was accomplished through the application of a yield per acre factor (0.8 lots per acre for a zoning lot size of 40,000 square feet as required in the watershed area). This factor is derived from a table of factors 'representing average values based on Long Island Regional Planning Board experience with conventionally designed subdivision plats. purposes, the saturation figure would have to be adjusted. Recent observations suggest that the pattern of rezoning on Long Island has become relatively stable. Changes to a higher density are often off- The saturation estimate is based on existing zoning, so that if land were to be zoned for a higher or lower density, or .acquired for public set by other changes to a lower density or by a land acquisition, thus minimizing the impact of any change in the ultimate saturation calcula- tion. 10 Step C. Average household sizes, based on 1980 information, were developed for the entire study area. These were applied to the unit counts including currently vacant units, to estimate potential saturation · population estimates. Step D. Potential housing and population counts were added to the figures estimated for 1980. The resulting numbers represent saturation esti- mates for the Mattituck Creek watershed. The results of the population analysis are shown in Table 1. In 1980 the total seasonal and year-round population in the watershed area was 2,433. A total of 784 seasonal and year-round occupied units were located in the area, · and there were 1,092 vacant lots in the watershed on property zoned for residen- tial use. Based on existing zoning, the saturation population for the watershed area is 6,189 - an increase of 3,756 over the 1980 population level. The total ' ~;/, 876 ' of dwelling units increases to under saturation development condi tions. The 1980 population density for the watershed area as a whole is 1.2 people/acre. At saturation development, the population density would be 3.1 · people/acre - appproximately a three fold increase. 11 Table 1 Population Analysis of the Mattituck Creek Watershed 1980 saturation Dwellin8 Units* Population Estimates** 784 2,433 ~ 1,876 6,189 ~ * Includes seasonal and "held for occasional use°" · *Includes seasonal Section 6 - Land Available for Development Residential uses dominate in the Mattituck watershed. The current zoning ordinance mandates a minimum reS~dential lot size of 40,000 sq. ft., or slightly less than one acre. Developable land in the Mattituck watershed can be assigned to one of three categories: vacant plots of less than two acres scattered among existing residen~tial development; parcels greater than two acres; and parcels under individual commitment and/or included within the agricultural district as provided for in the N.Y.S. Agricultural Districts Act. Based on current zoning, which requires a minimum lot size of 40,000 sq. ft., a parcel of less than two acres cannot be subdivided, whereas one of two acres or more has the potential for subdivision. Parcels smaller than 40,000 sq. ft. can be de~eloped if their creation predates the zoning ordi- ance. However, an owner of two or more contiguous substandard parcels may not develop each parcel separately but must conform to the existing zoning. Farmers who own and operate a 10 acre or greater parcel of farmland are eligible to place their farmland under individual commitment, and thereby re- ceive an agricultural value assessment'. The owner signs an eight year commitr merit each year. If the owner fails to refile a commitment form with the town assessor, he loses eligibility for the agricultural value assessment but is bound to the terms of the commitment for the remaining seven years. If the owner converts land to non-agricultural use, he must pay a penalty equal to twice the tax based on full value assessment of all the land under commitment (not Just the land converted). Farmers who own and operate a 10 acre or greater parcel of farmland can form an agricultural district containing at least 500 acres, and thereby be- come eligible for an agricultural value assessment. Several parcels of farm- land within the Mattituck Creek watershed are included within the agricultural . district in the Town of Southold. The agricultural district was created in October, 1979 and has a duration of eight years. The owner of a parcel with$n t~e agricultural district must apply to the town assessor for the agricultural value assessment each year. However, if the owner converts land to non-agricul- tural use, he must pay a rollback tax of up to five years in value on. the land converted provided the owner has received the agricultural value assessment. The map, "Lands Available for Development," is based on an analysis of 1980 aerial photography, a map of agricultural district properties, parcgls under individual commitment, and existing and proposed subdivision plats. This map shows that over half of the watershed area (1,215 acres) is still available fordevelopment. Developable land includes approximately 345 acres in the agri- cultural district and/or under individual commitment, 211 acres of vacant plots scattered among existing ~esidential development, and 659 acres consisting of parcels greater than two acres, which could be subdivided. 14 Section 7 - Dredgin~ History The history of dredging in }~ttituck C~e~ recounts the story of a port whose cour~ercial potential was never realized.. The natural inlet, which was narrow, crooked, and only 2 ft. deep at low water, prevented significant commerce from developing, ~although by the late 1800s a small amount of fertilizer was received, and potatoes and other farm products shipped. In 1890, in response to local requests the Army Corns of Engineers first surveyed the creek for possible improvements that might facilitate the provision of a cheap waterborne alternative to the Long Island Rail- road for transportation to New York City; allow increased commerce with Connecticut; and provide a harbor of refuge. In 1896, the Congreps approved the dredging of a seven ft. channel and the construction of two jetties. Work on one of the jetties began in 1901. The firs~ dredging occurred in 1907 and extended south to the mill dam at Waterville, where East and West Mill Roads now end at the creek. The dam closed the channel and a highway crossed over it; the tide gates were usually kept closed to create slack high water in the upper basin; when open, the highway practically closed the channel so that a rowboat could not pass under it when the tide was more than half up. The dam limited the tidal range in the upper basin to 1-2 ft., compared with the 4-5 ft. range at the inlet and Long Island Sound. Local interests were required to replace the dam (and causeway) with a draw bridge, which they did around 1914. The southern portion of the channel was dredged in 1914, and the entrance was extensively dredged for maintenance purposes in 1921, 1923, and 1927 (see Table 2). Commerce, however, did not grow as expected, in part because of the difficulties of maintaining the channel. During the ~arly. 1920's receipts and sbipments ~ and out of ~ttituck by water were still an order of magnitude less than the amount transported by rail. By 1925, the costs of maintenance dredging~and requests from local interests prompted Congress to authorize another study of the creek. The channel between the jetties was shoaling rapidly after maintenance dr~dging; project depths were available for less than one year, on the average, after dredging. The shealing was believed to be caused by heavy material (sand and gravel) being driven into the inlet by the action of storms from the northwest. Additional material was thought to be working its way aroun~ the west jetty due to longshore drift; ebb currents within the inlet were sufficient to remove these shoals or pr ent their accumulation. The pro- posed solution was a 250 ft. extension of the west jetty to the 12 ft. contour in the Sound; this impro*ement was completed in 1938. ~: Channel maintenance problems were not the only factor inhibiting com- mercial development within the creek. Dockage space and storage facilities were limited. The County maintained a 70 ft. bulkhead at the foot of Bayview Avenue at which farm products were shipped, and James Rambo owned an open pile pier at the extreme southern end of the creek at which farm products were shipped and sand and gravel were received. When surveyed in 1928, however, no oil companies expressed interest in establishing water deliveries of gaso- line to Mattituck. Thus requests from local commercial interests in the late 1920's to increase the channel depth were rejected by the Corps, since the benefit vs. cost of the project was already in question. Nevertheless, the entrance channel was maintenance dredged in 1935, 1938, 1946, 1950, 1955, 1961, and 1965 (see Table 2). The shoaling rate at the inlet channel during this p~riod waa on the order of 6,000-7,000 cubic yards per year. By the mid 1960s commerce witbin the creek had changed, and shipments Table 2 History of Federal DredRinF,, llattituck llarbor, New York FISCAL DREDGING yEAR DATES 1907 1922 3un-Nov 1921 192]' Aug-Sept 1923 1928 Sep-Oct 1927 1936 Nov 3$-~ay 36 1939 Sep-Nov 1938 19&7 Sap-Nov'IgC6 1951 Oct-gov 1950 1956 Aug-Sap 1955 1962 AuE-$ep 1961 1966 Sap-Oct 1965 D~PTH LOCATIOI~ OF SPOIL MAINTENANCE TOTAl,' coST(S) 1000 (FT.) LOCATION OF WORX DISPOSAL AREA QUANTITY CY* COST PER C'Y* p~R HONTH 7' Inlet to dam 7' Dam to head Shoals at entrance From 500'-1400' up- end of west Jetty Entrance channel 7~ 18001 of entrance channel 7I 71 ~ntrance cbanne~ 71 _~ Entrance cheneel ~ Entraoce channel 7~ Anchorage area end upstream end o~ channel (gev work) (New work) ** 13,~68 $7,131 .$3 2.2 (15,&68) co~c~ox(c) OR COVE~'~ ** &9,~00 $21,561 ** ** e* ** 49,186 $23,721 .48 2.5 GP ** 50,785 $22,2~7 .4~ 7.2 C ** 18,312 $8,102 .~ 6.1 C On beach, east of 53,893 $62,099 .78 18.0 C the east Jetty (78,893) On beach, east of 22,913 $1a,190 .62 11.& C the east Jetty (2a,613) On beach, east o~ 31,552 $30,292 .96 15.8 C the east Jetty On beach, east of &3,550 $35,282 .81 1&.5 the east Jetty (89,662) Upland disposal (Ne~ work) $65,070 $1.59 20.5 C et Long Creek &0,980 (71,026) 1966 Sep-Oct 1965 7' Long Island Sound On beach, west of 6,285 $7,288 $1.16 to Old Kill ~oad the west Jetty (12,39~) 1980 May 9°25, 1980 e* Entrance channel On beach, east of 2&.137 e* ** the east Jett~ : Date not evallable 3.1 C * C¥ (cubic yards) Ymintenance quantity in parenthesis fgom Ken Ulrich, USACE, N.Y, Distrlct (~Ltten co~mznictatiou~. 1977). now consisted almost entirely of petroleum products, including gasoline, fuel o~l, and asphalt. In response to requests from local interest, a 460 by 570 ft. anchorage area at the head of navigation was dredggd in 1965. The County of Snffolk provided the 50% local matching funds r~quried by the Corps; an upland spoil site on the south side of Long Creek was provided ~y the Town ~f Southold. This spoil site was also used in 196~ when the County dredged Long Creek in order to'improve tidal flushing. The Jetties were repaired around 1975; the last maintenance dredging at the inlet occurred in May 1980, at which time approxi- mately 24,000 Coy. of material were removed and deposited on the east side of the inlet (see Table 2). Petroleum deliveries were discontinued in the early 1970's but were resumed briefly around 1978; oil terminal facilities/on the creek have since been abandoned. Only a limited amount of fish and shellfish products are ipresently landed. Today the life blood of the creek is not commerce, but recreational boating and the associated commercial facilities. Marine commercial facilities include 4 marinas (with a total of over 200 slips) and a waterside inn;. a public park with slips and a launching ramp is located at the head of the creek. The Coastal Zone Management Plan developed by the Long Island Regional Planning Board recommended that the existing channel be maintained by the Corps (and.~ possibly d'eepened to 8 ft. or more) to provide a harbor of refuge, to support the regionally significant recreational boating industry, and to enhance the potential for expanded commercial fishing facilities. Section 8 - Marine Water Quality This section is based upon published reports dealing with marine water quslity in the Long Island Sound region and data supplied by regula- tory agencies. While Maftituck Creek has never been the subject of an in- tensive water quality study, the general processes affecting water quality trends in the creek can be inferred from the body of knowledge developed from the study of similar water bodies at other locations. In this section, use will be made of the various data in Table 3 describing the physical aspects of Mattituck Creek. gater Quality Considerations in Mattituck Creek Basic to the discussion of marine environmental quality in M~ttituck Creek is the assumption.that the abundance of dissolved oxygen is the factor controlling marine life and basic chemical reactions. Therefore, anything that decreased the dissolved oxygen results in a deterioration of environ- mental quality. Dissolved oxygen concentrations can be diminished by dis- charge of oxygen-demanding wastes or indirectly by the discharge of nutrients (phosphates and nitrates) that can cause an increase in the abundance of phytoplankton or other algae that consume dissolved oxygen when they decompose. Phytoplankton growth in estuaries is often limited by the availability of essential nutrients. In north shore coastal waters, nitrogen is likely to be the limiting element. As the concentration of nitrogen compounds in a bay increases as a result of effluent disc~'rge, stormwater runoff, or nutrient rich underflow, plant growth may be stimulated. The amount of plant growth is essentially controlled by the amount of nutrient added. Decomposing or- ganic matter reacts with dissolved oxygen. When the rate of oxygen consump- tion exceeds the rate of supply, the dissolved oxygen may eventually be used up. 19 Table 3 Mattituck Creek Fact Sheet mean high tide area mean low tide area high tide volume low tide volume mean depth mean tidal range estimated shoreline length estimated groundwater discharge 21 Sept. 1938 storm surge height base flood elevation used in the National Flood Insurance Program 0.2 square miles 0.1 square miles ~ 0.3 billion gallons 0.1 billion gallons 5.2 feet 4.9 feet 7.2 miles 5 million gallons/day 5.5 feet above mean high water 11 feet above mean sea level 2O E, E L The process caused by excess nutrient discharges resulting in high levels of productivity and subsequent depletion of dissolved oxygen is called '~- eutrophication. A generalized picture of water quality changes in the region over the course of a year can be constructed from data collected in Long Island Sound. These trends are no doubt reflected in the waters of Mattituck Creek. The surface and bottom water temperatures vary from 0° to 25°C (32° to ?7°F). The surface layers begin to warm in February and remain 2 to 3°C warmer than Zhe bottom waters 6ntil August or September when surface and bottom tempera- tures are identical. Surface cooling and fall storms destroy this stable condition. These seasonal changes in physical properties are mirrored in changes in nutrient abaundance and disMPlved oxygen concentrations. Thus, after the onset of phytoplankton production, usually in the form of an intense burst of growth known as' a bloom in February and March, the concentrations of nitrogen compounds (primarily nitrate) and phosphate in surface waters remain low during the summer. Low light intensity causes a decline in phytoplankton production during the fall. Nutrient leyels in the bottom water are high because of the decomposition of organic matter. Winter storms cause mixing of the nutrient-~ich bottom waters with the surface water, thus restoring high levels of nutrients in the entire water column. Dissolved oxygen concentratio~s are depressed during the summer as organic matter decomposes in the bottom waters. The stratification of the waters with the warmest waters on top prevents resupply of dissolved oxygen from the surface, from the atmosphere, or from photosynthesis.' When the waters are mixed in autumn, the dissolved oxygen concentrations in the bottom waters increase markedly. 21 In addition to the seasonal changes in Long Island Sound which are .~.inevitably impressed upon Mattituck Creek~ ~anges in nitrate and nitrate concentration occurring in ~he creek are also ~ue to nutrient additions from the watershed. Ammonia, is not common in Sound waters; therefore, it appears that its abundance in the creek is primarily the result of the decomposition of organic matter or the release of dissolved nutrients in sediments. With more information than is now available, it should be possible to construct a picture of the seasonal changes in the physical and chemical properties of Mattituck Creek. Departures from the "norm" could then be detected. Circulation in Mattituck Creek The classical pattern of estuarine circulation has been documented in Long Island Sound and probably occurs to some extent in Mattituck Creek.~ Tidal currents generally dominate water circulation in bays and obscure the estuarine circulation. Careful measurement of tidal currents in estuaries reveals that the ebb currents start earlier, persist longer, and generally have higher speeds at the surface than near the bottom. Conversely, flood currents dom.inate near the bottom. When these tidal currents are averaged, the estuarine circulation is usually obvious as a net seaward movement near the surface, and a net landward movement near the bottom. In coastal bays and creeks, ~articles in the'near-bottom waters are' moved landward because of estuarine circulation. Thus, particles can move from the Sound into Mattituck Creek.. In general, these particles are de- posited near the landward end of the bottom layer (sometimes called a salt wedge because of its general shape). .~rticles settling out of the surface layers are likely to have the same fate;, namely, deposition near the head of the creek. Larger particles carried by streams or runoff to the creek will h usually be dc~osited in this same area. ~ Because of the effect of estuartne circulation on particles, any dis- solved substance that is not involved in biological activity, such as common 'salt, will tend to move with the surface waters, becoming more dilute and dispersed as the surface layers flow se~ward. The substance is not retained in the estuary. Nutrients and other substances that are used by organisms tend to accumulate in bays. Nutrients are assimilated by organisms growing in the waters'and are incorporated into ceil'matter or skeletons. ~hen these or- ganisms or their predators die, they sink to the bottom and decompose. Nutrients released to the near-bottom waters move landward. EventuallY, the nutrients return to the surface layers and the cycle begins again. This process is not completely efficient. Some nutrients escape with the surface waters. Others are deposited and remain with sediments where they are eventu- ally buried. ~'~ In short, the circulation pattern in bays and creeks may not dilute and disperse' wastes containing particles or nutrients. Because of the estuarine 'circulation, both tend to be trapped in such areas. Water circulation in Mattituck Creek is dominated by the tides. Fresh- water discharge (direct stream runoff plus ground water seepage) is small compared to the total volume df th~ creek. Therefore, the circulation is basicallyan exchange of water between creek and Sound. During each tidal period (12.'4 hours) a volume of water equal to the tidal prism (high tide volume minus Iow tide volume) of the creek is exchanged with t~e waters of ~ong Island Sound. The tidal prism of Mattituck Creek is 0.2 billion gallons. One measure of the amount of time required to flush a dissolved substance from a bay can be obtained by dividing the mean bay volume by the tidal prism. This is defined as the tidal residence time of salt water in the bay. Flushing times calculated by tidal prism theory are based on the following, ass~lmpt£ons: (1) that flood tide waters are completely mixed with the water in the bay at the previous low tide, and (2) that ebb tide waters do not return to the bay during the next flood tide. Since complete mixing does not occur, flushing times based on tidal prism theory are, at best, approximations of estuarine dilution. The tidal residence time for the creek has been calculated to be 0.6 days or about 14 hours. This suggests that tidal flow between the Sound and the creek as a whole is unrestricted. It does not, however, provide any information about isolated portions of the creek, which usually have much longer tidal residence times owing to their restricted connections with the main portion of the creek. Another measure of circulation is' apparent fresh-water displacement time. The fresh water that enters a bay from various sources is mixed with the seawater of Long Island Sound. If a,steady state is assumed, the fresh- water discharge per tide equals the rat at which fresh water enters the bay. The fresh-water volume in the bay divided by the fresh-water discharge per tide gives an apparent fresh-water displacement time. The flushing time of the pollutant is identical to the time required to remove the accumulated volume of fresh water in the bay. Fresh-water volumes can be determined on the basis of surface salinities at the head and mouth of the bays. The fresh- water displacement time for Mattituck~Creek was calculated to be 5.6 days. Sediment Deposits . Bays, harbors and creeks along the north shore of Long Island function as sediment traps of varying efficiency~ Particles originating inside a creek, ! I II ! or carried there from outside by tidal currents, are likely to be trapped within the creek. Tidal currents are weaker toward the head efa creek, so that ebb currents may.not be strong enough to sceur and suspend the particles deposited by the preceding flood and slack water., Furthermore, the landward flow along a creek bottom acts to retain particles withi~ the ereek. Sheltered from waves, the sediments deposited near the head of a creek are typically of a finer grain than those accumulating near the creek entrance. As a general rule, a bay or ereek with restricted flow is a better sediment trap than one with unrestricted flow. Along the Sound shoreline, bluff erosion is a major source of sediment. At Mattituck Creek there is evidence of active sediment transport from west to east along this portion of the Sound shoreline; sediment has accreted' over the long-term west of the mouth of Mattituck Creek. Another natural source of sediment would be materials carried in suspension by tidal currents into the creek, where the particles settle out in the quiet waters or in ad- Joining tidal marshes. In the absence of large natural sediment supplies, man-controlled sedi- ment sources dominate in the interior portions of the creek. Erosion Of building sites denuded of vegetation is most likely a significant local source. Material spilled from sand/gravel barges was probably an important sediment source in the past. Solids are contributed by stormwater runoff and storm drains that discharge to the creek. Intermittent dredging activi- ties can also be a significant cause of turbidity and subsequent siltation. Review of Available Water Quality Data Most of the }~ttituck Creek has been classified by the State of New York as "SA," indicating that shellfishing fqr market purposes and primary and se~ondarycoutact recreation are the best usages for these waters. That ,:~po~tion of Long Creek west of the County ~r~ge has been classified as "SC," '~ ~dicating that this area i~ best suited for fishing and all other usages .~except bathing and shellfishing for market purposes. The tributaries to the creek have been classified as "C" waters. TheS~ Waters are to be.used for fishing and other uses except primary contact recreation or as a source of water supply for drinking, culinary or food processing purposes. The Suffolk County Department of Health Services was contacted to ascertain the availability of any water quality survey data collected by this agency in Mattituck Creek. Some nutrient and coliform data were collected at a ~ilimited number of stations located in the creek in 1970, 1972, 1973, 1974, ! and 1975. However, the scope of sample coverage was inadequate (usually only one station was sampled) and the format of reporting the data was not consistent. From this data, it canno~'~e determined with any confidence · whether or not sections of the creek are receiving excessive nutrient loads. Elevated nitrogen levels are suspected, however, in the 'extreme southern portion of the creek. ~ ~ Water quality data collected by the N.Y.S. Dept. of Environmental Conservation (DEC) in 1967, 1968, 1969, 1970, 1972, 1973, 1974 and 1976 for the ~purposes of certifying marine war,ers for the taking of shellfish for human consumPtion were reviewed. The following statements are based on DEC survey reports. 1. The observed salinity range for the creek was 24 to 28 parts per thousand - the same salinity range found in adjacent Long Island Sound waters. It appeared that fresh water entering the creek from various small tributaries had only a minimal effect on salinity levels. 2. Mattituck Creek serves as a major anchorage and refueling stop for pleasure craft utilizing the eastern end of Long Island Sound. ~ Partially burned fuel from boats, spillage from refueling operations, the discharge of sanitary boat waste, and stormwa~er runoff were identified as potential sources of pollutiom. 3. The effectiveness of subsurface waste disposal systems that were utilized by various establishments located along the shoreline was questioned because the water table at these locations is very close to ground level. 4. Coliform bacteria levels in waters at the head of the creek ex- ceeded the standard established for certification of shellfish areas. Correlation of data with meteorological conditions indicated that rainfall and its associated stormwster runoff caused the most serious degradation of water quality. Total coliform counts generally in- creased an order of magnitude after a significant rainfall. There- fore, water quality during rainy periods was considered the "worst condition" as compared to that occurring during fair weather. 5. The elevated total coliform counts found at the head of the creek were "most probably caused by naturally occurring organisms being carried from the adjacent farmlands to the creek by runoff."* This conclusion was substantiated by the failure to identify by field survey any direct source of fecal contamination to the creek, and by the low fecal coliform levels detected in the area. ~'t~present, about one quarter of the to~,a~l' creek - 30 acres -.is closed for the taking of shellfish. Bathing, however, is not prohibited in any portion of the creek. * N.Y.S. Dept. of Environmental Conservation, Matt~tuck Inlet Shellfish Growing Area #30 1974 Survey Report, p. 4. An interoffice memorandum prepared in 1966 by the Marine Fisheries Sanitarian of the N.Y.S. Conservat~o~:,~Dept.~ indicated that extensive dredging Operations conducted in Mattituck Creek in the early 1960's "resulted in such a serious depletion of shellfish that local baymen and residents report that it is impractical to try and harvest shellfish f~r commercial purposes from any areas in the creek."* Reference was made to the fact that previously, the creek had produced quantities of hard ~clams~ that supported a limited commercial fishery. Since the creek at that time no longer supported substantial quantities of shellfish, it was Iisted as "non-productive" by the State. It was pointed out, however, that the area could again become productive depending upon the success of new clam sets. Quentin R. Bennett, Marine Fisheries Sanitarian to David H. Wallace, Director N.Y.S. Conservation Dept., 22 June 1966. Section 9 - Natural Resources '. Natural resources include the'following ~hysical'and biological environmental resources: dunes, beach, bluffs, surface waters, forests, wetlands, farms, oldflelds, maritime vegetation spoil sites where eesaional vegetation occurs or is developing, and prime wildlife areas. The ~attituck Creek watershed has a rich diversity of natural environmental resources within its tidal wetlands and coastal uplands with close 'associa- tions between the two ecosystems (See map entitled "Natural Resoureea.") Farmlands (cultivated lands) exist both to the west and east of the creek 'with bluff and dune formation on Long Island Sound. Prime wildlife areas were identified for the land within the boundary. Prime wildlife aress inhlude those sites that contain sizeable areas of diverse vegetatiom with sufficient~.~rotected habitat. One of the Prime Wildlife.Areas within this study area is located along the Northeast sec- tion of the creek. Another area of importance to breeding wildlife popu- lations exists on the tidal marsh island owned by the Town of Southold in the middle of the southern end of the creek. A third area, the shore and uplands of Long Creek, is located in the eastern side of the study area. The identification of these areas was~based upon staff analysis and on formation pertaining to Prime Wildlife areas.contained in the NYS Depart- merit of Environmental Conservation, Division of Fish and Wildlife report, ~_~_reas of Particular Concern to the Preservation and Maintenance of Fish and Wildlife Populations in the Coastal Zone of Lon~ Island (1976). The saltwater wetlands (intertidal marah, high marsh and formerly connected tidal wetlands) were identified from the NYS Department of Environ- mental Conservation'a Tidal Wetlands Aerial Photograph Maps (197~). Dredge spoil areas were also identified from this map series. Areas of maritime flora, those areas that have some vegetative type of low shrub- like growth specifically associated with tidal or shore areas, and dune .and bluff lines were ide~tified by aerial photographic interpretation. Sandy areas which were adjacent to coastal areas, wetlands and maritime flora were classified as beach. Channel boundaries and depths were deter- mined from the U. S. Army Corps of Engineers' survey of Mattituck Harbor (i975). Farmland and oldfields were identified from aeriai photographs. The farmland category included lands primarily in agricultural use (cleared land, furrow marks); the oldfield categories are those areas that either ha~e not been in agricultural use for some time or have been partially cleared, with no apparent use. Areas of residential, industrial or com- ~mercial use and boating or recreational areas were designated as developed, and were classified as such. Section 10 - Croundwater The hydrogeologic conditions .found on the North Fork of Long Island play a critical role in the'ability of the area to accommodate more in- tensive land use and population increases. Local groundwater availability and~uality are crucial limiting factors on the nature and extent of develop- ment in any area that is virtually devoid of surface water resources and un- able to "import" from elsewhere. Available groundwater supply is limited by the extremely shallow aquifer found on the North Fork and by an annual average natural recharge of about 15 inches of precipitation per year. ~ >~The potable groundwater resource of the North Fork lies almost exclu- sively within the upper glacial aquifer. Naturally occurring saltwater is found in the deep aquifers below the North Fork. Thus, tapping the deeper aquifers as a solution to both water quality and water supply problems is not~'a viable alternative on the North Fork as it has been in western Long Island. The water table elevations on the North Fork are quite low, ranging from sea level to 10 ft. above mean sea level. Three salt water inlets (Mattituck Creek, Hashamomack Fond, and Dam Pond) and adjacent marshlands and inlets .divide the North Fork into four partially or completely separate island-like. hydrological areas. The first of these hydrological areas stretches from the western boundary of the North Fork to Mattituck Creek. This is the area of highest water levels on the North Fork with an elevation of 10 ft. above mean sea level in the central portion. In general, the water table aquifer on the North Fork decreases in elevation toward the east and towards both shores. The next hydrological area to the east, bounded by Mattituck Creek and Nashamomack Pond, has a high water table elevation of only 6 ft. above mean sea level. The two easternmost areas of the Fork, between Hashamomack Fond and'Dam Fond and from Dam Pond to Orient Point continue this trend with highest water table . elevations of only 4 ft. above mean sea level. These water levels have significance with regard to groundwater quality and development on the North Fork. The natural iow groundwater heads indi- cate that an extremely limited amount of pumpage can take place on the Fork before serious salt water encroachment will occur. The high water table elevations within most of the Matti'tuck watershed do not exceed 3 ft. above 'mean sea level. The highly permeable soils found on the North Fork not only allow for rapid groundwater recharge, but 'also permit relatively rapid transport of surface pollutants to the upper glacial aquifer. Significant pollution dis- charges could remain largely unchanged in concentration within the upper glacial aquifer for years because of the very slow flow of groundwater. Con- taminants entering the groundwater system near the center of the four hydro- !logical areas on the North Fork tend to remain in the ground water much longer than those entering near the shoreline. Current groundwater quality problems existing on the North Fork stem in part from high concentrations of chlorides, nitrates and pesticides. High chloride concentrations on the North Fork due to naturally occurring salty groundwater or salt water intrusion are found in several near-shore areas. ,The North Fork is surrounded on thr~e sides by salt water amd its fresh water supply is thus in contact with salt water along the entire peri- meter of the Fork. As stated earlier, salt water also occurs beneath the fresh water, with the fresh water floating on the salt water body. It is primarily the pressure of the fresh water column that dete=mines the level and location of the salt water body. Thus, decreasing this pressure through extensive pumping could cause both lateral and vertical salt water encroachment. 32 The assumed salt water inferface elevation ranges from near sea level at the near-shore areas and in the vicinity ~f zhe salty surface water bodies to'~400 ft. below sea level in the center of the western part of the Fork. The aquifer is generally shallower towards the east along the Fork° The groundwater under a large portion of the North Fork that is used for farming contains excessive concentrations of nitrates from agricultural ferti- lizers. Specifically, these areas are located in the northern half of the Fork to the east and west of Mattituck Creek and in the extreme eastern end of the Fork near Orient Point. Domestic septic tanks and cesspools do not appear to be a source of excessive nitrates at the present time. The pesticide aldicarb, which is a highly toxic carbamate pesti6ide man- ufactured by the Union Carbide Corporation under the trade name of Temik~ was detected in groundwater in eastern Suffolk County in August of 1979. The heavy reliance of Temik by potato farmers to control the golden nematode and the Colorado potato beetle and the consequent groundwater contamination led to the conduct of an extensive monitoring program by the Suffolk County Department of Health Services to determine extent and severity of the aldica~b problem. ©vet 8,000 water samples were col%e~ted and tested from East End wells. The results of the analysis indicated that water from approximately 13% of the wells exceeded the recommended guidelines of 7ppb; and, from another 13% of the wells contained traces of aldicarb ranging from 1 to 7 ppb. Of the 984 wells in the Mattituck area that were sampled for aldicarb contamination, 121 wells (12.3%) had concentrations of aldicarb in excess of 7 ppb and an equal number of wells ]lad concentrations of aldicarb between 1 and 7 ppb. The map entitled, "Aldicarb Contamination Recorded Within Private Wells," shows the approximate location of private wells within the Mattituck Creek watershed tlmt contained concentrations of aldicarb. As a result of the findings, Union Carbide offered to install granular activated carbon filters in -those homes whose water supply contained levels of aldicarb contamination above the recommended guidelines. Filters have been installed in over · '1,000 homes. The treatment units are effective in removing the aldicarb from the water supply. Although this action alleviated the immediate pro- blem by providing potable water of acceptable quality to the affected com- munities, it can only be considered as an interim solution to a long ter~ problem of groundwater contamination by pesticides such as aldicarb. Section 11 - Land Management Future development within the watershed-,s~ould be subject to review to determine impacts upon tile qhality of creek waters, limited groundwater supply,. and existing development. The To~ of Southold can protect marine water qual- ity, preserve groundwater supply, maintain open space and protect wil'~life habitat by implementing the management strategies developed for use in con- 'Junction with the land classifications found on the "Land Management" map. Site development guidelines can be prepared for use by the Town in its over- .sight of lot development. Minimum standards for site development can be enforced through inclusion in Town requirements for the issuance of building permits and certificates of occupancy. / This section discusses measures %~t can be employed to m~nimize adverse environmental impacts related to development located within the four categories shown on the Land Management map. The four categories include: Critical Watershed (shown in grass green and dark green on map), Primarily Undeveloped Properties (shown in yellow-green), Prime Farmland (shown in beige), and Developed Areas (shown in yellow-gold). Critical Watershed* - The critical watershed area depicted on the Land Menage- ment map includes developed areas, undeveloped areas and the following resouces: tidal wetlands, low marsh, high marsh, major swales leading to the creek, stream channels and the 100 year-floodplain (defined as land areas with a one percent chance of being inundated with water in any given year). It is the area that directly contributes stormwater runoff and sediment from various *~en a property overlaps one or more of tile above categories, Critical Watershed, Prime Farmland, etc., the recommendations for each category apply to that portion of the site within that category as indicated on the Land Management map. upland sources to the creek and includes priority sites where stormwater filtration and recharge basins should be located. ~e sites where the depth"' tO the water table is shallow will require special controls to minimize im- pacts on the water quality of the creek, as well as danger from flooding. The basic concept for this zone is conservation, which allows for confrolled, minimal development and for preservation. The tidal wetlands, the relatively undisturbed areas immediately adjacent to the creek, the major swales reaching the creek, and the dunes at the north of the study site should be preserved. All other properties within the area are in the conservation category. Developed properties already exist within the critical watershed area. The recommendations for developed properties 'include maintenance of existing natural vegetation, limitation of the creation of additional lawn area, and minimization of stormwater runoff. Limiting factors such as available potable water and ~the need to minimize additional impacts upon Mattituck Creek must be considered in determining the nature and locatiou of future growth on the undeveloped land area within the critical watershed. Future pumping from new wells'within this critical water- shed area can result in increased salt water intrusion and loss of nearby '~ells. The issuance of building permits for development of the vacant pro- perties within the critical watershed area should be contingent upon the sub- mission of detailed site plans indicating measures designed to mitigate adverse impacts. Issuance of a Certificate of Occupancy Should be contingent upon the installation of permanent stormwater and erosion control measures at the site. Certain properties within the critical watershed area should be a~quired for natural or structural stormwater control measures. Measures are needed to prevent flood damage to dwellings located within'the 100 year-floodplain. D~eveloped Areas - These argas include d$~loped parcels located outside the 'F ,[ [ critical watershed boundary. The recommendations for these properties include r~ductton of fertilizers, herbicides and pesticides use, elimination of excess lawn*~area, and maintenance of natural vegetation. ~'~ Primarily Undeveloped Properties - The lands included in this category require conservation measures to protect groundwater and the water quality of the creek. These areas also contain prime farm soils that should be conserved. The erosion potential of these lands is relatively high and development proposals should include erosion control measures. The approval of subdivision plats and the issuance of building permits should be contingent upon presentation of evidence that plats or site plans have been designed so as to minimize undesirable en- vironmental impacts. The issuance of a Certificate of Occupancy shouZd be com- .tingent upon satisfactory installation.of stormwater and erosion control measures. Prime Farmland - It is recommended that the prime farmlands remain in farmland usel If a property contains both prime farm soils and other farm soil acreage, development, if it occurs, should be located on the least productive soil. Section 12 - Results of Phase I FINDINGS Development problems at Mattituck Creek involve questions of public access, facility development and the relationship of facility use to environmental quality and resource degradation. The Tow~ of Southold is facing immediate development issues concerning the use of tidal wetlands and sites previously used for industrial purposes. The environmental quality of Mattituck Creek could be adversely impacted depending upon the type and extent of new development along the shoreline areas of the?reek. New development in the upland portions of the watershed and higher levels of usage of creek waters for boating activity could exacerbate the existing water quality problem in the southern portion of the creek. The Mattituck Creek drainage basin encompasses 2,000 acres of upland area. Ten subdivisions located within the watershed involving 63 lots for residential development are now at some stage of the planning review process. Within the watershed there are 345 acres of land under individual commitmen~ and/or included within the agricultural~ district, 211 acres of vacant plots scattered among existing residential'" velopments, and 659 acres of land con- sleting of parcels greater than two acres which could potentially be subdivided. These lands, totalling over 1,200 acres, could be subject to development in the future. ~ Most of the land in the watershed is zoned Residential and Agricultural. ltowever, significant areas along the creek shoreline have been designated as Light Business, General Business, L~ght Industrial and General Industrial. The wide array of uses permitted in the latter categories is regulated pri- marily by special exception permit procedures. The 1980 estimated total seasonal and year-round population in the watershed is 2,433. A total of 784 seasonal and.year-round occupied units are now located in the watershed area. The 1980 population density for the watershed as a whole is 1.2 people per acre. ~the~estimated saturation population for the watershed is 6,189. The total number of dwelling units could increase to 1,876 under saturation develop- ment conditions. The estimated population density would be 3.1 people per acre, Based on the existing zoning, Growth in the Mattituck Creek watershed is groundwater limited. Ground- ~ Water pollution from nitrates, saltwater intrusion and pesticides has al- ready necessitated the closure of private water supply wells within the ~.Watershed% Future growth within the watershed should be limited/controlled '~to assure the continued viability of the local groundwaters for potable water supply. An intensive groundwater quality/quantity study has not been completed for the Mattituck Creek watershed. Water quality in Mattituck Creek/~s primarily impacted from nutrients and'other pollutants carried in stonnwater runoff and from septic tanks located in the critical watershed area that directly borders the creek. Fa~m- iand, roads, and lawns are believed to be the primary sources of the pollut- ant loadings from stormwater runoff. Existing pollutant loadings in several locations need to be reduced so that water quality in the southern portion 10f the creek can be improved. Future development within the critical water- shed area can result in further degradation of the water quality of Mattituck Creek, and, therefor% additional development controls are needed to minimize further impacts upon the creek. The Mattitnck Creek has a rich diversity'of natural resources including prime agricultural soils, tidal wetlands and prime wildlife areas. Develop- ment, if allowed to occur, would threaten certain of these resources. An intensive water quality study has never been made for Mattituck Creek. General water quality conditions ia }~ttituck Creek can only be described in qualitative fashien. The general features of estuarine circulation cause the creek to act as a sediment (and pollutant) trap. Tidal circulation in the creek may not dilute and dispe~se nutrients'and particulate pollutants. As a result, runoff constituents, including coliform organisms, tend to be retaine~in the head of the creek and its tributaries. Intermittent dredging activities, erosion of building sites, and stormwater runoff can lead to siltation in various portions of the creek. Available water quality data is insufficient to determine whether or not the creek is receiving extensive nutrient loadings. At present, abgut 1/4 of the creek area is closed to shellfishing. Bathing is not prohibited in any portion ef the creek. Stormwater Tunoff is probably the main source of coliform pollution; other potential sources include underflow from sub- surface waste disposal systems and sanitary waste from boats. Since the beginning of the 20th century, the inlet at Mattituck Creek has been stabilized and periodically dredged by the Corps of Engineers. Federal dredging authorization was predicated on the desire to %mprove waterborne commerce in Mattituck Creek. More recently, an anchorage was provided for recreational boats. Given the significance of this creek as a harbor of refuge between Pt. Jefferson Harbor and Orient Point, it can be expected that 'the Corps of Engineers will continue to dredee to oro~ect dJ.mensi~nm as conditions dictate. At the present time, no commercial fisheries exist in the creek, al- though the creek does support a large amount of recreational fishing. OPPORTUNITIES map entitled, Development in the Mattituck Creek watershed is groundwater limited. Unconstrained development should not continue unless the conseq~encea of such development - the problems and costs associated with the effect of such development on both the quality and quantity of the water supply - are ac- ceptable to the psople in the Town of Southold. The alternative is to limit development and preserve water until additional sources of water supply are available. It is assumed that public water from the main portion of Long Island west of Riverhead will not be available to the Town of Southold within the foreseeable future. The location of the various development opportunities are shown on the "Opportunities." Opport~ty #I - Re-Usc of the Indus~_rl Area Adjacent to ~b~¢k Inlet. The industrial area consists of six parcels encompassing 13.6 acres. It is located entirely in the Critical Watershed, and groundwater supplies on-site are extremely limited. The phase out of various industrial uses in the area provides an opportunity for land reclamation and the establishment of other uses along this portion of the creek oreline. The area could ac¢onmodatea mix of recreation, marine recreation, marine commercial and various public uses, 'and as such, the zoning classification of these parcels should be modified to reflect less intensive use. This ineludes the B.6 acre par ~orthville Industries, whieh is used for dockage and the storage of equipment ~uttlized in the maintenance and operation of its off-shore oil terminal. ~se of this pareel in support of the ~orthv~lle terminal should, ho~ever, be allowed in the future as a non-conforming use. 41 Matt'ituck Inlet offers the only safe harbor on the north shore between Orient Point and Mt. Sinai Harbor. Accordingly, a commercial marina on part of the industrial area could prove an ·attraction for pleasure boats. The lo- cation of the marina could be enhanced by the provision of a private water taxi service from the marina to the head of the creek. From there, the vis~ ] itors could walk tO Mattituck's main commercial area to shop, dine or sightsee. :i~ ~ A marina at the Inlet entrance could result in increased traffic on the two'roads (Naugles and Luther's B~eakwater Roads) providing access to the Inlet area. However, the presence of a reliable water taxi service might re- duce the potential traffic increase by encouraging use of the creek itself. ~i! Public uses of the industrial area could include provision of park facili- ties that are compatible with those on the adjacent Mattituck Park District property, and the establishment of a public safety oriented facility, such as a Coast Guard auxilliary unit. Opportunity ~2 - Improveme~t of ~att~uck Par~ District Prop~t~ on ton~ I~and Sound East o~ Mat~tuck I~t. This site provides an opportunity to improve public access a~d to protect adjacent environmental resources. The temporary unimproved access road be- tween Bailie Beach Road and the east jetty should be abandoned, regraded and planted for stabilization purposes. A portion of the area occupied by this road should be utilized as a parking facility. Other facilities for the public could be accommodated at this site as required in the future. There is a need· to improve control of beach access by off-road vehicles (ORV) in this general location. town and A management plan for limiting ORV use could be implemented by the the Mattituck Park District. Suggested guidelines for ORV use are · included in Appendix B of this report, .Opportu,n.,Lty #~ _ Imp~oueme~ e~ Alat, ts.~uc~ Pa,.'tk P.L~t. ric:~ P,'tope~,t.y on L6u9 I,~aml Som~d West o,~ Ala~tue~ l~e~. ,~. Use of this site for recreational purposes and preservation of environ- · mental values can be fostered through site design .and imProvements. Site planning for the site should be done in conjunction with the re-use of the ~'adjacent industrial area. .Opportunity #4 - Town of Southold Prope~y Adjaee~ to Mat~uck Park Dist~c~ Lands at the Head of the Creek. .: ~. This parcel should be improved for the expansion of adjacent park uses . ~!and for the enhancement of the scenic corridor that is visible from County ~ ~Road 27.- ' Oppor~mity #5 - Stor~c~e~ Runoff Con~ol Sites. Seven sites have been identified as suitable for various types of runoff control projects involving biofiltration, flow attenuation, etc., which will be necessary to improve the water qua~i~y of Mattituck Creek and to prevent further degradation of water quality as vacant lands in the watershed area ::~are developed. In addition, the natural swale areas which drain, into the creek need to be preserved to prevent degradation of marine water quality. The swale at the head of Long Creek, should be preserved to as great an extent as possible in:order to protect the prime wildlife habitat found there. Oppo~nit~] #6 - Aeqttisi~on Of Tida~ (qe~_f~ands. Two privately owned tidal wetland parcels, together encompassing about 30 acres, are located along the northeast portion of the cre.ek shoreline. Both parcels have been slated for acquisition by the NYS Dept. of Environmental Con- servation under its tidal wetlands acquisition program. Title to these parcels should be secured by the State as soon as possible. Opportunity.#1 - Reduce F~t~e Develo~m ~ Impacts ~ SensL~ve Areas No~ S~ab~e ~or S~and~d Subdivision. Tile study'identified six areas where future development of standard ~ubdivisions would result in irreversible environmental impacts upon the resources of the study area. The six sites require special siting of strt~ctures, roads, lawns, septic tanks and stormwater drainage systems so ~hat prime agricultural lands~ natura~ drainage systems, woodland and other ~ensitive areas can be protected. The subdivision of the individual build- Lng:lots can be done in a manner to minimize environmental impacts and to pcotect the natural resoucces, while also protecting the scenic quality of .uhe area. Clustering of development on the larger parcels also provides an >.~opportunity ;to preserve ~he resources identified above while at the same time ~otiowing for environmentally acceptable growth. It should be noted that a ~eveloper realizes the same yield on his property when clustering, however, uhc ~patial arrangement of structures is modified in order to maintain environ- mental values. Both techniques can be used to maintain prime farmlands and to provide a buffer zone separating the tidal wetlaads and creek shoreline from future development in the upland area, from south of Mill Rd. north to Bailie Beach Rd. 0ppor~L~ ~8 - Preservation o~ Pr~le Ag~i~u,~al Lands. Preservation of approximately 490acres of prime agricultural lands (identified on the basis of prime agricultural soils) in the watershed as well as other areas in the Town of Southold should be assisted through changes in zoning classification. A special overlay district' should be created by the Tovm of Southold that would include all those areas within the Town containing prime, agricultural soils. Ail land within this overlay district currently 44 zoned Residential/Agricultural (40,000 sq. ft.) should be upzoned in accordance with one of the two following options: ~ 1. one and one-half acre (60,000 sq. ft.) zoning with mandatory clustering to be'imposed at the discretion of the Town; 65% of the acreage to remain.as open space and 35% to be developed. 2~ two acre (80,000 sq. ft.) zoning with mandatory clustering to be imposed at the discretion of the Town; 75% of the acreage to remain as open space and 25% to be developed. These options would not only preserve the prime agricultural soils, !n~t would also result in significant decreases in the saturation population of,the watershed. Under option one, the population of the watershed/would be 5,334 - a reduction of 13.8% (855 people) from the saturation population (6.189 people) under existing zoning. With option two, the population would '~e 5,040 - a reduction of 18.6% (1,149 people). 0pportu~ty #9 - 0~d Brid~e Landin~ a~ A~ Road. This site should be improved to p~v±de for public access, e.g. scenic overloo~ w~th benches, and shoreline fishing. 0pportu~t~ #10 - Prot¢~.'on o~ the Cr~¢k. t~es ~ith~n a distance of 1,500 ft. from shore (~¥$ To~ ~aw, Article ~, Sec- t~on 130, subsection 17). Therefore, the To~n o~ $outhold has authority to develop a navigation ordinance, which~could include such things as the estab- lishment of no wake zones, mooring areas, etc. Enforcement of this ordinance, especially during the summer boating season at Mattituck Creek and other town Waterways might'require additional town staff. Routine waterway patrols would provide a means for surveillance and reporting of illegal shellfishing, pollu- tion, dumping or construction activities. ~"~ Surveillance of environmental quality in Mattituck Creek should be initiated and maintained. A most val'uable cost-effective procedure appears"~ to be a detailed water quality survey in December, when nutrient concentra- tions are usually at a maximum, the waters are well mixed, and biological · ~ctivity is at a minimum. This would provide a basis for year-to-year ::omparisons of environmental quality in the creek° Surveillance should be contieued during July, August and September when environmental problems ~re likely to be most conspicuous. These surveys should include measurements of .~trients such as ammonia, nitrate, possibly ureas as well as measurements of the dissolved oxygen concentrations in surface and bottom waters. Depending ':~on the availability of funds, the sediment deposits in the creek should be · ~w~lyzed to determine which areas have been most affected by runoff, etc. in Ih~ past. Sediments should be studied at regular intervals (3-5 years) in ,,rder to monitor long-term changes. The volume and composition of stormwater runoff from roads and urban :~reas should be monitored to ascertain the magnitude of nutrient and other pollutant additions from this source to the creek. In this way the ma3or stormwater pollution sources can be identified. Based upon the monitoring data, it will be possible to evaluate the effectiveness of runoff control projects and to prioritize their implementation. Studies should be made of fish kills, "red ~ides," and debris strandings to eval~ate probable causes. A publicized telephone reporting service for citizens of the town observing unusual occurrences, such as "red tides" and fish kills, would be valuable. It is important to determine whether these highly visible (and often obnoxious) environmental problems are increasing in frequency or affecting wider areas. Eroding shorelines and upland areas should be stabilized to minimize sediment transport to the creek and the need.,,for maintenance dredging. Debris and construction equipment now stored at a site adjacent to Bayview Ave., should be removed. APPENDIX A S_peeZa~ Excep. ti0~ Uses permitted within "A" Residential and Agricultural zone by special exception by the Town of. Southold Board of Appeals include: 1. two £amily dwellings, conversion of existing buildings and.new eon- struction, not to exceed one such dwell±ag on each lot ¢outaining a minimum area of 80,000 square feet places of worship private educational institutions libraries, philanthropic, eleemosynary or religious institutions, hospitals, nursing and rest ~mes or sanitaria for general medical care, but excluding facilities for the treatment of all types of drug addictio~ 9. public utility rights-of-way as well as structures and other instal- lations necessary to serve areas within the town fraternity houses, golf courses and annual membership clubs childreu's recreational camp~s organized primarily for seasonal use labor camps boat docking facilities for the docking, mooring or aec0mmodatio~ of no more than two noncommercial boats other than ~hose owned and used by the owner of the premises for his personal use veterinarian offices and animal hospitals 11. cemeteries 12. stable and riding academies 13. funeral homes and undertaking establishments Uses permitted within tile "B" Light Business District ~y special exception '~ by ti~e Board of Appeals include: 1. all those uses permitted by special exception by tile Board Of Appeals Appendix A (8~'nt'd).,:. in the "A" Residential and Agricult.ural'District, with the exception of two family dwel%ings. 2. hotels and motels 3. tourist camps Uses permitted within the "B-I" General Business District by special ex- ,',.~ion by the Board of Appeals include: 1. all those listed under the "B" Light Business District 2. places of amusement 3. fishing stations public garages, gasoline service stations, (including partial self- service stations) and new and used car lots 5. cabinet' shops, carpenter shops, electrical shops, plumbing shops, furniture repair shops and bicycle and motorcycle shops. Uses permitted within the "C" Light Industry District by apecial exception ~"~' the Board of Appeals include: 1. industrial uses, including manufacturing, assembling, converting, altering, finishing, cleaning or other processing, handling or stroage of prodtLcts or materials, involving the use of only oil, gas or electricity for fuel 2. research, design and development laboratories; office buildings 3. wholesale storage and warehousing 4. building contractors' yards 5. public utility structures and uses 6. newspaper and printing establishments 7. bus and truck terminals (garages, parking facilities, loading docks, etc.') 8. food processing and packaging plants Appendix A (cont'd) 9. marina for the docking and mooring of all types of boats. 10. launching facilities 11. ferry terminals 12. yacht clubs; charter fishing docks 13. eating and drinking establishments 14. retail sales of boats and marine items 15. boat building; boat servicing; boat storage facilities 16. yards for sale and storage of fuel and building materials The uses listed below are permitted within the "C-i" General District only by special exception by the Board of Appeals: i. abattoirs Industrial 2. acetylene gas ~anufacture or gas manufacture from coke, petroleum or from any other storage thereof 3. acid manufacture 4. ammonia, bleaching powder or chlorine manufacture 5. arsenal 6. asphalt manufacture and asphalt mixing plants 7. blast furnace 8. cement, lime, gypsum or plaster of paris manufacture; ready-mix or bulk concrete plants and block manufacturing coke ovens crematories distillation of bones 11. 12. dwellings, all types 13. explosives manufacture or storage 14. fat rendering 15. fertilizer manufacture Appendix ~ (cont'd) 16. fireworks manufacture 17. garbage, offal or dead animals reduction or dumping 18. glue, size or gelatin manufacture 19. gunpowder manufacture or storage 20. automobile wrecking yards and all other junkyards 21. oilcloth or linoleum manufacture 22. oil, rubber or leather manufacture 23. ore reduction 24. paint, oil, shellac, turpentine or varnish manufacture 25. paper and pulp manufacture 26. petroleum refining, storage tanks. 27. potash works ' 28. rolling mill 29. rubber or gutta-percha manufacture 30. saltworks 31. sauerkraut manufacture 32. shoeblacking or stove polish manufacture 33. smelting 34. soap manufacture 35. stockyards or slaughterhouse~ ' 36. stone mill or quarry 37. structural steel or pipe works 38. sulfuric, nitric or hydrochloric acid manufacture 39. sugar refining 40. tar distillation or manufacture 41. tar roofing or waterproofing manufacture 42. tallow, grease or lard manufacture Appendix A (cont'd) 43. tanning, curing er storage of rawhides or skins 44. tobacco (chewing) manufacture or treatment vinegar manufacture 46. yeast plant 47. airports and airfields. 'the Board of Appeals, such use is not permitted in a "C-i" District except as a special exception by the Board of Appeals. ~A-$ APPENDIX B ~a~nZ S~a~¢gy for Cont~o~ o,~ O~iRoad V~c~es in Coa~a~ Ar~ Off-road vehicle usage in coastal areas should'be monitored by the relevant authorities to determine the commercial, residential and recre- ational needs for such usage, the levels of off-road vehicle travel by coastal area, the existence of conflicts with other users of these areas, and existing as well as potential damage to coastal resources that can be attributed to off-road vehicles. This information should be used to de- velop programs for managing off-road vehicle use that are consistent with the philosophy and objectives of utilizing the coastal areas in question. The programs should include appropriate regulations and penalties that are adequately enforced. Recommendations for minimizing the environmental impacts of off-road vehicle travel include the following: a. Close sensitive areas along coastal bays and lagoons (salt marshes and sand flats) to vehicle traffic. Primary dunes should be off limits to vehicle and pedestrian traffic. b. Establish and control necessary vehicle access points to the beach so as to maintain the primary dune elevation. Build wooden ramps at all vehicle crossings. Washovers and low points in the primary dune should be revegetated and/or snow fenced in order to build up these areas and prevent vehicle intrusion. Limit vehicle traffic in back dune areas to well-defined trails. These trails should be marked with borders of shrubbery, fences, posts, etc. in order to prevent vehicle departures into vegetated areas. The trail layout should avoid existing and potential blow- out sites and should be designed to minimize potential environmental damage while serving the needs and desires of the users of the area. B-1 d. Monitor trails and dune crossings. If a site exhibits continued deterioration, the trail ·and/or dune crossing at this site should be relocated. e. Limit off-road vehicle travel on the beach to the area betwegn the seaward base of the dune and the low tide mark. New·drift lines forming at the base of the dunes should be off-limits to vehicle travel. f. Prohibit vehicle access to the beach during periods of extreme high tide and active erosion of the beach in order to prevent vehicle intrusion on dune flanks. If warranted, close dangerous sections of the beach to traffic. In such instances adequate by-pass routes should be'provided. ~ .h. Identify nesting areas of least terns and other colonial birds with clearly marked signs. Vehicle and pedestrian traffic within these areas during the breeding and nesting season from May 1st to September 1st should be prohibited. Signs calling attention to the colonies should be post6~ at least 100 ft. from colony peri- meters warning pedestrians and vehicles not to approach any closer. B IBL IOGIL~PHy Division of Marine and Coastal Resources, N.Y,S Conservation Dept. Mattituck Inlet She' ..... ' - -- · ~r~sn ~rowin~ Area #30 Survey Report of 1969. Ronkonkoma, N.Y'. ~ebruary 1970. Reappraisal and survey reports for 1972, 1974, 1975 and 1976 Were al- s° consulted. Ceraghty and ~ller, Inc. H d~e°l°gy,~at~y Supply and Water Quality of the North Fork of Long Island, New York. Port W~s~iugto~, N.~.: N--~SSau-S~lk Regional--~-aanni~g ~oa-~. 1978. Gross, M.G., Davies, D.S., Lin, P.M. and Loeffler, W. ~]aracteristics and Environmental Quality_ of Six North Shore Bays, Nass-~u and Suffolk ~ Counties, Lonj' Island, New York Tech ', -- · ---- · ~rine Sciences Research Center · ~port Series #14. SUNY at Stony Brook. 1972. Malcolm Pirnie Engineers. Investigation of Wat~r R~soorces in the Town of S~ou~thold, Suffolk County, LoD~ Island New · ~ N.Y S. Of~^ ~= ~. ~-- ~ YorL. White Plains,/N.Y.: · ~= ~ r±annlng Coordination, 1967. Suffolk County Dept. of Health Services, ~rine Bathing Water Monitoring Section. Water quality data sheets for samples taken in Mattituck Creek in 1970, 1972, 1973, 197~ and 1975. Suffolk County Dept. of Health Services, Water Quality Unit. Annual ~arr~tive ~ej~or~l. Hauppauge, N.Y.: January, 1981. U.S/Army corps of Engineers, New York District· Environmental Assessment.: . Maintenance Dredging of Mattituck Harbor. June, 1976. U.S. Congress. House. Annual Report of the Chief of E-~ineers, U.S. Army, Part ~. H. Doc. 2922, 52nd Cong., 1st sess., 1891-1892. · Congress. House. Annual Report of the Chief of En~ineers~ . H. Doc. 8 (9134), 7~st Cong., 1st sess., 1929. U.$ Almay. U.S. Congress. House. ~_~port of tile Chief of Engineers, U.S. Arm¥~ 1965. H. Doc. v. 10-1, 89th Cong., 2nd sess., 1~65. Woodward-Clyde Consultants. Assessment of Geohxdrologic Conditions, North Fork andShelter Island__~o-~g Island~ Ne~ %-~r~. Denver, Colorado: ~977. Report p~epared for Nassau-Suffol~--~eegional Planning Board. Zaki, Mahfouz H. "Toxic Contaminants of Groundwater in Suffolk County." Paper presented at tile Long Island Regional Planning Board Seminar on Protection of Groundwater from Toxic and Hazardous Material, Hauppauge, N.Y.: 17 Novem~ 1980.- (in-press) C-1 MATTITUCK CREEK .¸I - ZONING ,',t MATTITUCK CREEK WATERSHED ANALYSIS IIIlmr i MATTITUCK CREEK~ T LANDS AVAILABLE FOR DE~/ELOPhlEfl! MATTITUCK CREEK .NATURAL RESOURCES I MATTITUCK CREEK : ALDICARB CONTAMINATION ~.TTITUCK (~REEK ¢ LAND MANAGEMENT MATTITUCK CREEK QPi)ORTUNITIES : . MATTITUCK CREEK Mattituck Inlet Advisory Committee Review of Mattituck Inlet Watershed Study - Phase I ~ Out of the M.I.A.C. discussions of the past year~ and Phase I of this Study there have evolved numerous concerns regarding. Natural Resources~ Zoning~ Land Management and many other issues which have been discussed .by this committee. By listing these concerns as outlined below~ it will be poss- ible to reach a consensus of concerns/recommendations that can be documented and submitted to the Town Board and L.I.P.B.. Concerns included in Phase I - Mattituck Creek Watershed Study i.e. Concern: i.e. Recommen: An intensive water quality study has never been made of Mattituck Creek that could be used to identify major stormwater pollution sources. The To~en Board request the County Dept. of Health to conduct a detailed water~qualitystudy/survey as out- lined on pages 4% & ~? of M.C.W.S,~ Phase I. ~ Concerns regarding Phase I - Mattituck Creek Watershed Study Concern: Feasiblity of Water Taxi service to reduce projected increased traffic on Nadgles and Luther's roads~ and provide visitors access to Mattituck's main commercial area to shop~ dine or sightsee. Recommen~ Concerns not included in Phase I - Mattituck Creek Watershed Study i.e. Concern: Commitment by To~ Board~ M.I.A.C.,and Planning Board to re-develop industrial properties before Phase II, Design Alternatives begins. i.e. Recommen: That an agreement between the M.I.A.C.~ T.B. and T.P.B. be made that the General Industrial Zone at Mattituck Creek is not a compatible use and zoning should be altered to reflect a less intensive use. ' On May 28th at our next meeting-$hese concerns/recommendations can be discussed and reviewed. A consensus reached on con./recomm. ~- May 28th-June ~th a draft report can be written. On June Sth at our following meeting the draft report documenting .Concerns/Recommendations can be reviewed by the committee and pending~ approval a final report of Phase I can be submitted to the Town Board.