Loading...
HomeMy WebLinkAboutStorm Water Runoff Detrimental Effects to Surface Water Quality 1994Program to Mitigate the Detrimental Effects of Direct Discharge of Stormwater Runoff to Surface Water Quality July 25, 1994 Town of Southolld TOWN OF SOUTHOLD PROPOSAL DESCRIPTION $OUTHOLD TOWN'S PROGRAM TO MITIGATE THE DETRIMENTAL EFFECTS OF DIRECT DISCHARGE OF STORMWATER RUNOFF TO SURFACE WATER QUALITY. Description of Project Location and Project Rationale: The North Fork is a narrow peninsula about twenty-five miles long. Due to its elongated shape, there are just two main east-west roads within the Town, State Route 25 and County Route 48. Of the two highways, SR 25 not only handles the bulk of the automobile traffic within the Town; it is the sole east-west link between Greenport Village and Odent Point. There are numerous locations where stormwater runoff from SR 25 is deposited directly into the Town's saltwater wetlands, creeks and bays, as well as its freshwater wetlands and ponds. Largely unfiltered, this discharge is considered a significant source of total and fecal coliform bacteria to the Town's surface waters. High coliform counts are the primary cause for the periodic and sometimes chronic closing of shellfish beds within the Town's creeks. Further, the direct discharge of storm or melt water from salted highways into freshwater ponds and wetlands may contribute to significant and detrimental salinity changes to these surface waters. Our concern is not the quantity of the runoff, but rather its quality. The introduction of freshwater via groundwater seepage and stormwater drainage is necessary to the proper and natural functioning of an estuarine ecosystem. However, pollutants in the water can have detrimental effects on estuarine flora and fauna. The Town has been addressing this problem since 1986, when an informal survey was made of the entire shorefront in order to locate all stormwater drainage pipes entering surface waters. Since then, two stormwater filtration beds have been constructed at the heads of creeks. The specially designed beds use phragmites and other wetlands vegetation to filter particulate matter from the stormwater before it enters surface waters. The locations of these projects are noted on the attached map. Of particular note is the Hobart Road project. The Hobart Road reed bed filters all the drainage entering the head of Town Creek in the hamlet of Southold. Funded jointly by the US Environmental Protection Agency and the Town, it was designed by the Town engineering and highway staffs with assistance from the Cornell University Cooperative Extension's Marine Science Division. In 1992 this reed bed facility was built by the Town's Highway department using private property over which the Town had negotiated an easement. Almost all of the stormwater runoff entering this site is from SR 25. The Town undertook this experimental project in order to bring back one of its most productive starter creeks for this shellfish. In 1990, Town Creek was closed to shellfishing by the NYSDEC. An investigation revealed that the Hobart Road drainage area at the head of Town creek was a significant source of contamination. As a direct result of the installation of the reed bed, the creek is now open seasonally, during the winter months. Presently, the Town is taking part in the development of the Peconic Estuary management program through its participation in the various committees responsible for its design and implementation. One of the many objectives of this program is to eliminate the introduction of contaminants by the direct discharge of stormwater into the creeks and bays of the estuary. Later this year, the Town will be completing its Local Waterfront Revitalization Program (LWRP). The primary focus of the LWRP is the conservation and protection of the Town's coastal waters on which two of the Town's three major industries, fisheries and tourism/recreation, depend. By way of illustration, the Town's seed clam and oyster program's average annual investment of $16,000 is estimated to yield a wholesale value of 1.4 million dollars per year. The Town intends for this proposal to supplement its own efforts. Our first priority is to address the ten sites set forth in previous correspondence to Jack Catanzaro, a copy of which follows. Description of ProJect Implementation In order to implement this project, the Town proposes specific design options for each of the ten sites noted on its Priority List of June 9th. The subsequent pages outline each project's location, a description of the proposed construction and a preliminary cost estimate. Description of Project Cost A summary of the preliminary cost estimates is provided below. More detailed cost estimate will be available after the engineering drawings are completed. Description of Project Maintanance It is expected that maintenance on State property would be the responsibility of the NYSDOT. However, if Town property or easements over private property are obtained by the Town for eventual connection with State drainage facilities, the Town would assume responsiblity for that which lies within its jurisdiction. Description of Project Goals and Benefits Implementation of this project as proposed will achieve the following goals: 1. To improve the quality of our marine and fresh surface waters by filtering stormwater runoff before it enters those bodies of water. 2. To utilize or mimic natural systems and landforms (as opposed to hard structures) in the design of stormwater retention and filtration facilities. Achieving these goals will result in the following benefits: 1. The water quality of the receiving waters adjacent to the discharge points on the priority list will be improved by the reduction in the overall level of particulate matter and pollutants. 2. The stormwater retention and mitigation facilities will present an unobtrusive, natural-looking addition to the landscape. 3. The Townspeople (whether baymen or recreational clammers) will benefit from a reduction of bed closings. 4. Improved water quality in the Town's creeks is anticipated to enhance the estuary's functioning as a shellfish and fishery resource. Implementation of this Proposal: This first-stage proposal is anticipated to take two years to design and complete construction. However, we recognize that changing or unexpected field conditions may delay this projected timetable. STORMWATER MITIGATION CONCERNS OF THE NORTH FORK The Project Rationale provides a bdef discussion of the extent of the work the Town is preparing to undertake to ensure and improve the quality of its surface waters. A more detailed treatment of the extent to which the Town may be expanding its activities in this area is set forth here. First, the Supervisor has directed the Board of Trustees, the Community Development Department, the Planning Department, the Highway Department, the Conservation Advisory Council, and the Transportation Advisory Committee to coordinate planning efforts on stormwater runoff mitigation. Second, in addition, the Board of Trustees, which owns the Town's underwater and wet lands, has a standing Shellfish Advisory Committee which works to ensure the protection and enhancement of the Town's shellfishery. To illustrate the potential economic value of that fishery alone, the Town's average annual investment of $16,000 per year in its clam and oyster seed program is estimated to generate a wholesale value of $1,400,000 per year. The Trustees and the Shellfish Committee are are updating and refining the 1986 list of runoff problem sites throughout the Town. This Committee also will be creating a prioritized listing of stormwater drainage sites that should be addressed first. This is a substantial undertaking for the Town's shoreline length (including its creekfront) is estimated to be more than 200 miles. There are more than one hundred drainage sites other than those on State Route 25 that are likely to require some remediation. Third, the Town Supervisor has met with the Commissioner of the Suffolk County Department of Public Works about the discharge sites that originate from County roads. The County Commissioner has committed his department to a review of those problem sites. Fourth, in the June 1994 Recommendations of the Town's Stewardship Task Force, the importance of the Town's surface waters to its economy and quality of life are explained. The relevant sections of that report are included here for convenient reference. TOWN OF SOUTHOLD STORMWATER RUN-OFF MITIGATION PROGRAM NEW YORK STATE ROUTE 25 PROJECT DESCRIPTIONS & PROPOSED CONSTRUCTION JULY 8, 1994 SITE # IA. HALLOCKS BAY: Route 25, 1938' East of Platt Road Existing site conditions: An existing recharge basin is located on north side of Rte.25. There is an existing road adjacent to the east side of the basin. This road contributes a large amount of run-off and silt to the problem at this location. The basin also has an overflow culvert that crosses under Rte.25 and spills into a drainage ditch that winds its way back to Narrow River & Hallocks bay. Easements and/or property to be acquired: Owners of the private property need to be contacted for permission to construct a drainage system that would trap the silt and divert the runoff before it enters the Main road. This run-off should be diverted directly into the recharge basin by installing a new manhole and headwall. Proposed Construction: The existing private road end will require a system of Catch Basins and Manholes to allow the run-off direct access to the Recharge Basin before it enters the main road. The existing site condition allows the runoff to spill out into the main road carrying with it large amounts of silt and topsoil. This road end will also require concrete curbs and asphalt paving to prevent the undermining of the proposed structures. The recharge basin will require dredging to remove any silt build up from previous farm runoff. The basin should be backfilled with clean sand & gravel to an elevation of 6" min. above the water table. The drainage ditch or spillway on the south side of Rte.25 will first require clearing and grubbing to allow access fore additional work. A system of dikes or weirs should be constructed down the length of the ditch at 100' intervals to allow for a uniform and controlled flow of surface water run- off. The first stage of the trench should be backfilled with a compacted granular material to act as a bio-filter. Cornell Cooperative Extension should be contacted for there expertise associated with the types and quantities of vegetation that could be planted within the remaining ditch sections to provide maximum filtration. TOWN OF SOUTHOLD STORMWATER RUN-OFF MITIGATION PROGRA24 NEW YORK STATE ROUTE 25 PROJECT DESCRIPTIONS & PROPOSED CONSTRUCTION JULY 8, 1994 SITE # lB. HALLOCKS BAY: Route 25, 800' EAST OF NARROW RIVER ROAD. Existing site conditions: There is an existing culvert below the road at this location. This culvert is also located at the low point of the state road. Under a current ~oject, this culvert is being repaired. To clean up the Road run off it would be necessary to establish a reed bed or bio-filter on the south side of the. road. Easements and/or property to be acquired: The bio-filter will need to be constructed on N.Y.State D.E.C. owned wetlands. An easement to or the purchase of property will be necessary. Proposed Construction: The project consists of construction of a storm water run off bio-filter on the south side of Rte.25 The storm wa[er runoff from the road will enter the bio-filter immediately adjacent to the south side of the existing culvert under the road. The first portion of the filter should be a sediment collection or recharge basin area that will overflow into a reed bed of aquatic plantings that will absorb the harmful nutrients in the run off. The entire filter area should encompass about 0.5 acres. A system of weirs and sluiceway should be used to control erosion. TOWN OF SOUTHOLD STORMWATER RUN-OFF MITIGATION PROGRAM NEW YORK STATE ROUTE 25 PROJECT DESCRIPTIONS & PROPOSED CONSTRUCTION JULY 8, 1994 SITE # 2. RICHMOND CREEK: Route 25, 800' East of Indian Neck Road. Existing site conditions: A system of catch basins extend both to the east & west of this location for a considerable distance. A drainage easement exists across the open land or buffer area of an approved subdivision. This easement extends in a southerly direction for about 500' until it reaches the head of Richmond Creek. This easement contains a direct outfall pipe that dumps into the creek. The easement was paved with asphalt and has since totally overgrown with vegetation. Easements and/or property to be acquired: None required. Proposed Construction: The existing Right-of-Way should be cleared and grubbed for its entire length. A system of 10' diameter x 4' deep leaching rings with cast iron manhole covers should be installed at 20' intervals to provide for sediment containment and recharge of the runoff. An outfall overflow pipe should extend to a headwall that would spill into a reed bed or bio- filter constructed within an excavated trench that can be backfilled with clean granular material that would act as a filter for the remaining run 0ff. TOWN OF SOUTHOLD STORMWATER RUN-OFF MITIGATION PROGRAM NEW YORK STATE ROUTE 25 PROJECT DESCRIPTIONS & PROPOSED CONSTRUCTION JULY 8, 1994 SITE # 3. JOCKEY CREEK: Rte.25 100' East of intersection with Main Bayview and Lower Road. Existing site conditions: A direct out fall pipe enters directly into the head waters of Jockey Creek. Rte.25 slopes to this point from about 3,000 feet in either direction. The area around and leading up to the site is very congested. This is proving to be difficult when it comes to considering a conventional approach to. treating the run off. Easements and/or property to be acquired: Some properties near the run off site are still vacant. It might be possible to purchase or gain easements to these particular pieces of land. These adjacent pieces of land will need to be verified prior to formulating design parameters. Proposed Construction: Unknown at this time due to the extent & complexity of the problem and the lack of information about existing drainage facilities underneath State Route 25. Technical assistance from N.Y.S.D.O.T. will be needed before solutions can be finalized. PRELIMINARY CONSTRUCTION COST ESTIMATE Theoretical Budget $ 400,000.00 +/- TOWN OF SOUTHOLD STORMWATER RUN-OFF MITIGATION PROGRAM NEW YORK STATE ROUTE 25 PROJECT DESCRIPTIONS & PROPOSED CONSTRUCTION JULY 8, 1994 SITE # 4. JAMES CREEK: Rte.25 & Bay Avenue. Existing site conditions: A direct out fall pipe enters directly into the head waters of James Creek. Rte.25 slopes to this point from about 3,000 feet in either direction. The area around and leading up to the site is very congested. This is proving to be difficult when it comes to considering a conventional approach to treating the run off. The area around the site is very low. Test holes will be required to verlfy if standard drainage rings along the shoulder of the road can be utilized. Easements and/or property to be acquired: It does not appear that any of the properties near the runoff site are vacant. It might not be possible to purchase or gain easements to a particular piece of land to solve the runoff problem. Proposed Construction: Unknown at this time due to the extent & complexity of the problem and the lack of information about existing drainage facilities underneath State Route 25. Technical assistance from N.Y.S.D.O.T. will be needed before solutions can be finalized. PRELIMINARY CONSTRUCTION COST ESTIMATE Theoretical Budget $ 400,000.00 +/-