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Wastewater Facilities Plan- FI
I ! I I ! i i i i i i I i i I I ! I Nenr~ A. R. WASTEWATXR FACILITIES PLAN FISHERS ISLAND TOWN OF SOUTNOLD, NEW YORK C-36-1149-01 Souther Engineering, Inc. A Division of Lombardi Associates, Inc. 25 Terrace Drive Vernon, Connecticut I I I I ! I I I i ! ! i I ! i I I I Acknowledgements This project was supRorted largely by a grant from the United States Environmental Protection Agency (Grant No. C-361149-01-0). Funding was also provided by the New mental Conservation ment Corpora ti on. York State Department of Environ- and the Fishers Island Develop- Engineering, Inc. John A. Dabrowski. The principal in charge of the project was Richard Lombardi, P.E., President of Henry Souther Chief Project Engineer was Majo.r contributions to the report were made by Terrence B. Hinchey and Armand Ruby III. Typing and secretarial assistance were provided by Cher~l A. Pasternak. Appreciation is also extended to the residents of Fishers Island, particularly Richard Baker, Raymond Doyen, William Haase and Edwin Homing, who provided valuable assistance during the course of the study. I I I I I I I I I I i t I I t I I I I Conclusions The existing ra:~ sewage discharge from the Fort ~'~right area to Fishers Island Sound is in violation of the point source discharge requirements of the Clean ~.¢ater Act of 1977 (Public Law 95-217) and t.%e New York State Order No. 2005. The raw sewage discharged from the 24 inch diametsr out- fall to the Sound appears to have no significant adverse environmental impact. The 8 inch diameter outfall has been destroyed and is no longer operable. The small amount of raw sewage flowing towards this outfall is believed to exfiltrate through the sewer pipe and manholes prior to the outfai1. Period- ically, sewage odors result. Infiltration into the Fort Wright sanitary sewer system is 'non-excessive. Inflow into the Fort Wright sewer system is excessive. Existing on-site sewage disposal systems on the island are generally operating adequately. Replacement of these systems is not required· The current practice of disposal of septage at the sanitary landfill cannot be relied upon into the future. In all probability, an alternate septage disposal practice must be adopted. Recommendations It is recommended that Community Sub-Surface Sewage Disposal Systems (Alternative C) be constructed to eliminate the discharge of raw sewage to the Sound and to comply with the aforemen- tioned Clean Water Act and State Order. This represents the most cost-effective, environmentally sound plan to provide sewage treatment and disposal for the Fort Wright area. The estimated project cost is $455,000 It is recommended that application for an 85 percent Federal~7% percent State Grant be filed with the New York Department of Environmental Conservation for the design and construction of the proposed facilities. ii I t I t I I I I I I I I I ! I I i I FISHERS ISLAND FACILITIES PLAN TABLE OF CONTENTS Acknowledgements Conclusions and Recommendations Table of Contents List of Tables List of Figures I. INTRODUCTION A. History B. Purpose & Scope II. DESCRIPTION OF FACILITIES PLANNING AREA A. Planning Area B. Population C. Political Jurisdiction D. Economy E. Services 1. Transportation 2. Water and Sewer 3. Power 4. Miscellaneous III. ENVIRONMENTAL INVENTORY A. Geologic History B. Surficial Geology C. Bedrock Geology D. Surface and Groundwater Hydrology E. Soils F. Vegetation G. Wetlands H. Floodplains I. Agriculture J. Fish and Wildlife Habitats K. Rare and Endangered Species L. Coastal Management Areas M. Climate and Weather N. Air Quality and Noise O. Cultural, Historical and Archeological Sites iii Page i ii iii vi i 3 3 4 4 4 4 5 5 5 7 8 9 I0 12 18 19 19 20 20 21 22 22 23 23 I I I t t t I I I I I i I t I I I I I IV. VI. VII. VIII. IX. TABLE OF CONTENTS (CONTINUED) DESCRIPTION OF EXISTING SEWERAGE FACILITIES A. On Site Sewage Disposal Systems B. Fort Wright Sewer System C. Sewer System Outfalls EVALUATION OF EXISTING SEWERAGE FACILITIES A. On Site Sewage Disposal Systems B. Fort Wright Sewer System C. Sewer System Outfalls 1. 24 Inch Diameter 2. 8 Inch Diameter ASSESS FUTURE SITUATION A. Land Use Projections B. Demographic and Economic Projections C. Flow and Wasteload Projections INFILTRATION/INFLOW ANALYSES A. Infiltration B. Inflow DEVELOPMENT AND EVALUATION OF ALTERNATIVES FOR THE FORT WRIGHT AREA A. Alternative B. Alternative C. Alternative D. Alternative E. Alternative A - Individual On Site Sub- surface Disposal Systems B Cluster Subsurface Dis- posal Systems C Community Subsurface Dis- posal Systems D Treatment & Discharge E - No Action SLUDGE HANDLING AND DISPOSAL A. Estimated Annual Sludge Quantities 1. Fort Wright Area 2. Fishers Island Excluding Fort Wright Area B. Current Septage Disposal Practice C. Development and Evaluation of Septage Dis- posal Alternatives 1. Disposal at Existing Landfill 2. Coincineration of Septage With Refuse 3. Sludge Lagoons 4. Land Spreading 5. Disposal at New London, Connecticut D. Summary Page 24 26 26 29 32 34 34 35 37 38 4O 43 45 47 49 5O 52 54 55 55 55 56 57 58 59 60 61 63 63 t 1 I i I I t t I t t I 1 I t I I I XI. XII. TABLE OF CONTENTS (CONTINUED) PLAN SELECTION ME?IT FORT WRIGHT WASTEWATER TREAT- A. Evaluation of Costs B. Environmental Factors I. General Discussion a. Direct Impacts b. Indirect Impacts 2. Specific Alternatives a. Individual On Site Subsurface Dis- posal Sgstems b. Cluster Subsurface 'Disposal Sys- tems c. Community Subsurface Disposal S~s tems d. Treatmen= & Discharge e. No Action C. Public Input D. Selected Alternative SELECTED ALTERNATIVE A. Preliminary Design B. Environmental Impacts 1. Direct Impacts a. Construction Impacts b. Operational Impects 2. Indirect Impacts C. Estimated Cost I~4RLEMENTATION ARRANGEMENTS A. Institutional and Legal Requirements B. Local Costs and Estimated User Charge APPENDICIES A. New York State Health Department Water Qual- ity Analyses B. Cultural Resources Survey C. Fishers Island Sewage Disposal System Survey D. Fishers Island School Septic System Inspection E. Manhole Inspection Logs (Examples) F. Wastewater Quality Analyses 24 Inch Outfall G. Effluent Quality Limitations Determination Notice N. Public Hearing BIBLIOGRAPHY v P a ge 66 68 68 68 69 7O 70 71 72 73 75 78 78 80 83 83 83 85 87 88 89 91 Table 1. 2. 3. 4. LIST OF TABLES Title Components of the Fort Wright System Summary of On-Site Questionnaire Flow and Wasteload Fort Wright Area Feasibility Summary and Estimated Costs For Septage Disposal Alter- natives Present Worth Analysis Preliminary Design of the Selected Alternative 'C' Estimated Total Project Cost Estimate of Local Costs Estimated User Charges Sewer Sewage Disposal ProJec=~ ons vi Page 27 27 3O 4O 64 67 81 88 92 92 ! ! ! t I I 1 i 1 1 1 I Fi gu re 1. 2. 3. 4. 5. 6o 7. 8. 9. LIST OF FIGURES Title Fishers Island, New York Soil, Floodplain, Test Pit and Standpipe Locations Key Map - Manhole Inspection and Water Quality Sampling Locations Fishers Island Water Record Fort Wright Area Water Record Proposed Locations for Treatment System Alternatives B and D Proposed Locations for Community Sub- surface Disposal System Alternative Alternative C Community Subsurface Disposal Systems Alternative D (Recirculating Sand Filter) Treatment Discharge See insert at back of report vii Page 41 42 51 53 ! I I I I I I I i I ! I I ! i i I I i I . INTRODUCTION A. ;!istory In 1974, the State of 'Jew York, Department of Environmental Conservation {:~YSDEC) issued an order to the Fishers Island Development Corporation to "take all the steps necessary for ti~e installation of a sewage treatment system", and discon- tinue discharging untreated raw sewage into Long Island Sound. The raw sewage in question is the discharga from the existing sewage collection system in the Fort ~right area. T~he Fish, ers Island Sewer District, wi]ich encompasses the Fort r;right area, was then formed; and an application for a Federal and State Grant was made to assist in the funding of the planning, design and construction required to comply wit;~ the State Order. Subsequently, a 75 percent Federal Grant and a 12~' percent State Grant :vas offered to the Town of Southold, Fishers Island Sewer District, for the preparation B. Purpose and Sco~e The purpose of this Facilities evaluate alternative of this report. Plan is to develop and approaches of complying wi~h the afore- mentioned State environmentally The Order and to select the most cost-effective, sound alternative. scope of ~ork includes the evaluation of existing conditions in the Fort ~right area, tl]e development -1- ! I 1 ! 1 ii and evaluation of possible sewage treatment alternatives leading to the recommendation of a specific alternative based on environ- mental factors, reliabilit~ and costs. The preliminar~ design of the recommended alternative is given, together with esti- mated costs including estimated user charge. The groundwork necessarg for implementation of the plan is outlined. In addition, the scope of work includes evaluation of sew- age disposal techniques on the island outside the Fort Wright area; and if improvements are found to be necessary, outlining the t~pe of improvements required and the associated costs. -2- I I I ! I I ! ! i i i t I i I i I II. DESCRIPTIOU OF FACILITIES PLANNI;'IG AREA A. Planning Area The planning area comprises the entire island and is shown in Figure 1. (The Fort Wright area which has been studied in depth, is outlined.) Fishers Island is located approximately three miles off the shore of Connecticut in Long Island Sound and is within the boundaries of the State of New York. Its total area comprises about 75 Almost the entire island use (country club, square miles. is in residential or recreational golf courses, beaches, etc.). There are significant commercial districts, industrial areas, nor no agricultural areas. Residential lots tend to be generally greater then two acres in the eastern the island. The western portion of the old Fort larger buildings which are now generally used for storage of vehicles, contractor's equipment, etc. B. Population The island serves primarily as a summer resort area; and therefore the population fluctuates considerably from summer to winter months. At the present time the year round popula- tion, as estimated by the Long Island Regional Planning Board, is 381. In the summer months the population increases to ap- proximately I000, and during peak summer weekends the popula- tion may be as high as 2000. large and are two-thirds of Uright has -3- I 1 I I 1 I i i 1 i I 1 I I I 1 1 tral island is divided t.%e ~.~estern t;lird maintained by the Political Jurisdiction Fisl~ers Island is part of the To~.zn of Sout.%old. The con- The wi thin government is in Southold, ?Tow York, on Long Island. into two parts. Roads and access Mays of the island are uublically owned and are Town of Southold. The area includes tho Fort Uright, Hay Harbor and ~est Harbor. Roads and access ways :¢ithin the eastern two-thirds of the island, separated from the west by a gate, are under private ownership and oper- ation; and therefore access to the eastern two-thirds of the island is limited. However, the Town of Southo!d has political the island serves as a summer being occupie4 only significant agriculture, Oyster farming is unJer- Essentially the only businesses on tl]e provide sunJry services or recreational for t~e year round and seasonal residents. jurisdiction over the entire island. D. Econom~ As described previously, resort area with the majority of homes during the summer months. There is no in(~ustry or commerce on tnu island. Ca3~en in Island Pond. island are those ~¢hich opi3ort uni ties E. Services Fishers Island is by means of ferry There is an aviation field on the and harbors at Harbor for the 1. Transportation Public transportation to from New London, Connecticut. western tip of the island in the Fort Wright area Silver Eel Cove, HaW Harbor, West Harbor and East -4- I I I I I I I I ! i I I I ! ! ! use of private ~ransportation. There is no public transpor- tation on the island. 2. Uater and Sewer The primary source of water supply on the island is Bar- low Pond, which is centrally located and has sufficient yield to serve the island during most periods. Middi~ located to the east of Barlow Pond, is used as a source usage. A during peak summer transfer water from Middle water receives treatment justment); treated water distributed to most Farms Pond, secondary portable pump is used to which it is tively small The Farm Pond (filtration, is stored in areas to Barlow Pond. The chlorination and pH ad- an elevated tank from of the island. A re!a- the Fort number of individual wells are in use. only sewage collec~ion system on the island is in Wright area. Individual on-site subsurface sewage disposal systems are in use outside the Fort Wright area. (N.B. Some individual on-site sewage disposal systems are in use in the Fort Wright area). 3. Power The island is fed by an also The Fishers Island power plant, which was used island prior to laying of the underwater cable, an emergency back-up system. 4. Miscellaneous Other services provided on the island include garbage collection underwater cable from Connecticut. to serve the now serves as telephone, (Fishers Island Garbage and Refuse District), -5- I I I I I I i I I I I I 1 I I I I I fire protection (Fishers Island Fire District/Fishers Island Fire Department), medical (Island Health Project, Inc.) and police (New York State Trooper, seasonal). -6- ! I I I I I I I I i 1 I ! i ! I I I I III ENVIRONMENTAL INVENTORY A. Geologic Histor~ The advance of the last Pleistocene ice sheet over southern New England extended several miles past the present Connecticut coastline, As the glacier advanced, beds of clay, fine sand, and silt were deposited by g~acial meltwater streams in shallow de- pressions beyond the glacial terminus. As the advance proceeded these older outwash and alluvial deposits were folded and crumpled by the overriding ice sheet, and material was pushed ahead of the ice. The maximum extent of the ice sheet is recorded by the end moraine deposits which form Fishers Island. The numerous hills composed of till, sand, and gravel and the kettle hole depressions found on Fishers Island are characteristic of'end moraine morphology. As the glacier retreated, the melting ice front created melt- water streams. The sand and fine gravel deposits laid down by these streams formed three large sand plains that span the width of the island. The fine grained bedded deposits occupying kettle holes were eroded from the hills surrounding kettle holes. A further retreat of the ice front changed conditions so that streams began to erode outwash deposits. As the ice retreated even more, sea ~ level began to rase. During the final stages of degalciation strong winds swept over barren outwash plains, eroding and transporting the fine sediments. The fine sands and silts were redeposited as a thin -7- I I I I I I I I I I I I I I I I I 1 I blanket over the landscape. Decaying organic matter and mud posits were formed into swamps and salt marshes. Beach de- posits accumulated along the shore lines, as the rising sea be- gan to stabilize and erode the coastline to its present con- fi gura ti on. B. Surfici&l Geology The surficial deposits of Fishers Island are mostl~ gla- cial deposits formed b~ the last Pleistocene ice sheet to cover southern New England. The surficial geolog~ was first mapped b~ H. L. Fuller.and published in 1905 b~ the Geologic Societ~ of America. The results of his stud~ are incorporated into the surficial geolog~ of the New London Quadrangle (Goldsmith, 1962), which covers the western third of the island, and the M~stic Quadrangle (Upson, 1971), covering the central and eastern parts of the island. The predominant deposits on Fishers Island are class- ified as end moraine. ,These deposits range from sand~, gravelly, and boulder~ till, to stratified sand, silt, and cla~ deposits. The complexit~ of the assembleges precludes mapping the till separatel~ from the stratified deposits. The end moraine overlies Gardiner cla~ and Jacob sand, which comprise the oldest deposit mapped on t~e island. These units are exposed in cliffs along the south shoffe, known locall~ as Isabella Beach. The~ consist of varied but distinct masses of cla~, fine sand, and silt, and minor gravel areas. Deform- ation of the laminated silt and cla~ beds ranges from minute -8- I I I I I I i I I I I I I ! I I I folding to severely crumpled bedding. Three large sand plains, of younger age than the end moraine, occupy topographic depressions in the central and eastern parts of the island. Evidence from test borings and exposures indicate a medium to coarse sand composition with minor gravel and silt layering. The remainder of the surficial material includes beach, salt marsh, and swamp deposits, alluvium, and artificial fill. The beach deposits consist of well sorted sand with localized pebble and boulder gravel. Salt marshes are delineated as areas of partly decomposed organic materials mixed or inter- bedded with estuarine silt and sand. Swamp deposits are similar to salt marshes except the silt and sand is of non-estuarine origin. Alluvium consists of silt, sand, and gravel deposited in the~ flood plains of recent streams. Artificial fill gen- erally consists of areas of earth fill. The surficial material in the Fort Wright area consists almost exclusively of end moraine deposits. Material class- ification data from several abandoned gravel pits indicate varying thicknesses and spatial occurrences of till, sand, silt, boulders, cobbles, and pebbles. of beach and salt marsh C. Bedrock Geology Little work has been Island. The remaining areas consist d~Posits, and artificial fill. done on the bedrock geology of Fishers The previously mentioned 1905 geological study reported I --9-- I I I I I I I I I I I I I I I I I I I that a drilled well revealed 260 feet of glacial till overlaying about 20 feet of clay above granite bedrock. There is no evidence of bedrock outcrops on the island, and bedrock is generally assumed to be at depth greater than 200 feet through- out the island. D. Surface and Groundwater Hydrology Although no published reports are available describing the hydrologic nature of Fishers Island, observation wells were installed and monitored to evaluate existing groundwater levels in the Fort Wright area. Three 125 inch long, 6 inch set in test pits for the purpose levels (see Figure 2). Physical a steel tape at periodic intervals. was installed at two of the sites to diameter Transite pipes were of recording groundwater measurements were made using A water stage recorder continuously measure the fluctuation of water levels over an extended period. At observation site Number 1 water levels reached a high point of 66 inches below ground surface. A water stage re- corder operating during a 5 week period was used to evaluate the fluctuation of water levels due to the tidal influence at this site. The variation due to tides amounted to about 2 inches, while~total groundwater level fluctuation amounted to 6 inches during the same period. At observation point Number 2 no water was observed in the pipe. The depth to the bottom from ground surface is 118 inches. -i0- At observation pipe Number $, the highest recorded water level was 94 inches from ground surface. A week-long record during the earl~ part of Ha~ showed groundwater levels below 113 inches from ground surface. The groundwater on Fishers Island is used at an undetermined number of private residences and as a back-up for the public water suppl~. Water qualit~ anal~ses of samples taken from the public wells for the New York State Health Department in- dicate the water is of good quality. Results from these analyses are shown in Appendix A. The surface waters of Fishers Island have been classified b~ the New York State Department of Health. Barlow Pond is classified as a Class A drinking water suppl~ bod~. It also is the onl~ surface water bod~ used for a water suppl~ in Suffolk Count~. The other water bodies are labeled Class D, as the~ are primaril~ used for drainage. Along the coast of Fishers Island, the water of Block Island Sound is Class SA, suitable for boating and shellfishing. -11- I I I I I I I I I I I I I I I I I I I E. Soils The major soil group of Fishers Island is the Carver- Plgmouth-Riverhead association. Generally this associatioa is described as "deep, rolling, excessively drained and well drained, coarse textured and moderately coarse textured soils on moraines."1 The association is found primarily along the north shore of Long Island but also includes Fishers Island and Plum Island. The Carver soils are deep and excessively drained with their surface, subsurface and substratum layers consisting primarily of sand with some gravel present primarilg in the substratum. The depth to the sand and gravel substratum ranges from 16 to 32 inches. The Plymouth soils are similar to Carver soils. The difference lies in the absence of a distinctive grey or light- grey subsurface lager found only in the Carver soils. The depth to the substratum is slightly deeper with a range of 20 to 36 inches. Both soil groups are found primarily on the steeper slopes of ridges and in rolling areas. Riverhead soils are deep and well drained with surface and subsurface layers of sandy loam. The substratum is again sand and gravel with depths ranging from 22 to 36 inches. These soils occupy upland flat areas or gently rolling terrain. The minor soils of the island generallg include Haven, ~lontauk, Rayham, and Wareham soils. The well drained Haven 1. Soll Survey of Suffolk Count~, New York. U.S. Dept. of Agriculture, Soil Conservation Service. April, 1975 -12- I I I I I ! I I I I I I I I I I I I I soils and well to moderately well drained Montauk soils are found on upland flat areas. The Raynham and Wareham soils are found adjacent to ponds and tidal marshes, and consequently have high water tables. The remaining land areas have been classified as cut or fill areas, beaches, dunes, escarpments and a soil of the Bridgehampton group. Fishers Island is used almost exclusively for summer res- idences and has no operating commercial farms. The trend of land use is for housing and recreation. Generally the sandy textured soils and steep slopes preclude farming, while slope is t~e primary limitation for use as a building site. The Fort Wright area of Fishers Island is the primary area of study with regard to subsurface sewage disposal. The soils within the region consist primarily of Cut and fill lands and filled areas, with smaller areas of Riverhead and Haven soils and Bridgehampton soils. The remaining land con- sists of beaches, dunes, and escarpments. See Figure 2 for the locations of test pits and Soil Conservation Service (SCS) soil types. The soils series have been assessed by the SCS to show the nature and degree of limitations with respect to subsurface sewage disposal. The Cut and fill land (CuB,Cuc) includes areas that have been regraded for housing, roadways, or other non-farm uses. Most of the cut land is in developed areas, therefore any assessment of sewage disposal limitations relates to small areas on individual building sites. The slope of the site de- termines the suitability for sustaining a sewage disposal system. -13- I I I I I I I I I I I I I I I I I I I the selection of areas for subsurface made on an individual site basis. generally belong are too deep and identifications. A test pit (TP #1) was excavated near t~e buildings by the existing sewer outfall on Fox soil profile was logged on 12/12/80 as follows: 0"-22" Black topsoil and demolition fill (including brick, stone, and dirt). 22"-44" Srown fine sand and silt loam. 44"-96" Mottled fine sand and silt, trace medium to coarse sand. shallower the slope the less severe the limitations. The sewage disposal shou!J be Although Cut and fill lands to the Carver-Plymouth association, most cuts fills too thick to make accurate soil series abandoned Lane. The Small boulders and cobbles found throughout profile. No water observed. Mottling at 44" A 125 inch long, 6 inch diameter Transite pipe was placed the test pit to observe groundwater levels. The soil material correlates closely with the general nature of the Cut and fill material as described by the SCS. The fill land (FE) is made up of areas where a "sandy material" has been placed over generally poorer soils to pro- vide better drainage for building sites. The fill area oc- cupies the southern portion of Fort Wright that was built up for the aviation field. The fill is classified as severely limited for sewage disposal due to a high water table and the -14- I I I I I I I I I I I I I I I I I I I Whistler Avenue profile was 0"-7" 7"-60" 60"-65" 65" -132" variability of the fill material. According to the SCS report, the Riverhead unit (RhB) is located south of Whistlers Avenue laterallg across the Fort area. A test pit (TP #2) was excavated in a treed area between and South Military Road. The following soil recorded for this site on 12/20/80: Topsoil Fill material consisting of sand, cobbles, and small boulders. Roots and topsoil. Fine to medium whitish sand. No water Mottling at 96" and Have~l soil and extends A 125 inch, 6 inch diameter observation of groundwater. The soils observed in the test pit Transite pipe was placed for could be classified as Fill material or they may be in an area that has been so deeply cut that no diagnostic horizons remain of the respec- tive series. This region has been regraded to a flat or gentle slope by removing the surface layer and the upper portion of the sub- soil. This soil is classified as slightly limited for sewage disposal. However, this assessment was made with regard to small plots of land within a built up area. The large area covered by this soil unit will be investigated further during the actual project design phase (Step 2) to identify -15- I I I I I I I I I I I I I I I I I I a suitable site for a large community sewage disposal field. The Bridgehampton soil (Bm) occupies the land formerly used as a National Guard Camp Area. The land has been regraded to a flat or gentle slope while maintaining the original char- acter of the subsoil and substratum. This soil unit is gen- erally found in built up areas and is therefore assessed as slightly limited for sewage disposal. In some areas the water table may be from 18 to 48 inches 'below the ground surface. The relatively high groundwater level and the iow surface ele- vation made this area unacceptable as a subsurface disposal Site. The remaining Fort Wright areas are classified as Plymouth soils (PLA), beaches (Bc), dune land (Du) and escarpments (Es). A test pit (TP #3) was excavated between Winthrop Drive and Officers Service Road, west of the existing tennis courts. The soil in this area is classified as Plymouth. The following soil profile was recorded on Topsoil Brown fine 0"-12" 12"-34" 34"-72" 72"-128" 12/20/80: sand and silt loam. Grey fine sand and silt Brown silt, little fine sand. No water Mottling at 46" A 125 inch, 6 inch diameter Transite pipe was set to mon- itor groundwater levels. The soils in this test pit area correlate very well with the dominant fine sandy texture of the Plymouth soils that are -16- I I I I I I I I I I I I I I I I I I I typical on Fishers Island. This soil is classified as slightlg limited for sewage disposal, since the permeability of this unit could possibly present a pollution hazard to lakes, springs, or shallow wells. However, the Fort Wright area covered by the Plymouth soil unit contains neither surface nor groundwater bodies that are utilized for recreation or potable water supply. Beaches occupy the areas between water a-t mean sea level and escarpments or dunes. Beaches are severe~ limited for sewage disposal because of the high water table. Dune land consists of mounds of sandy material shaped by the winds. These areas are moderately limited for sewage disposal as the water table is within 4 feet of the surface in places. Dune areas are extremely fragile to disturbances caused by building or any man-made alteration. These areas should be left un- disturbed to provide protection from coastal storms and high tides. Escarpments are very steep slopes bordering the Shore- lines. They were not assessed for sewage disposal limitations because of the variability of material and the excessive slope. -17- I I I I I I I I I I I I I I I I I I ! F. Vegetation Fishers Island is covered primarily with young deciduous forest, grassy meadows and substantial areas of cultivated grass lawn. The island was nearl~ clear-cut for grazing in the late 19th century, but in recent decades man~ areas have been allowed to undergo The prominent tree (Acer slatanoides), Red (Robinia sseudo-acacia), Oak (Quercus velutina), re-forestation. and shrub species are Norway Maple Maple (Acer rubrum), Slack Locust Yellow Brick (Betula lutes), Black Four-gum (N~ssa s~lvatica), Black Cherr~ (Prunus serotina), Sumac (Rhus ~labre and R_~. t~shina), Sassafras (Sassafras albidum), Ba~berr~ (M~rica ~ens~loanica) and Autumn olive (Ela~a~nus umbellate). In some areas vines, primaril~ Bittersweet (Celastrus scandens), have grown up through the forested areas in a jungle-like growth. There are also one known American Elm (Ulmus americanus) and a few hickories (Carla ss.) on the island. The island supports com- parativel~ few coniferous species, of which verg few or none appear to be native to the island. The conifers present in- clude several imported ornamentals, two hemlocks (Tsu~a can- adensis), a Worwag Spruce (Picea shies), and a single grove of planted pines (Pinus ss.). Throughout the forested areas and fields are located man~ t~pes of herbaceous vegetation, including numerous ferns, Bur- dock (Arotium s~.), Coltsfoot (Tussila~o farfara), Jewel Weed (Imsatiens sp.), Queen Anne's Lace (Daucus carotta), Black- -18- I I I I I I I I I I I I I I I I I I I eyed Susan (Rudbeckia hirta), Rabbit's Foot Clover (Trifolium arvense), and wild Rose (Rosa ru~osa), to name a few. There are several meadows containing primarily species such as Blue- stem (AndroRon ~erardii), Little Bluestem (Andro~o~on sco~arius), Switchgrass (Panicum vir~atum~, Timothy (Phleum pratense), Red Top (A~rostis alba), and Orchard Grass (Dac~lis ~lomerata). The tidal marshes and estuaries support the common Cattails (T~pha latifolia), Reeds (Phra~mites australlis), and various species of S$artina. Cultivated lawns comprise a significant portion of the Island, including two golf courses, a golf driving range and many public and private (residential) lawns. G. Wetlands Throughout Fishers Island there are scattered areas of both tidal wetlands and inland wetlands. As indicated by the New York State Department of Environmental Conservation Tidal and Freshwater Wetlands Inventories, the SCS Soil Survey of Suffolk County, and the United States Geological Survey Top- ographic series (New London and Mystic quadrangles), none of these wetlands areas are located in the Fort Wright area. See Figure 1 for the locations of wetlands elsewhere on the island. H. Floodplains A 1980 Flood Insurance Study funded by the United States Department of Housing and Urban Development set the 100 year flood elevation at 11 feet for Fishers Island. The majority higher than this elevation and therefore un- of the island is -I9- I I I I I I I I I I I I I I I I I I I likely to be subjected to flooding. Figure 2 shows those areas which are within the flood hazard area defined by the 100 year flood elevation in the Fort Wright area. I. ATriculture Agriculture has not been an important activity on Fishers Island for several decades. Cultivation of the island by native Americans probably began around 1000 A.D., continuing until the island was settled by Europeans in the 1600's. Through the early 1900's the island was used primarily for grazing of cows, horses, sheep and mules. Currently the only · remaining agriculture on the island, aside from several small family garden plots, is a two acre stand of corn located near the center of the island which is maintained Co provide food for wild ducks. There is in addition some aquaculture in the form of oyster farming which is undertaken in Island Pond. J. Fish and Wild Life Habitats Many species of wildlife are found on Fishers Island. Particularly significant among these are the very many and diverse species of birds. In addition to some year-round res- idents, many migratory birds live on the island seasonally, nesting and breeding in a wide variety of habitats during the warmer months. The island is also the winter home of some migratory birds. There are numerous migratory species which appear only briefly on the island, primarily during the spring or fall migratory periods. Because of the extensive coastline, -20- I I I I I I I I I I I I I I I I I I I there are of course a wide varie~ of seabirds among =hose species which have been observed. Although the number of bird species which can be seen in even a single visit to the island are too numerous to mention here, a booklet entitled Fishers Island Birds, printed in 1975, lists all of those species which were sited during the period 1970-1975, and their distributions and frequencies of ocourrence. Several species of mammals live on Fishers Island, in- cluding rabbits, muskrats, grag squirrels, field mice, and rats, inhabiting primarilg the wooded areas and fields. No large mammalian predators inhabit the island. Harbor seals have been observed to winter off the northern coast of the island, near Pine Island. Numerous saltwater fish and shellfish species thrive in the coastal waters surrounding =he island, including striped bass, bluefish, flounder, lobsters, clams and crabs of mang varieties. The most common freshwater fish which inhabit the island's ponds include bullheads, perch and bass. K. Rare and Endangered Species Three endangered species of birds inhabit Fishers Island. Piping Plover, Least Tern and Ospreg all currentlg nest The and breed on the eastern half of the island. and Least Terns inhabit rockg beaches where Piping Plovers there are not mang people. island, None of these species currentlg live The Ospreys, which have eight active nests on the prefer to nest atop telephone poles or in dead trees. in the Fort Wright area. -21- I I I I I I I I I I I I I I I I I I I At enacted Coastal Management Areas the time of this report, New York State had not yet laws establishing Coastal Zone Management regulations. Specific limits of coastal management areas of Fishers Island therefore cannot be defined. However, officials of the New York State Department Of Environmental Conservation have indi- cated that a project designed'to eliminate a raw sewage dis- charge into coastal waters is not likely to be in violation of coastal management statutes. Climate and Weather The climate is classified as humid-continental, because the Island's weather originates primaril~ over North American land masses. The surrounding ocean serves to moderate temper- ature extremes, however, reducing both the daily and annual variation in temperature. Humidity is high in summer, with prevailing winds from the south or southwest. High temperatures occasionally reach 900 or higher, with minimum temperatures often in the 60's and 70's in summer. Coldest winter temperatures are usually near O°-lO°F, with average daily maximum temperatures in the high 30's. Average annual snowfall is in the range of 26-32 inches. The generally moderate winter temperatures cause frequent extended periods of bare ground throughout the winter. Precipitation is generally higher in winter due to the proximity of the ocean. Annual precipitation is typically in the range of 40-48 inches. Hurricanes, tornadoes and earth- quakes are rare but occasional occurrences. -22 - I I I I I I I I I I I I I I I I I I I N. Air Qualit~ and Noise There are few, if any, significant sources of air or noise pollution on Fishers Island itself. Some burning of brush and other non-toxic refuse is done in the Fort Wright area. O. Cultural, Historical and Archeolo~ical Sites Fishers Island sustained native American inhabitants for many centuries prior to the arrival of English settlers in the seventeenth century. Through the early 1900's the area was used primarily for agriculture. Near the end of the 19th cen- tury the U.S. Army constructed Fort H.G. Wright on the south- western end of the island. Through the early 1950's, when the Fort was abandoned and sold, much of this area was disturbed or altered. Virtually all of the Fort Wright areas currently being evaluated for sewage disposal facilities have previously been significantly altered by the Army or private interests. A complete evaluation of cultural and historic resources is to be appended hereto (Appendix B). -23- I I I I ,I I I I I I I I I I I I I I I IV. DESCRIPTION OF EXISTING SEWERAGE FACILITIES A. On Site Sewage Disposal A survey questionnaire to the residents of Fishers Sgstems (See Appendix C) Island to obtain was distributed information cn the condition and performance of individual sewage disposal systems. The questionnaires were distributed to approximately 450 residences through the public water company. This enabled us to survey nearly all cf the residents, as few homes have individual water supplies. The return rate of questionnaires' has reached about 40 percent with 80 percent of these rep- resenting seasonal users. Nearly all of the water users surveyed (95 percent) represented single family dwellings, the remainder were split equally between multi family homes and businesses. There are two primarw types of sewage s~stems in current use On the island. The majority of residents (57 percent) in- dicated the~ have a septic tank/leachingpool or field tile s~s- rem. A tess pool~ leaching pool tgpe s~stem was indicated b~ the minorit~ of residents (37 percent). There was no s~stem t~pe specified b~ 6 percent of the respondents. The septic tank/ leach pool system is now required b~ the Suffolk Count~ Department of Health Services. The stan- dards pertaining to sewage and waste disposal systems have been in use since early in 1972. Prior to the enactment of these -24- I I I I I I I I I I I I I I I I I I I regulations, septic tanks were not required and tess pools were in common use. Consequentl~, a large number of these sgs- Cems are still being used today. Leaching fields consisting of trenches or beds are not used because of their high cost relative to the cost of leaching pools. Also, the current health code only requires leaching pools regardless of soil permeability. Onl~ a dozen residences have leaching fields as opposed to leaching pools. The Fort Wright residences are served primaril~ b~ the existing sewer s~stem. The Fishers Island Union Free School and al residences and businesses are served with individual septic s~stems. The school's s~stem consists of a septic tank, dis- tribution box, and eight leaching pools. The other residences and buildings are served by similar, smaller s~stems. -25 - I I I ! I I ! ! I I ! ! I ! I I I ! I B. Fort Wright Sewer S~stem The Fort Wright sewer sgstem was constructed around 1940 and was designed to serve the Fort H. G. Wright Military Post. During its peak use, the sewer system, which was much more ex- tensive than that which remains today, served a military pop- ulation estimated at 2000. A large base has now been demolished, and the now largely under private ownership. sewer system serves approximatelg around population estimated at 50 ulation estimated at 100. part of the military remaiaing buildings are Thus the remains of the 40 buildings, with a gear and a peak summer pop- The sewer s~stem was designed primarilg as a separate san- itar~ sewer system in that the old Fort Wright had a separate storm sewer s~stem. However, in recent years parts of the sanitar~ sewer system have been considered as a combined sys- tem, e.g. the Fishers Island School, constructed in 1971, con- nected its downspouts and ~ard drains into the "combined" sewer system. Figure 3 depicts the remains of the Fort Wright sewer s~stem. A substantial part of the remaining s~stem passes through an area of abandoned buildings and is no longer active. This is also shown in Figure 3. The approximate breakdown of the sewer s~stem is given in Table 1. Vitrified clay pipe is used throughout. C. Sewer System Outfa~ls The sewer s~stem was designed with two outfalls as shown 3. The largest part of the sewer system is on Figure -26- Componen ts of Current Usage 24" 18" Sanitary Sewer 700' 525' Storm Sewer .... Abandoned Sewer .... Total 700' 525' Table 1 the Fort Wright Sewer Sgstem Pipe Diameter 12" i0" 8" 1,965' -- 1,045' 275' 135' -- .... 1,005' 2,240' 135' 2,050' 2,215' 390 ' 8,865' 11,470' Total 6,450' 800' 9,870' 17,120' I I I I I t I I I t I I t I I i I ! I tributary Fishers Island Soun~ A ver~ small part of charge through an 8 inch feet north of Silver Eel to the 24 ingh diameter outfall which discharges to 1000 feet southwest of Silver Eel Cove. the sewer s~s=em was designed Co dis- diameter outfall, approximatel~ 300 Cove. Both outfalls were designed to discharge raw sewage and no treaCment is provided. The 24 inch outfall is at a depth of approximatel~ 10 feet, measured at iow tide. The 8 inch outfall appears to have been demolished by the elements and is no longer active. -28- I I 1 I I I I I I i ! I I I ! ! I V. EVALUATION OF EXISTING SEWERAGE FACILITIES A. On-Site Sewage Disposal Systems Information obtained from the Survey Questionnaires was evaluated to determine the general condition of the sub- surface sewage disposal systems on Fishers Island. The types of problems normally encountered with septic systems were out- lined to the respondents to obtain information on pas= or cur- rent failures. A sample questionnaire is included in Appendix C. Table 2 summarizes the responses from the questionnaires. As can be seen from Table 2, very few problems have been reported on existing on-site disposal systems, despite the fact that the majority of persons responding indicated thew had never had their septic tank or cesspool pumped out. How- ever, when considering the well drained soils encountered on the island, the iow population density and the frequently en- countered seasonal use, the adequate performance of existing on-site systems, despite a general lack of maintenance, is not unexpected. A field inspection of the Fishers Island School. on-site disposal s~stem was conducted on July 29, 1981 and an inspection report is included in Appendix m. This sys- rem was also found Co be in good condition and capable of adequa~el~ disposing of the school's sanitar~ waste through the design period (~ear 2005). -29- I ! ! I i I I I I I I I I I I I I I 1 TABLE 2 SUMMARY OF ON-SITE SEWAGE DISPOSAL QUESTIONNAIRE (excludes the Fort Wright Area) Surve~ questionnaires mailed out Surve~ questionnaires returned T~pe of dwelling: Single famil~ Multi-famil~ Business Average number of occupants Average lot size Average home size T~pe of use: Year round Seasonal T~pe of s~stem: Septic tank/leaching pool Cesspool/leaching pool No response Median age on field S~stem problems: Users reporting problems Nc problems No response T~pe of problems: Odors Back up Overflow of septic tank Surface discharge Wet ground over leaching field S~stems cleaned out S~stem never cleaned out Reported condition Excellent Good Fair Poor No response of s~stems: 450 177 (39~) 169 (95~) 3 (2~) ~ (3~) $.5 2.3 acres 4-5 bedrooms 36 (21~) 139 (79~) lO1 66 (37~) lO (6~) 20 ~;ears 17 (10~) 157 (sg~) 3 (l~) 20 (6~) 6 (3~) 5 (3~) 5 (2~) 2 (l~) 30 (17~) 147 (83~) ~o4 (59~) 57 (32~) ~ (4~) o (o~) 8 (4~) -30- I I I t I I I I ! I 1 I I I I I I I In summary, the existing facilities for subsurface sewage disposal on Fishers.Island are in generally good condition. There do not ~ppear to be any major functional problems that could pose a health hazard to residents. Preventive maintenance of the systems by pumping, every 1-3 years for annual residents and every 3-9 years for seasonal residents, could prevent most problems from ever occurring. A simple inspection of tank condition and condition of leaching pools could determine whether any repairs are necessary. Naintenance costs are very inewpensive compared Co replacement costs. -31- I I t I I l I I t I ! ! I I I 1 I B. Fort Wright Sewer $~stem The sewer system was inspected on March 10, 1981. As a part of this inspection, 23 manholes were opened and, where possible, the sewer lines were viewed with the use of mirrors and sunlight or with the use of a flashlight. Sample manhole inspection logs can be found in Appendix E. (The manhole num- bering system is shown on Figure 3.) Insert weir gauges were placed in key manholes when fea- sible in order CO measure the instantaneous flow. However, these field measurements can only be used for rough estimating purposes because of the very iow flow conditions encountered in relation to the size of the sewer. (Leakage around the sides of the insert, although not great, appeared to be greater than that flow actuallg passing through the V-notch). Groundwater level gauges were set at three locations as shown on Figure 2. Groundwater levels, although measured in March, were low~ and despite the tidal variations on the groundwater almost the entire sewer system was above the groundwater elevation aC the time of inspection. Ail sewer lines which were lamped (reflected sunlight and/or flashlight) did not show any obvious signs of deteri- oration such as offset joints, cracked piR~ crown corrosion, heav~ vious sewer pipe defects based on the March root intrusion, etc. In addition, there were no ob- signs of infiltration entering the s~wer system through or through manhole walls. In summarg, 1981 sewer inspection, infiltration into -32- I ! ! i i 1 I 1 I I 1 ! 1 i ! I I the sewer s~stem is thought to be minor. As stated in Section IV B, the majority of the sewer sys- tem was constructed as a separate sanitary sewer system, that is, a system designed to transport onl~ ssnitar~ sewage. How- ever, in the past, it has been considered as a combined sewer s~stem and storm waters connections have been made. During the manhole inspection program four storm water connections were found and a further three connections which are suspected to receive stormwater were identified. These locations are shown on Figure 3. Despite these known and/or suspected inflow connections, no visible signs of manhole surcharging were found. In fact, the evidence found during the March 1981 manhole inspection program would indicate that there is little or no flushing action in the sewers as a result of ~nflow, the majority of the lines inspected flowing very sluggishl~ with sewage debris settling in the invert. (Normal domestic sewage flows are so small that self cleansing velocities cannot be attained.) An Infiltration~Inflow Analysis follows in Section VII. -33- I I 1 I I I I i i t I 1 i i i I t 1 I C. Sewer System Outfalls i. 24 Inch Diameter This 24 inch diameter outfall was inspected during the manhole inspection program and was found to be in good struc- tural condition. The outfall extends approximately 100 feet into Fishers Island Sound and is approximately I0 feet below sea level at low tide. The elevation of the outfai1 is such that the seawater backs up into the last manhole approximately 1-2 feet above the invert during high tide. Thus the raw sewage mixes with the salt water prior to discharge from the outfall. The outfall has been strategically placed so as to take advantage of the fast currents of the Race which disperse the sewage very quickly. Water quality samples were taken adjacent to the outfall on August 22, 1981, between 8:15 a.m. and 9:30 a.m., which cor- responds approximately to low tide conditions. Weather con- ditions were very calm. Historically, the greatest use of the sewer system occurs on summer weekends; therefore, the time of sampling (summer, Sat., a.m.) was chosen because the sewage discharge was expected to be at or close to its peak rate. The tide was low and weather conditions very calm during the sam- pling; and therefore, the sampling program approximated minimum dilution conditions. Water quality samples were taken at four locations as shown on Figure 3, and the results are included in Appendix F. -34- I I ! I i I I i I I i I I I I t ! I For comparison purposes, raw domestic sewage, such as that entering tile outfall, would be expected to have a DOD concen- tration of 200 mg/1 + and a suspended solids concentration of 200 mg/1 ~. The effectiveness of the outfai1 in terms of dilu- tion and dispersion is well illustrated. Thus in summary, the 24 inch diameter outfall is strate- gically located to make full use of the dispersion and dilution available. 2. 8 Inch Diameter The remains of this 8 inch diameter outfall, as shown on Figure 3, were located during the sewer system inspection con- ducted in March 1981. The outfall has been severely corroded, fractured and otherwise damaged by wave action, corrosive en- vironment, etc., and is no longer operable. During the time of the inspection, the three buildings which are tributary ~o this outfall, were uninhabitated; and therefore, no sewage was discharging. However, the manhole adjacent to the remains of the outfall contained approximately 2 feet of standing sewage, which is thought to have been diverted from the main sewer sys- that rem via manhole #21 (See Figure 3). Therefore, it appears the raw sewage is slowly percolating through the broken out- fall pipe adjacent to manhole #19. During the warmer months a noticeable sewage odor is evident in this area, according to local residents. -35- 1 I ! I ! 1 I I 1 i 1 i i i 1 I ! I In summary, the 8 inch diameter outfall appears to have been destroyed b~ the elemen=s and is no longer operable. The small quantities thought to percolate manhole #19. of sewage discharged to this outfall are through the broken outfall adjacent to -36- I I ! I I I i I i ! I I i I i ! I i VI. ASSESS FUTURE SITUATION A. Land Use Pro~ections As discussed previously in Sections II A, II D and III I, land use on Fishers Island is primarily residential and rec- reational, with a few areas of limited commercial development, and very little agriculture or industry. There do not appear to be any factors evident which would influence or tend to cause a change in the present land use over the twenty year planning period. Also see the following section for a discussion of some factors relating to future land use. -37- I ! I I ! I I I I I i I I i I I I i I Demographic and Economic Pro~ections The generally recessionary state of the economy in the northeastern United States has tended to minimize the growth of economic development in the area including Fishers Island. No major public or private investments have occurred on the island in recent years! nor are. any anticipated within the near future. Because of the relatively restricted access to Fishers Island - ferry from New London, Connecticut being the pri- mary means of public transport - the island is somewhat iso- lated from the effects of developments in nearby Connecticut or Long Island areas. Essentially the only businesses in eration on the island are Chose which provide sundry services or recreational opportunities for the year-round and seasonal residents, and it appears likely that this situation will con- tinue for the foreseeable future. Although tourism is poten- tially a more significant source of trade and business portunities, no significant effort is apparently being made to attract more tourists to the island. The eastern 2/3 of the island is privately owned, and public access to this area, which includes the island's most attractive beaches, is re- stricted. Population trends on the island have paralleled those for the New England states in general during the past decade; from 462 year-round residents in 1970, to an estimated 395 in 1975, to 318 in 1980 (Long Island Regional Planning Board figures). A large proportion of the island's year-round residents are -38- I I I I I I I I I I I I I i I I I I I apparentl~ in Island School high of about older age categories. Enrollment in the Fishers has dropped sharpl~ in the last decade, from a 120 in the earlg seventies to abou= 50 currently. Seasonal population has probabl~ increased slightl~ during this period, although no firm figures are available. The num- ber of residences occupied on a seasona~ basis onlg remained con- s~ant from 1970 to 1975 at 184. It appears unlikel~ that an~ great increase will occur in either seasonal or qear-round population, based on the avail- able data. The Long Island Regional Planning Board's revised projections for Fishers Island predict a ~ear-round pop- ulation of 500 residents b~ the ~ear 1995. This projection is based on the assumption that economic conditions will even- tuall~ improve and stimulate increased population growth in the area, reversing the current population decline~ On the basis of these figures, a ~ear round population of 500 and a seasonal population of 1000 (4 persons per res- idence, 250 seasonal residences) will be assumed for the design ~ear 2005. Within the Fort Wright area, approximatel~ half of the population consists of ~eer round residents. This represents about 15 percent of the current total ~ear-round population on the island. Since under existing zoning laws there are onl~ one or two available building lots remaining in the Fort area, most of the new construction and hence population growth which occurs will tend to be elsewhere on the island. Because of the lack of ~ear-round business or emplo~ment opportunities, most of the population growth is likel~ Co be in the number of seasonal residents. -39- I I I I I I I I I I ! I I I I I I I I It is therefore safe gear-round island re_sidents living in will remain constant at 15 design year 2005, then, 75 idents will be assumed for (summer) population of 200 to assume that the percentage of the Fort Wright area percent of the total. For the (15 percent of 500) uear-round res- the Fort Wright area, with a peak for this area. C. Flow and Uasteload Projections A study of water use records was done for the entire island and for the Fort Wright area separately. The results of this stud~ are plotted in Figures 4 and 5. Approximate per capita water demand for the Fort Wright area was estimated at 50 gallons per day. This figure was doubled to include any contingencies and the water added to the sewer s~stem through infiltration and inflow. From this analysis, together with the demographic data discuased in the previous section, design flows of 20,000 gallons per day (summer) and 7,500 gallons per day (winter) were derived for the Fort Wright area. These fig- ures are summarized in Table 3. Table 3 Flow and Wasteload Projections Fort Wright Area Maximum population (summer) - Minimum population (winter) - Maximum per capita water demand (based on existing records) Estimated per capita sewage flow (including I/I) Design Average Flow (summer) - Desi'gn Average Flow (winter) * Note: "gpd" is gallons per day, "gpcd" per day. is gallons 200 75 50 gpcd* 100 gpcd 20,000 gpd 7,500 gpd per capita -40- . GALLONS//DAY X I0,000' o ~n o 0 iZ X SHJ. NO~ FISHERS ISLAND WATER RECORD fIGURE 4 JAN 1982 HENRY SOUTHER ENGINEERING INC. -4.].- Y X I00 0 0 0 0 0 0 0 0 ~ 0 · ,::C [:b .'. LL (,0, h::'o ~ ,,, o - ' ~ ~o z: z o_<xo _ o~ '...'i ["i' [' ' Ld"~ ' © 0 © 0 0 - ~ .o _~ o ~, o. ool...x H±~tO~NO~V9 FORT WRIGHT AREA WATER RECORD FIGURE 5 JAN 1982 HENRY SOUTHER ENGINEERING lNG, -,42- I I I I I I I I I I I I I I I I I I I VII. INFILTRATION/INFLOW ANALYSIS As discussed previously, the Fort Wright sewer s~stem was used much more extensivelF in the past that at the present time; large part of the sgstem has now been abandoned. The active part of the sewer s~stem, as shown on Figure 3 consists of approximatel~ 7000 feet of sewer ranging in size from 6 inches to 24 inches diameter for a total of approximatel~ 13 inch diameter miles. Vitrified cla~ pipe is used throughout. Infiltration Based on the March 1981 inspection of the Fort Wright sewer s~stem, infiltration into the sewer swstem is thought to be negligible for the following reasons: Almost the entire sewer s~stem was above the ground- water elevation as recorded at the three standpipe locations shown in Figure 2 II. The soils are ver~ sand~ and well drained. Based on the t~pe of soil~ local Copograph~ and proximit~ to the oosan, the groundwater elevation is not pre- dioCed to increase signifioantl~ above the levels recorded in March, 1981. III. Approximatelg 50 percent of the sewer s~stem was lamped. No major structural defects were located. No visible signs of infiltration were located. IV. Weir gauges which were inserted in the sewer s~stem during the March 1981 inspection in order Co estimate instantaneous flow conditions, recorded flows which were less than that which could be attributed to normal domestic use. (ThXs phenomenon can be ex- plained bw the fact that when analyzing flows from a ver~ small population (est. 40 persons) the rate of flow can var~ tremendousl~ simpl~ b~ the use of a single plumbing fixture.) -43- I I i I I I I I I I I I I I I I I I If the guidance of New York State Department of Environ- mental Conservation Technical Information Pamphlet #26 were to be applied to the Fort Wright sewer system, t~e 'nonexcessiva infiltration rate" of 6000-10,000 gpdil~ would correspond to an infiltration rate of 90,000-15~,000 gpd to the active sewer sgstem (including an estimated 2 inch diameter miles of house laterals). For comparison purposes the design sanitary sew- age flow, resulting from a peak summer population of 200 and 50 gpcd water demand (based on existing records) would be only i0,000 gpd. Therefore another approach must be used in eval- uating the possible existence of excessive infiltration. Excluding the "no action alternative'~, four main alter-. natives were considered for treating and disposing of the sew- age in the FO~ area (see Section V!I~). These four alternatives fall into two main categories, na~elg Treatment With Discharge to Fishers Island Sound and On-Site Disposal (subsurface). Design guidelines for on-site subsurfac~ disposal systems are based primarily on the t~pe and size of building to De served and only secondarily on actual sewage flows. In the case of Alternative A Individual On-Site Dis- posal Systems, the existing sewer system would be abandoned further analysis of infiltration conditions is nec- and thus no essary. In ~he case of Alternatives B and C, parts of the existing sewer system would be used in conveying the se~age to the sep- tic tanks. De based on teria which establish minimum requirements The volumes of the septic tanks, ho~¢ever, are to Suffolk County Department of Pu~li~ Health Cri- for residential -44- I I I I I I I I I I I I I I I I I I systems. These requirements call for a minimum septic tank size based on the number of residential dwelling units and a minimum leaching pool area based on separation from ground- water. Essentially, based on a minimum 24 hour detention time in the septic system, the septic systems are able to handle wastes in excess of 100 gpcd. Existing water use is only 50 gpcd; and therefore, existing infiltration levels grea~er than or equal to the actual domestic sewage flo~ could easily be accommodated in the septic systems as designed according to the Public Health Code. Eased on the f,larc:~ 1981 inspection, infiltration in the sewer system is not perceptible; and there- fore, it can be concluded that it is ;.;ell :.;ithin the 5'3 gpcd rate which t~%e septic systems are able to handle. Therefore in- filtration in the Fort Wright sewer system is not excessive when evaluating the subsurface disDosal alternatives. Under Alternative D, Secondary treatment with Ji$charge to Fishers Island Sound, a Design Average Flow of 20,3'30 gpd from a peak summer population of 200 was evaluated. This cor- responds to 100 gpcd. Since this alternative is not competitive from a cost-effectiveness standpoint when compared to selected subsurface disposal alternative (see Section ther analysis to evaluate reducing th~ 100 gpcd design is not necessary. E. Inflow Four locations where storm water connections enter the sewer system were identified during the manhole inspection pro- gram and a further three locations where inflow is suspected to the X A), fur- flow -45- I I I I I I I I I I I I I I I I I I I enter the s~stem were identified. These inflow connections in- clude footing drains, ~ard drains, catch-basins and downspouts. Subsurface disposal systems cannot Colerate high rates of flow which act as a slug load to the septic tank. Solids from the septic tank are washed out into the leaching area.leading to the eventual plugging of the leaching field. Similar problems would a~so result in a septic tank followed bg a recirculating sand filter s~stem which was considered to be the most viable treatment and discharge alternative. In this case, premature plugging of the filter necessitating ditional cleaning and replacement of the sand filter would occur. Therefore under all the alternatives considered herein, these inflow sources must be removed from the sewer s~stem. The proposed method of inflow elimination would be as follows. Storm water from the School and from the ca~chbasins at the east end of T~ler Lane would be allowed to flow down the North Nilitar~ Road sewer, which conveys onl~ storm water, and would be b~passed around manholes #5 and #6 (see Figure 3) and dis- charged into the Cove. (see Figure 3) would be Downspout connections Catchbasins adjacent to manhole #23 redirected to a proposed dry sump. would be disconnected and discharged to a suitabl~ located splash-block. cost to relocate the inflow awa~ tem is $10,000. The estimated construction from the sanitar~ sewer s~s- -46- I I I I I I I I ! I I I I I I I I I I VIII. DEVELOPMENT AND EVALUATION OF ALTERNATIVES FOR THE FORT WRIGHT AREA A. Alternative A - Individua£ On-Site Subsurface Disposal STste~ There are approximatel~ 40 buildings that are currentl~ disposing of sewage into the existing sewage collection s~stem in the Fort Wright Area. The feasibilit~ of providing individ- ual on-site sewage disposal swstems has been investigated in light of the current health code requirements. The Standards for sewage s~stems are established bg the Suffolk Count~ Department of Health Services. The~ require- that, as a minimum, a residential swstem consist of one 900 gallon septic tank and 300 square feet of leaching area and be located on the homeowners property. Leaching pools are commonl~ used due to the sand and gravel texture of man~ of the soils in the region. The depth to groundwater determines how man~ leaching pools are needed to provide the required leaching area. The bottoms of the pools must be kept at least 2 feet above the maximum level of the groundwater. The area designated as the leaching area must be large enough to ac- commodate a 50 percent expansion of the septic s~stem. The residences along Winthrop Drive and Whistlers Avenue consist of 15 single famil~ and 10 multi-famil~ residences. Groundwater monitoring in the area showed a maximum water level of 8 feet below the surface. This would require the use of at least 3 leaching pools per'single familw residence to provide the necessarw leaching area with adequate separation -47- I I i I I I I I I I I I I I I I I I I from groundwater. The multi-famil~ units require three pools for each family, ~ielding a range from 6 to 18 pools. Groundwater monitoring was not conducted in the vicinit~ of the three ex-Coast Guard cottages on Silver Eel Cove. Suf- ficient area is available around these cottages to install a subsurface sewage disposal s~stem. However, a more detailed on-site inspection to determine groundwater elevation would be necessar~ at this location as part of the Step 2 design work. The seven homes located between Trumbull Drive and North Hilitar~ Road consist of five single famil~ dwellings and two multi-famil~ units. There appears to be enough area to pro- vide on-site s~stems even for the multi-famil~ homes. How- ever; each site must be carefull~ analyzed with test pits to determine groundwater levels during the Step 2 design phase. Additional buildings include a single famil~ unit located on Whistler Avenue 500 feet west of the public school, a baker~ on T~ler Lane, a gasoline service station on South Militar~ Road, the movie theatre and the town garage. Each of these buildings could sustain on-site s~stems as the~ are not con- fined in densel~ developed areas. site will be required to design an Step 2. Individual testing of each appropriate s~stem during The remaining buildings include the Fishers Island Ferr~ District Office, the Coast Guard Station and a motel. These buildings are all located within 100 feet of the shore line on land with a fairlw iow elevation. The feasibilit~ of on-site -48- I I I I I I I I I I I I I I I I I I i svstems is dependent on the groundwater level. The qualit~ of the soils ma~ vary within each site as these areas have been cut, filled and paved. In some areas there may be some dem- olition fill material present as part of the subsoil. These sites mev require specially engineered septic s~stems to pro- vide on-site disposal. The estimated construction costs and annual operation and maintenance costs for this alternative can be found in Table 5, in Section X A. B. Alternative B Cluster Subsurface Disposal s~stems Under Alternative B, a series of eight cluster s~stems, each of differing size and designed to serve from 3 to 15 units each, would be constructed (Figure 6). The capital cost compu- tations are based on utilization of the existing sewage col- lection svstem and pumping into septic tank/leaching field t~pe s~stems. The existing sewer s~stem would be used to collect raw sewage to a number of points from where it would be diverted to pumping stations. The sewage would then be pumped into large septic tank sVstems from which the discharge would flow b~ gravitv to the leaching fields. There are five buildings whose sewage disposal needs could best be met b~ installing individual on-site sewage disposal s~stems. These buildings include the Sou~hold Highwa~ Garage, the movie theatre, Dick's Garage, N~F Wanda residence at Whistler Avenue and Fox Lane, and the baker~ on T~ler Lane. -49- I I I I ! I I I I I I I I I I I I I I C. Alternative STstems The three former Coast Guard units located along Reservoir Road would be served b~ a cluster s~stem. The estimated construction cost and annual operation and main- tenance costs for this alternative can be found in Table 5. C - Communit~ Subsurface Disposal The sewage disposal needs of the Fort Wright area could be met b~ the construction of two communit~ subsurface sewage disposal s~stems located approximately in the area shown in Ftgu=e 7. Each system would use part of the existing sewage collection system. In each system the flow would be collected at a point, diverted to a pumping chamber, and pumped into a septic tank/leaching field system. A schematic diagram of ~he two systems is provided in Figure 8. As Figure 7 shows, the residences along Winthrop Drive and Whistler Avenue would be served by a system to be located along the south side of Whistler Avenue near South Military Road. The residences along Worth Military Road, the Coast Guard Station, and the motel would be served by a system to be located near the existing outfall adjacent to For Lane. Individual on-site systems would be provided for the five buildings listed in the previous section. The estimated construction cost and annual operation and main- tenance costs for this alternative are included in Table 5. -50- EY~I ~TI N C? ALTERNATIVE C - COMMUNITY , sUBSURFAC,E D!SPOS Akl,, iSY s T,EM ii:N:i \ I I I 1 ALTERNATIVE C - COMMUNITY i FIiG~ Ul~ 8i. I JAN 19e2I NOT TO .SCALE 5T~',NK5 ~ ,~llO00 C~,L, EACH SUBSURFACE DISPOSAL SYSTEM 't ~ . HENRY $OUTHER ENGINEERING lNG. I D. Alternative D - Treatment & Discharge to the Sound The effluent limitations for discharge to Fishers Island I Sound, as determined b~ NYSDEC, call for secondar~ treatment and chlorination (see Appendix G). I In considering the relativelg small design flow and pop- I ! I ulation to be served and the probable difficultg in obtaining good, reliable and quick service on ang major equipment be- oause of the island location, ang sewage treatment plant con- sidered herein must be simple to operate, require minimum eration and maintenance and be based on Iow technolog~ equip- I I I ment requiring the minimum'of service. A preliminar~ screening, based on the above criteria, eliminated man~ treatment schemes for further consideration. These included activated sludge and its variations, trickling filters, rotating biological discs and chemical treatment. A septic tank followed b~ a recirculating sand filter and chlorination is believed to be the most desirable treatment I I and discharge alternative capable of meeting seconderg effluent standards from the standpoint of minimum operator control, no large mechanical equipment, iow technologg and suitabilitg for I I I small flows. Therefore, a septic tank, recirculating sand filter swstem has he, evaluated against the subsurface s~stem alternatives Figure ute 6 shows A, S and c previousl~ described. 9 is a schematic of the treatment scheme, and Fig- the approximate location of the sgstem. The estimated CH LOR I N E C_C)h.~ I i CxCx. b iPUPIl:::' 170 G.RN DI~T,~.,~UTION L.ATEI~.~,k5 ~ $.AND F'IL'I'"EI~ ALTERNATIVE D- (RECIRCULATING SAND FILTER) TREATME, NT ~ DISCHARGE t FIGURE 9 ,,JAN i982 I NOT TO SCALE "l HENRY 50UTHER E~!NEERIN6 INC. I I I I I I i I I I I I I I I I I I I construction cost and annual treatment s~stem are shown in E. Alternative E - No Action The greater portion of raw sewage from the Fort Wright area currentl~ discharges through a 24 inch outfall into Long Island Sound, with a much smaller volume Bercolating through the broken 8 inch outfall pipe into the surrounding ground. These discharges would continue unabated if the "No Action" alternative is selected. An evaluation of the environmental effects of this alternative is Rrovided in Section X B. operation and maintenance costs of this Table 5. -54- IX. SLUDGE HANDLING AND DISPOSAL A. Estimated Annual Sludge Quantities 1. Fort Wright Area Ail the alternatives for sewage treatment for the Fort Wright area, which were evaluated would generate approximately the same quantity sewage sludge (septage) to be disposed of from Assuming no change in the rate of seasonal occupancy (see Section VI B), complete pumping of the various septic tanks evaluated for the Fort Wright area on an annual basis is not thought to be necessary. Realistically, a 3-5 year pumping schedule appears to be sufficient. Based pumping cycle, the average annual septage from the Fort Wright area would be 10,000 and disposal in Chapter VIII, and type of time to time. on a three year to be disposed of gallons. 2. Fishers Island Excluding Fort Wright Area The existing on-site disposal systems on the island were evaluated in Section V A and the results are summarized in Table 2. Based on this evaluation, the existing septic systems appear to be functioning adequately and no change in the operation and management of these systems is anticipated. From the survey questionnaires returned, only 17 percent of the existing systems have ever been pumped out, with an average time between pumpings of 3.7 years. Thus the estimated annual average septage to be disposed of from the island excluding the Fort Wright area is 30,000 gallons. Thus, the total estimated annual average se~tage to be disposed of from the entire island is 40,000 gallons. -55- I I I I I I I I I I I i I i I I I I I B. Current Septa~e Disposal Practice Septage pumped from existing septic tanks and cesspools on the island is disposed of at the sanitary landfill, ~Thich is located south of Oriental Avenu~ approximately 4,000 feet east of Mount Prospect (see Figure I). The landfill site encompasses an area approximately 250 feet by 200 feet on a 20.8 acre parcel. The current practice of land filling refuse consists of excavating two trenches approximately 150 feet long and 25 fee~ wide into the sides of an existing mound. The garbage and refuse is placed in the trenches and covered with native material. When these trenches are filled to capacity they are backfilled and new trenches are excavated in the adjacent virgin material. The existing garbage mound is approximately 25 feet above the surrounding area. The disposal of septage is accomplished by dumping the sludge directly from the tank truck into an area directly west of the garbage mound. No records are kept as to the quantities of sludge or garbage disposed at the landfill. The material underlying the refuse site consists of recent alluvium, a mixture of sand, silt and gravel from the flood plains of former streams. The remaining area consists of mix- tures of gravel, sand, till, and clay. The parcel is bordered on the southern and eastern portions by a salt marsh. There are no residences or water wells within a 1500 foot radius of the landfill area. -56- i I ! I ! I I I ! I i i I I ! I I i I C. Development and Evaluation of Serrate Dispos. al Alternatives Various septage disposal alternatives are available to the residents of Fishers Island, depending upon whether the Fishers Island Sewer District (Fort Wright area) and the re- mainder of the island are addressed separately or together as a single entity. As discussed above, upon construction of wastewater treat- ment facilities in the Fort Wright area, essentially all res- idents of Fishers Island will be using similar types of waste- water treatment and disposal facilities and will be generating the same type of resid~ (septage) which must be disposed of from time to time. Thus the periodic disposal of sep~age is a problem common to all residents of the island. When considering the relatively small quantities of septage generated on the island, economy of scale becomes a very impor- tant factor. Assuming the 10,000 gallons of septage from the Fort Wright area, which must be disposed of annually, could be dried from an initial (wet) solids concentration of 10 percent to a (dry) solids concentration of 60 percent~ approximately 250 cubic feet of dried septage must be disposed of annually. The permitting and monitoring requirements for typical septage disposal practices such as landfilling, lagooning, or land ap- plication would be expensive for such a small operation. There- fore the following discussion of alternatives for disposal of the sludge on the island assumes sizing of facilities to handle septage not only from the Fort Wright area but from the entire -57- I I I I I I I I I I i I I I i I I i I island. This ma~ require the formation of a septage management district for ~he entire island should a request for Federal/State grant for funding of the facilities be made. The administrative and legal requirements for the formation of such a district ma~ be so burdensome and cumbersome as to outweigh an~ advantages gained from receipt of grant monies. Under these circumstances the residents of the island ma~ decide to opt for the hauling and disposal of septage b~ private contractors, as is the pres- ent.practice. A decision should therefore be made as to whether to pur- sue the formation of a septage management district for the island. However, as onl~ tionnaires on the on-site had ever had their septic Table 2) coupled with the 17 percent of those returning ques- disposal s~stems indicated that the~ tank or cesspool pumped out (see fact that ver~ few of those surveyed indicated an~ t~pe of problem with their s~stem! it seems ver~ unlikelg that there would be enough support in the communit~ to form an island-wide septage management district. The following sections describe some of the general sep- rage disposal alternatives available to Fishers Island, to- gerber with estimated unit costs. I. Disposal at Existing Landfill At the present time, plans are landfill in favor of an incinerator. in underwa~ to phase out the New York State is a~so the process of developing and implementing a virorous reg- -58- I t I t I I ! ! i I I I I 1 I I I I I ulation program for solid waste management facilities in the State. The current method of disposing of septage at the landfill appears to be in violation of some of the provisions of these new regulations; and therefore, it appears unlikely that the present practice of disposing of septage at the landfill will be permitted in the future. Thus the continued disposal of septage at the landfill over the duration of the 20 year planning period cannot be considered a feasible alternative. 2. Coincineration of Septa~e With Refuse Discussion with local officials indicate that the existing landfill will most likely ]]ave to be phased out by 1984; detailed investigations are to be initiated by the Town shortly to evaluate the feasibility of replacing the landfill with an incinerator. These investigations should address the coincineration of sep- rage mixed with refuse. Preliminary discussions with a manu- facturer of municipal refuse incinerators indicate that the incineration of septage along with refuse is feasible. Should the detailed investigations, which are to be conducted in the near future, show that the incineration of refuse combined with septage is both feasible and economical, then septage from the Fort Wright area (Fishers Island Sewer District) and from other areas of the island could be disposed of at the in- cinerator. An incinerator designed to accept refuse com- bined with septage would be able to handle septage from all parts of the island. -59- I ! t ! I I ! A detailed evaluation of the feasibility and costs of coincineration is beyond the scope of this report. Anw ef- forts in the direction of a coincineration program must be coordinated with the person or persons about to conduct the studW o~ the feasibility and cost of refuse incineration for Fishers Island. 3. Sludge Lagoons Anaerobic sludge lagoons are basically earthen pits with dikes constructed around the sides. More elaborate designs incorporate an underdrain/leachate collection system with ac- t ,I companging percolation beds. The septage is stabilized in the lagoon bW the dissipation of the liquid fraction through the underlying soil and ~nerobic decomposition of the retained solids. The solids must be removed on a periodic basis and disposed of in an acceptable manner if the lagoons are to be reused. The lagoons maW also be backfilled to permanentlW cover the solid material. ! The lagoon should be designed and constructed to provide maximum retention of solids while allowing percolation of the liquid fraction. To maximize the hydrologic gradient, approx- t '1 I imately the adjacent ground level. be at least 4 feet above groundwater would be required in the vicinity of groundwater contamination. one-third of the lagoon should be constructed above The bottom of the lagoon should levels. Monitoring wells the lagoon to check for Generally the lagoons are 3 to I t ! 4 feet deep with the and sludge removal. sides sloped to facilitate maintenance -60- I t ! I I i 1 I ! I I To adequately handle the expected yearly volume of sludge from the entire island, a lagoon 50 feet b~ 50 feet with a working depth of three feet would be required. (A smaller lagoon, 20 feet by 20 feet by 3 feet, would be required to handle sludge from only the Fort ~right Area). A two-lagoon system would allow the septage to settle for a period of one tO two years. This would enable the retained solids to reach a state where the material could be handled easily by machinery for removal or would be stable enough to support a permanent soil covering. If the solids are removed, they would have to be disposed of by incineration, landfilling, spreading 'or till- ing into the soil. The odors associated with lagooning can be controlled at the lagoon by providing a receiving manhole to allow dumping directly from the truck. Hydrated lime can be added directly to the discharge at this location to control the pH and odors. An investigation of the Fort ~right area was made with a view to choosing a desirable location for a sludge lagoon. The three criteria used were as follows: residential dwelling of 500 feet, minimum of 6 feet, and exclusion of flood plain. minimum distance to depth to groundwater A suitable site within the Fort ~right area using the minimum criteria given could not be found. 4. Land Spreadin~ Land spreading of septage can be accomplished by spreading, above surface subsoil injection, and plow and cover procedures. -61 - ! ! ! I I i Surface spreading can be accomplished by uniformly spreading septage from a moving truck. Subsoil injection is onlg pos- sible if a specially designed truck with injection apparatus is utilized. The plow and cover method involves spreading septage onto a plowed field followed by disking or harrowing to mix and cover the septage. Approximately 5 acres of land are required to adequ~tely dispose of the projected annual volume of sludge using any of the land spreading methods. Land spreading methods are applicable in areas where the soils are well to moderately well drained. The slope of the land should not exceed $ percent to prevent excessive surface run- off and possible contamination of surface waters. Low lying areas and flood plains must be excluded. A minimum separating distance of 4 feet above groundwater is required to prevent groundwater contamination. Generally a cover crop is required I I for nitrogen fixation and removal. recommended during active site use. required if wet soil conditions are Crop harvesting is not Storage facilities may be anticipated during the spreading period. A minimum separating distances of 500 feet between the spreading area and inhabited dwellings, public roads, beaches, and airport runways must be established to min- imize nuisance conditions. An evaluation of potential sites for land spreading of septage in the Fort Wright area was made using the following criteria: minimum distance to residential dwelling of 500 feet, minimum depth to groundwater of 4 feet and minimum tract of -62- ! ! ! ! ! ! not be 5. (which includes buffer zone). A suitable site could located within the Fort Wright area. Disposal at New ~ondon, Connecticut An alternative to designing and constructing a septage disposal facility on the island would be to transport the septage by tank truck to New London, Connecticut for disposal at a permitted septege lagoon or wastewater treatment facility. Transportation and manpower costs in addition to New York and Connecticut licensing permits for this alternative would boost the cost of septage pumping from the typical $50-$100 per 1,000 gallons to $200-$500. Thus the estimated annual cost for sep-. re, disposal for the Fort Wright area would be $2,000-$5,000 per year. Should the other alternatives considered herein prove to be unworkable, the intermittent pumping of septage from the Fort Wright treatment systems which is required could be accomplished by trucking the septage to Connecticut. m. Summary A summary of the septage disposal alternatives can be found in Table 4. Should the residents of the island desire to form a sep- rage management district to provide for disposal of septage following the anticipated closure of the landfill, it is rec- ommended that Alternatives $ and 4 be investigated in more detail. Should the residents of the island elect not to form such a district, then it is recommended that the sludge from -63- TABLE 4 FEASIBILITY SUMMARY AND ESTIMATED COSTS FOR SEPTAGE DISPOSAL ALTERNATIVES A1 terna ti ve Descripti on I. Disposal at Existing Landfill 2. Coincineration of Septage With Refuse 3. Sludge Lagooning 4. Land Spreading 5. Transport to Connecticut Cost Per Feasibility 10~0 Gallons ;;dt feasible -- Feasibility study -- to commence shortly Subject.to location $50-$100 of suitable site Subject to location $50-$100 of suitable site Yes $200-$500* *T~jpical cost per dwelling unit is $2.0-$100 per I;ear, depending on frequency of pumping t i i i ! 1 ! 1 i ! the proposed Fort Wright wastewater veged to Connecticut for disposal as necessary or coincinerated with refuse, should this prove economical (Alternative 2). Therefore, in summary, .at the present time, the periodic trucking of septage to New London, Connecticut for ultimate disposal at an existing approved septage disposal site or wastewater treatment facilit~ has been selected as the current choice for septage disposal from the Fort Wright area. The estimated annual cost for this operation is $2,500. treatment s~stem be con- (Alternative 5) feasible and -65- I I ! 1 i i I i i ! t i I i 1 I I X. PLAN SELECTION - FORT WRIGHT WASTEWATER TREATMENT A. Evaluation of Costs In order to make a cost comparison of the alternatives described in Chapter VII~,~a "present worth" analysis 3~as been prepared and is shown in Table 5. The present worth analysis is performed so that the alternatives, all of which have differing capital costs and annual operation and maintenance costs, can be compared directly. The "present worth" of an alternate may be thought of as the sum which, if invested now at a given rate, would provide exactly the funds required to make all future pay- ments over the design period. Current Federal guidelines dic- tate that the analysis be performed for a 20 year period at a discount rate of 7 5/8 percent. From Table 5 it can be seen that Alternative C, Community Subsurface Disposal, has the lowest "present worth" cost. -66- TABLE 5 PRESENT WORTH ANALYSIS Individual on- site disposal/sys- tems B - Cluster subsurface disposal systems C ~ Communitg subsur- face disposal/sys- tems Treatment & Disposal Construction Annual Present Worth Total Present Cost O&M of O&M Worth $388,000 $ 3,500 $ 35,000 $412,000 $ 6,200 $ 63,000 $423,000 $475,000 $331,000 $ 5,700 $ 58,000 $389,000 $435,000 $14,600 $147,000 $582,000 *20 years ~ 7-5/8% 1 i t 1 I I i I I ! ! I B. Environmental Factors 1. General Discussion Ail four of the secondary treatment alternatives des- cribed in Section VIII of this report would cause minor changes in the existing environment in the Fort Wright area. Ail four treatment alternatives have the positive environmental effect of eliminating the raw sewage discharge into Long Island Sound from the Fort Wright sewage collection system. The majority of the negative impacts which accompany implementation of the treatment alternatives are related to the construction process and will therefore be temporary. In addition, since vi. rtually all cons=ruction would occur in previously disturbed areas, and because of the relatively small scale of the project, it is concluded that none of the four treatment alternatives would negatively impact the environment sufficiently to prohibit its consideration. As discussed in Section X B 2 e, the "No Action" alternative contraven~ existing regulations and may present a minor source of surface water pollution. The following is a general discussion of environmental factors relevant to the four secondary treatment alternatives. a. Direct Impacts The four alternative treatment systems described in Section VIII all have significant similar- ities. Each relies primarily on septic tank/leach field (or sand will Differences filter) underground treatment. As such, the alternatives have somewhat similar effects upon the local environment. derive primarily from the size and location(s) -68- ! ! I ! I ! ! ! ! ! of each tgpe of system and destination of treatment effluent. None of the alternatives will impact wetlands, drinking water supply, air quality, agricultural lands, or rare or endangered species habitats. Coastal zone management policies have not been implemented in New York state which would apply toward this project. Direct environmental impacts from any of the four alternatives will be limited primarily to disturbances caused during construction and possible effects of leachate/ef- fluent on surface or groundwaters in the event of system failure. b. Indirect Impacts The implementation of any one of these plans is not likely to significantly increase popu- lation size in the area nor induce further industrial or com- mercial development. As discussed in earlier sections, further residential, commercial and industrial development is severely limited by the availabilitg of building lots, existing zoning regulations and the island's location and limited access to the mainland. The lack of proper sewage disposal facilities is apparently not a factor currently limiting economic or dem- ographic growth on Fishers Island. For these reasons, any of the four alternatives, while designed to accommodate expected population growth in the area, will not of themselves serve to induce such growth or other development. Indirect impacts re- sulting from the project are therefore likely No connections to the selected system will be elopment in wetlands or flood plains which is place. to be minimal. allowed from der- not already in -69- t I I I I I I ! ! '1 I I 1 I I ! I 2. Specific Alternatives A brief review of the significant environmental pertinent to each of the four treatment alternatives "no action" alternative follows. a. Individual On-site Disposal S~stem~ - This ternative factors and the al- entails excavation of relatively small areas at each of approximately 40 sites, followed by installation of septic tanks and leaching pools. The Suffolk County Health Code re- quires that all such construction be done on the owner's prop- erty and at a safe distance from water supply lines, buildings, etc. In most of these systems, the excavated area would be backfilled and regraded to the original contours. A small number of systems may require regrading to altered contour levels to provide the required leaching area and distance to groundwater. The sites would then immediately be foamed and replanted with grass to minimize erosion of the topsoil. Because the disturbed areas are relatively small and are generally located on fairly level groun~ soil erosion dur- ing the two to five days required for construction of each sys- tem is unlikely to be significant. The systems are required to be water is at least 8 feet below the finished ground surface, installed where ground- with the number of required leaching pools inversely related to the depth to groundwater. This regulation is designed to minimize contamination of groundwater supplies. Even if pol- lutants from the septic system effluent were to leach into the -70- I 1 I I I 1 I I 1 I i I I I I groundwater, they would not be drinking water supplies, which fro~ the Fort area. Although the exact locations site systems are difficult to pinpoint likely~ to contaminate public are located nearly two miles of all individual on- without more detailed subsurface investigation, it is apparent that some of the sys- tems will be located within the area designated as 100 year floodplain. Systems constructed to serve Dick's Garage, the motel, the Coast Guard Station, several storage buildings on or near Fox Lane, the bakery, and possibly the Southold Garage would be located within the 100 year floodplain. The system pro- posed for the movie theatre is also currently situated on the floodplain boundary, as is the system for the former Coast Guard Housing. In addition, at least one existing subsur- face disposal system (located on Winthrop Drive) is currently in the floodplain area (see Figure 2). b. Cluster Subsurface Disposal Systems - Environmental factors influencing this alternative are similar to those dis- cussed for individual on-site systems, but fewer and generally larger areas will be affected. port may be greater from these therefore be used as barriers nearby roads and catchbasins. Soil erosion or sediment trans- larger areas; hay bales would to prevent sediment buildup in Again, regrading to the original contours would follow installation where possible, and immediate foaming and re-seeding would be used to minimize erosion. As in the first alternative, the disposal systems would be appro- -71- I 1 I I I I I I 1 I I I I I I I ! I priately sized and constructed to avoid groundwater contamin- ation, but the distance to the public drinking water supply from the Fort Wright area minimizes the possibility of drinking water contamination even in the event of groundwater pollution. Also as in the previous alternative, some of the sys- tems would be located in or partially in the area designated as 100 year floodplain (see Figures 2,6). Cluster system #8 is fully within the floodplain area, as are smaller portions of systems #5 and #7. In addition, the individual on-site systems required under this alternative to serve Dick's Garage, the Bakery, and possibly the Southold Garage and the movie theatre would be located within the floodplain. Small sections of sewer would be constructed or altered to connect the existing sewer lines to the cluster systems, posing minor, temporary restrictions on vehicular movement and existing additional noise during certain periods of construction. c. Community Subsurface Disposal System This alternative employs two large subsurface disposal areas, each of which would be subject to similar environmental considerations as the two previous alternatives. Hay bales would be used around each site to control erosion.and sediment transport during construction, and regrading, loaming and seeding would follow installation. Groundwater contamination would again be unlikely to be problematic. -72- I 1 I I I I I 1 I I Most of the sewage generated in the Fort area would be disposed of in s large subsurface area located off Whistler Avenue, well above the 100 year floodplain boundary. However, the smaller community system, located near the existing 24 inch outfall, would be within the floodplain. Again, the individual on-sits systems required under this alternative to serve Dick's Garage, the bakery, and possibly the Southold Garage and the movie theatre would be located within the floodplain (Figures 2,7). This alternative would also require some construction and alterations of sewer lines. This work would be accomplished primarily in existing streets or vacant areas, and would not produce any significant environmental impacts aside from tem- porary inconvenience to motorists and some noise during con- struction. d. Treatment and Discharge - This alternative is similar to alternatives two and three in that the system m~kes use of the existing sewage collection system, with some minor modifications, to deliver wastewater to a septic tank treatment unit. A subsurface, recirculating, sand filter is used in- stead of leach fields to purify the septic tank effluent, how- I I i ever, and the resulting treated effluent is discharged to Long Island Sound through the existing 24 inch outfall fol- lowing chlorination. Construction impacts of this alternative are to those anticipated from alternatives two and three. similar Hay I ! I bales would be used to minimize erosion and sediment from the site during construction. Some alterations struction of connecting sewer lines would create temporary pediments to traffic and additional noise. -73- transport and con- im- I ! I I I I I I I I I I I I I I I I I AS before, serve Dick's Garage, Garage and the movie individual on-site systems required to the bakery, and possibly the Southold theatre would be located within the flood- plain. in the floodplain area. Ground elevation in this area is only 1-2 feet below the floodplain elevation, however, and a raised bed design could be used to elevate the treatment system above this level. Bunkers could also be installed around the site to provide flood protection (see Figures 2,6). The primary potential operational impact of this alternative concerns the possible effects of the treated ef- fluent upon the receiving waters. Under normal operating con- ditions this effluent would be treated to secondary treatment The treatment system itself would also be located with- much cleaner discharge than the Even if the sand filter were still receive primary treatment septic tank, again providing a somewhat than the current raw waste discharge. standards and would provide a current raw sewage discharge. to fail, the wastewater would by passing through the less polluted effluent A potential problem associated with the chlorination step is the possibility of overchlorination. Excess chlorine has been found to negativelv impact receiving waters, as it is toxic to fish, shellfish and microorganisms found in natural waters. With proper plant operation this effect can be minimized, and de- chlorination could be used if necessary to reduce chlorine tox- icity following chlorination. -74- e. No Action If nQ action is taken to treat the existing raw sewage discharge, this wastewater will continue to be discharged throuch the existing 24 inch outfall into Long Island Sound. This is of course in violation of existing state and federal laws and contravenes a 1974 Order to discontinue discharging untreated raw sewage issued by the Uew York State Department of Environ- mental Conservation. Because of the dilution provided by the coastal current aa it passes by the outfall and the relatively small volume of wastewater which is discharged on an average daily basis, the actual impact of the discharge on the sur- rounding environment is likel~ to be of minor significance, however. In an attempt to make a preliminar~ assessment of the impact of the existing discharge on the quality of the receiving waters, a set of grab samples were taken of the ocean water in the area of the outfall. Four South and West of the point, and one within taken at nearly low tide, on a Saturday morning at 9:00 a.m., on a fai.r-weather summer day (August 22, 1981). This was done in an effort to characterize "worst case" conditions, i.e., when the volume of sewage being discharged would be near its maximum level, and mixing and dilution by ocean water would be lowest. The results of the analyses of the samples are contained in Appendix F. samples were taken; one each North, outfall in a 20 foot radius of the discharge 5 feet of the discharge. The samples were -75- These results indicate that the existing discharge does not appear to be causing any significant pollution of Long Island Sound in the area of the outfall. Dissolved oxygen was at 7.0 my~1 or higher in each of the form bacteria counts were substantial "South" samples, these concentrations monly required for swimming areas. The currents in the area of the outfall four samples. While coli- in both the "North"and are below levels com- are generally fast moving, and the sewage outfall was originally designed to take advantage of these currents in dispersing pollutants from the discharge pipe. The amount of dilution occurring within this 24 inch diameter pipe itself may be sufficient to reduce pollutant concentrations to background levels. Because the shoreline in this area is very rocky, there is normally no recreational swimming done for at least 100 yards in either direction. There is also no shellfishing done in the area of the outfall, according to local residents. A visual inspection of the shoreline near the outfall revealed no indications of pollution from the discharge such as dead fish or birds. Common species of algae such as rockweed (Ascophylus s~.,Fucus vesiculosis), Irish moss and sea let- tuce (Ova lactosa? grow near the shoreline. As was discussed previously in Section VI B, future pop- ulation growth in the Fort Wright area is not anticipated to be substantial. Any new residences or businesses which are con- structed will probably be required to install individual septic -76- ! I I I I I I I I I 1 I I I I I I tank/leaching pool systems. Therefore the future environmental impact of the "no action" alternative is not likely to increase greatly over that which is induced currently by the existing discharge from the 24 inch outfall. Similarly, sewage draining to the former 8 inch out- fall would probably continue to percolate through the ground, some eventually see~ing through to the surface layer, causing noxious odors and some degree of pollution of Silver Eel Cove. The water in the Cove is fairly well sheltered from wind and wave actions, as well as from offshore currents. Mixing of this water is therefore likely to be much less efficient than that of the water surrounding the 24 inch outfall. However, it appears that the volume of raw sewage entering surface waters from this source is small, and some wind mixing and tidal ex- change of the Cove water will occur. Since any new residences or development will not be allowed to connect to this line, the flow of wastewater through this destroyed outfali is not likely to increase, and future environmental effects of the no action alternative are likely to remain at or near present levels. -77- I I I I I I I I I I I I I I ! I I I I C. Public Input An ongoing public participation program is being conduc- ted as part of t]]e facilities planning. T]]e purpose of this program is to ensure that the public is aware of the facilities planning being performed and to afford the public the oppor- tunity to comment on and provide input to the planning process. To this end, various informational documents have been mailed to public officials and property owners in the Fort Wright area. Also, two public meetings have been held at the Fishers Island School. A formal public hearing is to be held upon completion of this report. Testimony su%mitted at the public hearing is to be appended to this report (Appendix H). D. Selected Alternative Treatment alternatives A-D will all provide the equivalent of secondary treatment for the wastewater generated in the Fort Wright area. Since none of these four alternatives can be eliminated on the basis of environmental factors, and all pro- vide essentiallg equivalent water quality following treatment, the primar~ means used to choose the most appropriate alterna- tive is through an evaluation of costs. As was shown in Table 5 Alternative C, Communitg Sdbsurface Disposal S~stems, has the lowest "present worth" cost, and is therefore selected as the most appropriate method for treatment of raw sewage from the Fort Wright area. A comparison of environmental factors for the various al- ternatives also favors the selection of community subsurface -78- I I I I I 1 I I I I I I i I I I I I I systems. Of the three subsurface disposal alternatives considered (Alternatives A-C), Alternative C requires disturbing the few- est number of sites for its implementation. This alternative also has the advantage waters. Alternative D turbing relatively the of eliminating all discharge to surface (Treatment and Discharge), while dis- fewest number of sites, relies on a dis- charge to surface waters for ultimate effluent disposal. This presents more potential problems and requires more attention to system operation and maintenance than do the subsurface dis- posal methods. Alternative E "No Action", must be eliminated because it is in violation of existing regulation and presents a source of untreated wastewater discharging into Long Island Sound. In summary, Alternative C Community Subsurface Disposal, provides the most sensible and cost-effective alternative for treatment of the Fort Wright area sewage wastewater. -79- I I I I I I I I I I I I I I I I I t I XI. SELECTED ALTERNATIVE A. Preliminary Design The preliminary design.for the selected alternative, Com- munity Subsurface Disposal Systems, was based on the flow and waste- load forecasts developed in Section VI C and the requirements of the Suffolk County Health Code. This alternative, which was described is Section VII C and is shown on Figures 7 and 8, consists of two main subsurface disposal areas (with submer- sible grinder pump stations) and five individual on-site disposal systems. The preliminary design parameters for these components are summarized in Table 6. Groundwater monitoring wells would also be constructed adjacent to the two main subsurface disposal areas in confor- mance with the Suffolk County requirements, to monitor the level and characteristics of the groundwater at the site in order to determine water quality. As discussed in Section VII, for optimum performance of these subsurface disposal systems it would be necessary to separate stormwater inflow sources from the sanitary sewer lines feeding the disposal systems. This would be accomplished prior to in- itial operation of the facilities. Operation and maintenance requirements for the selected alternative are minimal. It is suggested that the two main sys- tems be inspected weekly, and the grinder pumps be removed and -80- I I I I I I I I i I I I I I I I I I I TABLE 6 PRELIMINARY DESIGN OF THE SELECTED ALTERNATIVE 'C' Community Disposal S~stems Swstem #i System Design tributary units 50* 20 Design average flow (gpd) 20,000 8,000 Grinder pump station capacity (gpm) 140 80 Total septic tank capacity (gals.) 20,000 8,000 Total leaching area (sq. ft.) 6,700 2,700 Other S~stems (not connected to S~stems #I or #2 above) Five (5) individual septic systems each with nominal 1000 gallon septic tank followed by 300 square feet leaching area. One (1) cluster septic system to serve three (3) single family homes; one (1) nominal 2000 gallon septic tank followed by 640 square feet leaching area. Based on SuffDlk County Health Code *Includes one (1) design tributary unit allowance sewage pumped from the Fishers Island Ferry. for -81- I I I I I I I I i I I I I I I I I I I cleaned every six months to reduce grease buildup. Septage sludge levels would also be measured every six months and .the septic tanks pumped out as required (anticipated once every three to five years). The five individual on-site disposal systems would be inspected annually and out as required (anticipated.once every depending on use). The selected alternative is also capable the septic tanks pumped three to nine years of treating and disposing of sewage from the Fishers Island ferry. The ferry's sewage tank (nominal 1000 gallon capacity) is currently pumped out at weekly intervals during the summer season and monthly during the rest of the year by a septage hauler at the New London dock. Under the selected alternative, the ferry's tank would be pumped out at Fishers Island by a septage hauler who would then discharge the sewage into a receiving manhole immediately adjacent then be bled into the controlled rate, thus wise disturb to Subsurface System #1. The sewage would 20,000 gallon septic tank system at a avoiding a slug load which would other- the system. -82- I I I I I I I I I I I I I I I I I I I B. Environmental Impacts As discussed previously, the magnitude and the nature of this proposed project limit the severity of the environmental impacts associated with its implementation. The areas which would be directly affected by construction are relatively small and have. previously been disturbed by former users of the prop- erty. The project itself is designed to rectify an existing environmental pollution problem by discontinuing the discharge of untreated sewage to the waters of Long Island Sound. The following is a discussion of the environmental considerations pertinent to the implementation of Treatment Alternative C~ Community Subsurface Disposal Systems. 1. Direct Impacts a. Construction Impacts Floodplains ~ as discussed in Section X B 2 c, the smaller community subsurface disposal system and the few in- dividual on-site subsurface systems required would be located within the limits of the 100-year floodplain. A flood over the community subsurface disposal area would probably not cause any physical damage to the disposal area or equipment (the pump specified is a submersible type). The flood waters would certainly inundate and temporarily saturate the disposal area, surpassing the absorptive capacity of the soil. The flood water would therefore mix underground to some extent with the sewage in the disposal area. Since the volume of the flood water would undoubtedly be substantially greater than the volume of the -83- I I I I I I I I I I I I I I I I I I I sewage present, the sewage would be diluted greatly by the flood water. Because of the sandy nature of the soil, the excess water would fairly rapidly percolate through the ground and an equilibrium level would again be reached. There is a slight pos- sibility that under flood conditions some sewage-contaminated flood waters could reach the ground surface. If so, the sewage would be highly dilute, and in most cases would probably be re- absorbed by the soil after the flood subsided. Mitigating measures which could be used to offset any potential problems associated with floods include elevating the disposal area by importing sandy fill material, or placing flood control bunkers around the site to prevent the flood waters from inundating the site. Wetlands - as discussed in Section III G, the disposal systems would not be located in wetlands. Coastal Zones As discussed in Section III L, reg- ulations applicable to this project have not been established by the State of New Yo~k regarding coastal zone management. Historic archeological sites Although much time and effort has been expended in an attempt to gain an assessment of the existence and importance of any such sites in the proposed disposal areas, bureaucratic and other delays h3ve so far pre- vented this issue from being resolved. When a cultural re- sources survey is completed, the report will be attached to this document as Appendix B. -84- I I I I I I I I I I I I I I I I I I I Scenic/recreational sites - The proposed treatment systems will mainly affect two vacant areas which are not par- ticularly scenic nor currently used for recreation. Noise - Some noise will be common throughout the construction period resulting from the use of heavy equipment such as backhoes and dumptrucks. This noise is not likely to be excessive and will be a temporary disturbance for nearby residents. There are no agricultural lands, parklands, endangered species habitats or wild, scenic, recreational or any other sort of lakes, ponds, streams or rivers in or near the af- fected areas. Similarly, air quality, groundwater quality and quantity, surface water quality and quantity, and aquifer re- charge areas will not be affected by construction processes. No population relocation will be required, and there will be no conflict with existing land use. Steps required to mini- mize erosion were discussed in Section X B 2 c. b. O~erational Impacts Energy demands - The energy required to intermittently run the two submersible energy use or demand on System failure pumps will not measurably increase the island. - E~ess storage capacity and the re- quired 50 percent reserve expansion area for subsurface leaching should be adequate to compensate for ~ correct any failure of the system to adequately process sewage. Surface and groundwater quality - The proposed sys- tems will serve to improve the quality of Long Island Sound -85- I I I I I I I I I I I I I I I I I I I water, by eliminating all surface discharges. surface disposal of the effluent then presents that groundwater may be contaminated, the soil Although sub- the possibility is generally effective at adsorbing pollutants from the water, and health regulatio~ require a sufficient depth to groundwater to min- imize the risk of contamination. As mentioned previouslg, the public drinking water supply is approximately two miles from the proposed treatment sites, and therefore not likely to be affected by an~ contamination of groundwater which might occur. A sludge disposal method has not been selected due to the un- availability of acceptable sludge disposal sites in the Fort Wright area and other factors discussed in Section IX. For the purpose of this discussion the only environmentally sound alternative currently available, disposal at New London, Con- This method Fishers Island, treated at an existing, approved facility necticut, will be assumed to be the chosen method. would not affect surface or groundwater quality on as the sludge would be in Connecticut. Surface and groundwater quantity - The selected treat- ment alternative would not alter existing drainage patterns in the Fort Wright area, nor affect the quantity only nealby body of water, Long Island Sound. 20,000 gallons per day during peak (summer) lons per day off-peak (winter) use would be water in the facilities planning area. This relatively small volume is not likely to significantly alter the existing ground- water hydrology of the area. of water in the An average of use and 7,500 gal- added to the ground- -86- I I I I I I I I I I I I I I I I I I I NO other aquatic ecosystems will be affected by this project, nor will air quality. 2. Indirect Impacts It is very unlikely that installation and operation of this system will induce further population growth or develop- ment on Fishers Island. As discussed in previous sections, future development is very much limited by existing zoning regulations, the location of and limited access to the island, and the Iow availability of building sites. Further develop- ment is apparently not currently limited by the absence of sew- age disposal facilities, and the installation of such will not substantially alter the character or accessibility of the island. -87- I ! I I I I I I I I I I I I I I I I I plan Estimated Cost The estimated total cost of constructing the selected (Community Subsurface Disposal Systems) is given in Table The struction and all istrative costs. TABLE 7 ESTIHATED TOTAL PROJECT COST total project cost shown includes estimated costs of con- related design, inspection, legal and admin- Construction Cost Community subsurface Disposal systems Stormwater Separation Subtotal Construction Contingency (15~) Total Estimated Construction Cost Other Related Costs Design $ 38,000 Field Survey & Subsurface Inspection 7,500 Construction Inspection 17,500 Operation & Haintenance Manual 3,000 User Charge System 4,000 Legal and Administrative 4,0001 Lsnd N/A Subtotal $ 74,000 TOTAL ESTIMATED PROJECT COST $455,000 ESTIMATED ANNUAL OPERATION AND MAINTENANCE COST (EXCLUDING DEBT RETIREMENT) $ 5,700 $321,000 I0,000I $331,000 50,000 $381,000 lIneligible for grant application -88- I I I I I I I I I I I I I I I I I I I XII. IMPLEMENTATION ARRANGEMENTS A. Institutional and Legal Requirements To obtain state and federal funding for the design and construction of the sewerage facilities proposed herein, the Town of Southold must legally form a Sewer District which would act as the local legal body responsible for executing appli- cations for such funding and which would be responsible for the operation and maintenance of these facilities. Prelim- inary steps have already been taken to form a Fishers Island Sewer District for this purpose and a "Conditional Order Es- tablishing Sewer District" was approved by the Town Board of the Town of Southold on November 10, 1977. Upon completion of this Facilities Flan, the order establishing a sewer dis- trict is to be reviewed by the State for compliance and con- sistency with state and federal requirements pertaining to sewer districts. The sewer district must be formed such that it has the necessary legal, financial and institutional pro- visions for construction and maintenance of the proposed facil- ities. The key steps for implementation of the project and the anticipated schedule for completion of the proposed facilities are outlined on the next page. -89- I I I I I I I I I I I I I I I I I I I Task Conduct Public Rearing Apply for Step 2 (Design) Grant State Review of Step 2 Grant Application Award of Step 2 (Design) Grant Design Apply for Step 3 (Construction) Grant State Review of Step 3 Grant Application Award of Step 3 (Construction) Grant Construction Facilities on Line -90- Date 5/82 6/82 6/82 - 9/82 9/82 9/82 - 3/83 3183 3/83 - 6/83 6/83 6/83 - 6/84 6/84 I I I I I I I I I I I I I I I I I I I Local Costs and Estimated UserlChar~e The estimated project costs and annual operation and main- tenance costs for the selected alternative are given in Table 7 The estimated user charge has been calculated and is shown on Table 9. Present federal rules and regulations regarding grants for construction of treatment works allow for an increase in the level of federal funding from 75 percent to 85 percent for systems using "Innovative/Alternative Technology." How- ever, this increase in the level of federal funding is subject to availability of funds. Therefore the estimated local costs have been calculated assuming federal funding at the 75 percent level and at the 85 percent level. in one-half of the remaining cost. State funding would be 12% percent ~;ew York State participates Hence the corresponding and 7% percent respectively. Certain legal mentation of gation. These costs in Tables 7 and 8. The estimated costs (1982) is in and administrative work necessary for the imple- the project is not eligible for grant appli- have been estimated and are also shown average cost per user based on present day the range of $180 - $230 per year. l"user" is equivalent to a "single family dwelling unit" -91- I I I I I I I I I I I I I I I I I I I TABLE 8 ESTIMATE OF LOCAL COSTS Level of Grant Participation Federal 85~ 75~ State 7%~ 12½~ Local Share 7½~ 12½~ I00~ 100~ TOTAL ESTIMATED PROJECT COST Less ineligible portion TOTAL ESTIMATED ELIGIBLE COST Local ~hare of eligible Plus ineligible cost TOTAL LOCAL SHARE Cos t $455,000 $455,000 1.4,000 14,000 $441,000 $441,000 $ 33,100 $ 55,100 14,000 14,000 $ 47,100 $ 69,100 TABLE 9 ESTIMATED USER CHARGES Level of Grant Participation ~ ~ (see Table 8) Annual debt retirement (20 ~rs./12~) Annual 0 & M TOTAL ANNUAL COST $ 6,300 $ 9,300 5,700 5,700 $ 12,000 15,000 Estimated number of initial users 66 66 Estimated average annual cost $182 $227 per user Estimated average monthl~ cost $i$ $19 per user l"user" is equivalent to a "single family dwelling unit". -92- I I I I I I I I I I I I I I I I I I I APPENDIX A