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HomeMy WebLinkAboutWater Resources Investigation 1967 TOWN OF SOUTHOLD SUFFOLK COUNTY, LONG ZSLAND,N.Y. INVESTIGATION OF WATER RESOURCES JUNE 1967 The preparatisn of this report was financially aided through a federal grant from the Department of Housing and Urban Development, under the Urban Plannin~ Assistance Pre,ram for the Bureau of Planning Administration, New York State Dffice of Planning Coordination. It was financed in part by the State of New York. MALCOLM PIRNIE ENGINEERS 226 Westchesver Avenue White Plains, N.Y. 106~4 SECTION II. III. IV. V. VI. VII. VIII. IX. TABLE OF CONTENTS INTRQDUCTION GENERAL CONDITIONS WATER SYSTEMS AND WATER USE GEOLOGY HYDROLOGY AVAILABILITY OF FRESH WATER PROTECTION OF GROUND WATER RESOURCES FISHERS ISLAND WATER RESOURCES CONCLUSIONS AND RECOMMENDATIONS PAGES 1-6 7-14 15-22 23-25 26-31 32-38 39-45 46- 5~ 52-57 NO, 1 2 3 h 5 6 7 FIGURES Location Map Rainfall - Cutchogue 1949-66~ incl. Typical Geohydrological Section Water Table Contours Water Levels in Wells S6558 and S6750 ( Area A) 1949-66, incl. Water Levels in Wells S6542 and S6524 (Area B) 19~9-66~ incl'. Water Levels in Wells S16787 ( Area D) and in S16753 (Area C) 1958-66~incl. FOLLOWING PAGE 7 29 28 31 31 31 PLATE PLATES Large Scale ~ap of Southold Reproduction of Plate 1 of USGS-W.S. Paper 1619-GG - Surficial Geological ~ap of Southold Reproduction of Plate 3 - USGS-W.S. Paper 1619-GG - MaD of Southold showin~ Location of Wells and Position of the Water Table in July 1959 Reproduction of Plate 2 of USGS-W.S. Paper 1619-GG - Geohydrologic Sections in Southold IN BACK COVER POCKET TOWN OF SOUTHOLD SUFFOLK COUNTY, LONG ISLAND, NEW YORK INVESTIGATION OF WATER RESOURCES JUNE 1967 I. INTRODUCTION The preparation of this report for the New York State Office of Planning Coordination was financially aided through a Federal Grant from the Department of Housing and Urban De- velopment, under the Urban Planning Assistance Pro~ram for the Bureau of Planning Administration, New York State Office of ?l~nning Coordination. It was financed in part by the State of New York, by the Town of Southold, and by the Village of Greenport. Purpose and Scope The principal purpose of this investigation and study was vo provide information on the water resources of the Town of Southold in connection with the overall plannin~ work under ~he Urban Planning Assistant Program for the Town. The following subjecvs were investigated and are dis- 3ussea in the reporv: (a) Available waver resources and the quantity of waver that may be obtained from the sources. (b) Past and presenv waver usage in various parrs of the Town. (c) Estimates of probable future waver consumption and effects of land usage on available water resources. (d) Evaluation of various land use proposals~ as re- lated vo available water. (e) Consideration of methods for protecting and devel- oping the waver resources of Southold~ as related vo plans for future developmenv. The studies included field investigations of surface and ~nderground conlitions and a review and analysis of data ob- tainem from previous investigations and reports. Information obtained during the investigations from records and operating experiences of the Greenporv Water System and data obtained from represenvatives of the U. S. Geological Survey, the New York State Water Resources Commission~ Suffolk County, the Town of Southold~ and from others familiar with local condi- vions were very helpful in connecvion with the studies. Field investigations included observations throughouv she sown related ~o agricultural~ residential~ and business de- veiopmenvs and vo public and private waver supply and sewage disposal facilities. Visits were made during and after periods ~f heavy rainfall to observe the exvens of surface pending ~.~ ru~-~_~ and during dry periods when there was maximum ~se of ~'~a~er for irrigation. The characuer of surface soils and underlying materials was investigated by sampling and observing samples of materials obtained from well drilling operations and from materials exposed in excavations. R~iationship of Water Resources ¥o Plannin~ The sole source of wa~er for the Town of Southotd is ground waver~ replenished each year by a relatively small part of the rain which falls upon the area within the Town. A large portion of the available ground-~ater is used for irri- gation~ and the supply of ground-water that may be withdrawn safely is limited ye less than twice the total amoun~ that is used a~ the present time. For these reasons~ the avaiiabili~y of wa~er is a major factor in sound planning for the future fieveiopmenv of Southold. In certain sections of Southold~ mach greater quantities of wa~er ~an be withdrawn than from other sections without contaminating the fresh water resources ~'~ith salt waver. This fact mus~ be considered in eonnection with future planning. Pr=:~-ious Investigations and Reports There is a wealth of informaticn available as ye geo!og- icai~ hymrological~ and ground waver conditions in Long island~ _.x Suffolk County 8nd in the Town of Southold. Two of the mssv reaenv and most significant reporvs covering Southold ground-waver conditions are the following: "Hydrology of the Shallow Ground-Water Reservoir of the Town of Southotd, Suffolk County, Long Island~ New York": New York State Water Resources Co~aission Bulletin GW-~5 (Hoffman~ J.F., 1961) "Geology and Ground-Water Resources of the Town of Southold~ Suffolk County, New York": Geological Survey Water-Supply Paper 1619 - GG (CrandeLl~ H.C.) The vwo reporvs present results of investigations of the U. S. Geological Survey in cooperation with the Suffolk County Board Of Supervisors, the Suffolk County Water Author- ity~ and the New York State Water Resources Commission. They are parr of an overall and continuing appraisal of ground waver conditions on Long Island which was commenced by the U. S. Geological Survey in 1932. Both of the above reporvs contain much informavion on existing wells~ elevations of ground-wa~er~ and geological and hydrological data. They provide an excellent review of results of previous svudies and reporvs. The plates in these vwo reporvs shewing numbered well locations throughout the Town and convours aha profiles showing elevaticns of ground raver relative ye mean sea level are of greav value in con- necvion with esvimating the availability of fresh wa~er in various parrs of Southold. Some of these data are reproduced herein. The fotlo~.:ing recenv reporvs also are of interesv in ~onnecvicn with the water supply situation in the Town of Southcld: "Engineering Repor~ on Water Sup.ply - Village of Greenporv - February 196~" By Holzmacher~ MeLendon & Murrell. "Water Resources of the Town of Southampvon~ Suffolk County~ New York December 1966~r -By Behre Dolbear & Company. "Pollution and Water Supply of the Town of Southampton January 1967" ~y John P. Hahoney~ Consulting Engineers. The firsv of the above three reports contains much in- formanion concerning the propersZ and operations of the wa~er sjs~em of the Village of Greenporv~ which serves water to the Village and adjacenv areas. The second and third are of inter- est because the waver situation in the Town of Southamp~on~ ~{hich comprises a large portion of the South Pork peninsula~ in m~ny respects is similar ye the situation in Southold in the North Fork peninsula. Ourren~ Investigations and Studies The cooperative studies of U. S. Geological Surv.ey and the New York State Water Resources Commission are continuing cvudias~ and additional data on underground water conditions a~] ~ithdrawals throughout Long Island are collected each year. ~he L~g Island District Office of Division of Water Resour{~es of the New York State Conservation Department is ay uresenv conductine an interim water study of the Nassau- Suffolk rezion in connection with a long-range plannin~ study, conducted by the New York State Office of Plannin~ Soordination. Tws additional interrelated investigations and studies are underway which will ~rovide much information on ~round- ~.~aver resources in Suffolk CounTy. Dne of these includes the construction of some 14 dee~ vest wells, some of which will extend into bed rocks . Two ~f the wells will be located in Southcld alone North Road, ~ne north of CutchoEue, and one northwest of the Village of Southold. This investigation is of particular interest, inas- much as very meaqer data exist on subsurface conditions in Southold below the existin~ irrieation and municipal wells, whic~ are not very deep. The other imvesti~ation is a comprehensive water su~plv study for Suffolk County, financed by the Stave under its ~rant program for wa~er supply planning. ti. GENERAL CONDITIONS hosa¥!o~ a~d Extent As shown on Figure 1~ the Town of Southold comprises une easverly 20-mile portion of the northerly peninsula~ !.~no~;n as the North Fork~ at the easterly end of Long Island. IT also includes Robins Island in Peconic Bay and Gutt~ Plum~ and Fishers Islands in Long Island Sound. The study area in- czuded in this investigation consists of the peninsular pop- 3icn of the Town of Southotd~ which has an area of ¥2.9 square ~niies and Fishers Island~ which has an area of ~.2 square miles. Fishers Island is located about 11 miles northeast from 0riens Point and 7 miles southeast from New London. Per convenience~ the waver situation in Fishers Island is aisc~ssed separavely in Section VIII of this repots. In ~he remainder of this report the mainland or p.eninsular portion of Lhe Town will be referred so as "Southold,"and Fishers Island ~.ill be designated by name. Geographical Features Southoli is almosv entirely surrounded by salt waver. In £eneral: vne nigher portions are adjacenv ~o or near Long Island Sound and rmse from 50 $o 150 feet above sea level. The !an~ slopes southerly for the moss pars toward Peconic~ Southold, ,~d Garainers Bays. Southold has no surface streams or lakes NEW JERSEY QU~ CO. KINGS ' RICHM~ · CONNECTICUT LONG NASSAU CO, SUFFOLK CO. NEW soUND isLAND TOWN OF $OUTHOL RIVERHEA; isLAND oG¢~ A.~ b p, ld'~ I C ~FISHERS ISLAND GARDINERS 5 9 ~, ~.o r5 z.o SC ALE IN MILE S TOWN OF SOUTHOLD LOCATION MAP 8 ~f appreciable size, but there are a number of fresh waver '.ponds~ some of which are a source of waver for irrigation. ~lu.cn of the land is open land: suitable for cultivation. There are a number of iow wet areas and salt waver marshes. Most of ~nese are located adjacent vo the numerous salt waver inlets along the southerly shore of the peninsula. Three salt waver inlets (Mattituck Creek, Hashamomack Pond~ and Dam Pond) and adjacent marsh!ands and ~nlets divide the penin- sula znvo four separate island-like hydrological areas. These areas, which are designated from west vo east as Are. as A~ B~ C, and D in Geological Survey Water Supply Paper 1619-GG: are ~onsidered separately in connection with estimating the po~en~mal yield of underground waver~ because areas for re- :barge and ground-water levels mn each are different. There are two small peninsulas, Little Hog Neck and Great Hog Neck: which extend southerly from the main Peninsula and are separated From it by sal~ water ~nlezs and marshes. These also must be considered separately in connection with ava:iabitity of ground-waver. there are a number of attractive beaches along the souther- ly irresular shore line of Southold. These beaches and the fact ~ ~ ~h~o the area provides excellent natural facilities for boating and bathing~ have resulted in the development of many areas a!¢ng the south shore for seasonal and permanen~ homes. Yhere are a few such developments along the northerly or Lcng Is!ani shore line. However, the rugged nature of the terrain and the fact that there are fewer favorable boat anchorages aha avvracvive beaches has limited recreational developmenvs along ~nis shore line. Plave A in the pocket in the back cover of this report is a map of Southold upon whic~ the developed areas of Southold are shown. The base map was prepared by Raymond and May, planning consultants for this projecv. This map shows the limivs of the four hydrological areas A~ B, C~ and D, and Livtle Hog Neck and Great Hog Neck~ which are described above. Climate Southold has a mean annual temperavure of about 50 degrees and an average rainfall of about ¥5 inches pep year in the wesvern and central portions~ in accordance with long-term records ay the Cutchogue Station. Shorter term records ay Orient Poinv~ East Marion, and the Greenporv Power House indi- cave thav average yearly rainfall is about 10 pep cent lower than ay Cutchogue. Rainfall is generally heavy in the fall~ winter~ and spring months and much less during the summer months. Yearly rainfall records ay the Cutchogue Station from i949 vo t966~ inclusive~ are shown on Table 1. This shows that voYal rainfall as Cutchogue in 1965 was only 26.7 inches and thas the average for 1963~ 196%~ and 1965 was only 31.7 inches. DuPing these three years , record low rainfall was experienced t0 many parts of the Northeast. TABLE 1 Annual Rainfall Records - Cutchcgue Station 1949 - 1966~ Inclusive Rainfall Year In Inches 1949 a5.21 195o 53.15 1951 6o.5o 1952 Record not complete 1953 51.18 1954 41.68 1955 35.15 1956 ~.96 1957 33.46 1958 51.47 1959 41.39 196o 38.12 1961 41.38 196e 4o.89 1963 33.16 1964 3~.,9 1965 26~8 1966 33.33 Figure 2 shows graphically rainfall at Cutchogue Station by years and by months from 1949 ~o 1966~ inclusive. Monthly and yearly rainfall records from 1960 ye 1966, inc!usive, a~ the Greenporv Power Plant and at the East Marion -{~l! Field are shown on Table 2. 11 TABLE~ 2 RAIN~ALL RECORDS - GREENPORT AREA - 1960 - 1966, INCL. GREENPORT POWER HOUSE STATION 1960 1961 1962 1963 1964 1965 1966 January 3.87 1.70 9.50 3.12 4.61 1.18 3.34 February 5.56 3.1~ 3.~5 3.06 3.65 2.67 3.87 March 1.96 3.95 2.56 3.45 2.49 1.92 2.15 April 2.82 7.04 3.82 .47 6.54 3.36 1.36 May 2.58 4.48 .83 3.85 1.31 2.01 6.31 June 2.05 1.49 3.25 4.35 1.77 1.93 1.67 July 5.25 2.28 1.45 2.68 ~.~ 2.94 .96 Augusv .98 4.13 6.11 2.96 1.32 2.95 1.89 September 9.09 5.72 3.72 2.12 3.09 1.93 5.12 October 2.37 2.66 4.76 .14 ~.99 2.03 3.07 November 3.09 3.01 5.67' 6.40 2.64 1.37 3.71 December 3.67 3.14 1.89 2.74 5.46 1.56 3.18 Total 43.29 42.74 42.01 35.34 41.81 25.85 36.63 EAST MARION WELL FIELD 1960 1961 1962 1963 1964 1965 1966 January 2.94 2.74 5.55 3.12 4.46 1.10 3.09 February 5.90 3.83 3.45 ~.06 3.58 2.74 3.46 March 1.75 4.22 2.56 3.45 2.57 1.28 2.21 April 2.70 8.25 3.64 .47 6.1~ 3.42 1.71 May 2.84 5.52 1.18 3.85 1.30 1.99 6.55 June 1.75 2.00 4.45 ~.35 1.56 1.46 1.58 July 6.84 2.09 .62 2.68 4.29 2.37 .95 Augusv 1.10 4.10 5.42 2.96 0.~82 2.13 1.92 September 9.57 9.89 1.87 2.12 3.27 1.62 4.86 October 3.21 2.94 5.01 .13 5.10 2.05 3.28 Nove~oer 3.20 3.46 5.33 5.84 2.71 1.41 3.70 December 3.94 2.92 1.90 2.46 5.37 1.02 3.16 Total ~5.74 51.96 40.98 34.49 41.14 22.59 36.~7 12 His¥orical DevelopmenE The ~evelopmenv ~f Southold dares back vo early in the !Tvh century. It is believed thav the first settlers were Englis~men who came to Southotd by way of New Haven. The early settlers cleared land and raised principally grain and forage crops. Since that time, agriculture has been an im- porvan~ factor in the economy of Southold. Early in the 19th cenvury~ shipping and whaling were developed ~o a considerable extenv. In 15~8~ the Long Island Railroad exvension vo Green- porv was completed and the Village became the imporvanv mari- time center on a combined railroad and shipping rouve between Net? York and Bosvon. The Village at presenv continues to be a cenver for commercial and recreational fishing activity. The main factor in the economy of Southold is agriculture, and this situtation probably will continue for many years. Topo- graphy~ ~limate, and soil conditions are favorable for produc- tion of vegetables. Conditions are particularly suitable for large scale povavo growing and also~ vo a lesser degree~ for raising such crops as cauliflower ~ cabbage~ and ~russel sprouts. Another factor in the economy of Sout~old is the summer resident and ~ourisv ~rade. This will continue ~o expand as the Long Island limited access highway sysvem and the residen- tial and industrial areas of wesvern Suffolk County are extend- ea easv?~rd. There are a number of unincorporated communities in 13 Southold. The principal cenver of population is the in- corporated Village of Greenport. From the westerly border vo Orient Point~ the unincorporated communities are: Mattituck~ Cutchogue, New Suffolk, Peconic, Southold, East Marion, and Orient. The railroad and~or main highway pass through each of these communities except New Suffolk , which is located on a peninsula in Peconic Bay. The following tabulation lists the U. S. Census Popula- tion of $outhold and of the Village of Greenport, from 1910 vo 1960~ inclusive. TABLE 3 U. S. CENSUS POPULATION FIGURES TOWN OF SOUTHOLD AND VILLAGE OF GREENPORT 1910 - 1960, INCL. Town of Village of Year Southold* Greenport 1910 10,577 3,089 1920 t0, 1~7 3,122 1930 11,669 3~ 062 19~0 12, o46 3~ 249 1950 11,632 3,028 1957 ~12,607 2~645 1960 13,295 2~608 * Includes the Village of Greenporv It is estimated that the presenv permanenv population ~f ~he Town is approximately 16,~00 and that there are about 27500 persons residing in the Village of Greenpor~. It is also estimated that the average population of Southold during she three su~.mmer months is approximately 32,000 persons. 70 ~0 ~ 50 '"t- ~ 4o L~ I0 Ll.I 0 I0.0 5,0 ..r I- o FIGURE NO, 2 70 60 50 40 20 I0 5.0 0 0 I0.0 t5 III. WATER SYSTEMS AND WATER USE General The waYer system owned and operated by the Village ef GPeenport is the only public water system in Southold. This system provides fresh water for domestic use and fire pretection service in areas within and adjacen¥ to the Village. There are also a few small private waver systems 'which supply water so ~roups ef homes. Hest ef the homes and business establishments that are not supplied by the Greenport system obtain their waver from small individual driven wells. Water used for irrigation comprises a major part of the waver withdrawn each year frem the ground. Mos~ of the irri- gation waver is from drilled wells from four to vwelve inches in diameter and from 15 t~ 150 feet deep. Greenport Water System In t895~ the Village of Greenport acquired the small waver sysvem of the Greenporv Water Company. The Village system has been expanded since that time to supply developed areas within and adjacent to the Village. The franchise area of the Village sysvem prior to 1958 extended from Hashamomuck Pond easterly to Shipyard Lane in East Marion~and from Long Island Sound to Greenporv Harbor. In 1958~ the Village purchased the system of the North 16 Fork I~aVer Company. It supplied waver To built up portions of the unincorporated village of Southold. Its franchise area exvended from Peconic Lane east vo Hashamomuck Pond and from Long Island Sound vo Peconic Bay. At that time~ the Greenport sysvem supplied about 1~000 consumers and the North Fork Water Company supplied about 280 consumers. The original well field of the Village of Greenport~ designated as Well Field No. t~ was adjacent to the Power Plant at Moores Lane within the Village. The use .of the No. 1 Well Field for waver supply was discontinued many years ago because of excess chlorides. It is now used for cooling waver a~ the Pcwer Planv. ~he waver is returned to the under- ground supply. Later~ additional wells were drilled at Well Field No. 2 on Moores Lane~ about 2~000 feet north of the Power House and at Well Field No. 3~ near the intersec6ion of Moores Lane and North Road. As the system was expanded and withdrawals of water from Well Field Nos. 2 and ~- increased~ a number of wells were developed in the East Marion area. This was necessary to avoi~ excessive withdrawals from the Moores Lane well fields. Well Field No. 5 on South Harbor Avenue in the Village of Southold is the field that supplied the North Fork Company~ and it is in use at presenv. Recentty~ two new ~?ells were developed north of Middle Road, near Norton's Lane in Southold. These wells have been connected ~o the GreenDort 17 and North Fork systems. ~hey supplied about 54 per cent of vhe water in 1966. Plate ~ shows the location of the six well ~ields des- cribed above. It also shows the location of the six-inch and larger water mains in the Greenport system~ lncludin~ those purchased from the North Fork Water Company in 1956 and the connecting mains between the vwo systems which were constructed recently. The easterly and wesverly limits of the franchise area of tha Greenport system is also shown on Plate A. A plan for extending the system easterly is under consideration. Table h below shows the total average daily water pump- age in gallons in the Greenport system from 1957 to 1966, inclusive. Year 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 TABLE h AVER_A. GE DAILY WATER PUMPAGE GREENPORT WATER SYSTEM Gallons Per Day 8~0,000 ~10~000 400,000 850~000 ~50~000 480,000 510,000 502j000 881,000 610,000 18 Maximum monthly waver consumpvion occurs during the s~nmer months and the daily average during maximum months is about double the yearly average. Maxim~a daily consump- tion is about three times the average daily consumption for the year. Table 5 below lists the number of active services a~d fire hydrants~ the quantity pumped in million gallons, and the percentage increases ~uring the pasv ten year period. TABLE 5 GROWTH OF GREENPORT WATER SYSTEM Active Services Fire Hydrants Water Pumped 1956 1966 Increase increase 973 1650 677 70 166 322 156 ~ 133 mg 222mg 89 mg 67 In the early part of the pasv ten year period~ the Village sold some water for farm irrigation~ but practically no Village water is used for farm irrigation at this time. It is estimated that present pumpage per service a~erages about 350 gallons per day and that pumpage per person averages about 100 gallons ser day in the Greenport system. Domestic Water Use From Private Wells About 10,000 permanenv residents ~in Southold, not supplied by the Greenporv Sysvem~ use an estimated average of 70 gallons per person per day~ or a total of 700,000 gallons per day. Some 15~000 summer residents use an aver- age of 80 gallons per day for Two months, or a total of about 72~000,000 gallons per year. This is equivalent vo an average of 200~000 gallons per day for every day in the year. The permanent and summer residenvs not supplied by the Greenporv Water Sysvem obtain their waver from individu- al wells. Waver Used For Irrigation For many years, Southotd producers of povavoes~ cauli- flower~ and other vegetable crops have utilized spray irri- gation vo supplement rainfall during an average period of 16 weeks each summer. The amounv of water used varies with the weather pattern and soil condition. On the average~ best results are obtained ~hen the ground receives the equivalent of about one inch of rainfall per week. About one half of this generally is con- ~ributed in vhe form of rainfall and the remainder by spray irrigation from water pumped from shallow wells. These extend into the fresh water that is stored in the sand and gravel unde~ tho top soil throughout a large portion of Southold. 2O Mosv of the producers of vegevable crops have becom~ experienced in the economical use of irrigation. It is estimated that during an average season, wa~er used for irri- gation varies from about 150,000 ~o 200,000 gallons per acre per year. At present, about 12,000 acres of vegetable crops are irrigated each year and the average amounv of water with- drawn for irrigation is abouv 2,000 million gallons, equivalent vo about 5.5 million gallons per day for each day during the year. Total Wa~er Withdrawal In Southold As shown in Tables = and 5~ the total pumpage of water in the Greenport System in 1966 was 222 million gallons, or an average of about 600,000 gallons per day. The estimated waver withdrawn for irrigation was about 2~000 million gallons~ or an average of 5,500,000 gallons per day. Table 6 below lists the estimated curren~ rate of with- drawal of ground waver from wells in Southold in average gal- lons per day for each day of the year. TABLE 6 ESTIMATED i966 WITI{DRAWAL 0F WATER IN SOUTHOLD Greenpor~ Water System Private Permanenv Homes Privave Summer Homes Private Irrigation Sysvems Total Withdra~al Average For Year Gallcns Per Day 600~000 700~000 200~000 5~500,000 7~000~000 21 Quality of Water The quality of the fresh waver from wells in Southold is generally very good~ from a chemical and bacteriological standpoint. However~ chlorides caused by intrusion of sea ~aver !~ave caused contamination in certain areas close to the shore line and to salt water inlets. The danger of future contamination caused by salt water intrusion is discussed in the nexv two sections of this report. The hardness of the water from wells of the Greenpor~ System ranges from about 40 vo 200 ppm~ or from soft vo hard. In generat~ ground waver in Southold used for domestic pur- poses and irrigation is moderately hard and is well within the limits of concentration of iron, manganese~ chloride~ sulfave~ and total solids prescribed by the U. S. Public Health Service for intersvave carriers. Except where chloride convenv has increased because of salt water intrusion~ chlorides in Southold ~ells generally range from 10 vo 50 ppm~ as compared to the 250 ppm limit generally considered the maximum concentration permissible for potable waver. Southold's ground-water supply generally is cool, clear~ and pleasing to the ~aste. Unlike certain areas of Long Istand, where there has been extensive residential developmenv prior to sewer construction~ there have been no serious prob- lems caused by detergents in the well waver. Greenport has a se~,~erage sysvem~ consisting of a primary plant with effluent 22 discharging into Long Island Sound. Other areas should be se~ered ay locations where there is a concentration of residenvia! developmenv and water is drawn from individual shallow wells. 23 IV. GEOLOGY Subsurface Conditions Most of the wells in Southold terminate at comparatively shallow depths.in upper Pleistocene deposits which are the source of the fresh water used in Southold. Three deeper wells have been extended through older formations in Southold: one in Orient Park (S189)~ one in Greenport (S~91)~ and one at Nassau Point (S3123). The first two exvended to bed rock and the third extended into the Magothy formation. Inform- ation obtained from these three wells, and also from other deep wells in the eastern ~arv of Long Island~ indicates that it is probable that the water contained in the older and deeper formations is too high in chlorides for domeBtic use and that no substantial quantities of fresh water for use in Southold may be obtained from these older formations. Bed rock in Southold is from abouv 1,000 feet below the surface in the western part vo about 500 feet in the eastern part. Above the bed rock is the Raritan formation containing the Loyd sand member, the clay member~ and post-Raritan de- posits which are of the Cretaceous age. Above the Cretaceous deposits are unconformed layers of Gardiner's clay and the upper Pleistocene deposits of varied depth, which consist of stratified and unstratified sand~ gravel, and gravel with some clay. Most of the ground-water used in Southold is with- AREA A S6558 MALCOLM PIRNIE ENGINEERS WHITE PLAINS~N.Y- PARAMUS~N J. ,(ATTITUCK ~ 'S6542 SUFFOLK L 0 NG AREA B SOUND LITTLE AREA C PECONIC GOUTNOLD / ' B,~ Y /~ EAST MARION GREENPORT SHELTER THE PREPS, RATION 0~ THIS EXHIBIT WAS FINANCIALLY AIDED THROUGH A FEDERAL GRANT FROM THE DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT, UNDER THE PLANNING A~SIBT~ ANCE PROGRAM FOR ~'HE BUREAU OF COMMUNITY PLANNING, NEW YORK STATE OFF, iCE OF PLANNING COORDINATION. tT WAS FINANCED IN PAR[ SY THE STATE OF NEW YORE AREA D FIGURE ORIE~ S~6787~,2 ~ GARDIN~'R'S BAY ORIENT POINT TOWN OF SOUTHOLD SHOWN ARE WATER TABLE CONTOURS, JULY 1959 ( ONE FOOT INTERVAL AND DATUM MEAN SEA LEVEL) REFERENCE U,S.G.S. WATER SUPPLY PAPER 16Ig-GG~ PLATE ~000 500 ~ 0 I000 ;~O00 SCALE It~ FEET BASE MAP BY RAYMOND ~ MAY ASSOCIATES NO.4 24 drawn from these deposits, which ~enerall¥ consist of coarse sand and gravel. Physical characteristics of this material are shown in Table 4 of Water Supply Pa~er 1619-GG by mechan- ical analyses of samples from 28 wells in various areas of Southold. More recent deposits, found alon~ the shores and marshy areas, include beach and dune sand and gravel, in some areas mixed with clay. More complete discussions of the geology of Southold are given in U.S.G.S. Water Supply Paper 1619-GG, the Bulletin GW-45 of the New York State Water Resources Commission, and the numerous references on the geology of Southold contained in those two reports. The current comprehensive Nassau-Suffolk water resources study with its deep well program should provide much valuable information on subsurface ~eological conditions in eastern Suffolk County. It should shed much light on the question of availability of fresh water from deep wells in Southsld and on the lower limits of fresh water in the upper permeable ~lacial deposits. Surface Conditions The almo.st continuous strip of high ground along the Long Island shoreline of Southold is comprised of till over- lying sand and gravel. The surface material in most of Southold is sand and gravel outwash covered by one to three 25 feet of top soil, consistin~ of loam of various de~rees of porosity. These areas are generally excellent croplands. Surface clay of various depths exist in some areas. This is true of a sizable area along Moores Drain. This stream dis- charges a comparatively large quantity of fresh water into a salt water bay southwest of Greenport at times of heavy rain- fall. Sand and gravel shore deposits exist alon~ the north and south shore line of Southold. Orient Point Park consists of a long narrow sand spit between Long Beach Bay and Gardiners Bay. Plate 1 of U.S.G.S. Water Supply Paper 1619-GG is a sur- ficial geological map of the Town of Southold. It is repro- duced and included herein as Plate B in the back of this report. The top soil in the uplands or croplands of Southold varies in permeability, as indicated by permeability tests of samples of loam taken at depths of from one-half foot to two feet below the surface. The surface soils range from sandy to silt loam, locally known as sassafras sandy loam, sassafras loam, and sassafras silt. It is suitable for production of large yields of vegetable crops when water is applied by spray irri~ation durin~ dry periods. The character of the soil and the gently slopin~ Topography permit advantageous use of mechanical equipment for planting, cultivating, and harvestin~ crops. 26 V. HYDROLOGY Recharge of Ground-Water The only source of replenishment of the Underground fresh water supply of Southold is the rain which falls on the land. The sandy loam top soil and the underlying sand and gravel permit much of the rain to enter the ground. The ~ently slopin~ terrain and large areas of cultivated lands retard overland flows, as indicated by observations of run-off and stream flow during periods of heavy precipitation. It is estimated that the amount of rainfall that discharges overland to salt water each year averages about 15 per cent and may be as low as 10 per cent in extremely dry periods. A relatively large portion of rainfall returns to the atmosphere through evaporation from the soil and through the transpiration processes of natural vegetatiom and crops. These losses vary with distribution of rainfall, atmosnheric condi- tions, and temperatures. It is estimated that they range from 40 to 60 per cent of rainfall and average about 50 per cent. Assuming 10 per ceflt of rainfall is lost through run-off and 50 per cent through evaporation and transpiration, the re- maining 40 per cent is available for recharge. The estimated annual recharge on this basis is about 18 inches in the western ~art of Southold during a year of average rainfall, and was about 12.8 inches during the record 3-~ear dry period 1963, 1964, and 1965. The total area of Southold is about 43 sauare miles. Re- ducin~ this to 40 square miles because of ~avemcnt and clay areas, the computed annual average recharge in wesvern Southold is about i2~500 millicn gallons in a year of average rainfall and abouv 8,900 million gallons in the three dry years of record. The recharge probably would average about ten per cenv less in %he eastern parr of the peninsula, where rainfall records indi- cate that average precipitation is somewhat less than in the ~esvern part. Storage of Underground Water Information obtained to date from records of well drilling operations in Southold indicates that the available fresh water supply is stored in the sands and gravels of the upper Pleistocene glacial deposits, which are 200 feet or more in thickness. These ~eposits contain fresh water and also salt water. Because of its lesser specific gravity~ the fresh water floavs or resvs on ~ne heavier salt water. The surface of the fresh waver slopes from a few feet above a mean sea level in the central part of each of the areas A, B, C~ and D To sea level ay the Sound, bays, and salt waver inlets. The elevation of fresh waver varies each year in accordance with rates of recharge and withdrawal of waver by pumping. Also~ a considerable amount of ground-water gradually seeps laterally'through the porous underground material into the surrounding bodies of salt waver. Huch information is available as to ground-water levels in Souvhold from 19%9 so date. Wells in Long Island are number- ed in accordance with a sysvem established by the New York State _~.P- v~r Resources Commission. Records of ground-water !evals~ ,s measured by static levels of water in wells throughouv Long Z~i~td~ are maintained ay the office of the U. S. Geological :~rve'v in Mineola. Plate 1 of New York State Water Resources ~.ulletin ~W-~5 shows by con,ours ground-water elevations in ~ouoaol~ in April 1950. Plate 3 of Water Supply Paper 1619-GG is a similar map of Southold~ showing by contours levels of the ,~uver table in July 1959. This plate ~s reproduced and included as Plate C at the end of this report. It shows the locations of wells in Southold by numbers. Measurement of static water, levels in these wells provide the wa~er surface data from which the con- yours were esvablis~ed. As shown on Plate 1 of Bulletin GW-~5 an~ Pla~e 3 of WS Paper 1619-GG~ the water table throughout Southold was considerably lower in April 1950 than in July 1959. ~his was caused by the fact that withdrawals for irrigavion ~ere greater and rainfall was somewhat less in the two to three year ~eriod that preceeded the July 1950 series of measurements. The limits of Areas A~ B~ C~ and D~ and L~ttle Hog Neck and ~at Hog Neck are shown on Plates A and C For convenience, vnese limits and the underground water level contours in July 1959~ taken from Plate 3 U.S.G.S. Water Supply Paper 1619-GG~ are shown on Figure ~ a reduction of the base planning map. The highest ground-water levels are in Areas A and B in the western ~art of Southold~ and ground-water levels in Areas C.and - ~nd in Little Hog Neck and Great Hog Neck are generally lower. As ~how~ on Plate C~ high ground-water levels inJuly 1959 were ~o 8 feet above mean low tide in Areas A and B~ and only ~- ~ a~ 3 fee~ above the mean sea level in Areas C and D and _ foov above sea level in Little Hog Neck and Great Hog Neck. The quantity of fresh waver stored underground in each of the six island-like areas mentioned above depends on the vo!~ne and permeability of the materials which store the water. The lateral limits of each are shown on Flare C. There is sufficient information on svatic wa~er levels To establish upper limits of the fresh water. However, only a few ~ells in Southold are deep enough vo establish the division or interface between fresh and salt water. Because of the general uniformity of the underlying sands and gravels~ it is probable that the'division between fresh and salt water conforms To the Ghyben-Herzberg principle or formula. This formula is in the form of the following equation~ in which h = depth of fresh water below sea level; t = height of fresh waver above sea level; and g = specific gravity of sea water as compared to a specific gravity of 1 used for fresh water: t g-1 Using a specific gravity of 1.025 for sea water~ the equation indicates that fresh water will extend 40 feet below sea level i'or each foot that it extends above sea level. This formula provides a reasonable method for determining the approximate ~ivision between fresh and salt waver when both wavers are stored in an unconfined fairly uniform material. Figure 3 is an idealized section of an island or peninsula~ sho~'~ing the relationship of fresh waver and salt water. Similar FIGURE NO. 3 ~-SEA LEVEL SURFACE WATE TYPICAL GEOHYDROLOGIC SECTION SHOWING RELATION OF FRESH AND SALT WATER (ACCORDING TO THE GHYBEN- HERZBERG PRINCIPLE) MALCOLM PIRNIE ENGINEERS WHITE PLAINS, N.Y. - PARAMUS~ N.J. 3o .~?vic;~s are included ~n a number of hydrological studies to iilustraEe application of the Ghyben-Herzberg principle. As an aid in estimating the approximate quantity of water ~-vored im each 'of the six hydrological sections~ Plate 3 was included im Water Supply Paper 1619-GG. (It is reproduced as F!ate D of this report.) It shows~ by a longitudinal section and f~ve vransverse sections~ the upper~ lateral~ and lower limits of the. underground fresh water reservoir. The inter- ~'aces or zones of diffusion bevwean fresh water and salt waver were obtained by applying the Ghyben-Herzberg princil,!e to the waver table elevations in July 1959, as shown by the sections on Plate D. In WS Paper 1619-~G~ Crande!l computed the. volume of the fresh water aquifer iu each area, and applied a specific yield of 22 per cent to obtain an estimated total volume of fresh wa~er in s~orage. Table 7, which follows~ shows his es~imate~ volume of fresh ground-water in s~orage in~ July 1959. Although these estimates can be considered only as approximations, they are based on reasonable assumptions as ~o underground conditions. They indicate that over 90 per cent of the fresh water storage at Southold is in Areas A and B and that less tham 10 per cent is in Areas C and E~ Little Hog i~eck and Greav Hog Neck. 31 TABLE 7 Estimated Volume Estimated Volume of Deposivs Satu- of Fresh Water rated with~Fresh in. Storage Water Area ( Mill. cu. ft. ) ( Mill. Gallons ) A 28,200 ~6~000 B 82,000 134,000 C 6,400 10,400 D 6~00 10~00 Little Hog Neck 600 1,000 Greav Hog Neck 2~900 4~700 126~500 206~500 Note: Figures in Table 7 are taken from WS Paper 1619-GG, pp GG-23 and GG-2% Varlatior~s in Ground-Water Levels Figures 5, 6, and 7 show variations in grcu~;d-water Aevels i~ cervain wells in Areas A and B from 1949 vo 1966, l. nclusive, and in certain wells in Areas C and D ~'rom 1959 to 1966, inclusive. The low ground-water levels in 1949 and !P50 were caused by excessive withdrawal for irrigation purposes. The very low ground-water levels in 1966 resulted from record low rainfall from 1963 through 1965. Deficient rainfall also caused comparatively low ground-water levels i.~ 1957. 7.0 6.0 5.0 4.0 3.0 -- 2.0 .J .J Ill ~. 6.0 w -J ~ 4.0 -J bJ 3,0 2.0 1.0 FIGURE NO. § 7.0 6,0 5.0 4.0 $.0 2°0 6.0 5,0 4,0 :5.0 2.0 1.0 1950 1951 1952 195:5 1954 1955 1956 1.957 195 1960 1961 1965 1964 1965 1967 8.0 FIGURE N0.6 9,0 8.0 7~0 7,0 6.0 5.0 ILl IL. Z J J . ~.0 0 Z I-- <[ 2.0 ~ 4.0 -J bJ u.I 3.0 ._l ~: 2;0 6.0 5.0 4.0 2.0 4.0 3.0 2.0 1.0 .0 0 1949 1950 1952 1954 1955 1956 1957 1960 1962 1963 1964 1965 1966 1967 1968 FIGURE NO.7' 5,0 5.0 - 4.0 4..0 -- 2.0 1.0 0 5.0 4.0 3.0 2.0 LO 1958 1959 1966 32 Vi. AVAILABILITY OP FRESH WATER Salt Water Intrusion The d~nger of sait waver intrusion is the principal limiting factor in the amount of waver that can be safely xithdrawn from the ground in various parts of Southold. This is because the fresh waver in storage is surrouneed on all sides and below by salt water~ as shown on Plates C and D. The ~anger of salt water intrusion is more serious at locations where the static level of the fresh water is only a little above mean sea level. This is particularly true in Areas C and D, Little Hog Neck and Great Hog Neck~ and areas adjacent vo bodies of salt water in the other parts of Southold. With- drawals of water from these areas for domestic use and irri- gation can nov be increased to any appreciable extent without 3ausing contamination of the supply by either lateral or tutti- sat intrusion of salt waver. A number of instances of salt waver contamination in Southo!d are recorded in Water Supply Paper 1619-GG and other reports. In some instances~ the contamination has been caused by lateral movement of salt water into the fresh water where the wells were located close to bodies of salt waver. Excess 3htorides caused by vertical movement of the salt water has been experienced in the pasv~ particularly during periods of low rainfall~ in water withdrawn from wells used for irrigation an ?;aver supply. 33 Esvimatea Safe Yield A number of factors affect the quantity of fresh water ~ha% may be safely withdrawn from the ground in various parts of Southold. The principal factors are amount and distribution of rainfall, character of surface and underground.materials, purpose for which the land is used, location of points of with- arawal in reference vo salt water, and the elevation of and variations in ground-water levels in the general vicinity of the points of withdrawal. Records of rainfall, ground-water levels, and underground ~onditions in Southold developed during wev and dry periods for the past 15 to 20 year period generally are available. To a lesser degree~ records of the quantity and chloride content of water withdrawn in various parts of the Tov;n are available and are helpful in considerations as to the safe yield of unaer- ground waver during periods of low rainfall. Based on a study of the records and experienc~~ on with- drawal of water during the pasv 15 or 20 year period, it is esvimated thav the approximate yield of Southold~s ground-water supply is approximately ~0 per cenv of recharge during periods ~f three consecutive yea~s. In Section V of this report, it ~as svated that estimated annual recharge during periods of average rainfall is abouv 12,500 million gallons and is about ~O0 million during extremely dry periods~ such as those ex- 's.~ri£naed recently. Using %0 pep cent of recharge for yield, vhe estimate~ yield in a period of average rainfall would be ~D00 million gallons, or an average of 14 million gallons ~er ~ay, and ~uring a three-year period of minimum rainfall, ~he yield ~ould be about 3,600 million gallons~ or an average of 10 million gallons. For purposes of this study~ an average of !0 million gallons per day will be considered as the safe o£ ~y ~eather yield of the underground water supply of Southold. At present~ an average of about 7 million gallons of fresh ~aver per day are withdrawn for domestic and irrigational uses. ~n accordance with the above estimates of available yield, an additional withdrawal of about 10 million gallons per day could be made during years of average rainfall. However, the safe yield of a water sysvem must be based on years of record lo~ rainfall. This indicates that withdrawals of 10 million ga!lons~ or o million gallons in excess of 1966 withdra~als~ may be safely made in the future under conditions of witndrawai designed ~o prevenv salt waver intrusion. Rslationship of Available Ground-Water ~o ~lanning As shown in Table 6 of Section IiI~ total estimated with- ira~?al of ground-waver was an average of 7 million gallons per ~ay for each day during the year of which an average of 5.5 ~i!!ion ~al!ons per d~y was used for irrigati~g vege~ab!e crops. Assumin~ that vhe number of acres irri~ate~ and ~rrigation practices 35 ~iil remain about the same as in 1966~ the safe yield estimate ~f t0 million gallons per day in dry weavher indicates thav about 3 million gallons per day will be available for domestic use. It is estimated that future average per capita waver use in Southold will be about 120 gallons per day for permanent residenvs and about $0 gallons per capita per day for an average of two months per year for summer residents. This is equivalent to 16 gallons per capita per lay for each day of the year. The 120 gallon per day allowance for permanenv residents ig higher than presens use and is based on the assumetion that domestic~ commercial~ and light industrial use will increase in the future. It is probable that the number of seasonal residents will increase in the fuvure as Suffolk County developments extend in an easserty direction. Assuming that summer residents increase three-fold to abou~ ~5~000 persons within the next 20-year period~ this will mean additional water consumption of about 500~000 gallons for each day in the year. This will leave about 2.5 million gallons for an increase in permanent residential use. Assuming a per capita consumption of 120 gallons per day~ the remaining 2.5 million gallons will provide for more than 20~000 persons~ or a total of 36.000 permanent residents~in aadition To ~5~000 seasonal residents. As stated above~ these estimases.assume that the amount of waver used for irrigation ~.;ili be equivatsnv ~o 5.5 million gallons per day for 365 days a year. Zrrigation waver use of 200,000 gallons per acre per year is equivalent to the consumption of about 5 permanent residents, or more than 30 summer residents. If withdrawal of wa~er for irrigation is decreased in the future~ the safe yield will provide a supply for a greater number of additional permanenv and/or summer residents than indicated in the previous paragraphs. Conversion of Salt Water Considerable progress has been made during recenv years in research, and in pilot plant and plant scale operations relayed ~o conversion of salt and brackish waver to fresh waver. However, costs of consvruction and operation of saline wa~er conversion plants are generally prohibitively high, e×cep~ where an adequate supply of fresh water is unavailable. Several operating plants of 3 million gallons and less per day are in oDeration or are in the planning or construction stage of developmenv. These include operating plants located in the Virgin Islands, Saudi ~rabia, North Carolina, and t e Naval Base ay Guantanamo Bay~ Cuba. However, the cist of con- struction, maintenance, and operation of these plants is very high. Lower costs are estimated for large plants which will combine power production with salt water conversion by utili- zation of atomic energy. Financial arrangements of a large ~lant of this ~ype at Long Beach] California, recently have been completed. This plant is ~eing designed to produce 37 150 million gallons of fresh water per day, as welt as large quantities of power for use in the Los Angeles area. Condi- tions at that location are comparativel~ favorable for a large atomic power and saline conversion plant. The New York State Atomic and Space Development Authority has been developing plans for a combined atomic Dowered elec- trical generating and saline water plant at Surfside in the Town of Riverhead. The initial water plant will have a capacity of about one million gallons per day, with provision for future increases in capacity, Preliminary plans for this installation have been in progress,for some time. At present the plant is being designed ~ and operation is scheduled for 1970. An agreement has been made with the Town of Rivcrhead to purchase one million gallons of fresh water a day at an initial cosy of 35 cents per 1000 gallons, with a provision for a gradual increase to 45 cents per 1000 gallons in the first 10-Meat period. The plant will be located on Long Island Sound, relatively close to the border line of the Towns of Riverhead and Southold. The capacity of the Power Plant will be 2500 kilowatts. The Long Island Lighting Company has agreed to purchase electric power from the install- ation at a cost of 15 mills per kilowatt hour. There is more than sufficient ground-water available in the western portion of Southold for present and probable future needs, unless an unforseen industrial demand for fresh waver develops. It does not appear to be economically feasible 38 f~r Southold to utilize converted sea water from this plant =or domestic, commercial~ and irrigation use in the foreseeable fuvure. However, if industries which use a large quantity of fresh water are developed in the western part of Southold, they may find it advantageous to obtain water from the proposed Surfside Plant. 39 VII. PROTECTION OF GROUhYD-WATER RESOURCES Zt is essential that Southold employ every available means vo provect its limited ground-water supply. Following are me~hods that should be investigated and considered: 1. Control of future water withdrawals. 2. Location and spacing of wells. 3. Extension of public water facilities. 4. Discontinue approval of projects which include dredging channels inland from salt water estuaries or bays. 5. Construction of dikes across drainage channels near shorelines. 6. Recharge of aquifer with surface waters. Control of Future Withdrawals At presenv the installation of wells for public water supply and commercial and industrial use is subject to the approval of the State Water Resources Comm~issio~-. 2tare regulations also require filing of data for record purposes on wells other than small wells serving individual homes or buildings. However, the state do~s not exercise control over installations and the amounts of water that may be withdrawn from irri~ation wells. The location, spacing, and amount of water withdrawn fr~m large wells are important factors in the protection of the fresh water supply in Southold from salt waver intrusion. 4o Ti~e advisability of vhe Town exercising control over future well installations from a legal, engineering and administrative svandpoint should be given serious consideration. Location and Spacing of Wells The location, spacing, and depth of wells of large capa- city depend upon a number of factors, and each new installation shauld be considered individually. Such wells should be constructed at some distance from salt water and at logations where minimum static ground-water levels are two feet or more above mean sea level. In general, they should be spaced at least 500 feet apart and about 1000 feet from the shore of salt water bays or inlets. Samples of water should be taken and tested for chlorides~ particularly at times of low ground- water levels and heavy withdrawals. Pumping should be dis- continued whenever a definite increase in chlorides is indicated. Wells vo provide large quantities of water for public water supply should be constructed in the central portions of Areas A and ~ , where ground~water levels are comparatively high. Extension of Pnblic Water Supply Facilities The Greenport Water System supplies water to about one third of the total permanent population of Southold. Most of the remaining permanent and summer residents are supplied by shallow individual wells. The water from many of the wells thav are close to salt water ~s of poor quality. In areas wi~ere homes are not very far apart, there is always the danger 41 of pollution. Also, excess removal of fresh water from the ~rou~d-water table near the shore eliminates the existing ~atural fresh water barrier. As the population becomes more dense in many areas of Southold, public water supply facilities should be provided. The Greenport Water System should be gradually extended east- ward along Main Road to supply water to the unincorporated villages of Orient and Orient Point. The East Marion Wells and a new well near Main Road north of Orient village could be used to advantage to supply the comparatively small water consumption in this part of Southold ~ which has been designated Area D. Certain areas adjacent to the Main and North Roads, and alon~ the southerly shore line of Southold, between the pre- senv limits of the Greenport Water System and Mattituck, including built-up areas of Mew Suffolk and Mattituck, should have public water service with adequate fire protection facil~- ties in the near future. This service could be supplied best by extension of the Greenport System or by a new system developed and operated by the Suffolk County Water Authority. Both organizations are experienced and competent to provide efficient service. Decrease ~ insurance costs and increase in property values resulting fr~m an adequate water system will compensate to a considerable e×ven~ for the cosv of the service. Z~ia~d Salt Water Channels I~ recent years, approval has been given to extending [~land from salt water bays or estuaries certain dredged channels to provide for development of marinas or water re- sidential property. As shown on Plates A and B, in the vi- cinity of each natural or dredged channel extending inland, the contours representing very low ground-water levels extend for a considerable distance from the shoreline of the estuary. This provides a shorter distance of travel, and thereby in- creases the loss of fresh water from storage and the possibility of salt water in~rusion into nearby well supplies. Recently, applications for approval of such projects have been made. There are many sites along the water front of Southold where such developments can be made at low oost. Many future applications for approval of construction of inland salt water ~han~els can be expected unless approvals for such developments are denied by the Town. Numerous coves and bays along the South Shsre provide sites suitable for marinas a~d water front residential properties, and ~t is not necessary to-endanger tbs underground water supply by the extensio~ of salt water cha~nels ~nland. Drainage Channel Dikes The surface c.ontours on the Geological Survey maps of 2outhold and field ~bservations indicate that there are a .:'~mber o~ drainage channels that extend to the south shore _!~e of Southold, across which it may be feasible ~,o provide 43 low dams or dikes no restrict surface and under,round drainage of fresh water into salt water inlets or bays. In some instances it might be advisable to construct excavated ponds above the dikes to store fresh water at elevations above mean tide level. Available information indicates that many of the drainage basins are covered by marsh deposits ~'which would tend to store the fresh water above sea level. Some of the dikes would .serve to convert existing salt water inlets into fresh water ponds. Zt probably would be advisable to provide sheet pile cut-offs under some of the dikes. Inlet and outlet facilities in the dikes will be necessary to control the water above and below each dike. Each installation would provide a water barrier which would retard fresh water underflow from the ground-water storage basins to th.e sea. The locations which offer the most promising possibilities for this type of installation are numbered 1 to 16, inclusive, on Plate A. Surveys and borings are necessary at each location to establish the feasibility, effectiveness, and cost. Recharge of Surface Waters The State Highway Department and some of the Counties and Towns in Long Island have designed highways and, in some instances, storm drainage systems to discharge into excavated recharge basins extending into the coarse sand and gravel material. Some have' been constructed in Southold. This practice should be continued. For a number of months each year~ the Village of Green- oort oumns water from a pond located on Moores Drain and dis- charges it on lands around wells in Well Fields Nos. 2 and 3. The water level in the wells is raised and an increase in the yield results. Much of the surface of the drainage area of Mcores Drain is comparatively impervious, and during periods of heavy rainfall large amounvs of fresh water are discharged into Pipes Cove. Additional storage ponds for recharge should be ccnstructed on Moores Drain. The sewage of Greenporv is now treated in a primary plant and the effluent is discharged through a subaqueous outZall extending into Long Zsland Sound. Extensive experimental methods for complete treatment of the effluent from its activated sludge treavmen~ plant and discharge of the effluent in~o the ground to form a fresh waver varrier are being con- ducted in Nassau County by ~he County and the U. S. Geological Survey. This program includes the construction of a complex recharge well and nearby vest wells to permit a series of tests on the effect of the recharge of the treated wastes on the water-bearing sands at various depths. It is expected that this program will provide considerable data relative to the feasibiZity of treating large quantities of liquid wastes to such a degree that they can be returned to the ground and in- crease the available underground fresh water supply under conditions such as those prevailing in Long Island. Similar treatmenv and recharge of ground-water squifer have been undertaken in California and other states. At present it is nov necessary nor economically feasible for Greenport to change its method of disposal of sewage. However, the aforementioned method should be given consideration for disposal of sewage from Greenport and other thickly settled areas of Suffolk County in the future. 46 VIII. Fishers Island Water Resources General Conditions Fisaers Island is in Long Island Sound, about 11 miles northeast from Orient Point and 7 miles southeast from New London. It is about 6 miles long and about one-half to a mile in width, and its area is 4.2 square miles. The inset on the right hand pcrtion of Plate A shows the main features of the Island including roads, ponds and the location of the water supply mains. Fishers Island has long been famous as an attractive summer resort. Its rolling hills, irregular shareline and large areas of natural woodlands provide exceptionally beau- tiful scenery. Most of the easterly portion of the Island is owned by The Fishers Island Club and its members. In this section there are a number of summer estates that were established many years ago, and also extensive areas of undeveloped fields and woodlands. A large part of the westerly half of the Island is owned or controlled by Fishers Island Farms, Inc. Many people spend all or ~art of the summer in this part of ~ishers Island. Portions 6f the western part of the-Island have been used'from time to time for military e~tablishments, but these hav~ been ~e~tivate~. A ferry from New London provides access to the Island. Many persons use privately owned boats and planes to reach the Island. 47 The climate is about the same as in other parts of Southold. However, the ~opography and underground conditions are different. There are hills up to about 160 feet high in both easterly and westerly portions of the Island. Much of the land is undevel- oped and generally is less pervious than the mainland areas of Southold, and a much larger portion of the rain drains overland to fresh water ponds and to the surroundin~ coves and bays. Glacial deposits occur in some areas and these are possible sources of fresh water, but the water from wells in these deposits generally is high in iron and in some cases it is high in chlorides. Population and Water Consumption The permanent population of Fishers Island varies between 400 and 500 persons. It is estimated that maximum peak ~opu- lation during summer weekend periods is about 5,000 persons. The Fishers Island Estates Corporation owns the watar system which supplies water on a retail basis to the eastern ~ar~ of the Zsland and, on a wholesale basis, to Fishers Island Farms, Inc., which cwns and operates the distribution system in the western part of the Island. As indicated on Flate A, these two systems provide water service to most of the developed areas throughout the Island. The followin~ tabulation lists the amount of water pumped from the treatment plant each mont~ in 1965 and in 19~6, ex~resse~ in ~erms of 1,000 gallons ~er month. 48 Tab le 8 WATER PUMPED FROM THE FISHERS ISLAND TREATMENT PLANT (1~000 GALLONS PER MONTH) 1965 1966 January 2,366 2,288 February 2,~84 2,272 March 1,772 2,266 April 2,244 3,037 May 6,401 4,033 June 10,087 7,589 July 14,419 14,123 August 11,770 12,060 September 7,185 6,215 October 3,665 ~,279 November 2,708 2,882 December 2, a20 4,780 Total Av. Daily 186 170 Av. Day - Max. Mcnth 465 458 Av. Day - Min. Month 57 73 As shown in Table 8, average daily pumpage in 1965 was 186,000 gallons per day. During July, the month of maximum consumption, it was 465,000 gallons per day. Maximum daily use occurred on July 14, 1965, when pumpage of 628,000 gallons was recorded. There is no indication that there will be a substantial increase or decrease in water consumption during the nexv 10 or 20 year 9eriod. ~9 Existing Water SysTem ~he main source of water supply is from two shallow fresh water Ponds, Barlow Pond and Middle Farms Pond. Normallv, both Ponds provide ~ravity flow co the suction of low lift ~umps which raise the water for treatment to a filtration planv t~av has a nominal capacity of one million ~allons per day~ The 1963-66 extremely dry period depleted the available svorage in the two Ponds to an a~arming degree, and a 6-inch v~st well and an 8-inch gravel packed well with 12-inch ouver casin~ were installed near Middle Farms Pond in the summer o~ 1966. Water was discharged from this well into the Pond during the latter part of 1966. Initial tests of the well water indicated that it contained more than desirable ~uantities of iron. Possibly the water qualit~ will ±mprove with use. The use of these wells was discontinued earl~ in 1967 when the Ponds were filled by surface runoff resulting from normal rainfall. The wa~er treatment plant is located near ~arlow Pond. It is a well designed and operated plant with a nominal capacity of 1 million gallons. Thi~ plant is adequate for ~resent and probable future use. The high lift vum~s are rated~at 800 gallons per minute. The clear water storage basin at the plant has a capacity of 400,000 gallons. 5O it is feasible to add storage to the surface supply system by utilizin~ Treasure Pond. A portion of a larger ~ond, Zsiand Pond, could be utilized for storage by providing dikes to main- vain the northerly portions of the Pcnd as a fres~ water Pond. This Pond became salted during a hurricane storm and the lower ~orvion is now used to produce seed oysters. The new well and test well, which have a combined installed pumping capacity of 250 gallons per minute, are available for supplementing the surface supply, if this is necessary. The two new wells provide means for increasing raw water supply when mixed wivh stored surface waver. Additional pumping and testing should~be carried out periodically to determine whether iron content has been reduced to satisfactory limits. Should unexpected increase in demand occur, iron removal and chlorination facilities could be added to permit regular use of the well waver. The distribution system consists of a princi~a~ 10-inch feeder main extending easterly and westerly from the treatment plant, and smaller branch mains. A million gallon capacity storage reservoir, located on Chocomount Hill about 1~~ miles east of the treatment plant, floats on the system and controls the s~avic pressure. A 500,000 gallon storage reservoir, known as the Bell Hill Reservoir, originall~ ~rovided storage on the westerly part of the system. This is an uncovered reservoir and it is understood vhat it has not been used for many yea~s by order of the State Health Department. 51 There are approximately 80 hydrants in the system. Hydrant ~esvs made by the New York Fire Insurance Ratin~ Organization a few years a~o indicated that only a few hydrants could deliver 500 gallons per minute and many of them could not deliver 250 ~allons per minute au 20 pounds per squ~re inch residual ~ressure. A detailed investigation of the adequacy of the distribution sysvem is beyond the scope of this report. Howevsr, it is apparent that the system is inadequate vo provide sufficient waver co many of the existing hydrants in both easterly and westerly parts of the Island. A competent water works consul- tant should be engaged to make a detailed investigation and reporv on the need for additional distribution storage and/or mains and the recommended improvements should be undertaken as soo~ as possible to provide sufficient water a~ hydrants for adeqmate fire protection. 52 IX. CONCLUSIONS AND RECOMMENDATIONS }enerai Southold nas no surface svreams or lakes of appreciable size, and its sole source of fresh waver is ~round-waver stored mn the relatively eervious glacial deposits which exist throuzh- our most earts of the peninsular portion of the Town. Most of the wells which withdraw water for eublic water supply, irrisation, and individual domestic use are comparatively shallow wells which extend from a few feet to about 100 feet into the ~lacial deeosits. Estimaves of Safe Yield Rainfall in Southold averages about 45 inches a rfear. Durin~ the record three year dry eeriod ( 1963, 1964, and 1965) the average was only about 32 inches, and in 1965 only 26.7 {nches were recorded at the CutchoEue Staticn. A relatively larEe portion of the rainfall revurns to the s.b~o: ~ere through evaporation from the soil and through the transsiravion of natural vegetation and cultivated croes, and about 15 Der cen~ ~lows overland to saltwater. It is estimated that 50 per cenu of the rainfall, envers the sround and that abcut 200 million zailons of fresh water is stored above saltwater durin~ average eeriods of rainfall. However, onlv a portion of this can be };ithdrawn withouv causin~ convamination of the fresh wa~er sueelv ~.~ith saltwater. Some of the stored ~resh waver flows laterally v~ the various bodies of waser which almost comeletelv surround 53 Southold. Furthermore, it is not safe to withdraw fresh waver from any ~ortion of Southot~ to such an extent that the ~round- ~ater level is below 1 or 2 feet above mean sea level because of dan~er of contamination by saltwater. As described in Section VI of this report, the ~an~er of saltwater intrusion is the principal limitin~ factor in the amount of fres~ waver that can be safely withdrawn from the ~round in various parrs of $outhold. In this section of the report, it is stated that the estimated safe yield is about 6,000 millio~ ~allons per year during normal periods of rainfall and about 3,~00 million gallons per year, or an average of about 10 million gallons per day in an extremelv dry period. These estimates are based o~ a number of factors, includin~ records of ground-water elevations, withdrawals for various ~ur~oses, and hydraulic compUtations based on data obtaine~ from various sources. Fortunately, there have been extensive past investi- gations made by representatives of the U. S. ~eolo~ical Surve~ amd others on ground-water conditions in Southotd which ~rovide much useful data. Estimates of Population and Water Use It is estimated ~hat the present population of Southold is about 16,000 an~ that peak population in summer months is about ~wo times this fi~mre The water system owned and operated by the Village of Oreenporv is the only ?ublic wa~er sysvem in Southold. It supplies more than 600,000 ~allons -oar da~ of wa~er vo about 54 ~,000 ~ersons in areas within and adjacent To the Village. ~t is esvimated that abouv 10,000 psrmanenv residents o~ Southol~, not supplied by the Green~ort system~use an average of about 700,000 gallons per day and that some 15,000,000 summer residents use about 72 million gallons per year or the equivalent of an average of 200,000 gallons for eac~ day of the year. The total estimated withdrawal of water for domestic use now averages 1.5 million gallons per day. Approximately 12,000 acres of vegetable crops are irrigated during dry ~erio~s eac~ year. It is estimated that average withdrawals for this purpose is about 5.5 million gallons per day, and that total withdrawals average about ? million gallons per day. The quality of well Water is generally good. Zt ra~es from soft vo hard and at most locations it is moderatelv hard. Iron content is greater than desirable i~ the water from certain wells. There have been no serious ~roblems caused b~ detergents, but this may be & future ~roblem in develope~ areas, unless these areas are sewered. The Village of Green~ort has a sewerage sysuem. The above estimates of safe yield and presen~ withdrawal indicave that at least 3 million ~allons ~er day of water, i~ addition vo ~resent withdrawals, are available durin~ the driest ~eriod of record. Assuming that the amount of water withdrawn for irrigation remains constant, the additiona2 ~ield w~ll ~rovide ~ufficienv wa~er for a vocal of about 35,000 ~ermanent residents and about -5,000 seasonal residents. Average irri~ation use is esuivalent vo about 200,000 gallons per acre ~er year, or about the averag~ consumation of 5 permanent residents or more than 30 summer residents. The above estimates indicate that the available ~round-water in various parts of Southold must be considered in connection with sound ylanning for the most effective utilization of lands in various points of the Town. The water resources of Southold are limited vo an amount which does not greatly exceed present use. It is essential that Southold must employ every available means for protectin~ this limited ground-water supply. The followin~ suggested methods should be investigated and be given consideration: 1. Control of future water withdrawals. 2. Location and spacing of wells. 3. Extension of ~ublic water facilities. Discontinue approval of projects which include dredging channels inland from saltwater estuaries or bays. 5. Construction of dikes across drainage chan~els near shorelines. ~. Resharge of aquifer with surface waters. The need for considering each of the above methods and how they should be implemented are discussed in Section ~f the reoort. Possible Supplies other than Ground-Water The feasibility of utilization of fresh water sources other than ~round-water has been aonsidered. One of these 55 sources is waver from the atomic power and saline conversion ~lant now being planned by the New York Atomic S~ace Develoument Authority. This plant will be located on Long Island Sound, ay Surfside in Riverhead, not far from northwesterly uart of Scuthold. This project is described on pages 37 and 38 of the report. The present contractual cost of water, 35 cents ~er 1000 gallons a~ the plant with a gradual increase To 45 cents, is far greaver than the cost of ground-water. It does not appear economically feasible for Southold to util±ze converted sea waver from this ~lant in the foreseeable future. There is an excess of ground-water in portions of the Town of Riverhead, east and west of the built-up sections. Should industrial developmen~ in the westerly portion of Southold un- expectedly increase, it may be possible to utilize some of this excess ground-water. Fishers Island Water Resources Fishers Island, an attractive summer resor~ in Lonz Island Soun~ near the Connecticut and Rhode Island shorelines, is one of the five islands within the Town of Southold, and it is included in the study area covered by this report. It is about 6 miles lon~; its area is ~.2 square miles; and the ~ermanen~ population is about 450 persons, with a ~e~k of about 5,000 persons during holiday weekend ~eriods. A privately owned central waver supply syste~ extends vhrou~hou~ the Island. The principal source of water is surface waver which is drawn from vwo small relatively shallow ~onds in the ~envral portion of the Island. The surfaces of the Ponds when full are only a few feet above sea level. Average daily water use is about 200~000 ~allons; average daily use in July, the -seak month, is about 470,000 ~allons; and a maximum daily pumpage ~f 465 gallons was recorded in July 1965. The available water in the vwo presently used storage reservoirs was drawn down, in the summers of 1965 and 1966, vo a de~ree that caused concsrn. A test well and larger well were driven in the summer of 1966 and used to supplsment the water in one of the ponds during the latter part of 1966. Since then, more than aormal rainfall has increased storage,and the use of the wells has been discontinued. Tests in 1966 indicated that the well waver convained much more iron than is desirable. Two other ponds are available for additional svorage and it may be feasible To draw down some of the ponds lower than ~resenvty can be accomplished, without causin~ saltwater i~- vrusion. This can be determined by a testing pro~ram of wate~ in t~e ~onds. Should the wells convinue vo produce water high i~ ~ron convent, iron removal facilities can be ~ro~ided at the wells and, if necessary, they could be regularly used. The existing treatment plant, which has a nomina~ capacity ~f ~ne million gallons per day, is adequave and well o~erated. The distribution sysvem comprises a main 10-inch feeder e~xvendin~ easterly and westerl~ from the vreatment plant which 57 is in the centra~ portion of the Zsland, and a number of smaller mains. At ~resenv, there is only one storage tank in the dis- tribuvion system which is located on a hill about 1~ miles easverly from the treatment plant. A second tank is. needed in the westerly part of the Island. Hydrant flow tests made a few years a~o indicate that the ~istribution system is inadequate to provide proper auantities of w~ter for fire protection purposes. This situation has been confirmed by our present investigations. It is recommended that competent water supply engineers be re- tained to make a detailed study of the distribution system and storage facilities and to recommend needed improvements. SECTION A-A' FROM LONG ISLAND SOUND TO GREAT PECONIC BAY (AREA A) / / / / o F SECTION B-B' FROM LONG ISLAND SOUND TO LITTLE RECONIC BAY (AREA B) 5O SECTION O D' FROM LON~ ISLAND SOUND rO GREENPONr HARBDR (AREA C) 690-105 O-Gl(IN POCKET) SECTION F-F' FROM HERRICKS LANE TO PLUM GUT (,l()ll~l)l{OI,O(,l( ST( lIONS IN TIlE TOWN OF ,$()t IIIOLI), SUFFOLK COUNTY ~ NEW YORK SOUTHOLD , N.Y. INVESTICATION OF WATER RESOURCES PLATE D REPRODUCTION PAPER 1619-G G ) WATER - SUPPLY OF PLATE 2 OF MALCOLM PIRNIE ENGINEERS SCALE ' AS NOTED WHITE PLAINS, N.Y. DATE ' JUNE 1967 UNITED qTATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY ,-1 /_ Qo G R E A T P E C / )uck Pond Point / .5'~. / ,4 N D ~ 0 N WATER-SUPPLY PAPER PLATE I D REE I S £ ,4 N D osh ~ ,q£,4CH 1619 GG 0 N I C SOUND G~IRDINERS B/IF LITTLE CONIC : o* / / ~ ' / / ~ ~ SOUTHOLD , N Y. / / ~ / ~ / ~ / water Resources ~ / ~ / / ~ / PLATE B / % / / % / l.~..oouc~,o, o~*.~ ~o~ MAP OF THE TOWN OF SOUT[I~~~ ISLAND, NEW YORK ~ / . [. = '~ = 2 ' ~ ~ ~,L~S ~ / ~ WHITE PLAINS, N.Y. DATE : JUNE 1967 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY )¸98 R E EXPLANATION Well for which Icg is given in table 2, or Icg is shown graphically on geohydrologic precipitatiun station 0 Approximate center of populated A A' N / I 592 ,4 Y MAP OF THE //-AREA \ \ \ \, /LITTLE HOG TOWN L I P K C N D ~------ AREA C 6782 T T L E 0 N C ' ~' L) OF SOUIHO 1 , LONG AND POSFFION OF THE tie /$L S 0 HOG / ISLAND, NEW WATER L TEl? mND UND O/ U WATER-SUPPLY PAPER PLATE 5 / YORK,, SHOWING LOCATION OF WELLS TABLE IN ,JULY 1959 : ~ £ OAIG LYEACH ARDINER$~ BAY ./ SOUTHOLD , N.Y. INVESTIGATION OF WATER RESOUROES PLATE C REPRODUCTION OF PLATE 3 OF (WATER- SUPPLY PAPER 1619-G6 ) I 2 5 ] MILES MALCOLM PIRNIE ENGINEERS SCALE ' WHITE PLAINS, NY. DATE 1619 GG AS NOTED JUNE 1967 ~-~%,, AR~A A + AREA B + AREA C + AREA D LONG ISLAND SOUND EASTERLY LIMIT OF GRE WATER SERVICE FRANCHISE / '~ / I / / WESTERLY LIMIT __ __..._. WATER SERVICE J58 OF GREENPORT FRANCHISE / - / / /// / ~ 'S 654,c CUTCHOGUE WELL-FIELD / /NO. 4 'iGREENPORT EAST LEGEND (~) WELLS (WATER LEVELS SHOWN FIGURES 5,6 AND ?) WELL FIELDS GREAT 8AY PEGONI¢ '/NEW SUFFOLK COUNTY NEW YORK IOBINS ISLAND / / / PLANNING AND URBAN RENEWAL CONSULTANTS ~ WELL -~ RION / ~ -< ' " ' ~--- EXISTING PIPES ON WELL FIELD/ , 1'"~/8 .'St:>t ~ ~ '"' ) -~UT OLD ~ ~ x ~ ORIENT '" - ~-- SOUTHOLD Y ~ \ SHELTER ISLAND % Necl~ EXISTING PIPES NORTH FORK 6 INCHES LARGER J ISLAND ,/ FISHERS THE PREPARATION OF THIS EXHIBIT WAS FINANCIALLY AIDED THROUGH A FEDERAL GRANT FROM THE DEPARTMENT OFHOUS- lNG AND URBAN DEVELOPMENT, UNDER THE PLANNING ASSIST- ANCE PROGRAM FOR THE BUREAU OF COMMUNITY PLANNING, 'L ~r NEW YORK STATE OFFICE OF PLANNING COORDINATION. IT WAS FINANCED IN PART BY THE STATE OF NE~W YORK, IN FISHERS ISLAND NUMBER ORIENT POINT TOWN OF SOUTHOLD PL.'ATE A SHO',',N At;,'. ~NA': '~ TASLE CONTOURS, JULY 1959 ( ONE FC'O~ :%~"r"~\AL A~ DATUM MEAN SEA LEVEL ?EFEREK.~CE ~S. 5..':. ',~*A'"':.-~ SUPPLY PAPER t619-GG, PLATE 3 3000 4000 5000 .~.,$f ,a.'.,-r .<' -.~,~igl~,C ~ MAY ASSOCIATES