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HomeMy WebLinkAboutPlum Island Geology & Groundwater ResourcesGeology and Ground- Water Rcsources of Plum Island Suffolk County, Ne York By H. C. CRANDELL CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1539-X Prepared on behalf of the ~Zlgricultural Research Service, U.S. Department of .dgricult~re UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1962 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printin~ Office Washington 25, D.C. CONTENTS Abstract ......................................................... X- l Introduction ...................................................... 1 Location of the area ............................................. 1 Purpose and scope of the investigation ........................... 3 Previous investigations ......................................... 3 Well-numbering system ........................................ 4 Acknowledgments ............................................. 4 Geography ............. ~ .......................................... 4 Topography and drainage ...................................... 4 Climate 5 History of development ....................................... 7 Geology .......................................................... 7 Ground water ................................................... 12 Occnrrence~ movement, and storage .............................. 12 Water-level fluctuations ........................................ 16 Ground-water withdrawal .......................................... 16 Sea-water contamination ........................................... 17 Chemical quality of the ground water ................................ 20 Conclusions and recommendations .................................. 20 References cited ................................................... 22 Basic data ........................................................ 25 ILLUSTRATIONS PLATE 1. 2. 3. 4. FIGURE 1. 2. 3. 4. 5. 6. 7. [Plates are in pocket] Well-location map. Surficial geologic map. Geohydrologic cross sections. Water-table map. Page Map showing location of Plush Island ...................... X-2 Photograph ct outcrop on southeastern shore ...... : ......... 9 Photograph of outcrop on northern shore ................... 11 Cross section showing Ghyben-Herzberg principle .......... 15 Hydrograph of average water levels .................... 17 Cross section showing vertical sea-water encroachment ....... 18 Cross section showing movement of ground water toward a well being pumped ......................................... 19 III IV CONTENTS TABLES TABLE 1, 2. 4, Physical characteristics of upper Pleistocene water-bearing materials on Plum Island ............................... X-26 Water levels in observation wells on Plum Island from January through May 1959 .................................. 27 Chemical analyses of water from wells and ponds on Plum Island_ 28 Logs of wells, drill holes, and test pits on Plum Island ........ 30 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES GEOLOGY AND GROUND-WATER RESOURCES OF PLUM ISLAND, SUFFOLK COUNTY, NEW YORK By H. C. CI~A~n~LL ABSTRACT Plum Island, which has a total area of about 1.3 square miles, is about 2 miles off the northeast tip of Long Island. It is underlain by Cretaceous and Pleisto- cene unconsolidated deposits resting on a southeastward-sloping Preeambrian bedrock surface. The island's fresh ground-water reservoir is contained in stratified upper Pleistocene glacial deposits and probably assumes the shape of a shallow lens, in accordance with the Ghyben-IIerzberg principle. Precipitation is the only source of recharge to this reservoir, but it is more than sufficient to replenish the fresh-water draft.' This draft was about 31 million gallons in 1958. The well field of the Department of Agriculture probably has been contaminated slightly by sea water during the past few years--possibly as a result of the hurri- canes of 1954 and 1955, by vertical encroachment of sea water, or both. Recom- mendations to control and alleviate this contamination include a water-conserva- tion program, artificial recharge, a continuing water-level and chloride-monitoring program including construction of "outpost" wells, and the establishment of an alternative or auxiliary well field. INTRODUCTION LOCATION OF THE AREA Plum Island is in the town of Southold, Suffolk County, Long Island, N.Y. (tlg. 1). The town of Southold occupies a narrow peninsula at the northeastern end of Long Island and also includes a northeastward-trending chain of four small islands. Plum Island is the first of these islands and is separated from the tip of the South- old peninsula by a strait about I mile wide. The island has an area of about 1.3 square miles and lies ahnost entirely between fat 41010' and 41°11'15'' N. and long 72010' and 72012'30'' W. It is about 1)/~ miles northeast of Orient Point, town of Southold, and about 12 miles southwest of New London, Conn. The bodies of water sur- rounding Plum Island include Long Island Sound on the north, Block Island Sound on the south, and the treacherous current of Plum Gut separating the island from Orient Point on the west. The island is included on the Plum Island topographic quadrangle X-1 X-2 CONTRIBUTIONS TO Tt-IE YIYDROLOGY OF TI-IE UNITED STATES GEOLOGY AND GROUND WATER OF PLUM ISLAND, l~. Y. X-3 map of the U.S. Geological ~Survey, which was published in 1954 at a scale of l: 24,000 with a contour interval of 10 feet. PURPOSE AND SCOPE OF THE INVESTIGA?ION Because of the isolation afforded by Plum Island, the Agricultural Research Service of the U.S. Department of Agriculture has estab- lished there a large laboratory facility for the study of contagious animal diseases. Prior to the establishment of the facility in 1954, the island had been occupied by military installations, for which a well field had been constructed to furnish the necessary fresh-water supplies.. After abandonment of these installations, the well field was reconditioned and equipped for the use of the laboratory. How- ever, owing to the exposed position of the well field, withdrawals of ground water or sea-water inundation during occasional violent storms make saline contamination of the ~ound water an ever- present hazard. Because of this situation and the priniary importance of a dependable fresh-water supply to the operation of the facility, the Department of Agriculture in August 1958 requested thc Geo- logical Survey to investigate the ground-water resources of Plum Island and particularly the availability of ground-water supplies additional or auxiliary to those from the existing well field. The investigation, which extended from December 1958 to June 1959, included study of (a) the areal extent, thickness, and character- istics of the water-bearing sediments; (b) the hydrologic properties of the aquifer; (c) the conditions under which salt-water contamina- tion may be taking place or impending; (d) the extent and nature of any overdevelopment of the ground-water reservoir; (e) the establish- ment of an effective monitoring program to observe any future trends toward salt-water contamination or depletion of the ground-water supply; and (f) the location of an area suitable for an additional or auxiliary well field. Also, pertinent data from previous investiga- tions, logs of test holes, and chemical analyses of ground water have been included in this report to present the geology and hydrology of the island niore comprehensively. PREVIOUS INVESTIGATIONS Plum Island has received only brief notice in the published geologic and hydrologic literature of the Long Island area. The extensive ero- sion of the island's shoreline is noted by Mather (1843, p. 20), and Mer- rill (1886, p. 343) mentions a similarity of geologic features to those of parts of the north shore of Long Island. Veatch and others (1906, p. 336) present the log of a well drilled by the U.S. Army on Plum Is- land in 1899, and Fuller (1914) presents the island's geology more extensively. X--4 CONTRIBUTIONS TO THE HYDROLOGY OF TI{E UNITED STATES From time to time several short water-supply reports have been pre- pared by consulting firms speeifically for the agencies concerned. WELL-NUbIBERING SYSTEM On Long Island, the Geological Survey uses a well-numbering sys- tem cstahlishcd by thc New York State Water Resources Commission. Each well nu~nber is assi~,med in serial order as drilling reports are re- ceived by thc Commission, and is prefixed by the initial letter of the county in which it is located. Thus, a well in Suffolk County is desig- nated by the letter "S" followed by the assigned number (as S10361). ACKNOWLEDGMENTS Thc writer acknowledges the assistance gained from data' furnished by Alexander D. Crosett & Associates, C. W. Lauman & ~o., Inc., Mathies Well & Pump Co., the U.S. Ar~ny Corps of Engineers, and the U.S. General Services Administration. The excellent cooperation of many members of the staff of the Plum Island Animal Disease labora- tory is especially appreciated. GEOGRAPHY TOPOGRAPHY AND DRAINAGE Plum Island is roughly triangular in outline, ranging in width from about 300 feet near the northeastern end to about 1 mile at the south- western end. The island's total length is almost 3 miles from Plum Island lighthouse on the ~vest to East Point. Low beach ridges that seldom reach more than 10 feet in altitude alternate with marshy depressions in the southwestern part of the island; and an undulating terrain of slight relief, characterized by many depressions, scattered boulders, and low hills less than 40 feet in altitude, occupies the north- western part. An almost'featureless plain slopes gently to the north- east and thence to the southeast in the central part of the island and separates two ridges of irregular hills. The southeastern hills range in altitude from about 40 to about 75 feet, ~vhcreas the northwestern group rises to an altitude of more than 100 feet at the reservoir near its west- ern terminus. A small group of hills at the eastern end of the island reaches an altitude of more than 85 feet and, although separated from most of the island by a low narrow strip of land, it forms a continu- ation of the northwestern ridge. The hilly areas terminate at the shoreline in steep bluffs as much as 50 feet high, and the beaches are covered with many large boulders. However, the southeastern and south~vcstern shores are occupied by broad attractive sandy beaches having only scattered cobbles or boul- ders. The island's vegetation consists mainly of beach grasses, wild shrubs, bushes, and some deciduous and coniferous trees. GEOLOGY AND GROUND WATER OF PLUM ISLAND~ N. 'Y. X--5 Plum Island has no permanent streams; most runoff occurs in poorly defined natural channels that drain into the sea or into ponds and mar- shy areas. However, an artifical channel has been dredged to drain the swampy area in the southwestern part of the island and to control mosquito breeding. A sea gate is used to control the flow in this chan- nel, and it has recently (1959) been kept closed to retain ponded rainwater. CLIMATE The marine environment, of Plum Island controls its climate. Mod- erate temperatures predominate, and ah~mdant precipitation occurs during the fall, winter, and spring. The following table, compiled from information collected by Mordoff (1949) and periodic climatic summaries of the U.S. Weather Bureau, contains climatological data from those stations nearest Plum Island. Mean annual temperature and precipitation at stations near Plum Island Station Bridgehampton Cutchogue ......... New London Orient Point ...... Distance (miles) and direction from Plum Island Temperature Precipitation Period of record (years) 17 south~southwest ...... 41 19 southwest ....... 40 12 northeast__ 77 4 southwest Period of Mean record annual (years) (k~ches) 41 48. 41 53 46. 31 77 44. 83 17 45. 67 A 3-inch rain gage was installed on the island in September 1958. Its record through April 1959 is shown below with monthly precipi- tation records for the same period from the stations at Orient Point, Bridgehampton, Cutchogue, and Groton, Conn. The Groton station is about i mile southeast of the New London station, which it replaced in 1953. Preegpitation, in inches on Plum Island and at four nearby stations Month Plum Island Orient Point Groton, Conn. Bridgehampton Cutchogne 1958 October ......... November ........ December ........ 1959 January February ......... March ........... April 4. 28 1. 37 2. 70 2. 10 2. 68 6. 22 3.70 4. 88 1. 95 2. 35 2. 31 2. 88 5. 56 4. 01 5. 37 2. 84 2. 51 2. 77 3. 62 6. 81 4. 23 6. 55 2. 88 3. 58 2. 27 2. 76 7. 83 4. 03 5. 59 2. 39 2, 26 2. 19 2. 49 5. 80 4. 10 602630 O---61 2 X-6 CONTRIBUTIONS TO TI:IE I-I~DROLOGY OF TI~iE U~ITED STATES GEOLOGY AND GROUND WATER OF PLUM ISLAND, N. Y. X-7 HISTORY OF DEVELOPMENT Plum Island was probably settled near the be~nning of the 18th century. A lone tombstone on the island is inscribed, "Thomas Gardner, 1724 to 1786, son of John Gardner of Narragansett." In 1826 the U.S. Coast Guard purchased 3 acres of land at the western end of the island for the construction and operation of a lighthouse. A. S. Hewitt sold 150 acres to the U.S. War Department in 1897 and 690 acres, the remainder of the island, in 1901. Fort Terry was con- structed by 1899 and was manned from that time through World War II. In June 1948 the War Department transferred an additional 47 acres to the Coast Guard and the rest of the island to the War Assets Administration for subsequent disposal. The Agricultural Research Service of the U.S. Department of Agriculture took com- plete possession of the island in 1954, and the Animal Disease and Parasite Research Division established the Plum Island Animal Disease Laboratory. GEOLOGY Although no geologic formations older than the Pleistocene crop out on Plum Island, it is inferred that older formations are present at depth. A generalized stratigraphic section of the formations believed to be in the Plum Island area and their water-bearing characteristics are shown in the following stratigraphic section. The estimated thicknesses and descriptions of the formations are based largely on the log of well S189 (Leggette and others, 1938), drilled in 1935 about 4 miles southwest of Plum Island at Orient Beach State Park on the North Fork peninsula of Long Island, and the general work on Long Island stratigraphy by Surer and others (1949). Crystalline rocks of probable Precambrian age form a bedrock basement, whose surface in the Plum Island area presumably slopes to the southeast at about 80 feet per mile, as it does on most of Long Island. Resting on this surface are younger semiconsolidated or unconsohdated deposits of Cretaceous and Quaternary age, which probably were eroded from the elevated parts of the bedrock surface north of Plum Island. The Lloyd sand member of the Raritan formation of Late Creta- ceous age ;vas deposited on the Precambrian surface. The Lloyd generally consists of beds of coarse quartz sand and gravel, fine sandy clay, clayey sand, and some very thin layers of clay. Although the Lloyd sand member is an excellent aquifer and yields a good supply of fresh water in the main part of Long Island, it probably contains brackish or salty water in the Plum Island area. The Lloyd grades apward into the predominantly gray silty and solid clay of the clay CONTRIBUTIONS TO THE lq'YDROLOGY OF 'I~i-IE UNITED STATES member of the Raritan formation. The clay member contains some sandy layers, but its general pemneability is very low and therefore it is not an aquifer Above the Raritan formation, and separated from it by an uncon- formity, lie the varicolored post-Raritan deposits of Late Cretaceous ~gc, which consist of fine saml, silt, layers of solid clay, i and local beds of coarse sand and gravel in the lower part of the Unit. An extension of the Magothy formation of New Jersey is included in the post-Raritan deposits of Long Island, but its vertical limits are not easily distinguished in logs of wells that penetrate thes~ deposits (Perlmutter and Crandell, 1959). Several water-bearing zqnes in the post-Raritan deposits are excellent aquifers and yield large supplies of fresh water in most of Long Island, but in the Plum Island area they probably contain only brackish or salty water. During Tertiary and possibly early Quaternary time, the post- Raritan deposits of Late Cretaceous age were eroded into a hilly terrain of moderate relief. On this irregular surface were laid down Pleistocene glacial deposits, which on Plum Island consist largely of sand and gravel. It is the upper and more permeable part of these deposits that contains Plum Island's chief reservoir of fresh ground water. The complex Pleistocene glacial history of Long Island and its vicinity has been studied by several geologists, including Veateh and others (1906); Fuller (1914); Fleming (1035)} MaeClintock and Richards (1936); Thompson and others (1937); and Suter and others (1949), who have established the fact that Long Island was sub- jected to two or more periods of glaciation. However, the present investigation is concerned with only the most recent glaciation, which tentatively has been con'clated with the Wisconsin stage of the Pleis- t.ocene epoch by several of the above writers. The following discus- sion is based in part on their findings and in part on recent field observations and data obtained from the logs of wells, drill holes, and test pits (table 4). The location of the wells and test holes is shown in plate 1. During the Wisconsin stage, a part of the I-Iudson-Onta~io lobe of the great Laurentidc ice sheet was responsible for the creation of most of the present topographic features and surficial deposits of Long Island and vicinity (Flint, 1947). The Wisconsin ice in its south- ward movement accumulated rock debris from the land over which it passed and shoved additional material ahead of it. After passing over most of Long Island and the deposits of earlier ice advances, as well as the beds of sand ami gravel deposited ahead of the ice by its melt-water streams, the movement of the ice front was checked by increased melting. This released the accumulation of rock debris held GEOLOGY AND (,;ROUND WATER OF PLUM ISLAND; in the ice and, ~dth llle mater/a} prc-v:io'usl? pushed ahead, crea~:ed ridge of stralified sand ami g'ravel along t;}m ice front. This ridge the southern term. hms of the ice shee~, is known on Long [lshmd as the Ronkonkoma lenninal mondne. Melt, waters also spread a broad apron o~ well-sorted sa, nd and gravel sonth of tNe termimd morah:le. Continued :melt,ing and lack of nourishment, in th~ region of ice Fleming (1~}35), the Harbor t~ill end moraine, part; of which is on remained s/m~,]onary and ar'eat qnanl:ities of melt w~ner deposited large coalesdng ot~twash fans of st,ratified s~nd and gravel, which were/hen covered wiLl~ till by a la[er' rea.alva.rice of l;}m ice (fig'. In Che, central p~;rt of the sontheastern sl~oreline of the b~land, gray to grayish-brown sandy to solid clay is exposed in several localities (pl. 2). Beemse of th.e appe~r~m, ce and stratign~phk~ position of this clay, it is /enta. tively assigned lo I,he Gardinm's day in this repcn% although no snbstanti~tting rossi.1 eviderlce has been t'ot~nd, l'rreg~lar Nodies of the day in shorelh~e exposures may have been formed by X-JO CONTRIBUTIONS TO THE HYDROLOGY OF THE U~ITED STATES ice shoving or "snowplowing" during an earlier advance of the ice, or possibly the weight of the overlying ice and outwash deposits may have forced the plastic clas' upward, much as toothpaste is squeezed from a tube. Study of well and test-hole logs does not indicate that this clay underlies the whole island (pl. 3). If the clay u~lerties the island, it probably is con,~de~ablv thinner than the 10-to 15-foot sections exposed on the southeastern shore and may occur as small discontinuous lenses. The retreat of the Wisconsin ice and its subsequent stagnation along the present trend of Long Island's north shore provided the opportunity for the rapid melt-xvater deposition of the large coalescing outwash fans of stratified sand and ga'avel that make up the core of the Harbor Hill end moraine. A broad outwash channel partly re- moved and covered these deposits at the southwestern end of Plum Island when the ice front again retreated northward. A subsequent readvance of the icc and its slow wastage deposited a veneer of un- stratified silt, sand, gravel, and boulders (till) on the preexisting stratified materials, including the low-lying southwestern part of the island. The great accumulation of stratified drift presented an ob- stacle to the thin readvancing ice, so that most of the material it carried was deposited on the northern face of the ridge. This till veneer is only about 5 to 10 feet thick along the southeastern shore, but it appears to be as thick as 40 feet, or more, where ;vave erosion has exposed it in steep bluffs on the northern shore (figs, 2, 3, and pl. 3). Mel{~ ~vater also scoured the northeastward-trending channel in the central part of the island and filled it with outwash material consisting largely of medium to coarse sand and gravel. The water supply on Plum Island is drawn from wells screened in thi~ material. As'the melting of the Wisconsin ice continued~ the sedllevel rose correspondingly. During recent time, wave~'~ erosion hasl removed large quantities of glacial drift, and wave action and tidal currents have redeposited some of this material in the form of low beach ridges in the southern part of the island. The older of these ridges, which alternate with marshy depressions, have almost east-west trends, but successively younger ridges approach north-south trends (pl. 2). In those areas where the bluffs contain till, wave erosion of surrounding finer sediments has left the present shoreline strewn with large boulders or glacial erratics. The rate of shoreline erosion evidently has been rapid, at least since thc construction of Fort Terry's concrete gun emplacements. Several of these, which initially were high on the bluffs, have been undermined by wave action and now lie demolished on the beach. Table I contains data on physical properties of upper Pleistocene outwash or stratified drift in which 10 observation wells (pl. 1) were GEOLOGY A]~TD GR0'U]ND WATEt OF P]blJ3/][ ISI~AND~ N'. Y. screened. A power auger was used to obtain samples for analysis and to provide holes in which well screens and casin~ were driven to construct the observation wells. The hydrologic la/ooratory of the Geological Survey provided the determina, tions of sl~ecific~ yield coef[icient of permeabi]ily Oable 1), and tl'm mechanical analyses made by the writer. The sediments consSst mainly of angular quartz grains and rock I)artic]es and smaller amounts of bio~ite, fe]dspar, mag'nelJt% garneI, and }~ornb]ende, Particle diamelers are greater than 0.25 ~mn (medium sand), and most ar~, about 0.5 nmi (ooa,rse in plate 3, section A ~t' is draw~ al{rog a northeast-southwest line passing through well S17135 and well. S17137, whieh is in well field. Well 817130 is projected about 200 feet [o t,he southeast into the ]~ne of tho se<~t,ior~. .A'e the :northeaste:tm end of the section a. steep bluff, largely composed of till, rises above tI~e boulder-strewn shor{:line. Till (mtstratified drift) b[a. nke~ts stratified drift, in the northeast, em, par[ o[ tile sect, ion but is believed ~o be truncated near well S17135 by the ou~ash.-filled channel, which may extend to a depth of 35 feet below sea level. The beach-ridge deposits wMch X-12 CONTRIBUTIONS TO THE I-IYDROLOGY OF THE UNITED STATES occupy the southwestern part of the section extend perhaps 5 or 10 feet below sea level and presumably overlie the channel outwash and stratified drift. Section B-B' of plate 3 trends northwest-southeast and intersects section A-A' at well S17135. Well S17129 also is in the line of section 21-/~'. and drill bole 13 and test pit 3 are projected into it about 100 feet to the northeast and to the southwest, respectively. The northwestern ball of section ~-B' is almost identical to the north- eastern third of section A-A~. The central part of section /~-B' crosses the outwash-filled channel at almost a 90° angle to its trend, and a layer of till less than 10 feet thick again veneers the underlying stratified drift at thc southeastern end of the section. The Gardi- ners(?) clay appears at the shoreline, but its lateral extent and thickness are indefinite, GROUND WATER OCCURRENCE, MOVEMENT, AND STORAGE The replenishment of the ground-water reservoir on Plum Island depends solely on precipitation, which averages about 45 inches each year. Part of this precipitation runs off, part is returned to the mosphere by evaporation and by transpiration of plants, and part seeps into the ground. Of this last part, some eventually reaches the ground-water reservoir and may become available for use through the island's water-supply system. Overland runoff from Long Island as a whole has been estimated by Burr and others (1904) as 20 percent of drought-year precipitation (35 inches) and 33 percent of average-year precipitation (45 inches). However, Leggette (ire Paulsen, 1940) has estimated that only 5 percent of storm precipitation, even during hurricanes, reaches Long Island streams as overland runoff. Hoffman (1959) suggests that runoff of about 10 percent of the annual precipitation may prevail in the town of Southold, which includes most of the North Fork of Long Island. This estimate is based on the low moisture-retention capacity of the prevailing silty-loam soil, excellent subsoil drainage of the silty loam by the underlying sand, retardation of overland runoff by the furrows of cultivated fields, and flatness of the terrain in most of the North Fork. On Plmn Island, in contrast to most of Southold, much of the land surface consists of glacial till, which is not as per- meable as the loam and underlying sand; vegetation covers most of the island instead of large expanses of cultivated fields; the island has considerable topographic relief--steep slopes extend to the sea, es- pecially along the northern shore; and the small area of the island allows runoff only a short distance to travel before it discharges into the sea. These factors suggest that a higher runoff figure should be GEOLOGY AND GROUND WATER OF PLUM ISLAIN~D, N. Y. X-13 applied to Plum Island--probably about 15 percent of the annual precipitation. Much of the precipitation is returned to the atmosphere by evap- oration and by transpiration of plants. A combination of these two processes is called evapotranspiration. Although evapotranspiration on Plum Island cannot be estimated closely, Hoffman (1959) has estimated that the annual evapotranspiration in the town of South- old should range from about 21 to 26 inches. The evaporation, based on the precipitation records of the Cutchogue gage, was esti- mated to be 12 inches for the year of least annual precipitation (1908), 17 inches for the year of greatest annual precipitation (1948), and 14 inches for the year in which annual precipitation closely approached the long-term average (1949). Average annual transpiration was estimated to be 9 inches. Although the transpiration rate on Plum Island may be somewhat ]ess than that for the cropland area of the town of Southold, the evaporation rate on Plmu Island probably is greater than that in Southold because of the large ponds in the south- western part of the island. Thus, the total annual evapotransph'a- tion rate for the island probably is within the 21- to 26-inch range. Recharge to the ground-water reservoir on Plum Island is the difference between precipitation and the sum of runoff and evapo- transpiration. This sum may range from about 75 percent of the annual precipitation in very dry years to about 60 percent in very wet years. Thus, only 25 to 40 percent of the total annual precip- itation would be available for recharging the ground-water reservoir. If the total area (1.3 square miles) of the island is considered, re- charge from precipitation during a year of average precipitation would be about 328 million gallons. However, the eastern taillike area of Plum Island and a part of the island's southwestern area probably provides little recharge to the ground-water reservoir in the main body of the island. The total area of the island .available for recharge, therefore, is reduced by about 50 percent to an effective recharge area of about 0.66 square mile. Thus, recharge during a year of average precipitation woukt be about 164 million gallons. The paved and built-up areas of the island, which would prevent infiltration of precipitation, are considered in these revised estimates. The fresh ground water available for use on Plum Island is con- tained in the interstices of the upper Pleistocene gladal deposits. This ground-water body is under water-table or unconfined condi- tions. It is also believed to occur as an irregularly shaped lens, xvhich overlies glacial deposits saturated with salt water (pl. 3). As the specific gravity of the fresh ground water is less than that of the underlying salt water, the fresh water tends to :float on the salt water generally within the boundaries of the island. Figure 4 presents a 602630 0---61 X-14 CONTRIBUTIONS TO T~E I-IYDROLOGY OF TYIE UNITED STATES hypotheticM cxoss section of an island composed of permeable sand and surrounded entirely by sea water and demonstrates this relation under ideal conditions. Fresh water fills the sand to the depth at which its head is balanced by the head of the salt water. At equi- librium, the depth of fresh water below sea level at any point on the island is proportional to the fresh-water bead above sea level and dependent on the difference between the specific gravities of fresh and salt water. This relation is summarized in the following equation, which is often referred to as the Ghybdh-Herzberg principle :i t g--1 where, ~depth of fresh water below sea level, t--height of fresh water above sea level, and g~--~specific gravity of salt water as compared to the assumed specific gravity of 1 of fresh water. Although the specific gravity of sea water varies somewhat from place to place, the average of 1.025, if used in the Ghyben-Herzberg formula, shows that fresh water would extend 40 feet below sea level for each foot it extends above sea level. Hubbert (1940) has shown that the Ghyben-Herzberg formula may apply only under conditions of hydrostatic equilibrium and is approximately correct ohly under low hydraulic gradients. The 40:1 ratio probably is approximately correct on Plmn Island and has been used to define the shape (pl. 3) of the flesh-water lens and to estimate flesh ground-water storage. The upper surface of the unconfined fresh-water lens on Plum Island is marked by a water table, whose configuration is shown in plate 4 by contour lines referred to mean sea level. These contour lines are based on water-level measurements made on April 9, 1959, in 10 observation wells and several ground-water ponds and swamps in the western part of the island. The contour lines represent the shape of the water table as it approaches the spring seasonal maxi- mum level. In effect, the movement of ground water on Plum Island is radially away from the highest point on the xvatcr table, whose maximum obscrved altitude is 2.53 feet above mean sea level, at well S17131. However, a relatively narrow ground-water divide passes through the highest points on the water table and generally bisects the trend of the 2.5-foot closed, contour shown in plate 4. From the vicinity of GEOLOGY AND GROUND WATER OF PLUM ISLAND~ Br. Y. X-15 Sea level Well 4.--Idealized cross section of an island showing relation of fresh water to salt water, according to the Ghyhcn-}Ierzberg principle. From Petitt and Winslow (1957, pl. 8). this divide, ground water moves toward the sea along lines normal to the water-table contours. Section ]~-B~ in plate 3 illustrates this moven~ent by means of arrows that indicate the direction of flow in the vertical plane. Thc ground-water discharge by lateral outflow into the sea is dependent on thc permeability o(' thc glacial deposits (table 1) and the hydraulic gradient, and it probably approaches the amount of recharge to the ground-water reservoir. Most of the lateral outflow takes place at or below sca level. The fresh ground water in storage under Plum Island is contained in upper Pleistocene glacial desposits estimated to be 1,700 million cubic feet in volume. However, not all the water fillinff the inter- granular spaces of this large body of sediment is available. The vol- X--J6 C01XVTRIBUTIONS TO TI-IE I-IYDROLOGY OF TI-IE UI~ITED STATES ume of available ~vater is roughly equivalent to the specific yield (table 1) of the deposit. The average specific yield of the saturated glacial deposits of Plum Island, established from table 1, is about 21.8 percent. When this figure is applied to the volmne of sediments under the whole island, it is computed that about 2,800 million gallons of fresh gro~md water was in storage in April 1959. However, a factor of about one-half must again be applied as in recharge estimates; effective storage, therefore, would be about 1,400 million gallons. During January 8 to May 28, 1959, weekly waterdevel measure- ments were made in 10 observation wells (table 2) on Plum Island. The average of these measurements is given in the hydrograph on figure 5. Although the period of record is too short to define long- term fluctuations, the spring (April-May 1959) high shown in figure 5 coincides generally with the pattern of water-level fluctuation in ob- servation wells on the North Fork peninsula of Southold. From this it is inferred that water-level fluctuations of the ground-water body on Plum Island would follow the seasonal fluctuation pattern of the shallow ground-water body of thc North Fork peninsula. GROUND-WATER WITHDRAWAL In a balanced hydrologic system natural discharge equals recharge plus or minus changes in ground-water storage. When artificial with- drawal from wells is iutroduced, the system is at first unbalanced by removal of water taken from storage. Later the balance is :re-estab- lished when part of the recharge replenishes the water artifici&lly with- drawn. The effective recharge to the ground-water reservoir of Plum Island may range from 164 lnillion gallons annually or 0.45 mgd (million gallons per day) in an average year, to 131 million gallons annually or 0.36 mgd in a dry year. Practically, however, it is neces- sary to restrict, the withdrawal to an amount substantially less than the recharge in order to avoid a heavy demand on storage and to pre- vent sea-water encroachment. Monthly pumpage, in millions of gallons, from supply wells on Plum Island from January 1957 through May 1959 is shown in the table below. Monthly p~mpage, in millions of gallons, from supply wells on Plum Island from January 1957 through May t959 Year Jan. Feb. Mar, Apr, May Yune July Aug, Sept, Oct, Nov. Dec, Total 1957 ~ .... 1.82 1.72 1. ,7,2 !. 65 1.47 1.84 1.83 2. 05 L 78 I. 65 1.39 1.47 20, 42 1958 ~_ 1.98 I 1.94 2 25 2.76 2 75 2.39 2,85 2.60 2.55 2.97 2.84 3.16 31.04 Daily average: 0.06 million ga}Ions. Daily average: 0.09 ~hillion gallons. GEOLOGY AND GROUND WATER OF PLUM ISLAND, 10 20 31 10 20 28 10 20 31 10 20 30 10 20 31 JANUARY FEBRUARY MARCH APRIL MAY 1959 F]~V~E 5.--Hydrograph of average wa~r levels ~ne0~xred in 10 wells on Plum Island. Pu:mpage during 1958, a year of above-average recharge, totaled only about 31 million gallons, or an average of 0.09 nlgd. However, during the first 5 months of 1959 pumpage increased by 3.84 million gallons over pumpage for the same period in 1958, and was almost double that for the first 5 months of 1957. To minimize the effect of pumping in contributing to possible sea-water encroachment, total withdrawals during any one year probably should not exceed about 75 million gallons, or 0.2 regal--assuming that such withdrawals are made from points as widely spaced as economically feasible within the area of effective recharge. SEA-WATER CONTAMINATION Sea-water contamination of fresh ground w~tcr in thc area of the well field on Plum Island can present various problems, according to thc extent of contamination. The U.S. Public Health Service (1946) recommends that the chloride concentration in drinking water not exceed 250 ppm (parts per million). Water having a chloride concentration of 250 pp~n probably would taste very slightly salty, but even higher concentrations of chloride are not h~r~nful to the human body or to livestock. Several factors indicate that, although ground-~vatcr supplies on .Plum Island are ample for present and foreseeable needs, sca-water contamination of the well field is a potential hazard. The topo- CONTRIBUTIONS TO TYIE I-IYDROLOGY OF TYIE T3-NITED STATES WELL B~IN~ PUMPED Sand and lng fresh water Sand ar~l grave~ co~tainin~ sar water graphic position of the well field, between 10 and 15 feet above mean sea level in the south-central part of the island, exposes the well- field area to occasional inundation by storm waves or soaking by salt spray. Winds of gale or hurricane force presumably can sweep enough salt water over the well field to cause considerable contam- ination. For example, chloride determinations lisied in table 3 for water from the supply wells indicate an increase from about 10 ppm to as much as 40 ppm between 1951 and early 1959. Although the data are not conclusive, they suggest that this increase may have resulted, at least partly, from contamination by the hurricanes of 1954 and 1955. The ~round-water reservoir might also be encroached by sea water, as illustrated in figure 6, by the upward movement of a salt-water tongue toward the pumping wells, or by landward migration of the zone of diffusion between thc fresh-water lens and the surrounding salt water (fig. 7). Section A-A' on plate 3 suggests that the well field is located where the thickness of thc fresh-water lens and the depth to the zone of diffusion begin to diminish southwestward. If pmnping at high rates were continued for prolonged periods--par- ticu]arly during drought--water levels in the well field would de- cline, and thc fresh-water head would be reduced so that it could no longer balance the head of thc salty water at the contact between fresh and salt water. Salty water would then move upward toward the well field. An extensive thick layer of relatively impermeable material such as the Gardiners clay might provide some protection GEOLOGY AND GROUND WATER OF PLUM ISLA/q'D~ 7. Y. X-19 Water lever prior to pumping I -water res FIGURE Z--Idealized cross section showing movement of ground w~ter toward a well being pumped. against salt-water contamination of thc well field if it lay between the underlying salt w~tcr and the well screens. However, the geo- logic conditions previously described indicate that the clay is neither thick nor continuous on Plum Island. X-20 CONTRIBUTIONS TO TYIE I~YDROLOGY OF TtIE U~ITED STATES CHEMICAL QUALITY OF THE (~ROUND WATER Table 3 summarizes the findings of several laboratories in regard to the chemical quality of the fresh ground water on Plum Island. One analysis was made in 1939 and the rest between 1951 and 1959: The Geological Survey made comprehensive chemical analyses of water from observation wells S17128, S17134, and S17136i near the island's northwestern and southeastern shores (pl. 1), as well as chloride determinations in water from most wells and ponds. For comparison, the standards of the U.S. Public Health Service (1946) are given below in terms of the maximum allowable concentration for certain common constituents: Parts per million Iron (Fe) ~nd manganese (Mn) together .............................. 0. 3 M~gnesium (Mg) .................................................. 125 Chloride (C1) ..................................................... 250 Sulfate (SO4) ...................................................... 250 Dissolved solids (for water of good chemical quality) ................... 500 Except for the generally high iron and manganese content of water from both observation and supply wells, the quality of the bq'ound water meets the Public Health Service standards. Present water- treatment practices effectively control the iron-manganese problem and raise thc pH of the slightly corrosive water. The high-chloride concentration in water from observation well S17130 suggests that the well screen is within the zone of diffusion between fresh and salty ~vater, as sho~vn in section A-A~, plate 3. CONCLUSIONS AND RECOMMENDATIONS The investigation has shown that water-bearing sediments of con- siderable thickness underlie Plum Island, but only the upper P]eis~ tocene glacial deposits contain a relatively thin lens of fresh ground water. The lowest point on this lens probably does not lie more than 100 feet below mean sea level. Thc sediments that contain the ground-water supply are characteristically uniform and permeable and are apparently uninterrupted by ]ess permeable material. Sed- iment texture and specific-yield determinations also indicate that ground water can be withdrawn safely from wells in thc interior parts of the island. Obviously, such withdrawals should not be made near the periphery of the island because of the potential hazard of sea-water encroachment. From available data, the shape of the fresh ground-water lens is thought to follow es. sentially the Ghybcn-Herzberg principle, which states in general that for each foot of fresh water above sea level 40 feet of fresh water is below sea level. The amount of fresh ground water in storage probably exceeds 1,500 million gallons~ GEOLOGY AND GROUND WATER OF PLUM ISLAND~ ~. ¥. X-21 Rechaxge, even during years of drought, is considered to be more than adequate to replenish present (1959) modest ~dthdrawals from storage in the ground-water reservoir. The chemical quality of the ground water is satisfactory according to Public Health Service standards, and only a small amount of treatment for a few problem constituents is necessary. Plum Island is small and surrounded b.y sea water and its fresh ground-water reservoir is subject to contamination by encroaching sea water, but definitive evidence that the well field was being con- taminated by sea-water encroachment was lacking in early 1959. A slight increase in chloride concentration in the water from the sup- ply wells occurred between 1951 and early 1959, and the location of the well field suggests the possibility that so,ne slight contaznination may have resulted fi'om the hurricanes of 1954 and 1955. However, this contamination could have resulted from the vertical or lateral en- croachment of sca water. The following four measm'es could offset the danger of sea-water contamination of Plum Island's flesh ground-water supply: 1. A reduction in the total use of fresh water could be effected by instituting a water-consexvation campaign. All water-supply equipment and mains should be carefully maintained and ex- amined periodically for evidence of leakage. As fresh water is a precious commodity on the island, all personnel should be in- structed to keep faucets tightly closed when not in usc and to report defective plumbing immediately. The effectiveness of such a program can be determined by comparing pumpage rates or waste-water (sterilized by the laboratories) discharge rates with those for a similar period before the institution of conser- vation measures. 2. The ground-water reservoir could be artificially recharged by re- turn of sterile waste water and storm runoff to the ground. Such water could be collected in natural depressions near the ground-water divide (pl. 4) jn the central part of the island. In particular, natural depressions in the hilly north-central part of the island conld be deepened, ami runoff frmn storms could be diverted into these basins through culverts built along natural drainage channels. The till cover in these basins should be removed down to the underlying stratified drift, whieh would allow watex to infiltrate at the optflnum rate. The recharge basins should be cleaned pcriodically to remove accmnulated fine sediments, which retard infiltration. 3. Of utmost importance is a continuation of the water-level and chloride-monitoring program. Water levels in the observation wells should be measured periodically to monitor changes in X-22 CONTRIBUTIONS TO TI-IE tIYDROLOGY OF TI-IE UI~ITED STATES gTound-water storage, i)etermination of chloride in raw water from supply wells and surrounding observation wells should be made at regular intervals, especially during periods when the water table is low and pmnpage is increased. It is only through the accmnulation 'of such data over a considerable period that clear evidence of sea-~vatcr encroachment or ovcrdcvelopmcnt of the well field can be established. In this regard, the construction of two "outpost". wells would aid greatly in defining the position and movement of the interface be- tween fresh and salt water. One "outpost" well should be placed between thc ~vell field and the sea, especially in that area south of the well field where the fresh-~vater lens is thinnest and the hazard of sea- water encroachment is greatest. The other outpost well should be placed at the site of S17135 to monitor the position of the interface under the center of the island. The wells should be about 300 feet deep, or deep enough to penetrate the upper part of the post-Raritan deposits. Cores and electric logs would p:rovide sufficient data to de- termine the position of the interface between fresh and salt water and the thickness of any confining clay layer. The wells could then be screened just above the interface, and periodic determinations of chlo- ride in water from them would indicate whether or not the interface is migrating toward thc well field. 4. An additional source of supply of fresh ground water is desirable. An additional well field not only would serve as an auxiliary sup- ply if the present well field were contaminated or otherwise dis- abled, but it would also provide a means of reducing the draft on the ground-water reservoir at the present field by alternate pumping of the well fields. The best location for a second well field probably would be near observation well S17135,!where it would be protected from sea-water inundation. Also, it would be immediately adjacent to the present booster station and the main pipeline leading to the reservoir. Table 3 indicates that wa- ter fi'om the observation well at this location had the lowest chlo- ride concentration of all samples from similar wells installed in December 1958. The specific yield at this location is satis- factory, and the area is very near the water-table divide, which would afford the wells maximum protection from sea-water encroachment. Wells in this vicinity probably would need to be no deeper than about 50 feet. REFERENCES CITED Burr, W. H., Hering, Rudolf, and Freeman, J. R., 1904, Report of commission on additional water supply for city of New York: New York, Martin B. Brown Co. GEOLOGY AND GROUND WATER OF PLUM ISLAND~ 1~. Y. X-23 Fleming, W. L. S., 1935, Glacial geology of central Long Island: Am. Jour. Sci. v. 30, p. 216-238. Flint, R. F., 1947, Glacial geology and the Pleistocene epoch: New York, John Wiley & Sons, 589 p. Fuller, M. L., 1914, The geology of Long Island, N.Y.: U.S. Geol. Survey Prof. Paper 82, 231 p. Iloffman, J. F., 1959, Ilydrology of the shallow ground-water reservoir of the town of Southold, Suffolk County, L.I., N.Y., with particular reference to sea-water encroachment: U.S. Geol. Survey open-file report. Ilubbert, M. King~ 1940, The tlieory of ground-water motion: Jour. Geology, v. 48, no. 8, p. 785-944. Leggette, R. M., and others, 1938, Record of wells in Suffolk County, N.Y.: New York State Water Power and Control Comm. Bull GW-4, p. 93-97. MacClintock, Paul, and Richards, If. R., 1936, Correlation of late Pleistocene marine and. glacial deposits of New Jersey and New York: Geo~. Soc. America Bull, v. 47, no. 3, p. 289-338. Mather, W. W., 1843, Geology of New York; pt. 1, Comprising the geology of the first geological district: Albany, N.Y., Carroll and Cook, 653 p. Merrill, F. J. It., 1886, On the geology of Long Island: New York Acad. Sci. Ann., v. 3, nos. 11-12, p. 341-364. Mordoff, I~. A., 1949, The climate of New York State: Cornell Ext. Bull. 764, 72 p. Paulsen, C. G., 1940, Hurricane floods of September 1938: U.S. Geol. Survey Water-Supply Paper 867, 562 p. Perlmutter, N. M., and Crandell, It. C., 1959, Geology and ground-water supplies of the south-shore beaches of Long Island, N.Y., in Lowe, K. E., ed., Modern aspects of the geology of New York City and environs: New York Acad. Sci. Annals, v. 80, art. 4, p. 1060-1076. Petitt, B. M., Jr., and Winslow, A. G., 1957, Geology and ground-water resources of Galveston County, Texas: U.S. Geol. Survey Water-Supply Paper 1416, 157 p. Surer, Russell, deLaguna, Wallace, and Perlmutter, N. M, 1949, Mapping of geologic formations and aquifers of Long Island, N.Y.: New York State Water Power and Control Comm. [now the New York State Water Re- sources Comm.] Bull. GW-18, 212 p. Thompson, D. G., Wells, F. G., and Blank, ti. R., 1937, Recent geologic studies of Long Island with respect to ground-water supplies: Econ. Geology, v. 32, p. 451-470. U.S. Public Ilealth Service, 1946, Public IIealth Service drinking water standards, 1946: Public Health Repts., v. 61, no. 11, p. 371-384. Veatch, A. C., and others, 1906, Underground water resources of Long Island, New York: U.S. Geol. Survey Prof. Paper 44, 394 p. X-24 CONTRIBUTIONS TO THE I-IYDROLOGY OF TI-IE IYNITED STATES GEOLOGY A_ND GROUND WATER OF PLUM ISLAND~ lq'. Y. X--25 TABL~ 2.--Water levels in observation wells on Plum Island, January through May 1959 [Water levels,in fcet above or below (--) mean sea level. All wells were installed by the Geological Survey by augerlng and drtving in December lg58, Screenandcaalngdlameterisl~4in. Seepl. lforloeations] Altitude Depth of below raeasur. Well land ingpoint San. 8 Jau. 15 Jan. 22 Jan. 23 Feb, 5 Feb, 12 l~eb, 19 Feb, surface at top of (feet) easing (feet) ]1712~ ......... 34 16. 30 L 10 L 18 L 21 0.91 0.96 1.07 1.41 1, ]17123 ........... 63 35.71 ,89 1.03 1.10 .74 . si . ss 1.22 ]17130 .......... 53 38, 45 ,26 .51 ,83 -. 23 ,45 .38 1. t 8 ]17131 ...... 79 65.09 2.25 2.18 2.12 2.09 2.06 2.12 2.0 ]17135 44 36.38 1,65 1.47 1,51 1,40 1.34 1.44 1.61 1.5 ]17136 ....... 23 8,61 i 1,69 1,46 1.56 1.35 1.35 1.60 L78 1.7 ]17137 .......... 33 16,51 [ 1.41 1,16 1.22 1.08 .98 1.20 1.39 1.3 Well Mar, Mar, Mar. Mar, IApr, Apr, Apr, Apr, Apr, May May May Mai 5 12 19 23 2 9 16 23 30 6 14 21 28 ]17128 .............. 1.22 1.56 1.50 1,53 1.76 L86 1.86 1.86 1.92 1.70 1,58 1,36 1.2 317131 ......... 2.11 2.24 2,24 2,21 2.40 2.53 2,68 2,88 3.15 3.19 3,22 3.11 3,6 317132 ............ 1.23 1.24 1,07 .98 1.58 1.38 1,54 1.77 1.68 1.56 1,40 1,31 1.6 317133 ......... 1,35 L47 1.39 1,26 1,73 1,74 1.70 2,04 2.02 1,93 1,71 1.56 1.4 317135 ........ 1,55 1.86 1.88 1,91 2,14 2,37 2.18 2,53 2.45 2.49 2,19 2,03 1.8 317136 .............. 1.63 2.30 2.20 2,07 2.36 2.52 2.47 2.33 2.22 2.15 2,00 2.08 1.5 317137 ........ 1,13 1.94 1.94 1.73 2,16 2,38 2,30 2.05 2.16 t.93 1.67 1.66 1.3 X-26 CONTRIBUTIONS TO THE I-i'YDROLOGY OF THE ]T~ITED STATES TABLE 3.--Chemical analyses of water [Chemical constituents in parts per million. All ~' Manganese ~ - (Mn) Well or pond ~ Date of collection ~ O ~ ~o Supply wells S10261 .......... 30 Apr. 18, 1955_.__ A 5.5 Trace 510262 .......... 34 Aug. 29, 1955.... B 10 0 ...... 0 S10263 .......... 32 Oct. 29, 1951 ~___ C ...... 0 Apr. 18 1955 .... A 6.5 Trace S10265 ......... 30 Oct. 29, 19512___ C ...... 9.3 Apr ]8, 1955_.._ A 6.5 Trace .................................... S10266 .......... 29 Oct. 29, 1951 ~... C ...... 0 .................................... Apr. 15, 1955___. A 7.0 Trace .................................... 310267 .......... 29 OCt. 29, 1951 3... C ...... 1. 0 .................................... 310268 .......... 29 Apr. 13, 1955 _.._ A 8. 0 .1 .................................... 310269 .......... 27 Aug. 29, 1955 .... B 10 0 ...... 0 4.8 310270 .......... 28 Apr. 18, 19&5 .... A 8. 0 . l .................................... Apr. 24, 1959 .... Y Composite sample (all supply wells) ....... M~Y 17, 19,39 .... D ....... 1 .................................... June 14, 1953 .... E ...... 1.8 .................................... Apr. 20, 1955....~ A 6.0 Trace Observation wells 817128 .......... S17130 .......... S]7131 S17132 .......... S17133 S17134 S17135 .......... S17136 S17137 .......... 34 Dec. 3, 1958 ...... ..... do ..... do 49 ..... do ..... do .......... 33 ..... do Ponds PI May 1952 ..... April. 24, 1959.-. P2 .............. May 1952 ..... Apr. 24, 1959 P3. May 1952 Apr. 24, 1959 .... P4 May 1952 PS. do P6 .............. do .......... Apr. 24, 1959 P7_ do ~ A, The Bowers Co.; B, South Shore ,,~alytical and Research Laboratory, Inc.; C, U.S. Army Chemical Corps.; D, Connecticut State Department of Health; E, Suffolk County Health Department; F, U.S. Geological Survey; G, C. W. Lauman & Co., Inc. ~ Date of report. GEOLOGY AND GROUND WATER OF PLUM ISLAND, 1~'. Y. X-27 from wells and ponds, on Plum Island wells are screened in upper Pleistocene deposits] Total hardness as CaCO~ Supply wells--Continued Observation wells--Continued 36 32 3,400 42 90 32 52 35 Ponds--Continued 8.800 ........................................ 700 Z_';;;;;; ;;;;.';;; L'ZZ;Z ;;Z;;_'_'; ;;7_';;;; 6, 800 ........................................ 50 ........................................ ~ Ziiiiii iZZZiiii ii.'iiiii iiZZii iiZiiZ X-28 CONTRIBUTIONS TO TI-IE I-IYDROLOGY OF THE UNITED STATES Table i.--Lo#s of wells, drill holes, and test pits on plum Island [ Matcrial [ Thickness Depth (feet) (feet) Well S17128 tLand surface about 16 ft above mean sea level. Bottom of casing at 34 it; screen at 31-34 ltl 9 9 Sand, coarse, brown, and gravel; much clay .............. Sand, medium to coarse, brown~ and gravel; some cobbles and boulders; some clay ............................. Sand, coarse; some gravel Sand, medium to coarse ............................... Sand, clayey, brmvn to gray ........................... 14 27 9 2 23 50 59 61 Well S17129 [Lmad surface about 35 ft above mean sea level. Bottom of casing at 53 ft; screen at 50-53 10 10 Sand, medium to coarse, brown, and gravel; some clay .... Sand, medium to coarse, and gravel; some cobbles and boulders; some clay ................................. Sand, fine to coarse, grayish-green, and gravel; some clay_ Clay, sandy, brown ................................... Sand, medium to coarse, brown ......................... Sand, fine to coarse, dark-brown, and gravel; some silt .... Clay, sandy, gray ..................................... 5 19 1 15 19 1 15 34 35 5O 69 70 Well $17130 [Laud surface about 38 ft above mean sea level Bottom of easing a~; 53 ft; screen at 50-53 ltl 7 Sand, medium to coarse, brown, and gravel; some clay Sand, medium %o coarse, brown, and gravel; some cobbles and boulders; some clay ........................... Sand, fine to coarse, grayish-green to brown; some gravel; clay Sand, medium to coarse, brown Sand, coarse, light-brown Sand, clayey, grayish-bro~v-~,-~ac~i~n-g- ~i-o- ~;~-~-e-l~ 4 24 12 23 5 7 11 35 47 7O 75 Well S17131 [Laud surface about 65 ft above mean sea level. Bottom of casing at 79 ft; screen at 76.79 ltl Sand, medlum, brown ................................. 8 8 Sand, medium to coarse, brown, and gravel .............. 30 38 Sand, medium to coarse, brown ......................... 32 70 Sand, fine to coarse, light-brown; some gravel; silt ........ 25 95 Clay, dark-gray ...................................... 1 96 Well S17132 [Land surface about 36 ft above mean sea level Bottom of casing at 4~8 ft; screen at 45-48 17 17 Sand, fine to coarse, brown and gravel; clay .............. Sand, coarse, dark-brown, and gravel; streaks of black clay ............................................... Sand, medium to coarse ............................... Sand, coarse, reddish-brown ............................ Clay, dark-gray ...................................... 20 3 10 1 37 40 50 51 GEOLOGY AND GROUND WATER OF PLUM ISLAND, N.Y. X-29 Table 4.--Logs of wells, drill holes, and test pits on Plum Island--Continued Material Thickness Depth (feet) (feet) Well S17133 [Land surface about 43 It above mean sea level. Bottom of casing at 59 ft; screen at 56-59 ltl Sand, fine, and grayish-brown clay ...................... Sand, fine to coarse; some gravel; streaks of clay Sand, fine to coarse, grayish-green; some feldspar pebbles; silt Sand, medium to coarse, brown; some gravel Sand, medium to coarse; clay Clay, sandy, grayish-brown 4 10 21 15 10 1 4 14 35 5O 60 61 Well S17134 [Land surface about 15 ft above mean sea level. Bottom of casing at 28 It; screen at 25-28 ltl Sand~ fine to coarse, and gravel; clay .................... { 5 Sand, medium to coarse, reddish-brown; some gravel ...... 11 16 Sand, coarse, brown ................................... I 6 22 Clay, sandy, brown ................................... 4 26 Sand, medium, brown ................................. 16 42 Well S1713~ [Land surface about 36 It above mean sea level. Bottom of casing at 44 It; screen at 41-44 Sand, medium to coarse; some gravel; clay .............. 5 Sand, medium to coarse .............................. 19 24 Sand, medium, light-brown ......................... 16 40 Sand, coarse ..................................... 15 55 Clay, dark-brown ..................................... 1 56 Well St7136 [Land surface about 8 It above mean sea level. Bottom of easing at 23 ft; screen at 20-23 ltl Sand, medium brown; some clay ....................... 8 8 Sand, coarse, and gravel ................................ 3 11 Ssmd, medium ........................................ 14 25 Well Sl?lg7 [Land surface about 16 It above mean sea level Bottom of easing at 33 It; screen at 30-33 ltl Clay, sandy, grayish-brown 5 5 Sand, medium to coarse ................................ 4 9 Sand, medium to coarse, and gravel ..................... 13 22 Sand, coarse, and gravel ............................... 20 42 X-30 CONTRIBUTIONS TO TIlE IIYDROLOGY OF TIlE UNITED STATES Table 4. Logs of wells, drill he, les, and test pits on Plum Island--Continued Material Thickness Depth (feet) (feet) Drill hole 1 ILand surface about 40 ft. above mean sea level] Grass matting, roots Sand, coarse, bro~vn, and gravel; traces of silt; trace vegetation Sand, medium to coarse, brown, and gravel Sand, medimn, dark-brown, and gravel; some cobbles Sand, medium to coarse, dark-brown, and gravel; small boulders 0.5 0.5 3.5 4 5 9 12 21 10. 5 31.5 Drill hole 2 [Land surface about 22 ft. above mean sea level] Grass matting, roots ................................ Sand, a little silt; trace of gravel ................... Sand, medium; trace of gravel ...................... Sand, some medhlm to large gravel; a little silt ........... Sand; some medium gravel .......................... Sand, coarse; trace of gravel .......................... Sand, medium to coarse; a little gravel; trace of silt ....... 0.5 0.5 2.5 3 5 8 10 18 4 22 5 27 3 3O Drill hole 3 [Land surface about 7 ft. above mean sea level] Grass matting, topsoil and roots ..................... I Sand, medium to fine, brown; a little gravel; trace of slit__I Sand; some gravel trace of silt; a few small boulders .... I Sand, medium to coarse; some fine to coarse gravel ..... 1 2.5 16. 5 10 1 3.5 20 30 Drill hole 4 [Land surface about 17 ft. above mean sea level] ~,opsoil, sandy; roots and vegetation_ ~ Sand, medium, brown; a little gravel; a little silt Sand, medium to coarse, brown; some gravel 4~ 5.5 24. 30 Drill hole 5 [Land surface about 19 ft. above mean sea level Topsoil, sandy; roots .................................. Sand, fine to coarse, brown; a little gravel; a few small 6-in. boulders Sand, medium, brown; a little fine to medium gravel 1 25 4 26 30 Drill hole $ [Land surface about 14 ft, above mean sea level] Topsoil; tree roots ................................. Sand, fine, and silt; slightly plastic ..................... Sand, medium to coarse, brown; some fine to medium gravel Sand, coarse, brown Sand, coarse, brown; trace of gravel 1 3 15 3 3 19 22 25 GEOLOGY AIqD GROUIqD WATER OF PLUM ISLAND~ Iq. Y. X-31 Table 4.---Logs of wells, drill holes, and test pits on Pl~.m Island--Continued Material Thickness Depth (feet) (feet) Drill hole 7 [Land surface about 10 ft. above mean sea level] Topsoil, sandy; grass roots ............................. I 1 1 Sand, fine, brown; some silt I 2 3 Sand, medium to coarse, brown; some grave[ ........... I 13 16 Sand, medium to fine ................................. 2 18 Sand, medium to coarse, gray; trace of gravel; trace of silt__ 7 25 Drill hole 8 [Land surface about 21 ft. above mean sea leve Topsoil, sandy; roots .................................. Silt; some fine sand ................................... Sand, medium to fine, brown, and gravel Sand, fine to medium, brown, and gravel; small boulders_ Sand, fine, silty, brown Sand, medium to coarse, brown; some gravel 1 4 3 Il 2.5 8.5 l 5 8 19 2L5 30 Drill hole 9 [Land surface about 30 ft. above mean sea level[ Topsoil, sandy; grass and brush roots .................. I 1 Sand, silty, brownish-gray ............................. 3 4 Sand, fine to medium; some gravel ...................... 12 16 Sand, medium; some large gravel; a few small stones ...... 9 25 Drill hole l0 [Land surface about 34 ft. above mean sea level[ Topsoil, sandy; roots .................................. Sand, fine, silty, gray ................................. Sand, medium, gray; trace of silt ....................... Sand, fine, silty, gray Sand, medium to coarse, brown; some grave! ............. Sand, medium to coarse, brown, and gravel; small boulders_ 1 9.5 1 2 7 1 5.5 15 16 18 25 Drill hole 11 [Land surfaCe about 22 tt above mean sea level] Topsoil; sandy; roots ................................. Sand, fine, brown; trace of silt Sand, fine to medium, brown; lenses of gray silt Sand, fine to medium, brown; some gravel Sand, fine ~o medium, brown; some gravel; a few small boulders ....................................... 1 5 10 16 9 25 Drill hole 12 [Land surface about 45 ft above mean se~ level] Topsoil, sandy; roots ................................. 1 1 Sand, fine to medium, brown; some silt ................... 3 4 Sand, medium, brown; some gravel; trace of silt; a few small stones ........................................ 16 20 Sand, fine to medium, brown; some gravel ................ 5 25 X-32 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES Table 4.--Logs of wells, drill holes, and t~st pits on Plum Island--Continued Material q'hickness Depth (feet) (feet) Drill hole 13 [Land surface about 50 ft above mean sea level] Topsoil, sandy; grass matting; roots ..................... Sand, fine, brown; some silt Sand, fine to medium, grayish-brown; trace of silt Sand, fine, brown; trace of silt Sand, fine to medium, brown; a little medium gravel Sand, medium, brown; a little silt; trace of gravel Sand, medium, brown; a little gravel 1 3 1 3 8 2 7 1 4 5 8 16 18 25 Drill hole 14 [Land surface about 45 ft above mean sea level] Topsoil, sandy; grass and shrub roots ................... I 1 Sand, fine, and silt .................................... 3 4 Sand, medium, brown; some gravel ..................... 12 16 Sand, medium to coarse, brown; trace of gravel ........... 9 25 Drill hole 15 [Land surface about 32 ft above mean sea level] Topsoil, sandy; grass roots; matting ..................... 1 1 Sand, fine, silty, gray; trace of clay ..................... 3 4 Sand, medium to fine, brown; Some gravel ............... 9 13 Sand, medium, to fine, brown .......................... 7 20 Drill hole 16 [Land surface about 10 £t above mean sea level] Topsoil, sandy; grass roots ............................. 1 1 Sand, fine to medium, brown ........................... 7 8 Sand, fins, silty, grayish-brown ......................... 2 10 Sand, medium to fine, brown ........................... 10 i 20 Drill hole 17 [Land surface about 62 ft above mean sea level] Clay, very fine, brown, sandy; loam; topsoil .............. 2 2 Sand, brown; gravel and boulders ....................... 18 20 Drill hole 18 [Land surface about 63 It above mean sea level] Clay sandy, brown; loam .............................. 2 2 Sand, brown; gravel and boulders .... 2 .................. 18 20 Drill hole 19 [Land surface about 74 ft above mean sea level] Clay, sandy, brown; loam .............................. 2 2 Sand, brown; gravel and boulders ....................... 38 40 GEOLOGY AND GROUND WATER OF PLU1VI ISLAND, 1~. Y. X-33 Table 4.--Logs of wells, drill holes, and test pits on Plum Island--Continued Material Thickness Depth (feel) (feet) Drill hole 20 [Land surfz~e about 66 ft above mean sea level] Clay, sandy, brown; loam .............................. 1. 5 1. 5 Sand, brown; gravel and boulders ....................... 18. 5 20 Drill hole 21 [Land surface about 58 it above mean sea level] Clay, sandy, brown; loam .............................. 4 4 Sand, very fine, silty, light-brown; silt ................... 12 16 Sand, fine, brown ..................................... 4 20 Sand, fine, medium $o coarse, brown; small gravel ........ 20 40 Drill hole 22 [Land surface about 10 ft above mean sea level] Clay, soft, sandy, brown; loam Clay, sandy, brown and gray Sand, brown, and gravel ............................... Sand, brown, and gray; clay; traces of gravel Sand, brown, and gravel ............................... Sand, fine, light-brown ................................ 2 3 3 2 2 8 2 5 8 10 12 2O l)rili hole 23 [Land surface about 3 ft above mean sea level] Sand, fine to medium, brown ........................... ]. 5 1. 5 Sand, fine to medium ................................. 7 8. 5 Sand, fine to coarse, brown; gravel ...................... 3. 5 12 Sand, fine to coarse, gray; gravel ....................... 8 20 Drill hole 24 [Land surface about 2 ft above mean sea level] Sand, black; roots; decayed vegetation .................. 0. 5 0. 5 Sand, fine, light-pink .................................. 1 1. 5 Sand, fine to medium, brown ............. ~ ............. 6. 5 8 Sand, fine to coarse, gray; gravel ....................... 8 16 Sand, fine, gray ...................................... 4 20 Test pit 1 ]Land surface about 25 ft. above mean sea level] 0.5 0.5 1.5 2 Grass matting and roots ............................... Sand, fine; trace of fine to medium gravel Silt, fine to coarse, gray; some gravel; a little sand; trace of clay Sand, fine to medium, brown; some fine to medium gravel_ Sand, fine, brown; a little coarse silt; trace of vegetation___ Sand, fine to medium, brown; some fine to medium gravel_ 1.5 2.5 1 3 3.5 6 7 10 X-34 CONTRIBUTIONS TO THE HYDROLOGY OF TI-IE IYNITED STATES Table 4.--Legs of wells, d~/ll holes, and test pits om Plu~ lda~d--Continued Material ~ Thickness Depth (feet) fleet) Test pit 2 ]Land surface about 22 ft above mesh sea level] : Grass matting ........................................ Silt, fine to coarse; some sand; trace of gravel and clay .... Sand, fine to medium; pockets of clay; trace of roots Sand, fine to medium; a little clay; a little gravel Sand, medium to coarse; trace of gravel Sand, medlnm to coarse; a little fine to coarse gravel O. 5 .5 1 1.5 3.5 3 0.5 1 2 3.5 7 10 Test pit 3 [Land surface about 25 ft above mean sea level] Topsoil, sandy; grass roots ................. ~ ........... 1 1 Sand, fine; some silt ................................... 2 3 Sand, fine; la.y, ers of gray silty sand; little gravel .......... 3. 5 6. 5 Sand, fine to coarse; some fine to medium gravel ......... 1.5 8 Sand, medium ........................................ 2 10 Test pit 4 [Land surface about 18 ft above mean sea level] Topsoil, sandy; grass roots ............................. I 1 Sand, fine; some silt; trace of grass roots ................. I 2 Sand, medium, and silt in layers ........................ I 3 Sand, medium, and gravel .............................. 5 3. 5 Sand, medium, brown; fine to coarse gravel .............. 2. 5 6 Test pit 5 ]Land surface about 13 it above mean sea level] Topsoil, sandy: grass and shrub roots ................... I 1 Sand, fine; so~e silt ................................... 1.5 2. 5 Sand, fine to medium; some gravel; trace of silt .......... 1. 5 4 Test pit 6 {Land surface about 5 ft above mean sea level] Topsoil, sandy; grass roots ............................. 1 1 Sand, medium to coarse, brown ......................... 2 3 Test pit 7 [Land surface about 6 ft above mean sea level] Sand, fine to medium, light-brown; trace of gravel ........ 4. 5 4. 5 Sand, coarse ................................................... i__ 4. 5+ GEOLOGY AND GROUND WATER OF PLUM ISLAND~ N. Y. X-35 Table 4.--Legs of wells, drill holes, and test pits on Plum Island--Continued Material Thickness ~Depth (feet) (feet) Test pit 8 [Land surface about 5 ft above mean sea level] Sand, fine; roots; vegetation ........................... 0. 5 0. 5 Sand, fine to medium, light-brown ...................... 3. 5 4 Test pit 9 [Land surface about 7 ft above mean sea level] Sand, fine to medium, light-brown ...................... 4 4 Te~t pit 10 [Land surface about 4 ft above mean see level] Sand, fine to medium, white ........................... 1. 5 1. 5 Vegetation, decayed, black (peat) ....................... I .3 1.8 Sand, fine to coarse, white ................ ~ ............ t 2. 2 4 Tat pit 12 [Land eurfaee about 12 ft above mean ~ea level] Clay, sandy, brown; and loam .......................... 3. 3 3. 3 Sand, fine to medium, light-brown ....................... 7 4 Tat pit 13 [Land surface about 25 It above mean sea level] Sand, very fine, silty, brown; some gravel ................ 4 4 Test pit 14 [Land surface about 25 ft above mean sea level] Sand, very fine, silty brown ............................ 4 4 Test pit 15 [Laud surface about 50 ft above mean eea level] Clay, fine, sandy, brown; loam; some large gravel and boulders ........................................... 4 4 Tat pit 16 [Land surface about 58 ft above mean sea level] Cinder road fill ........................................ 0. 5 0. 5 Sand, fine, brown; clay; loam; large boulders ............. 2. 5 3 Sand, fine to medium, brown; some large gravel .......... 1 4 Contributions to the Hydrology of the United States, 1960 GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1539-X This tl/-ater-Supply Paper was prepared as separate chapters ~I-X UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1962 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director CONTENTS [Letters designate the separate chapters published or in press] (A) Exploratory drilling for ground water in the Mountain Iron-Virginla area, St. Louis County, Minn., by R. D. Cotter and J. E. Rogers. (B) Jet drilling in the Fairbanks area, Alaska, by C. J. Cederstrorn and G. C. Tibbitts, Jr. (C) Ground-water reconnaissance of Winnemucca Lake Valley, Pershing and Washoe Counties, Ney., by C. P. Zones. (D) Correlation of ground-water levels and air temperatures in the winter and spring in Minnesota, by Robert Schneider. (E) Ground-water geology and hydrology of the Maynard area, Massachu- setts, by N. M. Perlmutter, with a section on An aquifer test in deposits of glacial outwash, by N. J. Lusczynski. (F) Aquifers in melt-water channels along the southwest flank of the Des Moines lobe, Lyon County, Minn., by Robert Schneider and Harry G. Rodis. (G) Ground-water geology of Karnes County, Tex., by R. B. Anders. (H) Ground-water resources of Olmsted Air Force Base, Middletown, Pa., by Harold Meisler and Stanley M. Longwill. (I) Evaluation of bank storage along the Columbia River between Richland and China Bax, Wash., by R. C. Newcomb and S. G. Brown. (J) Geology and ground-water resources of Yuma County, Colo., by W. G. Weist, Jr. (K) Ground water in the coastal dune sand near Florence, Oreg, by E. R. Hampton. (L) Geology and ground-water resources of the Fairfax quandrangle, Vir- ginia, by Paul M. Johnston. (M) Saline ground water in the Roswell Basin, Chaves and Eddy Counties, N. Mex., by James W. Hood. (N) Ground-water resources of Hamilton County, Nebr., by C. F. Keech. (O) Hydrogeologic reconnaissance of San Nicolas Island, Calif., by W. L. Burnham, Fred Kunkel, Walter Hoffmann and W. C. Peterson. (P) Geology and ground-water resources of Dougherty County, Ga., by Robert L. Wait. (Q) Reconnaissance of the hydrology of the Little Lost River basin, Idaho, by M. J. Mundorff, H. C. Broom, and Chabot Kilburn. (R) Selected bibliography on evaporation and transpiration, by T. W. Robin- son and A. I. Johnson. (S) Water in the Coeonino sandstone for the Snowflake-Hay Hollow area~ Navajo County, Ariz., by Phillip W. Johnson. (T) Geology and ground-water resources of the Lake Dakota plain area, South Dakota, by W. B. Hopkins and L. R. Petri. (U) Geology and ground-water resources of Hale County, Tex., by L. C. Wells and J. G. Cronin. (V) Availability of ground water in the Bear River valley, Wyoming, by Charles J. Robinove and Delmar W. Berry, with a section on Chemical quality of the water, by John G. Conner. (W) The hydraulics of river channels as related to navigability, by W. B. Langbein. (X) Geology and ground-water resources of Plum Island, Suffolk County, N.Y., by H. C. Crandell.