Hydrologic Effects of the 

1962-66 Drought on 

Long Island, New York

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1879-F

Prepared in cooperation with the New 

York State Department of Conservation, 

Division of Water Resources; the Nassau 

County Department of Public Works; 

the Suffolk County Board of Supervisors; 

and the Suffolk County Water Authority
Hydrologic Effects of the 

1962-66 Drought on 

Long Island, New York

By PHILIP COHEN, 0. L. FRANKE, and N. E. McCLYMONDS

CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1879-F

Prepared in cooperation with the New 

York State Department of Conservation, 

Division of Water Resources; the Nassau 

County Department of Public Works; 

the Suffolk County Board of Supervisors; 

and the Suffolk County Water Authority

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1969
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 20 cents (paper cover)
CONTENTS

Page

Introduction _____________________________________ Fl

Purpose and content of report ______________________ 1

Meaning of "drought" ___________________________ 3

Acknowledgments _____________________________ 3

Deficient precipitation ______________________________ 4

Annual precipitation ____________________________ 4

Monthly precipitation ____________________________ 7

Declining ground-water levels _________________________ 7

Annual water levels ____________________________ 7

Monthly water levels ____________________________ 10

Decreased streamflow ______________________________ 10

Annual streamflow ______________________________ 10

Monthly streamflow _____________________________ 10

Decreased water in storage -_____..__________________-_ 12

Conclusions ____________________________________ 16

References cited __________._____.._________________ 17

ILLUSTRATIONS

Page 

FIGURE 1. Map of Long Island and vicinity showing location of selected

hydrologic-data-collection points _______________ F2 

2-9. Graphs showing 

2. Long-term annual precipitation at Setauket ____ 5

3. Cumulative departure from average annual precipitation at Setauket _______________ 5

4. Percentage of time that various values of annual 

precipitation were equaled or exceeded at 

Setauket for the period of record _________ 6

5. Monthly precipitation, water years 1960-67, and 

long-term average monthly precipitation at 

Setauket _________________________ 8

6. Average annual ground-water levels in 14 key

observation wells _____ ___ _ _ 9

7. Average monthly ground-water levels in 14 key

observation wells __________________ 11

8. Combined annual average streamflow of 19 principal streams _________ _ _ _ 12

9. Combined monthly average streamflow of 19 principal streams _____________________ 13 

10. Net change of ground-water levels in the unconfined aquife" 15

in
CONTRIBUTIONS TO THE HYDROLOGY 

OF THE UNITED STATES

HYDROLOGIC EFFECTS OF THE 1962-66 DROUGHT ON 

LONG ISLAND, N.Y.

By PHILIP COHEN, 0. L. FRANKE, and N. E. MCCLYMOJ TDS

ABSTRACT

The hydrologic system of Long Island, N.Y., showed a marked response 

to deficient precipitation in the years 1962-66. By 1966, streamflow was the 

lowest of record in many Long Island streams, and ground-water levels had 

declined a maximum of about 10 feet in the central part of the island. Although the drought apparently ended in the early months of If 77 and 

ground-water levels and streamflow recovered somewhat since then, groundwater levels and streamflow were still considerably below long-term average values in September 1968.

INTRODUCTION

PURPOSE AND CONTENT OF REPORT

Hydrologic records of various kinds have been collected on and 

near Long Island, N.Y. (fig. 1), for more than a hundred years. 

Since the mid-1930's, when the U.S. Geological Survey began a 

continuing program of water-resources studies on Long Island 

in cooperation with several State and county agencies, the collection of hydrologic records on Long Island has been more intensive 

than in most places in the United States.

The truly vast amount of hydrologic data obtained on Long 

Island has afforded unusually good opportunities to document and 

evaluate hydrologic phenomena both natural phenomena and 

phenomena associated with the activities of man. One ratural 

hydrologic phenomenon, the recent (1962-66) northeast drought, 

was especially well documented on Long Island and is the subject 

of this report. The report considers, largely in a graphic format, 

the deficiency in precipitation during the period 1962-66 and 

the hydrologic consequences of that deficiency namely, declines 

of ground-water levels and related decreases in streamflow and 

ground-water storage in Nassau and Suffolk Counties. Kings and

Fl
74

73 c

41°

FIGURE 1. Long Island and vicinity showing location of selecte
EFFECTS OF 1962-66 DROUGHT ON LONG ISLAND, N.Y. F3

Queens Counties are excluded from the analysis mainly Hcause 

factors related to urbanization make a precise quantitative analysis of the effects of the drought on the hydrologic system in these 

counties virtually impossible.

For the most part, the approach taken in this report is to consider, largely in a descriptive manner, the drought and its effects 

as they are illustrated on the accompanying graphs, diagrams, and 

maps. The few statistical techniques used (except perhaps the 

technique of frequency analysis) and the parameters tl at are 

cited are simple and should be readily understood by most by men.

MEANING OP "DROUGHT"

Most technical reports concerned with one or more aspects of a 

drought carefully develop the point that the word "drought" has 

many different meanings, and in one place or at one time the 

word may be used to describe a very different set of circumstances 

than in another place or time. (See Thomas, 1962, for an ercellent 

review of the meaning of "drought".) Droughts commorly, but 

not always, are defined in terms of one or more of the following 

factors: (1) precipitation, (2) soil moisture, (3) public-water 

supply, (4) above-ground or underground storage capacity, (5) 

crop failures, and (6) general economic hardship. Almost always, 

regardless of the specific definition used, a "drought" is related 

to, or is caused by, having less water available than is desired or 

expected. (See Yevdjevich, 1968, for methods of determining 

whether a "drought" has occurred or is occurring.) Within this 

context the drought described in this report represented r. series 

of events closely related to, and largely caused by, inadequate 

precipitation inadequate in terms of the amount desired IT local 

residents and the amount normally expected.

ACKNOWLEDGMENTS

Virtually all the data on ground-water levels and streamflow 

used to develop the information given in this report were obtained 

as part of a program of water-resources studies that is being carried on by the U.S. Geological Survey in cooperation with the New 

York State Division of Water Resources, the Nassau County Department of Public Works, the Suffolk County Water Authority, 

and the Suffolk County Board of Supervisors. We are grateful to 

our colleagues in those agencies whose support included, but was 

not limited to, the collection of many of the data presented in 

this report.

The report was prepared under the immediate supervision of 

B. L. Foxworthy, former Hydrologist-in-Charge of the Geological
F4 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

Survey Subdistrict Office on Long Island, and under the general 

supervision of Garald G. Parker, District Hydrologist, U.S. Geological Survey, Albany, N.Y.

DEFICIENT PRECIPITATION

ANNUAL PRECIPITATION

During the past two decades, precipitation data have been collected at nearly 30 stations on Long Island. The maximum average 

annual precipitation, about 51 inches, occurs near the middle of 

the island, and the minimum average annual precipitation, about 

40 inches, occurs along the coast in southern Nassau County and 

on Plum Island. The long-term average precipitation for all Long 

Island is about 44 inches per year (Cohen and others, 1968, p. 30).

Data collected at Setauket (fig. 1) provide the longest continuous record of precipitation on Long Island. The average for the 

81-year period of record at that station, water years 1887-1967, 

is 44.5 inches, nearly the same as the long-term average for all 

stations on Long Island. (The "water year" is the 12-month period 

beginning October 1; it is designated by the calendar year in which 

the 12-month period ends.) Accordingly, precipitation data from 

Setauket are emphasized in this report.

Annual precipitation at Setauket ranged from a low of 30.8 

inches in water year 1966 to a high of 56.4 inches ir water year 

1898, and, in general, years of above- and below-average precipitation seem to have been randomly distributed (fig. 2). Only twice 

during the entire period of record was precipitation above or 

below average for 5 consecutive years. It was above average from 

1887 through 1891, when the cumulative excess wag 33.0 inches 

(fig. 3), and it was below average from water years 1962 through 

1966, when the cumulative deficiency was 41.7 inches.

Largely because water year 1962 was the first year of belowaverage precipitation in the 5-year sequence, the drought is somewhat arbitrarily assumed to have begun on Long Island in that 

year. The qualification "somewhat arbitrarily assumed" is used 

mainly because precipitation in water year 1962 was only slightly 

below average (1.2 in.), and because, for all practical purposes, 

virtually none of the adverse features associated with a drought 

were noted on Long Island during that year.

Two additional noteworthy features of the recent drought can 

be deduced from figures 2 and 3. First, the 1962-66 drought was 

the most severe of record in terms of the total deficiency in precipitation and in terms of its duration. The next largest deficiency 

in precipitation for a consecutive number of years, about 23 inches, 

occurred in the 3-year period, water years 1909-11. Second, the
EFFECTS OF 1962-66 DROUGHT ON LONG ISLAND, N.Y. F5

81-year average, 

44 50 inches

I 40 

O

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30

20

1887 1890 1900 1910 1920 1930 

WATER YEAR

1940 1950 1967

FIGURE 2. Long-term annual precipitation at Setauket.

1887 1890 1900 19?0 1930 

WATER YEAR

1950 1960 1967

FIGURE 3. Cumulative departure from average annual precipitation at

Setauket.

increasing deficiency in annual precipitation with each succeeding 

year of the 1962-66 drought intensified the severity of the drought. 

Sufficient data for Long Island are not available to evaluate the 

probable frequency of occurrence of the 5-year 1962-66 drought, 

and an analysis of the frequency of that multiyear event, based

329-637 O - 69 - 2
F6 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITE! STATES

on regional or worldwide data, is beyond the scope of this report. 

Sufficient data are available, however, to evaluate tH frequency 

of occurrence of annual precipitation (fig. 4). For example, annual 

precipitation probably will be equal to, or greater than, 30.8 inches, 

as it was in 1966, about 99 percent of the time. Similarly, annual 

precipitation probably will be equal to, or greater than, 31.9 inches, 

as it was in 1965, about 98 percent of the time. (F«e Mitchell! 

1968, for an additional discussion of the frequency of occurrence 

of droughts with special reference to the drought described in 

this report.)

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0.1 1.0 5 10 20 3040506070 80 90 95 ?9.0 99.9

PERCENTAGE OF TIME

FIGURE 4. Percentage of time that various values of annurl precipitation 

were equaled or exceeded at Setauket for the period o* record.

The odds against the annual precipitation being as little as it 

was in 1966 are roughly 60-80 to 1, and the odds agairst precipitation being as little as it was in 1965 are roughly 35-40 to 1. Thus, 

if the simplifying assumption is made that annual precipitation 

at Setauket is randomly distributed, the odds against the precipitation being as low as it was in the 2 successive years, 1965 and 

1966, are considerably more than 100 to 1. The validity of the 

assumption of total random distribution of annual precipitation 

undoubtedly is questionable. However, the preceding discussion is 

useful inasmuch as it illustrates (1) the difficulties involved in 

estimating how frequently a drought of the length and severity 

of that experienced on Long Island in 1962-66 might occur, and
EFFECTS OF 1962-66 DROUGHT ON LONG ISLAND, N.Y. F7

(2) the probable large order of magnitude of the odds against 

such an occurrence.

MONTHLY PRECIPITATION

Average monthly precipitation on Long Island is fairly uniform, 

and for the period of record at Setauket it ranged from a lov of 3.1 

inches for June to a high of 4.1 inches for August (fig. 5). The 

long-term monthly average was about 3.7 inches (44.50 in. per 

yr divided by 12 months).

Monthly averages for water years 1960-67 also are shown in 

figure 5 (dashed lines). Below-average precipitation and an increasing deficiency from year to year in water years 1962-66 are 

clearly indicated by the dashed lines. As is shown on the graph, 

however, precipitation was above average in some months in each 

of the 5 drought years.

It is significant to note that it is virtually impossible tc select 

readily the specific month when the drought began. On the other 

hand, the monthly data seem to indicate that, at least with respect 

to precipitation, the drought may have ended in February or 

March 1967.

DECLINING GROUND-WATER LEVELS

ANNUAL WATER LEVELS

Ground-water levels have been measured in 14 key observation 

wells on Long Island (fig. 1) since the late 1930's. These wells 

tap the uppermost unconfined aquifer on Long Island and, accordingly, water levels in these wells respond rapidly to changes 

in the rate of ground-water recharge. All the natural fresh-water 

recharge on Long Island results from the infiltration of precipitation falling on the island. Thus, ground-water levels in the 14 

wells responded markedly to the 1962-66 drought (fig. 6).

The average altitude of the water levels in the 14 key wells for 

the period 1940-67 was nearly 46.5 feet. The annual average level 

was about 1 foot above the long-term average in 1961, and it declined to a point about 1 foot below the long-term average in 1963. 

By 1966 the annual average level had declined about 7 feet below 

the 1961 level to a point about 6 feet below the long-term average 

level. In 1967, when the drought apparently was broken, the annual average level recovered about 0.3 foot.

The ground-water reservoir of Long Island is intensively developed for public-supply and other uses, and ground-water withdrawals, which have been on the order of 400 million gallons per 

day in recent years, have been increasing steadily, especially since 

the mid-1940's (Cohen and others, 1968). The fluctuations of
1959 1960 I 1961 I 1962

CALENDAR YEAR 

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WATER YEAR

FIGURE 5. Monthly precipitation, water years 1960-67, and long-term 
EFFECTS OF 1962-66 DROUGHT ON LONG ISLAND, N.Y. F9

1940 1950 1955 

WATER YEAR

1960 1965 1967

FIGURE 6. Average annual ground-water levels in 14 key observatior wells.

ground-water levels shown in figure 6 undoubtedly reflect in part 

the effects of pumping. In addition, other factors, such as decreased natural recharge related to urban development and decreased artificial recharge related to the discontinued use of cesspools and the construction of sanitary sewers (Franke, 1968), have 

been partly responsible for the declines of ground-water levels on 

Long Island, especially since the mid-1950's.

Sufficient data are not available to determine accurately what 

proportion of the decline in water levels during 1962-6** was 

caused (1) directly by the drought as a result of decreased precipitation and related decreased recharge, (2) indirectly by the 

drought as a result of increased ground-water withdrawals for 

lawn sprinkling and other needs related to abnormally low precipitation, or (3) by factors unrelated to the drought. Nevertheless, the striking similarity between figures 3 and 6, especially for 

1961-67, strongly suggests that most of the changes in the annual 

average ground-water levels were related to below average precipitation and the resulting decreased recharge.
F10 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

MONTHLY WATER LEVELS

Monthly water-level data from the key observation wells (fig. 7) 

provide additional insight into the effects of the drought on the 

hydrology of Long Island. The seasonal trend in water-level fluctuations highest water levels in the winter and late spring, and 

lowest water levels in the late summer and early fall can be 

attributed largely to seasonal variations in natural recharge rates 

and partly to seasonal pumping patterns. The downward trend 

in ground-levels from 1962 to 1966 is clearly visible. Also, the 

decline in ground-water levels was abruptly halted and reversed 

in the winter of 1967 when, as previously noted, the drought seems 

to have been broken by sustained average and above-average 

precipitation in several consecutive months.

DECREASED STREAMFLOW

ANNUAL STREAMFLOW

On the average, more than 95 percent of the streamflow on Long 

Island is derived by seepage into the stream channels from the 

ground-water reservoir. In other words, less than 5 percent of 

the streamflow is overland runoff (Cohen and others, 1968, p. 40). 

Accordingly, the flows of Long Island's streams closely reflect 

changes in ground-water levels in the shallow unconfined aquifer 

(the part of the ground-water reservoir that is in direct hydraulic 

continuity with the streams). The close relationship between 

streamflow and ground-water levels on Long Island is confirmed 

by the fact that the shape of the curve in figure 8, which shows 

the combined average flows of the 19 principal strep ms on Long 

Island, is very similar to the shape of the curve shoving average 

annual ground-water levels (fig. 6).

In water years 1940-67 the combined flows of the principal 

streams averaged 291 cfs (cubic feet per second), and ranged from 

a high of 401 cfs in 1956 to a low of 155 cfs in 1966. The lowest 

flows of record were noted in 14 of the 19 streams in July or August 

of water year 1966, the same months in which record-low groundwater levels were noted in many of the observation wells. Flows 

in 1967 generally were only slightly more than those ir 1966; nonetheless, a distinct upturn in the combined-flow hydrograph was 

noted in that year, corresponding to increased precipitation (fig. 

2) and to a slight recovery of ground-water levels (fig. 6).

MONTHLY STREAMFLOW

Monthly flow data for the 19 principal streams for water years 

1960-67 (fig, 9) confirm many of the observations made in the 

preceding text. For example, seasonal streamflow fluctuations 

correspond fairly closely to seasonal fluctuations in ground-water
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F12 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

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1940 1945 1950 1955 

WATER YEAR

1960

FIGURE 8. Combined annual average streamflow of 19 principal streams.

levels. (Compare figs. 7 and 9.) In addition, the slight but distinct 

upturn in the streamflow hydrograph in the winter of 1967 also 

seems to have signaled the possible end of the drought. Despite 

the increase in streamflow, however, the discharge of many of 

Long Island's streams in 1967 was considerably b^low average, 

and record-low flows were noted in three of the streams in that 

year.

DECREASED WATER IN STORAGE

The amount of fresh water stored on and beneath the surface of 

Long Island decreased markedly as a result of the drought conditions in water years 1962-66. The decreases involved surface 

water, soil moisture, and ground water.

Most of Long Island's lakes are small and shallov-* (less than a 

square mile in area, and commonly only a few tens of feet or less 

in depth), and although a few of the lakes are perched and, therefore, their levels are not related to the water table, most of the
EFFECTS OF 1962-66 DROUGHT ON LONG ISLAND, N.Y. F13

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F14 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

lakes are in direct hydraulic continuity with the shallow unconfined aquifer. Accordingly, the levels of most of th°. lakes are at 

about the same altitude as the water table adjacent to the lakes, 

and the lake levels fluctuate in response to changes in the altitude 

of the water table. Inasmuch as the lakes are shallow, declines 

of the water table and of the lake levels of only a few feet, such 

as those that occurred in water years 1962-66, caused large parts 

of many of Long Island's lakes to become dry and caused a decrease in the amount of water in storage therein. Unfortunately, 

data are not available to compute the decrease in rtorage in the 

lakes during the drought.

As the ground-water levels declined during the drought, parts of 

the upstream reaches of many of Long Island's streams also became dry. In addition, the depth of water in those parts of the 

streams in which there was perennial flow was below average during the drought. Thus, the amount of water stored in the stream 

channels during water years 1962-66 was below average. Again, 

sufficient data are not readily available to compute this decrease 

of surface water in storage. However, the total decrease of surface water in storage (in both the lakes and stream*) during the 

drought was small relative to the decrease of subsurface water 

in storage.

The net decrease in soil moisture during the drought undoubtedly was many times greater than the decrease of surface 

water in storage; data again, however, are not available to evaluate quantitatively this parameter.

Sufficient data are available to estimate the net decrease of 

ground water in storage from water years 1961-66. As shown in 

figure 10, the declines in ground-water levels ranged from somewhat more than 10 feet in northeastern Nassau Courty and northwestern Suffolk County to less than 2 feet near the shorelines. 

Larger declines were noted in southwestern Nrssau County 

(shaded area in fig. 10), largely as a result of decreased artificial 

recharge related to widespread sewering (Frankc, 1968), but 

consideration of these declines is beyond the scope cf this report.

The contours showing the net declines of ground-water levels 

(fig. 10) approximately parallel the water-table contours (not 

shown) ; the largest declines were in the area of the regional 

ground-water divide on Long Island which is in north-central 

Nassau and Suffolk Counties. This relation between the altitude 

of the water table and the magnitude of the decline in the water 

table is consistent with the theoretically expected re^onse of the 

ground-water system to any factor that causes an islandwide
41'

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10 15 20 MILES

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FIGTJSS 10. Met chan~a of ground-v:ator brels in ths u
F16 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

decrease in ground-water recharge. Because the ground-water 

system of Long Island is hydraulically connected to the surrounding ocean, ground-water levels can decline only sligHly, if at all, 

in the unconfined aquifer near the shorelines, and any islandwide 

declines will increase with increasing distance from the shorelines. 

The computed volume of aquifer material that was dewatered 

from 1961 to 1966 was about 0.7 cubic mile. Assuming that the 

specific yield of the dewatered aquifer material is 0.20, it follows 

that the net decrease of ground water in storage during the 

drought in Nassau and Suffolk Counties was about 0.14 cubic 

mile, or about 155 billion gallons. An estimated 60 trillion gallons 

of fresh ground water is stored beneath the mainland of Nassau 

and Suffolk Counties, excluding the forks (Cohen and others, 1968, 

p. 26), and an estimated 35 trillion gallons of fresh ground water 

is stored beneath the salty bays and ocean adjacent to Long Island. 

Therefore, it is apparent that the most severe drought of record 

on Long Island caused a decrease in the amount of fresh ground 

water in storage that was equal to only a small fraction of 1 percent of the total fresh ground water in storage beneath the island.

CONCLUSIONS

The cumulative departure from average precipitation at Setauket during the drought years of 1962-66 was nearly 42 inches 

(fig. 3). In other words, during the 5-year drought period, the 

deficiency in precipitation was nearly equal to the entire amount 

of precipitation normally expected in a given year. Expressed 

solely in terms of deficient precipitation, the drought was the 

most severe of record for Long Island.

Much of the water supply for the two westernmost counties on 

Long Island, Kings and Queens Counties, is derived from mainland surface-water sources, and that supply was seriously affected 

by the drought (Barksdale and others, 1966). Virtually none of 

the public-supply water used on Long Island is drawn directly 

from surface-water sources on the island. Accordingly, the marked 

decrease in streamflow and the decline in lake levels had practically 

no effect on Long Island's water supply. However, the decreased 

streamflow and the decline in lake levels did impair the aesthetic 

and recreational features of those bodies of surface water and, 

therefore, caused a moderate amount of economic loss, inconvenience, and displeasure.

The ground-water reservoir of Long Island is th°. sole source 

of fresh public-supply water for the roughly 2.5 million people 

in Nassau and Suffolk Counties. Despite the fact that groundwater levels declined markedly in these counties, the decline had
EFFECTS OF 1962-66 DROUGHT ON LONG ISLAND, N.Y. FIT

a negligible effect on the total volume of fresh ground wrter in 

storage beneath the island and on the yield of the hundreds of 

large-capacity public-supply wells. A few small-capacity shallow 

wells became dry, and the capacity of a few others was reduced 

markedly; but the decreases in the total water supply related to 

these factors were negligible. Nevertheless, where such events 

did occur, there was an adverse economic impact.

Deficient precipitation and soil moisture adversely affected some 

of the farms and nurseries on Long Island during the drought. 

In some places, additional agricultural costs were incurred because 

of the need to increase the use of ground water for irrigation. 

In many places, however, the fact that ground water was readily 

available minimized the economic loss.

The ground-water reservoir of Long Island has long been recognized as a vital and major economic asset. The 1962-66 drought 

very dramatically confirmed this recognition. In the midst of the 

most severe drought of record, residents in Nassau and Suffolk 

Counties were still able to water their lawns at will because of the 

large amount of water available from the Long Island groundwater reservoir. In contrast, their less fortunate neighbors in 

Kings and Queens Counties faced, first, severe restrictions on 

lawn watering and, eventually, during the last 2 years of the 

drought, complete curtailment.

Finally, in terms of precipitation, the drought seemingly ended 

in the winter of 1967. However, streamflow and ground-water 

levels are still (Sept. 1968) near record lows. Under conditions 

of average precipitation and average recharge rates, it may take 

years for ground-water levels and streamflow conditions to return 

to normal. Of course, abnormally high amounts of precipitation or 

certain changes in the hydrologic regimen resulting from the activities of man (artificial recharge, for example, see Parker and 

others, 1967) would shorten the time required. Other changes 

in the hydrologic regimen, such as increased pumpage or changes 

that cause decreased recharge, could result in a situation in which 

ground-water levels and streamflow on Long Island might never 

return to their pre-1961 values.

REFERENCES CITED

Barksdale, H. C., O'Bryan, Deric, and Schneider, W. J., 1966, Efect of

drought on water resources in the Northeast: U.S. Geol. Survey Hydrol.

Inv. Atlas HA-243. 

Cohen, Philip, Franke, 0. L., and Foxworthy, B. L., 1968, An atlas of Long

Island's water resources: New York State Water Resources Comm.

Bull. 62, 117 p.
F18 CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

Franke, O. L., 1968, Double-mass-curve analysis of the effects of sewering 

on ground-water levels on Long Island, New York in Geological Survey 

research 1968: U.S. Geol. Survey Prof. Paper 600-B, p. B205-B209.

Mitchell, J. M., 1968, Some remarks on the statistical predictability of 

drought and related climatic anomalies in Proceedings of the Conference 

on the Drought in the Northeastern United States: New York Univ. 

School Eng. and Sci., Geophysical Research Lab. TR-68-3, p. 129-159.

Parker, G. G., Cohen, Philip, and Foxworthy, B. F., 1967, The role of artificial recharge in the scientific management of water resources: Am. 

Water Resources Assoc. Proc. National Symposium or Ground-Water 

Hydrology, San Francisco, Calif., p. 193-213.

Thomas, H. E., 1962, The meteorologic phenomenon of drought in the Southwest: U.S. Geol. Survey Prof. Paper 372-A, 43 p., 1 pi.

Yevdjevich, V. M., 1968, Objective definitions of hydrolof-ic droughts in 

Proceedings of the Conference on the Drought in the Northeastern United 

States: New York Univ. School Eng. and Sci., Geophysical Research 

Lab. TR-68-3, p. 182-201.

U. S. GOVERNMENT PRINTING OFFICE : 1969 O - 329-637