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Stuart L. Schoff

Publications and source records attributed to Stuart L. Schoff.

10 recordsLinked to original sources
USGS1969

Ground-water resources of the Lambayeque Valley, Department of Lambayeque, northern Peru

Ground water in the Lambayeque Valley has been developed mainly for irrigation of sugarcane and rice. The locality is on the coastal plain of northern Peru, about 650 km (kilometers) northwest of Lima, the national capital. The area considered in this study is about 1,670 sq km (square kilometers) and is mainly on the alluvial fan of Rio Chancay and entirely in the Department of Lambayeque. Chiclayo, the departmental capital and largest city, has a population, of about 46,000. The climate is hot and virtually rainless. Agriculture is dependent on irrigation. The available water, whether in stream s or underground, is introduced from the Andean highlands by Rio Chancay. Rocks in the area range in age from Cretaceous, or possibly Jurassic, to Quaternary and in lithology from dense and hard igneous, sedimentary, and metamorphic rocks to unconsolidated sediments. The bedrock contains and yields water only in small quantities, if at all. The principal water-bearing strata are in the alluvium comprising the fan of Rio Chancay. Where ground water in the alluvium has been most intensively developed, the productive zone is within 20 m (meters) of the land surface and is composed approximately as follows: (1) relatively impermeable soil, clay, and clayey sand, 5 to 10 m thick, (2) permeable sand and gravel, 6 to 10 m thick, at places including one or more layers of clay, so that several water-bearing beds are distinguishable, and (3) relatively impermeable mixtures of clay, sand, and gravel extending below the bottom of wells. Unit 3 in the deepest test continued to 102 m. Unit 2 is the principal source of water tapped by irrigation wells. In the northern part of the area wells locally yield water rather freely from strata as deep as 73 m, but elsewhere in the area the strata deeper than 20 m are not very productive. Wells at and near Chiclayo yield only small amounts, and the deepest well disclosed, in 100 m of material, only 5.5 m of material that can be considered as possibly water bearing. Water in the alluvium of the eastern part of the area occurs under water-table conditions at depths from 1 to 8 m below the land surface. The water table declines during pumping for irrigation and rises when pumping is stopped. Recharge comes mainly from infiltration on irrigated fields and from irrigation ditches and probably varies greatly from year to year at any given place. The ground-water reservoir is replenished when pumps are idle; therefore, it is concluded that the recharge is sufficient to offset withdrawal at a rate comparable to that of 1957, which was about 81 million cum (cubic meters). A study of the effect of protracted pumping on yields of wells suggests that the rate of recharge locally, and for a short period, was more than 76,000 cu m per day. This recharge presumably declined rapidly to zero when irrigation was suspended in the locality. A pumping test showed the transmissivity to be about 950 cu m per day per m and the storage coefficient to be about 0.07. Based on these coefficients, the drawdown caused by one well discharging 10 lps (liters per second) for 6 months would be only 0.066 m at points 4,000 m distant, but 50 wells at the same rate and distance would create 3.3 m of drawdown. As actual distances between wells range from 100 to 300 m where the wells are most numerous and as the average discharge rate is nearer to 20 than to 10 lps, the cumulative effect of the actual pumping is certain to be considerable. If it were not for the recharge resulting from infiltration of irrigation water, the pumping of so many wells probably could not be long sustained. The waters from wells of the Lambayeque Valley compare favorably, in most respects, with the standards established by the U.S. Public Health Service for water for human consumption. Chemical analyses of 10 samples of ground water show that the dissolved solids, silica, bicarbonate, sulfate, and sodium increase in the downstream direction, where

Water Supply Paper↗
USGS1948

Ground water in the Blanchard area, McClain County, Oklahoma

A letter from Lloyd L. Bowser, City Clerk, dated January 8, 1948, in behalf of the town council and Mayor Walter Casey, indicates that a serious shortage of water is faced by the town of Blanchard, McClain County, Oklahoma. The town is near the eastern boundary of Grady County, where an investigation of the ground-water resources is being made by the Oklahoma Geological Survey in cooperation with the U.S. Geological Survey as part of a State-wide investigation. Information obtained thus far may aid the town by showing where additional ground water for municipal supply may be sought.

Oklahoma↗
USGS1948

Ground-water conditions in the vicinity of Enid, Oklahoma

This memorandum summaries matter discussed at a meeting of the City Commission of Enid, Oklahoma, on Thursday, January 15, 1948, at which the write presented a brief analysis of the ground-water resources available to the City of Enid and answered questions brought up by the commissioners.

Oklahoma↗
USGS1948

Ground water in the Beggs area, Okmulgee County, Oklahoma

This memorandum discusses the geology of the Beggs area in Okmulgee County, Oklahoma, as it is related to the availability of ground water. Geological reports and unpublished data from the files of the Oklahoma Geological Survey, together with local information furnished by R.W. Steinman, Beggs Water Superintendent, are the basis for the statements that follow.

Oklahoma↗
USGS1948

Ground water available in the Davenport area, Oklahoma

This memorandum describes the ground-water resources in the vicinity of Davenport, Lincoln County, Oklahoma. It is based on a one-day trip to Davenport made by the writer on February 11, 1948, to obtain information in addition to that in the ground-water files in Norman on the availability of ground water for public supply or other uses in the Davenport area. Davenport is a town of about 1,000 in east-central Lincoln County, Oklahoma, on U.S. Highway 66, about half way between Oklahoma City and Tulsa. It is in an area of undulating to gently rolling topography underlain by rocks of Pennsylvanian age. The area is drained into Deep Fork of the Canadian River, by Dry Creek and its tributary, Chuckaho Creek.

Oklahoma↗
USGS1948

Ground water in the Anadarko area [Caddo County], Oklahoma

This report offers a preliminary interpretation of the geology and ground-water hydrology of the Anadarko area, Oklahoma. L.V. Davis prepared the accompanying map from aerial photographs and furnished much of the geologic information, and records of the State Mineral Survey (WPA) were used in the preparation of the section on the Rush Springs sandstone. (available as photostat copy only)

Oklahoma↗
USGS1941

Contamination of Lake Wewoka and fresh-water sands by disposal of oil-well brines near Wewoka, Seminole County, Oklahoma

This report deals with ground-water conditions in an area about 5 miles wide from east to west and 8 miles long from north to south, in Tps. 8 and 9 N., Rs. 7 and 8 E., in Seminole County, Oklahoma, including the town of Wewoka and Lake Wewoka. The possible contamination of the lake waters from oil-well brines disposed through a well 3.75 miles north of the lake, and other effects of brine disposal, are considered. The investigation was made at the request of Frank Raab, member of the Oklahoma Planning and Resources Board, and Don McBride, Chief Engineer of the Division of Water Resources who has the responsibility of preventing contamination of water supplies in Oklahoma. Field work was done July 5 and 6, 1941, by Robert H. Dott, Director of the Oklahoma Geological Survey; C.G. Lalicker, Department of Geology, University of Oklahoma; and S.L. Schoff, Assistant Geologist in the Ground Water Division, Water Resources Branch, of the U.S. Geological Survey. Lalicker spent both days studying the rocks exposed in the vicinity and measuring their thickness. A copy of the composite section measured by him is attached. Dott and Schoff spent one day collecting the well information summarized in Table 1, and one day with Lalicker on the stratigraphy.

Oklahoma↗