Rates of water movement through the floors of selected stormwater basins in Nassau County, Long Island, New York
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Water-Resources Investigations Report↗
Geology topics
Henry F. Ku
Publications and source records attributed to Henry F. Ku.
Base flow of streams in Nassau County sewer districts 2 and 3, Long Island, New York, 1978-79
South-shore streams on Long Island, N.Y., are small, widely spaced and have few or no tributaries. Their gradients are gentle, averaging 10 feet per mile. All streams in the area studied have a mean annual discharge of less than 20 cubic feet per second, and most are from 3 to 10 miles long. Under natural conditions, about 95 percent of total streamflow originates as ground-water seepage from the upper glacial aquifer; the remaining 5 percent consists of direct runoff. Thus, the streams of Long Island function as ground-water drains, the flow of which in dry weather is controlled directly by ground-water levels adjacent to the stream channels. Monthly low-flow discharge measurements of 18 south-shore streams in Nassau County from 1978-79 are tabulated in this report. Measurement sites were established at 1,000-foot intervals between the southern tide-affected reach and the northern headwaters of each stream. The measurements provide a data base for the 'Flow Augmentation Needs Study,' supported by the U.S. Environmental Protection Agency, which will evaluate the need to replace streamflow lost through lowering of the water table as a result of sewage in Nassau County Sewer Districts 2 and 3.
New York↗
Distribution and trend of nitrate, chloride, and total solids in water in the Magothy aquifer in southeast Nassau County, New York, from the 1950's through 1973
Concentrations of nitrate, chloride, and total solids in water in the Magothy aquifer, southeast Nassau County, N.Y., show a steadily increasing trend from the early 1950 's through 1973. Vertical distribution of nitrate, chloride, and total-solids concentrations as shown in cross sections of the study area indicate downward movement of these constituents from tens of feet to a few hundred feet in this time period. Maximum concentrations are in a zone underlying the areas of Westbury, Hicksville, and Plainview. Nitrate (as nitrogen) concentration increased from 4-5 mg/liter to 7 mg/liter in the area of Westbury and from 3 to 10 mg/liter in Plainview during the period 1950-73. Lowest nitrate concentrations are in the area south of a line running from North Merrick to South Farmingdale. Also, during the period analyzed (1950-73), a 10-mg/liter line of equal-chloride concentration on a cross section in the Westbury area moved downward a distance of less than 50 feet, and in the area of Hicksville, nearly 150 feet. Total-solids concentration doubled during the period 1950-73 in the area of Plainview, where maximum downward movement of pollutants was observed. (Woodard-USGS)
Water-Resources Investigations Report↗