Water quality in the Delaware estuary for two years of drought: 1965 and 1966, from Trenton, New Jersey to Reedy Island, Delaware
No abstract available.
Geology topics
Publications and source records attributed to Walter B. Keighton.
No abstract available.
Sustained flows of fresh water greater than 3,500, 4,400, and 5,300 cubic feet per second into the Delaware River estuary at Trenton, NJ assure low salinity at League Island, Eddystone, and Marcus Hook, respectively. When the discharge at Trenton is less than these critical values, salinity is very sensitive to change in discharge, so that a relatively small decrease in fresh-water discharge results in a relatively great increase in salinity. Comparison of the discharge-salinity relations observed for the 14-year period August 1949-December 1963 with relations proposed by other workers but based on other time periods indicate that such relations change with time and that salinity is affected not only by discharge but also by dredging; construction of breakwater, dikes, and tidal barriers; changing sea level; tidal elevation; tidal range; and wind intensity and direction.
During the 14-year period from August 1949 to July 1963, the U.S. Geological Survey, in cooperation with the city of Philadelphia, collected samples of river water once each month in the 43-mile reach of the Delaware River from Bristol to Marcus Hook, Pa., and daily at Trenton, 10 miles upstream from Bristol. This part of the Delaware is an estuary into which salt water is brought by tides; fresh water flows into the estuary at Trenton, NJ, and farther downstream from the Schuylkill River and other tributaries of the Delaware. In March, April, and May, when fresh-water flow is high, the average concentration of dissolved solids in the water at Bristol was 76 ppm (parts per million), and at Marcus Hook 112 PPM In August and September, streamflow is lower, and the average concentration of dissolved solids increased to 117 PPM at Bristol and 804 PPM at Marcus Hook. Major salinity invasions of the Delaware River occurred in 1949, 1953, 1954, 1957, and 1963. In each of these years the fresh-water flow into the tidal river at Trenton was low during the period from July to October. The greatest dissolved-solids concentrations in these monthly samples were 160 PPM at Bristol and 4,000 PPM at Marcus Hook. At times the dissolved-oxygen concentration of the river water has become dangerously low, especially in that reach of the river between Wharton Street and League Island. At the Benjamin Franklin Bridge, one-third of the samples of river water were less than 30 percent saturated with oxygen; however, no trend, either for better or for worse, was apparent during the 14-year period. It is useful now to summarize these monthly analyses for the period 1949-63 even though a much more detailed description of water quality in this reach of the estuary will soon become available through the use of recording instrumental conditions. This compendium of water-quality data is useful as an explicit statement of water quality during the 14-year study period and is valuable for directing attention to water-quality problems for selecting instrument sites, and for making comparative studies with the more detailed information which is already being obtained with the aid of recording instruments.
No abstract available.
This report has been prepared for the guidance of personnel of the Water Resources Division who are engaged in water-quality investigations of tidal rivers. The study of tidal rivers is beset with many complexities not present in the investigation of non-tidal rivers. The periodic rise and fall of the tide may result in a corresponding periodic change in salinity at a sampling location on the tidal river. When the fresh water discharge is low, saline water may intrude up-river, and any factor changing the relative elevations of the ocean and the mean river level has an effect on the extent of salt-water intrusion. Variations in water composition between samples taken at several locations up or down river, at different depths, or at several locations across the stream are likely to be more pronounced than for similar sets of samples from a non-tidal stream. The nature of these variations and factors responsible for them are discussed, and the need for consideration of them in planning a sampling routine is stressed. The nature and mechanism of ocean-water intrusion in tidal rivers is discussed and sampling procedures for its detection are described. lllustrative examples - mostly from the work of the United States Geological Survey or State agencies - show various methods for correlating and presenting data from quality-of-water surveys of tidal rivers. Each tidal river presents an individual problem which can best be understood from a study of the factors involved. To that end the report is supplemented by an annotated bibliography of selected publications in the field.