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Robert L. Cory

Publications and source records attributed to Robert L. Cory.

9 recordsLinked to original sources
USGS1980

The asiatic clam, Corbicula fluminea (Müller), in the tidal Potomac River, Maryland

The Asiatic clam, Corbicula fluminea (Müller), has extended its range to include the tidal fresh-water portion of the Potomac River, Maryland. Though patchily distributed, the clams have attained densities of 665 m −2 . Size-class distributions indicate that the clams first appeared in 1975. About 90% of the population belong to year-class I and were less than 12 mm in length. Elsewhere, this species has created severe water quality problems; it should be closely watched in the Potomac.

Estuaries↗
USGS1980

Water quality in Rhode River at Smithsonian Institution Pier near Annapolis, Maryland, January 1976 through December 1978

Water temperature, salinity, turbidity, dissolved oxygen, pH, and water level data were continuously monitored and recorded from the Smithsonian Institution pier near Annapolis, Md., from January 1976 through December 1978. Daily maximum and minimum values are tabulated and summarized, and monthly averages and extremes are presented. Water temperature ranged from 0.0 to 33.9 Celsius. Both high and low extreme values exceeded those recorded during the previous 6 years. Salinity patterns showed normal seasonal variations and were related to the Susquehanna River inflow, which controls the upper bay salinity. Salinity between 13 and 15 parts per thousand in November and December 1978 were the highest recorded over a 9-year period. Turbidity varied seasonally, with lowest values in winter and highest in spring. Dissolved oxygen ranged from 2.0 to 18.7 milligrams per liter. Large variations between summertime daily minima and maxima indicated the high state of eutrophication of the water being monitored. Hydrogen-ion activity (pH) ranged from 7.0 to 10.2 over the 3-year period. The pH changes reflect daily variation in partial pressure of carbon dioxide, which varies inversely with the dissolved oxygen. Water level variation at the monitoring site for the 3-year period was 1.89 meters, with highest water 0.59 meter above mean high water and lowest 0.83 meter below mean low water. An apparent decline of 0.07 meter below previously recorded mean high and mean low water was associated with stronger winds and a prevalance of westerly winds in February during the winter of 1976-1977. (USGS)

Water-Resources Investigations Report↗
USGS1974

Water quality in Rhode River at Smithsonian Institution Pier near Annapolis, Maryland, April 1970 through December 1973

Water temperature, salinity (computed from specific conductance data), turbidity, dissolved oxygen, pH, and water level data were collected by a continuously recording water quality monitor located in the Rhode River, at the Smithsonian Institution's pier near Annapolis, Md., from April 1970 through December 1973. Data, as presented in this report, consist of daily maximum and minimum values summarized by week to give weekly averages and extremes. Temperatures showed an overall range from 0.7 to 32.6°C. The water temperature data indicate successively warmer winters. Salinity ranged from 1.05 to 14.03 parts per thousand. In June 1972, salinity dropped markedly as fresh water from tropical storm Agnes entered the Rhode River from Chesapeake Bay. Most of the fresh water entering upper Chesapeake Bay as a result of tropical storm Agnes came from the Susquehanna River. Turbidity was usually low, averaging about 14 Jackson Turbidity Units; however, during spring and early summer of 1972, values averaged about 23 Jackson Turbidity Units. This increase in turbidity was due to the high Susquehanna River flows during that period. Extremes of turbidity ranged from about 5 to 80 Jackson Turbidity Units. Dissolved oxygen ranged from 0.0 to 19.8 milligrams per litre. Large daily changes in oxygen indicated a high state of biological metabolism. Values of pH ranged from 6.8 to 10.1 and daily changes coincided with oxygen changes. Tide-dominated water levels had an overall range of 5.9 feet (1.8 metres) and a mean tidal range of 1.5 feet (0.46 metres).

Maryland↗
USGS1970

Temperature and water-quality conditions of the Patuxent River estuary, Maryland, January 1966 through December 1967

The effect of power plant cooling water in raising natural water temperatures at a location near the power plant on the Patuxent River estuary is clearly evident from thermograph records. Surface temperature at a station 333 m (1,000 ft) downstream from the discharge canal was raised an average of about 4 C, and at times by as much as 8 C. Temperature rises were greatest during the winter. Infrared imagery showed that elevated surface temperatures could be detected about 5.5 km (3 nautical miles) upstream at flood tide. Temperature profiles obtained from airborne radiation equipment revealed a complicated surface temperature pattern and also showed the effects of density differences and wind action on the steam-electric station (S.E.S.) effluent plume. Mean annual salinity for a 5-year period (1963–1967) was highest in 1966, about 12.3 ‰, and lowest in 1967, about 9.9‰. Dissolved oxygen values for 1966–1967 ranged from 3.2 to 15.6 mg/l, and saturation ranged from 55 to 152%. Turbidity levels were inversely related to salinity, with the highest annual, mean of 28 JCU (Jackson Candle Units) occurring in 1967, the lowest salinity year. The extreme tide range was 2.1 m (6.7 ft); mean water levels at the Patuxent Bridge were highest in summer and lowest in winter. Water stages are more affected by wind speed and direction than by flow in the river.

Maryl↗
USGS1969

Thermal additions and epifaunal organisms at Chalk Point, Maryland

Two sets of test panels, one in the intake and the other in the effluent canal of a steam-generating station, were submerged at monthly intervals in 1967. The panels were analyzed for epifaunal species composition, abundance, seasonal attachment, and total biomass production. The average surface-water temperature rose 6.3 C above ambient on the effluent side, and the biomass production of the epifaunal organisms found there increased nearly three times that of the intake. An earlier and larger set of some attached organisms occurred in the effluent, but there was little change in species composition between the intake and effluent canals. During the summer when high surface-water temperatures prevailed, there seemed to be a reduced number and/or disappearance of flatworms and colonial hydroids, along with increased barnacle growth.

Maryland↗
USGS1967

Temperature and water-quality conditions for the period July 1963 to December 1965, Patuxent River Estuary, Maryland

Graphs and tables obtained from continuous records of surface-water temperature from five stations for the period july 1963 through December 1965 and of surface, salinity, dissolved oxygen, turbidity, tide-stage, wind data and bottom temperature from a single station are presented herein. Effects of powerplant cooling water on water temperature were obvious at a station near the plant's discharge point. Surface-water density at the Patuxent River Bridge varied from 1.0033 to 1.0127 with least change during the period May to September. Salinity ranged from 3 to 16.5 parts per thousand. Average salinity in the spring of 1965 was double that of spring 1964. Turbidity was high during the winter, and peak values were obtained during prolonged periods of high wind velocities. Dissolved oxygen values ranged from 386 to 15.0 parts per million, and percentage saturation of oxygen from 49 to 144 percent. The extreme tidal range was 5.7 feet; mean water levels were highest in summer and lowest in winter and spring.

Maryl↗