Water quality of Cedar Creek reservoir in northeast Texas, 1977 to 1984

Abstract

Water in Cedar Creek Reservoir in northeast Texas had volume weighted average concentrations of < 140 mg/L of dissolved solids, < 30 mg/L of dissolved sulfate, and < 25 mg/L of chloride between January 1977 and August 1984. The water was soft to moderately hard; the total hardness concentrations ranged from 55 to 75 mg/L as calcium carbonate. Thermal stratification in Cedar Creek Reservoir usually begins in late winter or early spring and persists until late fall. Stratification or summer stagnation causes significant seasonal and areal variations in concentrations of dissolved oxygen, iron, manganese, total inorganic nitrogen, and total phosphorus. Seasonal temperature and dissolved oxygen cycles cause the recycling of dissolved iron and manganese between the water and bottom sediments. Of 22 water samples collected for trace element analysis, 15 contained barium in concentrations ranging from 40 to 300 micrograms/L, and 19 contained arsenic in concentrations ranging from 1 to 26 micrograms/L. However, these concentrations are below the maximum contaminant limit for barium and arsenic in drinking water. The concentrations of total inorganic nitrogen, total nitrogen, and total phosphorus were largest during summer stagnation in water near the bottom at the deepest sites. Water near the surface of Cedar Creekmore » Reservoir during summer stagnation and throughout the reservoir during winter circulation had total phosphorus and total inorganic nitrogen concentrations of less than 0.1 mg/L. Total nitrogen concentrations near the surface ranged from 0.3 to 1.1 mg/L from January 1980 to August 1984. 11 refs., 16 figs., 25 tabs.« less