Douglas Reservoir

Ecological Health Indicators at
Douglas Reservoir, 2007

Dissolved oxygen

Consistent with findings from previous years, dissolved oxygen concentrations at both the forebay and mid-reservoir monitoring locations were very low during the summer, especially in the bottom half of the water column. TVA has installed aeration equipment to add oxygen to the deep water near the dam and to improve conditions downstream from the dam in the French Broad River. Learn more about these improvements.

Chlorophyll

Chlorophyll rated good at the forebay and poor at the mid-reservoir monitoring location. Summer chlorophyll averages are generally higher at the mid-reservoir site, rating poor in most years. Chlorophyll ratings at the forebay have been variable, rating good, fair, or poor. Rainfall and the resulting runoff have played a significant role in year-to-year variation.

Fish

The fish community rated good at the forebay and fair at the mid-reservoir monitoring location. As in previous years, TVA collected a good number and variety of healthy fish at the forebay. The fish community received its lowest score to date at the mid-reservoir location because the catch rate was relatively low and fewer fish species were collected than normal. Sampling results at the mid-reservoir location were affected by low water levels, a result of the extremely dry conditions.

Bottom life

Bottom life rated at the low end of the fair range at both monitoring locations. As in previous years, TVA found relatively few animals in samples collected from the reservoir bottom, and the animals collected were primarily species capable of tolerating poor conditions.

Sediment

Sediment quality rated good at both locations. Low levels of chlordane, a pesticide previously used to control termites and crop pests, were detected in sediment samples from the mid-reservoir monitoring location in some previous years, causing sediment quality to rate fair.

 

See definitions of ecological health indicators and monitoring locations.