Surface-Water Quality and Nutrient Loads in the Nepaug Reservoir Watershed, Northwestern Connecticut, 1999-2001

Water quality was characterized at three tributary watersheds
to the Nepaug Reservoir—Nepaug River, Phelps Brook,
and Clear Brook—from October 1998 through September 2001
to document existing water-quality conditions and evaluate
potential future effects of the removal of sand and gravel from
areas of the watershed. Some removal operations may include
removal of vegetation and top soil and steepening of slopes.
Routine water samples collected monthly in all three watersheds
were analyzed for nutrients, organic carbon, major ions,
and fecal indicator bacteria. Results of the analyses indicate
that, in general, the water quality in all three tributary watersheds
is good and meets standards established for drinkingwater
supplies for nitrate, but does not always meet contact-recreation
standards for bacteria. Median concentrations of total
nitrogen, total phosphorus, and total organic carbon were highest
in the routine monthly samples from Phelps Brook and lowest
from Clear Brook. Samples also were collected during
selected storms to examine changes in concentrations of nutrients
during periods of high streamflow. The maximum values
measured for total nitrogen, total phosphorus, and total organic
carbon were in storm samples from Clear Brook.