Estimated loads and yields of suspended solids and water-quality constituents in Kentucky streams

Loads and yields of suspended solids,
nutrients, major ions, trace elements, organic
carbon, fecal coliform, dissolved oxygen, and
alkalinity were estimated for 22 streams in
11 major river basins in Kentucky. Mean daily
discharge was estimated at ungaged stations or
stations with incomplete discharge records
using drainage-area ratio, regression analysis, or
a combination of the two techniques.
Streamflow was partitioned into total and base
flow and used to estimate loads and yields for
suspended solids and water-quality constituents
by use of the ESTIMATOR and FLUX
computer programs. The relative magnitude of
constituent transport to streams from groundand
surface-water sources was determined for
the 22 stations. Nutrient and suspended solids
yields for drainage basins with relatively
homogenous land use were used to estimate the
total-flow and base-flow yields of nutrient and
suspended solids for forested, agricultural, and
urban land.
Yields of nutrients?nitrite plus nitrate,
ammonia plus organic nitrogen, and total
phosphorus?in forested drainage basins were
generally less than 1 ton per square mile per
year ((ton/mi2)/yr) and were generally less than
2 (ton/mi2)/yr in agricultural drainage basins.
The smallest total-flow yields for nitrogen
(nitrite plus nitrate) was estimated at Levisa
Fork at Paintsville in which 95 percent of the
land is forested. This site also had one of the
smallest total-flow yields for ammonia plus
organic nitrogen. In general, nutrient yields
from forested lands were lower than those from
urban and agricultural land.
Some of the largest estimated total-flow
yields of nutrients among agricultural basins
were for streams in the Licking River Basin, the
North Fork Licking River near Milford, and the
South Fork Licking River at Cynthiana.
Agricultural land constitutes greater than
75 percent of the drainage area in these two
basins. Possible sources of nutrients discharging
into the Licking River are farm and residential
fertilizers. Estimated base-flow yields of
suspended solids and nutrients at several basins
in the larger Green River and Lower
Cumberland River Basins were about half of
their estimated total-flow yields. The karst
terrain in these basins makes the ground water
highly susceptible to contamination, especially
if a confining unit is thin or absent.