The Clarks Run
watershed is in southeastern Boyle County. The land is in the inner subregion of
the Bluegrass physiographic region, characterized by undulating terrain and
moderate rates of both surface runoff and groundwater drainage. The watershed
lies partly above fractured shales through which groundwater can easily move but
which stores very little water. Other parts lie over interbedded clay shales and
siltstones. There are also areas of interbedded shales and limestones (these are
20% limestone; water conduction is poor because of the clay content of the
shale) and areas of interbedded limestones and shales (>20% limestone,
allowing groundwater flow where the clay content is low enough).
Waterways. Clarks Run empties into the Dix River east of Danville,
near Little Needmore. Among the creeks that feed it is Balls Branch.
Land and water use. Land in the watershed is more than 80%
agricultural. It includes the southern half of Danville, and therefore is about
8% residential, and about 8% commercial or industrial. Five businesses and
organizations hold permits for discharges into the creeks. See tables for
Agency data assessment. Three assessed segments of Clarks Run include
one that does not support its designated uses, based on biological and/or
water-quality data. One fully supports its uses, and one only partially supports
its uses. Organic enrichment from municipal point sources, urban runoff, and
storm sewers contribute to the impairment of these streams. Pesticides from
urban runoff also contribute in the nonsupporting segment. See tables for
Watershed rankings. The ranking formula provides a preliminary
ranking by synthesizing a broad spectrum of watershed characteristics, current
conditions, and threats. This watershed ranks in the group with the lowest need
for protection and/or restoration. This rating is for the watershed on average:
particular sites and particular waters within the watershed may vary widely. See
tables for details.
Volunteer data. Data show high levels of bacteria indicative of fecal
contamination in Clarks Run (above 200 colonies/ml). A significant amount of the
triazine herbicide atrazine was detected (>1 microgram per liter); however,
the concentration of atrazine was well below the EPA’s maximum contaminant
level of 3 micrograms per liter. See tables for details.