The project site is located within the Yalobusha Watershed in Chickasaw County, Mississippi, on Little Topashaw Creek, a fourth-order stream. The project reach lies between the county road bridge on the Chickasaw-Webster county line at RK 3.4 and the mouth of Dry Creek, which is located about RK 1.1.
Soil borings indicate that floodplain soils are silty deposits underlain by sand.
Channel bed materials are comprised primarily of sand with median sizes between 0.2 and 0.3 mm. However, cohesive materials occur as massive outcrops and as gravel-sized particles.
Collections of invertebrate, fish, and physical habitat data were made during June and September, 1999 and 2000. Physical habitat conditions were marked by extremely shallow flow and sand-dominated substrates. Nineteen species of fish were found. No fish was captured that was longer than 20 cm. A ranking based on macroinvertebrate collections placed the Little Topashaw site near the bottom of a set of sites located throughout the Yalobusha watershed.
Low-flow discharge measurements for transects located upstream, within, and downstream from the study reach indicate significant exchange between surface water and groundwater.
Physical and chemical water quality parameters are generally within accepted limits. Low concentrations of persistant organochlorine pesticides are measurable, but this phenomenon is quite common. Very low concentrations of some currently-used cotton insecticides have been measured. Most pesticides currently used in the watershed are dissipating before reaching the stream. Coliforms do not indicate any discrete sources.
In Situwood density varied from 0.30 to 1.39 for LWD and from 0.67 to 1.14 for living trees.