Crooked Creek IA 03-SKU-918

Assessment Comments

Stream use assessment.

Basis for Assessment

Used a review of the field sheet from the July 1991 DNR stream use assessment at Coppock to change the assessment of support of the Class B(LR) aquatic life uses from "not assessed" to PS due to (1) indications on field sheet of stressed and diseased fish ("hookworms") believed due to warm weather/water and low flow conditions, (2) indication on field sheet that local WWTP has an "isolated" impact on water quality, & (3) presence of less than a majority of the expected fish taxa (4 of 8) for streams in the Southern Iowa Rolling Loess Prairies subecoregion (47f) (although field notes indicate that seining was difficult due to rocks and snags).   Habitat quality is relatively high, with very diverse substrates and numerous pool/riffle sequences.   The only significant impact to the physical characteristics of the stream noted was streambank erosion, which is a common problem in the lower reaches of larger tributaries.   The data upon which this assessment is based are more than 5 years old.   Follow-up monitoring is needed to update this assessment, to determine the status of the aquatic communities, and to determine the degree to which the Class B(LR) uses may be impaired.