Deep River IA 02-IOW-681

Assessment Comments

Stream use assessment in 1991.

Basis for Assessment

Used a review of the field sheet from the June 1991 DNR stream use assessment in Poweshiek County to continue to assess support of the Class B(LR) aquatic life uses as PS due to (1) relatively poor fish community diversity (5 species from 1 family) for streams in the Southern Iowa Rolling Loess Prairies subecoregion, (2) presence of less than a majority of the expected fish taxa (3 of 8) for streams in this subregion, and (3) indications on the field sheet of frquent channel alterations.   The data upon which this assessment is based are more than 5 years old.   Follow-up monitoring is needed to update this assessment, to better define the status of the aquatic communities and habitats, and to determine the degree to which the Class B(LR) aquatic life uses may be impaired.   A comparison to results of a fish survey conducted by ISU in July 1981 (JRO-62-1981) near the same location suggests a potential decline in the biological integrity of this stream.   The ISU survey showed a relatively diverse fish community of 13 species from 4 families and the presence of a majority of the expected fish taxa (7 of 8) for this subregion.   Although the DNR stream use assessments were not intended to document all species present (as was the ISU survey), the results of the two surveys are sufficiently different to justify follow-up monitoring.