East Big Creek IA 02-CED-503

Assessment Comments

1991 stream use assessment and 1996 DNR Fisheries surveys.

Basis for Assessment

Used a review of the field sheets from the August 1991 DNR stream use assessments, and a review of results of a July 1996 stream survey by the DNR Fisheries Bureau, to continue to assess support of the Class B(LR) aquatic life uses as FST due to (1) presence of a moderately diverse fish community (12 species from 3 families in the 1996 survey) for streams in the Iowan Surface subecoregion (47c), (2) presence of a majority of the expected fish taxa (7 of 11) for streams in this subregion, and (3) indications of high quality aquatic habitats on the field sheets from the 1991 DNR stream use assessments, with very diverse substrates, sometimes numerous pool/riffle sequences, and no significant impacts to the physcial characteristics of the stream.   The 1991 field sheets do, however, note "murky water" and a potential influence of a WWTP.   Additional monitoring should be conducted to better determine the impact of the WWTP on the aquatic communities of this stream.   Neither the 1991 stream use assessments or the 1996 fisheries survey found centrarchids or ictalurids in this stream, and their absence may be related to a chemical water quality problem.   Follow-up monitoring is needed.   A fish kill was reported on this stream and on Big Creek on April 23, 1997.   An estimated 11,000 fish were killed over a 2 mile reach of stream.   The cause of the kill was apparently high levels of ammonia related to the type of explosive used at a quarrying operation along the stream.