East Branch Buttrick Creek IA 04-RAC-1150

Assessment Comments

Assessment is based on results of DNR fish surveys in 1996 near Paton.

Basis for Assessment

Changed 1994 assessment of support of the Class B(LR) uses (=PS) to FST due to a stream fish survey in October 1996 that showed (1) an extremely diverse fish community with a total of 28 species from 5 families, including the (soon to be) federally-threatened Topeka shiner, two species considered rare in Iowa (slender madtom and Iowa darter) and smallmouth bass and (2) habitat quality equal better than several other tributaries of the North Raccoon River sampled (Hardin, Cedar, Lake, and Camp creeks); creek is a system of long pools separated by short riffles of glacial cobbles.   All the North Raccon tributaries sampled had the same general characteristics (long pools; short riffles), but E.  Buttrick had what appreared to be less turbid, have less siltation of coarse substrates, and less periphyton growth on coarse substrates.   Continued support of the aquatic life uses is threatened by channel straightening in headwater reachs and delivery of sediment and nutrients to the stream in nonpoint source runoff from agricultural areas.   Results of the 1996 fish survey are described in field notes (JRO-1, 2, and 7-1996).