Bloody Run IA 01-YEL-433

Assessment Comments

Assessment is based on (1) results of water quality monitoring conducted for the Sny Magill / Bloody Run project from 2002-04 and (2) IDNR summary of trout reproduction (2002).

Basis for Assessment

SUMMARY:  The Class B(CW) coldwater aquatic life uses are assessed (monitored) as "fully supported" based on results of ambient chemical/physical water quality monitoring conducted from 2002 through 2004.   Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this coldwater stream.   Sources of data for this assessment include (1) an updated summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau in April 2002 and (2) results of IDNR physical/chemical water quality monitoring conducted at Bloody Run Creek from January 2002 through December 2004 at Site 1 (STORET station 10220003).

EXPLANATION:  Based on the updated summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau in April 2002, the Class B(CW) uses remain assessed as "fully supported" (see assessment for the 2002 report).   According to this summary, this reach of Bloody Run Creek is in the category of Iowa trout streams that have fairly consistent natural reproduction and are capable of maintaining a viable population for the target trout species without any stocking.  

The Class B(WW) aquatic life uses were also assessed (monitored) as "fully supported" based on results of water quality monitoring at Site 1 (BR01) on Bloody Run Creek from 2002 through 2004.   None of the 36 samples analyzed for dissolved oxygen, ammonia, or pH violated the respective Class B(CW) aquatic life criteria.   One of the 36 samples violated Class B(CW) criteria for temperature:  the water temperature of this stream on July 1, 2002 (21C) slightly exceeded the Class B(CW) criterion of 20C.   According to U.S.  EPA guidelines (U.S.  EPA 1997b, page 3-17), however, a violation frequency of less than 10 % for conventional parameters such as temperature suggest "full support" of aquatic life uses.   Thus, the percentages of violation of the Class B(CW) temperature criterion at this station (3%) does not suggest an impairment of aquatic life uses.

Fish consumption uses remain "not assessed" due to lack of fish tissue monitoring in this stream reach.