Assessment Comments
Assessment is based on surveys by the IDNR Fisheries Management Section in 2000 and and IDNR Fisheries Research Section in 2002: Fish IBI = 44 (fair).
Basis for Assessment
SUMMARY: The Class A (primary contact recreation) uses remain "not assessed." The Class B(WW) aquatic life uses remain assessed (evaluated) as "fully supported / threatened" (minor impacts) based on results of fish surveys conducted by (1) the IDNR Fisheries Management Section (Boone) in 2000 and (2) the IDNR Fisheries Research Section in 2002. Fish consumption uses remain "not assessed."
EXPLANATION: The Class A uses remain "not assessed" due to the lack of water quality information for this segment upon which to base an assessment.
The Class B(WW) aquatic life uses remain assessed as "fully supported / threatened" based on the previous assessment for this river segment (see assessment for the 2000 report above) and on 2002 IDNR Fisheries sampling results. Updated information from the IDNR Fisheries Bureau suggests that problems with growth and reproduction of smallmouth bass continue. Habitat quality is still seen as a key factor, but water quality--specifically, high levels of ammonia-nitrogen--may also be impacting the smallmouth bass populations in this segment. Due, however, to the lack of routine, ambient monitoring in the Middle Raccoon River, the data to support this hypothesis do not exist. Nonetheless, the continuing problems with the smallmouth bass population in this segment suggests that the Class B(WW) uses should remain assessed as "fully supporting / threatened."
This assessment was partially based on data collected in 2002 as part of a DNR Fisheries stream sampling project: Manchester research station. A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the Fisheries sampling data. The biological metrics are based on the numbers and types of fish species that were collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (F-IBI). The index ranks the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2002 evaluated Fish IBI was 44 (fair). The aquatic life use support was assessed (evaluated) as Fully Supporting/Threatened (=FS/T), based on a comparison of the F-IBI score with biological assessment criteria established for previous Section 305(b) reports. The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2001.
Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this river segment.
