Assessment Comments
Assessment based on 2005 IDNR/UHL biocriteria sampling data: 4/8 coldwater biological indicators met the criteria - Partially Supporting (PS).
Basis for Assessment
[Note: Prior to the current (2008) Section 305(b) cycle, this stream segment was designated only for Class B(CW) aquatic life uses. Due to changes in Iowa’s surface water classification that were approved by U.S. EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is also now presumptively designated for Class A1 (primary contact recreation) and Class A2 (secondary contact recreation) uses. This segment remains designated for coldwater aquatic life use (now termed Class B(CW1) uses), and for fish consumption uses (now termed Class HH (human health/fish consumption) uses. This stream segment also remains identified as an “HQR” (high quality resource) water.]
SUMMARY: The presumptive Class A1 (primary contact recreation) uses and the presumptive Class A2 (secondary contact recreation) uses are "not assessed" due to the lack of information upon which to base an assessment. The Class B(CW1) coldwater aquatic life uses are assessed (monitored) as "partially supported" based on results of biological monitoring. The source of data for this assessment is the results of IDNR/UHL biological monitoring from 2005. Fish consumption uses remain “not assessed” due to lack of fish contaminant monitoring in this stream segment.
EXPLANATION: The assessment of the Class B(CW1) aquatic life uses was based on data collected in 2005 as part of the IDNR/UHL stream biological sampling project. A series of eight (8) coldwater biological indicators, which reflect stream water quality and habitat integrity, were calculated from the biocriteria sampling data and supplemental IDNR Fisheries Bureau data. The coldwater biological indicators are based on the numbers and types of coldwater benthic macroinvertebrate taxa and fish species that were collected in the stream sampling reach. Sites that score 5-8 are Fully Supporting (FS), sites that score 2-4 are Partially Supporting (PS), and sites that score 0-1 are Not Supporting (NS). The 2005 coldwater biological indicator score 4/8. The aquatic life use support was assessed (monitored) as Partially Supporting (=PS), based on a comparison of the coldwater biological indicator score with biological assessment criteria established for this Section 305(b) report. The coldwater biological indicators were determined from a statistical analysis of data collected at coldwater stream ecoregion reference sites from 1994-2004 and with assistance from the IDNR Fisheries Bureau.
