Assessment Comments
Assessment based on 2004 and 2009 IDNR/UHL biological monitoring data: 1/4, 2/4 coldwater biological indicators met the criteria - partially supporting (PS).
Basis for Assessment
Note: Prior to the 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.
SUMMARY: The Class A1 (primary contact recreation) uses and the Class A2 (secondary contact recreation) uses remain "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 IDNR/UHL biological monitoring in 2004 and 2009. Fish consumption uses are not assessed due to the lack of fish contaminant monitoring in this assessment segment.
EXPLANATION: The assessment of the Class B(CW1) aquatic life uses is based on data collected in 2004 and 2009 as part of the IDNR/UHL stream sampling projects. A series of four (4) coldwater biological indicators, which reflect stream water quality and habitat integrity, were calculated from the biocriteria sampling data. The coldwater biological indicators are based on the numbers and types of coldwater benthic macroinvertebrate taxa that were collected the stream sampling reach. Sites that do not receive any type of trout stocking are scored on the benthic macroinvertebrate data only. Non-trout stocking sites that score 3 or 4 are fully supporting (FS), sites that score 1 or 2 are partially supporting (PS), and sites that score 0 are not supporting (NS). The 2004 coldwater biological indicator score was 1/4 and the 2009 score was 2/4. 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 1994-2008 and with assistance from the IDNR Fisheries Bureau.
This aquatic life use assessment is considered "monitored" because there were two or more samples collected in multiple years from 2004-2009.
Fish consumption uses remain "not assessed" due to lack of fish tissue monitoring in this stream reach.
