Assessment Comments
Assessment is based on results of IDNR/UHL biological (biocriteria) monitoring in 2000: FIBI = 15 (poor); BMIBI = 56 (good) and on 2000 Fisheries data: FIBI = 51 (good). Non-riffle habitat FIBI BIC = 32, BMIBI BIC = 62.
Basis for Assessment
[Note: Prior to the current (2008) Section 305(b) cycle, this stream segment was designated only for Class B(LR) 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 now presumptively designated for Class A1 (primary contact recreation) uses. The stream remains designated for aquatic life uses (now termed Class B(WW2) aquatic life uses). Thus, for the current (2008) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]
SUMMARY: The presumptive Class A1 (primary contact recreation) uses are "not assessed" due to the lack of information upon which to base an assessment. The Class B(WW-2) aquatic life uses are assessed (evaluated) as "partially supported" based on results of IDNR/UHL biological (biocriteria) sampling in 2000. The 2001 sampling data are now greater than five years old; therefore, this assessment is now considered "evaluated" instead of "monitored". Due to the previous (2004; 2006) Section 303(d) impairment of aquatic life uses, however, this assessment segment remains in Category 5b of Iowa's 2008 Integrated Report.
EXPLANATION: The assessment of the Class B(WW2) aquatic life uses was based on data collected in 2000 at the Michaelson Marsh Area (Kossuth Co.) as part of the DNR/UHL stream biocriteria project. The 2000 FIBI score was 15 (poor) and the BMIBI score was 56 (good). The aquatic life use support was assessed as partially supporting (=PS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004. The non-riffle habitat FIBI BIC for this ecoregion is 32 and the BMIBI BIC for this ecoregion is 62.
The assessment was partially based on data collected in 2000 as part of a DNR Fisheries stream sampling project: Manchester research station. The 2000 evaluated FIBI was 51 (good). The aquatic life use support was assessed (evaluated) as Fully Supporting (=FS), based on a comparison of the FIBI score with biological impairment criteria (BIC) established for previous Section 305(b) reports. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004. The non-riffle habitat FIBI BIC for this ecoregion is 32.
