Assessment Comments
Assessment remains based 2001 IDNR/UHL biological monitoring data: FIBI = 33 (fair), BMIBI = 66 (good). FIBI BIC = 36, BMIBI BIC = 51.
Basis for Assessment
Note: Prior to the 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 (2010) 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 "fully supported" based on results of IDNR/UHL biological (biocriteria) sampling in 2001. The 2001 biological sampling data are now more than five years old; therefore, this assessment is now considered "evaluated" instead of "monitored".
EXPLANATION: The Class B(WW2) aquatic life uses remain assessed (evaluated) as “fully supporting” based on biological data collected in 2001 as part of the IDNR/UHL stream biocriteria project. The 2001 FIBI score was 33 (fair) and the BMIBI score was 66 (good). The aquatic life use support was assessed (evaluated) as fully supported (=FS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports. The FIBI score exceeded teh FIBI BIC using the FIBI UAV of 7 points and the BMIBI also passed the BMIBI BIC. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004. The FIBI BIC for this ecoregion is 36 and the BMIBI BIC for this ecoregion is 51.
This aquatic life assessment is considered "evaluated" because there were not two or more samples collected from this segment in multiple years from 2004-2008. Additionally, because these data are now considered too old (greater than five years) to accurately characterize current water quality conditions, the assessment category is considered “evaluated” (indicating an assessment with relatively lower confidence) as opposed to "monitored" (indicating an assessment with relatively higher confidence). Despite this change in assessment methodology and type, this waterbody remains in IR Category 2a.
