The Class A1 uses are assessed (monitored) as "partially supported" based on results of ambient monitoring for indicator bacteria (E. coli). The geometric means of indicator bacteria (E. coli) in the 24 samples collected during the recreational seasons of 2012 through 2014 at IDNR station 10440001 near Oakland Mills were as follows: the 2012 geometric mean was 121 orgs/100 ml, the 2013 geometric mean was 86 orgs/100 ml, and the 2014 geometric mean was 266 orgs/100 ml.  Only the 2014 geometric mean exceed, and then only slightly, the Class A1 criterion of 126 orgs/100 ml. Eight of the 24 samples (33%) exceeded the Class A1 single-sample maximum criterion of 235 orgs/100 ml. According to U.S. EPA guidelines for Section 305(b) reporting and IDNR’s assessment/listing methodology, if a recreation season geometric mean exceeds the respective water quality criterion, the contact recreation uses should be assessed as "impaired" (see pgs 3-33 to 3-35 of U.S. EPA 1997b). Thus, because at least one recreation season geometric mean exceeded criteria for Class A1 uses, these uses are assessed as “impaired.”

Results of ambient chemical/physical water quality monitoring suggest “full support” of the Class B(WW1) aquatic life uses. None of the 36 samples collected during the 2012-2014 assessment period at the IDNR/SHL monthly station violated Class B(WW1) water quality criteria for pH, ammonia-nitrogen, temperature, chloride, or sulfate. One of the 36 samples (3%) violated the Class B(WW1) criterion for dissolved oxygen. According to U.S. EPA guidelines for Section 305(b) reporting, if more than 10% of samples exceed state criteria for conventional parameters such as dissolved oxygen, the aquatic life uses should be assessed as "impaired" (see pgs 3-33 to 3-35of U.S. EPA 1997b). According to IDNR’s assessment/listing methodology, however, the results from station 10440001 do not indicate that significantly greater than 10% of the samples exceed either the Class B(WW1) criteria for dissolved oxygen. Thus, these results do not suggest impairment of the Class B(WW1) aquatic life uses.

The results of biological monitoring conducted in 2000, 2008 and 2011-2013 as part of the IDNR/SHL stream biocriteria projects also suggest “full support” of the aquatic life uses. A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the biocriteria sampling data. The biological metrics are based on the numbers and types of fish species and benthic macroinvertebrate taxa that were collected in the stream sampling reach. The biological metrics were combined to form a fish index of biotic integrity (FIBI) and a benthic macroinvertebrate index of biotic integrity (BMIBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2000 FIBI score was 30. The 2008 BMIBI scores were 49 (fair) and 57 (good). The 2011 BMIBI score was 43 (fair). The 2012 BMIBI score was 38 (fair). The 2013 BMIBI scores were 16 (poor) and 45 (fair).  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 from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008. The FIBI BIC for this ecoregion is 33 and the BMIBI BIC for this ecoregion is 41. This segment passed the FIBI BIC (using the uncertainty adjustment value (UAV) of 7 points) 1/1 times in 2000 and passed the BMIBI BIC 3/4 times in the last seven years (2008-2014). This assessment is considered evaluated because the drainage area (533.2 mi2) above this sampling site was greater than the maximum limit (500 mi2) that was used to calibrate the Iowa wadeable stream impairment criteria. Even though this segment passed the FIBI BIC (using the UAV +7) and passed the BMIBI BIC (4/6), it is uncertain as to whether or not this segment is meeting the aquatic life criteria because the site used for the assessment doesn’t fall in the calibrated watershed size.

Results of continuous monitoring of dissolved oxygen (DO) and temperature conducted in 2012 at the IDNR station 10440001 near Oakland Mills suggest “partial support” of the Class B(WW1) aquatic life uses. The lowest DO concentration recorded in 29 days of continuous monitoring was 2.8 mg/L. The daily DO minimum concentration failed to meet the 24-hour DO criterion (5 mg/L) in 15 of 29 days. The percentage exceeding (51.7%) was greater than (failing) the 10% impairment threshold used to assess conventional water quality parameters. The associated statistical analysis confidence level test was high (>90%). The 16-hour DO criterion (5 mg/L) was exceeded in 8 of 29 days. The percentage exceeding (27.6%) was greater than (failing) the 10% threshold with high statistical confidence (>90%). The maximum stream temperature recorded during the sensor deployment period was 34.5 degrees (C). The temperature criterion for warmwater interior streams (32 C) was exceeded in 9 of 29 days. The percentage exceeding (31%) was greater than (failing) the 10% impairment threshold with high statistical confidence (>90%). Due to violations of the 16-hour DO criterion and stream temperature criterion, the B(WW1) aquatic life use is assessed as impaired for DO and temperature. The assessment type is “evaluated” because they are based on data collected from a single year within the current data assessment period. In order to meet the requirements for a “monitored” assessment, the IDNR’s continuous monitoring assessment methodology requires monitoring data from two or more years within the assessment period.

Fish consumption remain are “not assessed” due to the lack of recent fish contaminant monitoring in this river segment.  Previous assessments were based on results of fish contaminant monitoring conducted by USGS in 1995 as part of the NAWQA project. These data are now considered too old (greater than 10 years) to accurately characterize current water quality conditions.