The Class A1 (primary contact recreation) uses are assessed (monitored) as "partially supported" based on levels of indicator bacteria that exceeded state water quality criteria. The geometric means of indicator bacteria (E. coli) in the 24 samples collected during the recreational seasons of 2014 through 2016 at DNR station 10440001 near Oakland Mills were as follows: the 2014 geometric mean was 266 orgs/100 ml, the 2015 geometric mean was 167 orgs/100 ml, and the 2016 geometric mean was 370 orgs/100 ml. All three recreation season geometric means exceeded the Class A1 geometric mean criterion of 126 orgs/100 ml. Twelve of the combined 24 samples (50%) exceeded Iowa’s Class A1 single-sample maximum criterion of 235 orgs/100 ml. According to U.S. EPA guidelines for Section 305(b) reporting and DNR’s assessment/listing methodology, if the geometric mean is greater than 126 orgs/100 ml., the primary 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 "partially supported."

Results of chemical/physical water quality monitoring at DNR station 10440001 near Oakland Mills suggest “full support” of the aquatic life uses. Monitoring showedno violations of Class B(WW1) water quality criteria for 36 Ammonia samples (maximum = 1 mg/L), 36 Dissolved Oxygen samples (minimum = 5.5 mg/L), 36 pH samples (range = 6.8 to 8.7), 36 Temperature samples (maximum = 29.8° c), 36 Chloride samples (maximum = 180 mg/L), or 36 Sulfate samples (maximum = 250 mg/L) occurred during monitoring from January 2014 to December 2016. According to U.S. EPA guidelines for Section 305(b) water quality assessments (U.S. EPA 1997b, page 3-17), the EPA guidelines allow up to 10% violations of these conventional parameters before impairment of water quality is indicated. Thus, these results thus suggest “full support” of the Class B(WW1) aquatic life uses.

The results of biological monitoring conducted in 2012-2013, 2016 as part of the DNR/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 2012 BMIBI score was 38 (fair). The 2013 BMIBI scores were 16 (poor) and 45 (fair). The 2016 BMIBI scores were 39, 57, 57, 57 (all fair). No FIBI (fish community) samples were collected in this assessment segment. The aquatic life use support was assessed (evaluated) as fully supported (=FS), based on a comparison of the BMIBI scores with biological impairment criteria (BIC) established from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008. The BMIBI BIC for this ecoregion is 41. This segment passed the BMIBI BIC 4/7 times in the last five years (2012-2016). 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 BMIBI BIC (4/7), 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 DNR 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 DNR’s continuous monitoring assessment methodology requires monitoring data from two or more years within the assessment period.