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 ambient station near DeWitt were as follows: the 2014 geometric mean was 106 orgs/100 ml, the 2015 geometric mean was 179 orgs/100 ml, and the 2016 geometric mean was 295 orgs/100 ml. Two of the three recreation season geometric means exceeded the Class A1 geometric mean criterion of 126 orgs/100 ml. Ten of the combined 24 samples (42 %) 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 Iowa 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."

Additionally, The Class A1 (primary contact recreation) uses are assessed (evaluated) 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 6 samples collected during the recreational seasons of 2014 through 2016 at the USGS station near DeWitt were as follows: the 2014 geometric mean was 50 orgs/100 ml, the 2015 geometric mean was 0 orgs/100 ml, and the 2016 geometric mean was 0 orgs/100 ml. None of the three recreation season geometric means exceeded the Class A1 geometric mean criterion of 126 orgs/100 ml. One of the combined 6 samples (17 %) 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 Iowa 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). Also, if significantly more than 10% of the samples exceed Iowa’s single-sample maximum value of 235 E. coli orgs/100 ml, the Class A1 uses should be assessed as "partially supported." This assessment approach is based on U.S. EPA guidelines (see pgs 3-33 to 3-35 of U.S. EPA 1997b).All geometric means for the recreation seasons of 2014-2016 at the USGS station near DeWitt are below the geometric mean criterion. The percentage of violations of Iowa’s single-sample maximum criterion for E. coli (235 orgs/100 ml), however, is significantly greater than 10%. Thus, the primary contact recreation uses are assessed as "partially supported."

In contrast to the water quality aquatic life assessment, the aquatic life assessment based on biological sampling suggests the aquatic life uses are "partially supporting". This evaluated biological assessment was based on data collected in 2012 and 2014 as part of the DNR/SHL large river sampling project. A series of biological metrics that reflect stream water quality and habitat integrity were calculated from the biological sampling data. The biological metrics are based on the numbers and types of benthic macroinvertebrate taxa collected in the stream sampling reach. The biological metrics were combined a benthic macroinvertebrate index (BMIBI). The index rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2012 and 2014 BMIBI scores were 28 (poor) and 56 (good). The aquatic life use support was assessed (evaluated) as partiallysupporting (=PS), based on a comparison of the BMIBI scores with biological impairment criteria (BIC) established from a statistical analysis of biological data collected at stream ecoregion reference sites from 1994-2008. The BMIBI BIC for this ecoregion is 51. This assessment is considered evaluated because the drainage area (2334 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 site failed the BMIBI BIC (1/2), it is uncertain as to whether or not this segment is meeting the aquatic life criteriabecause the site used for the assessment doesn't fall in the calibrated watershed size.. According to DNR’s assessment/listing methodology, impairments based on “evaluated” assessments are of lesser confidence and are thus not appropriate for Section 303(d) listing (Category 5 of the Integrated Report). DNR does, however, consider these impairments as appropriate for listing under either Category 2b or 3b of the Integrated Report (waters potentially impaired and in need of further investigation).

Fish consumption uses remain assessed as "fully supported" based on results of the 2008, 2010, and 2014 EPA/DNR or DNR fish tissue sampling on the Wapsipinicon River north of McCausland. This site has been sampled for whole-fish common carp since 1994 on an every-other-year basis as part of DNR trend monitoring. This site was scheduled for trend sampling in 2012, but drought-related low water conditions prevented sample collection. The site was again sampled, however, for the 2014 trend sampling. The results from the 2008 and 2010 samplings show low levels of the primary contaminants (chlordane, PCBs and mercury) in the composite whole-fish samples of common carp. In the 2008 samples, the levels were as follows: mercury: 0.0959 ppm; total PCBs: <0.09 ppm; and technical chlordane: 0.042 ppm. In the 2010 sample, the levels of contaminants were as follows: mercury: 0.0768 ppm; total PCBs: <0.09 ppm; and technical chlordane: 0.052 ppm. In the 2014 sample, the levels of contaminants were as follows: mercury: 0.1 ppm; total PCBs: <0.24 ppm; and technical chlordane: 0.11 ppm. [Note: the high non-detect levels for total PCBs (0.24 ppm), which is above the 1 meal/week consumption advisory threshold of 0.2 ppm, resulted from high detection level (0.08 ppm) for the individual Aroclors (1248, 1254, and 1260). PCBs were reported as less than detection (<0.08 ppm) for all three Aroclors in this 2014 trend sample.] The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of support of fish consumption uses in Iowa’s rivers and lakes. The fish contaminant data generated from the 2008, 2010, and 2014 fish tissue samplings conducted at this river segment show that the levels of contaminants do not exceed any of the advisory trigger levels, thus indicating no justification for issuance of a consumption advisory for this waterbody.