Maquoketa River IA 01-MAQ-19

The Class A1 (primary contact recreation) uses remain assessed (monitored) as "not supported" due to violations of Iowa’s water quality criteria for indicator bacteria. The geometric mean of E. coli in the samples collected during the 2012 recreation season at station 15280002 was 123 orgs/100 ml, and the geometric mean in the samples collected at this station during the 2013 recreation season was 154 orgs/100 ml. Two of the 14 samples collected over the two recreation seasons (14%) violated Iowa’s single-sample maximum criterion. According to U.S. EPA guidelines for Section 305(b) reporting and DNR’s assessment/listing methodology, if a geometric mean of E. coli is greater than the state criterion of 126 orgs/100 ml., the primary contact recreation uses should be assessed as "not supported" (see pgs 3-33 to 3-35of U.S. EPA 1997b). Because the 2013 recreation season geometric mean was slightly greater than the Class A1 criterion, the Class A1 uses of this segment remainassessed (“monitored”) as “not supported”.

Results of more monitoring in 2012 and 2013 suggest a significant decline in bacteria levels compared to earlier monitoring. The geometric mean of E. coli in the seven samples collected in May and June 2012 at the monitoring station downriver from Dundee was 123 orgs/100 ml and was thus below the Class A1 criterion; only one of the seven samples (14%) exceeded Iowa’s single-sample maximum criterion of 235 orgs/100 ml. Similarly, the 2013 geometric mean was relatively low (154 orgs/100 ml) and, again, only one of the 7 samples exceeded Iowa’s single-sample maximum criterion. For comparison, the 2006 geometric mean in this segment was 2,198 orgs/100ml). Thus, although the impairment of the Class A1 uses will remain due to the 2013 geometric mean being slightly greater than the criterion, the available monitoring data suggest a significant decline in levels of indicator bacteria.

The Class B(WW1) aquatic life uses remain assessed (evaluated) as “fully supporting” based on results of chemical/physical water quality monitoring in 2013. Water quality monitoring conducted from August to November 2013 at station 15280002 showed no violations of Class B(WW1) criteria for dissolved oxygen, ammonia, or pH in the seven samples collected. The results of monitoring from these stations are consistent with the previous assessments of aquatic life uses in this segment: “fully supported.”

In agreement with the water quality sampling, this monitored biological assessment based on data collected in 2013, 2014, 2015 and 2016 as part of the DNR Fisheries Bureau sampling project also suggests that the class B(WW1) aquatic life uses are "fully supporting". 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 fish species collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (FIBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2013-2016 FIBI scores (n=10) ranged from 60 (good) to 71 (excellent). 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 from a statistical analysis of biological data collected at stream ecoregion reference sites from 1994-2008. While it is still undetermined if the Fisheries sampling sites contain stable riffle habitat, this segment passed the riffle FIBI BIC (3/10 times) and passed the non-riffle habitat FIBI BIC (10/10 times). The riffle habitat FIBI BIC for this ecoregion is 65 and the non-riffle habitat FIBI BIC for this ecoregion is 44.

This aquatic life assessment is now considered "monitored" based on a change in the 2010 DNR assessment methodology. DNR now requires a segment have two or more biological samples collected from the segment in multiple years in the most recent five year period (2012-2016) to be considered “monitored”.

Fish consumption uses remain “not assessed” due to the lack of fish contaminant monitoring in this assessment segment.