The Class A1 (primary contact recreation) uses are assessed as “not supported” due to violations of Iowa’s water quality criteria for indicator bacteria.   Results of USGS monitoring from 2012 through 2014 showed that recreation season (March-November) geometric means based on the 17 samples collected were above Iowa’s Class A1 water quality criterion of 126 orgs/100 ml:  the 2012 geometric mean was 298 orgs/100 ml, the 2013 geometric mean was 367 orgs/100 ml., and the 2014 geometric mean was 370 orgs/100 ml.   Similarly, results of Iowa DNR monitoring in 2011 showed that the recreation season geometric mean based on the 8 samples collected (439 orgs/100 ml) was well above Iowa’s Class A1 water quality criterion of 126 orgs/100 ml.   Too few samples were collected during the 2010 recreation season (two) and during the 2012 recreation season (three) to calculate a meaningful geometric mean.   Monitoring was terminated at this station in June 2012.  The Iowa DNR assessment/listing methodology for the 2016 IR cycle requires that at least seven independent samples be collected during any given recreation season in order to calculate a geometric mean that is to be compared to the Iowa water quality criteria for indicator bacteria.   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 are "not supported".   Thus, because at least one recreation season geometric mean exceeded criteria for Class A1 uses, these uses are assessed as “impaired.”   

The Class B(WW1) aquatic life uses are assessed (monitored) as "fully supported" based on results of water quality monitoring in this assessment segment by the U.S. Geological Survey during the 2012 through 2014 period.   No violations of state water quality criteria occurred in results of USGS monitoring for dissolved oxygen (27 samples), pH (30 samples), ammonia (29 samples), for for chlorphyrifos, dieldrin, or DDE (30 samples).

In agreement with the water quality sampling, the evaluated biological assessment based on data collected in 2008 as part of the IDNR 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 2008 FIBI score was 45 (fair).  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.  The FIBI BIC for this ecoregion is 36.  This assessment is considered evaluated because the drainage area (1688 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 passed the FIBI BIC, it is uncertain as to whether or not this segment is meeting the aquatic life criteria because it doesn’t fall in the calibrated watershed size.  

Fish consumption uses are assessed (monitored) as "fully supported" based on the 2010, 2012, and 2014 Iowa DNR fish tissue samplings on the Maquoketa River northeast of Maquoketa.   This site has been sampled for whole-fish common carp since 1995 on an every-other-year basis as part of fish contaminant trend monitoring.   The whole-fish samples of common carp from these three years had generally low levels of the primary contaminants: mercury:  maximum of 0.136 ppm; total PCBs: maximum of 0.45 ppm; and technical chlordane: maximum of 0.059 ppm.   While results from these samplings show that levels of chlordane and mercury are well below levels of concern, the level of total PCBs in the sample of whole-fish common carp from the 2006 sampling (0.45 ppm) exceeded the 1 meal/week trigger level as defined in Iowa’s revised (2006) fish consumption advisory protocol.   

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 levels of total PCBs in the sample of whole-fish common carp collected in 2006 exceeded the 1 meal/week trigger level as defined in Iowa’s revised (2006) fish consumption advisory protocol.   According to IDNR’s assessment methodology, the single occurrence of contaminant above an advisory trigger level does not suggest impairment of the fish consumption uses but does suggest the need to conduct additional fish contaminant monitoring.   The IDNR/IDPH advisory protocol states that two consecutive samplings that show contaminant levels are above the trigger level in fillet samples are needed to justify issuance of an advisory.   Thus, the results for the  whole-fish sample from the 2006 sampling on the Maquoketa River did not warrant issuance of an advisory but did indicate the need to conduct additional monitoring to better define contaminant levels in fish from this river segment.   Additional monitoring in 2008, 2010, and 2012, however, showed that levels of total PCBs were below the advisory trigger level (0.105 ppm and 0.107 ppm, and 0.162 ppm, respectively).  No PCBs (Aroclors) were detected in the sample of whole-fish carp for the 2014 sampling (detection level of 0.08 ppm for Aroclor 1248,1254, and 1260).   The results therefore, continue to suggest "full support" of the fish consumption uses.