[Note: A TMDL for pathogen indicators in this segment of the Maquoketa River was prepared by IDNR and approved by EPA in 2006.   Thus, this impairment remains in Category 4a of Iowa's Integrated Report.   Because, however, the Section 303(d) impairment related to decline in the freshwater mussel community of this river segment was not addressed in the TMDL, this waterbody remains in IR Category 5b (impaired; TMDL required).]

The Class A1 (primary contact recreation) uses are assessed (monitored) as "not supported" based on levels of indicator bacteria that exceeded state water quality criteria.   The geometric mean of indicator bacteria (E. coli) in the 13 samples collected at station 10490002 NW of Maquoketa during the recreational seasons of 2012 (95 orgs/100 ml) and 2013 (92 orgs/100 ml) met the Iowa water quality criterion of 126 orgs/100 ml) to protect primary contact recreation uses.   However, the geometric mean of indicator bacteria (E.  coli) in the five samples collected during the recreational season of 2014 at the IDNR ambient monitoring station NW of Maquoketa  (10490004) (491 orgs/100 ml) was well above the Class A1 criterion of 126 orgs/100 ml).  Six of the 8 samples (75%) exceeded Iowa’s single-sample maximum criterion 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 the geometric mean is greater than the Iowa Class A1 geometric mean criterion of 126 orgs/100 ml., the primary contact recreation uses should be assessed as "not supported" (see pgs 3-33 to 3-35 of U.S. EPA 1997b).   

Results of monitoring from the monthly IDNR/SHL ambient stations near Maquoketa from 2012 through 2014 suggest “full support” of the Class B(WW1) uses.   Results of monthly monitoring at stations 19490002 and 10490004 show no violations of Class B(WW1) water quality criteria for dissolved oxygen, pH, or temperature in the combined 29 samples collected.   
As noted in previous Section 305(b) assessments for this river segment, results from the 1998-99 statewide assessment of freshwater mussels in Iowa streams (Arbuckle et al.   2000) suggest a potential impairment to the aquatic life uses of this stream segment.   As part of this study, sampling results from 1998 and 1999 (Arbuckle et al.   2000) were compared to results from stream sites surveyed in 1984 and 1985 by Frest (1987).   In general, this comparison showed sharp declines in the numbers of mussel species ("species richness") in Iowa’s streams and rivers from the mid-1980s to the late 1990s.   Results of this comparison were used by staff of the Iowa DNR to assess the degree to which the aquatic life uses of the sampled stream segments are supported.   For purposes of Section 303(d) listing, this assessment was based on the percent change in the number of species of freshwater mussels found in the 1984-85 survey versus the 1998-99 survey.   Greater than a 50% decline in species richness from the 1984-85 period to the 1998-99 period suggests an impairment of the aquatic life uses.   Species richness of freshwater mussels at the one sample site in this stream segment was 5 in the 1984-85 period and was 0 in the 1998-99 period for a percent change of minus 100%.   Based on these results, the “full support” of aquatic life uses suggested by results of chemical monitoring from IDNR ambient and TMDL monitoring programs is downgraded to "non-support" for purposes of both Section 303(d) listing (greater than 50% decline in species richness) and Section 305(b) reporting (low species richness reported in the 1998-99 survey).   As presented by Arbuckle et al.   (2000), the potential causes of declines in species richness of Iowa's freshwater mussels include siltation, destabilization of stream substrate, stream flow instability, and high in-stream levels of nutrients (phosphorus and nitrogen).   Their study also suggested the importance of stream shading provided by riparian vegetation to mussel species richness.   Additional monitoring is needed to better define the biological status of this stream segment as well as the site-specific causes and sources of impairments of these uses that may exist.   (Note:  because the data from Arbuckle et al.   (2000) are now older than ten years, the assessment category is changed from a “monitored” (i.e., a higher confidence assessment) to “evaluated” (i.e., lower confidence assessment).   Despite this change in assessment category, the impairment indicated by these data remains in IR Category 5 (i.e., Section 303(d) list) until more recent data suggest a good cause for de-listing.)   

Results of biological sampling conducted in 2003, 2005, 2012, 2013 and 2014 suggest that the Class B(WW1) aquatic life uses should be assessed (evaluated) as “partially supported” (IR 3b-u).   This biological assessment was based on data collected in 2003, 2005, 2012, 2013 and 2014 as part of the IDNR/SHL large river stream sampling project and 2003 IDNR Fisheries sampling.   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 and fish species collected in the stream sampling reach.   The biological metrics were combined to make a fish community index of biotic integrity (FIBI) and a benthic macroinvertebrate index (BMIBI).   The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum).   The 2003 FIBI score was 58 (good) and the 2005 FIBI score was 60 (good).  The 2003 Fisheries bureau FIBI score was 48 (fair).  The 2012, 2013 and 2014 BMIBI scores were 45, 50, 50 (all fair) and 58 (good).  The aquatic life use support was assessed (evaluated) as partially supporting (=PS), 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 36 and the BMIBI BIC for this ecoregion is 51.   This site passed the FIBI BIC 3/3 times in the past 12 years and passed the BMIBI BIC 1/4 times in the past five years.   This assessment is considered evaluated because the drainage areas (754, 813 and 940 mi2) above the sampling sites were 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 and failed the BMIBI BIC, it is uncertain as to whether or not this segment is meeting the aquatic life criteria because the sites used for the assessment don't fall in the calibrated watershed size.   

Fish consumption uses are assessed (monitored) as "fully supported" based on the 2010, 2012, and 2014 IDNR 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 RAFT 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.