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 means of indicator bacteria (E. coli) in the 24 samples collected during the recreational seasons of 2014 through 2016 at the North Fork Maquoketa River near Hurstville (station 10490001) were as follows: the 2014 geometric mean was 1131 orgs/100 ml, the 2015 geometric mean was 536 orgs/100 ml, and the 2016 geometric mean was 2148 orgs/100 ml. All three recreation season geometric means exceeded the Class A1 geometric mean criterion of 126 orgs/100 ml. Nineteen of the combined 24 samples (79%) 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 "not supported." Only four indicator bacteria samples were collectedat USGS site on the North Fork Maquoketa River near Fulton in 2014 and were not used for this assessment.

The fish kill occurred before September 19, 2016 due to the poor condition of fish carcasses at the time of the investigation. The kill affected approximately 7,821 fish in 23.8 miles of stream(s) in two counties. The fish were valued at $16,503.13 and the investigation expenses were $1,741.04. The following partial information is from the fish kill data base:

Based on the extent of decay it is probable that the fish kill occurred during the previous week. We identified the following 17 fish species dead in the kill area: Bluegill, Bluntnose Minnow, Central Stoneroller, Channel Catfish, Common Shiner, Creek Chub, Fantail Darter, Gizzard Shad, Green Sunfish, Highfin Carpsucker, Hornyhead Chub, Northern Hogsucker, Redhorse (unidentified species), Smallmouth Bass, Spotfin Shiner, Stonecat, White Sucker. This was an extensive fish kill of large magnitude that appeared to have occurred during a period of high stream discharge. It is likely that this was the most significant (numbers of fish, monetary value, and lost recreational value) fish kill that I have investigated during the past 14 years. Valuation and estimates of fish lost are grossly underestimated by this investigation given the extent of fish decay, high stream discharge, and high stream turbidity.

According to DNR’s assessment/listing methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired.” If a cause of the kill is identified, and the cause is either known, or suspected, to be a “pollutant”, the assessment type is considered “monitored” and the affected waterbody is a candidate for Section 303(d) listing. Fish kills attributed to a pollutant, but where a source of the pollutant was not identified and/or where enforcement actions were not taken against the responsible party, will be placed into Integrated Report subcategory 5b. The intent of placing these waterbodies into Category 5 is not to necessarily require a TMDL but to keep the impairment highlighted due to the potential for similar future kills from the unaddressed causes and/or sources. If, however, a consent order has been issued to the party responsible for the kill and monetary restitution has been sought for the fish killed, the affected waterbody will be placed in IR Category 4d (impaired but TMDL not required). DNR records indicate that at the time of this assessment, the party responsible for the 2016 kill hasn't been identified nor has DNR sought and has received restitution for the value of the fish killed and the investigation costs incurred. Thus, this assessment segment is appropriate for Category 5b of Iowa’s Integrated Report.

Results of chemical/physical water quality monitoring at the North Fork Maquoketa River near Hurstville (station 10490001) suggest “full support” of the aquatic life uses. Monitoring showed no violations of Class B(WW1) water quality criteria for 35 Ammonia samples (maximum = 0.3 mg/L), 36 Dissolved Oxygen samples (minimum = 7.6 mg/L), 35 pH samples (range = 7.5 to 8.3), 36 Temperature samples (maximum = 24°C), 36 Chloride samples (maximum = 28 mg/L), or 36 Sulfate samples (maximum = 31 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.

Results of USGS monitoring near Fulton also suggest full support of the Class B(WW1) aquatic life uses. None of the approximately 10 samples collected from March 2014 to August 2016 violated Class B(WW1) criteria for ammonia, dissolved oxygen or pH.

The Class B(WW1) aquatic life uses also remain assessed (evaluated) as “fully supporting” based on biological sampling. This biological assessment was based on data collected in in 2012-2016 as part of the DNR/SHL stream sampling projects. A series of biological metrics that 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 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 2012-2016 BMIBI scores were 48, 53 (both fair), 59, 67, 73 (all good). There were no FIBI samples collected in the previous five years. The aquatic life use support was assessed (evaluated) as fully supporting (=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 51. This segment passed the BMIBI BIC 4/5 times in the last five years. This assessment is considered evaluated because the drainage area (563 mi2) above the 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 both the BMIBI BIC, 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.

Monitoring data collected from the DNR/SHL ambient fixed station near Hurtsville (10490001) during the 2010-2014 data assessment period were sufficient to complete a Nutrient Impact Assessment (NIA). Data analysis methods and screening benchmark values for nutrient stressor and response parameters described in the DNR’s 2016 NIA methodology were used to examine for nutrient impacts often associated with low biotic index scores and violations of dissolved oxygen (DO) criteria. Nutrient stressor: The median concentration of total phosphorus (TP) was 0.22 mg/L among samples collected during the June 15- October 15 index period. The TP benchmark (0.10 mg/L) was exceeded in 18 of 20 samples. The percentage exceeding (90%) was greater than (failing) the 50% threshold with high statistical confidence (> 90%). Nutrient response parameter: The median concentration of algal chlorophyll A suspended in water (WCHLA) was 11 ug/L. The WCHLA benchmark (20 ug/L) was exceeded in 2 of 20 samples. The percentage exceeding (10%) was less than (passing) the 50% threshold with high statistical confidence (> 90%). The median rating of filamentous algae coverage (FLMA) on hard substrates was 0 (absent). The FLMA benchmark (3; 50%-75%) was exceeded in 0 of 8 observations. The percentage exceeding (0%) was less than (passing) the 50% threshold with high statistical confidence (> 90%).

The results of this “evaluated” assessment indicate the presence of elevated levels of the nutrient stressor parameter (TP) and low levels of the nutrient response parameters, WCHLA and FLMA. This combination of results is interpreted as representing a moderate risk of aquatic life use impairment due to nutrient enrichment. Continuous monitoring data were not available to examine for violations of DO criteria; however, the benthic macroinvertebrate index (BMIBI) results described suggest full attainment of aquatic life uses. Based on the assessed risk level, the stream segment is considered a moderate priority for follow-up nutrient impact monitoring.