[Note: A TMDL for indicator bacteria (E. coli) was prepared by DNR and approved by EPA in January 2009. Thus, the bacteria impairment for this segment is placed in IR Category 4a (impaired; TMDL approved).]

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 the East Fork of The Des Moines River near St. Joseph (STORET station 10550001) were as follows: the 2014 geometric mean was 231 orgs/100 ml, the 2015 geometric mean was 187 orgs/100 ml, and the 2016 geometric mean was 270 orgs/100 ml. All three recreation season geometric means exceeded the Class A1 geometric mean criterion of 126 orgs/100 ml. Eleven of the combined 24 samples (46%) 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."

The Class B(WW1) aquatic life uses are assessed (evaluated) as “partially supporting” based on data collected in 2012-2016 as part of the DNR/SHL stream ambient biological sampling projects. 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 2012-2016 BMIBI scores were 31, 40, 43 , 54 (all fair) and 56, 57, 65, 66 (all good). There were no FIBI/fish community samples collected in this segment in the previous five years. The aquatic life use support was assessed (evaluated) as partially supporting (=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 non-riffle habitat FIBI BIC for this ecoregion is 32 and the BMIBI BIC for this ecoregion is 62. This assessment is considered evaluated because the drainage areas (977 and 927 mi2) above the sampling sites was greater than the maximum limit (500 mi2) that was used to calibrate the Iowa wadeable stream impairment criteria. Even though this segment failed the BMIBI BIC (2/8), 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. 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).

A fish kill occurred south of Algona on October 6, 2013. A length of 0.5 miles of stream was affected due to an unknown cause, source and responsible party. The fish valuation and investigation expenses were not calculated.

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 was not identified during the DNR investigation, or if the kill was attributed to non-pollutant causes (e.g., winterkill), the assessment type will be considered “evaluated.” Such assessments, although suitable for Section 305(b) reporting, lack the degree of confidence to support addition to the state Section 303(d) list of impaired waters (IR Category 5). Waterbodies affected by such fish kills will be placed in IR subcategories 2b or 3b and will be added to the state list of waters in need of further investigation. Because no cause or source was identified for this 2013 fish kill, the Class B(WW1) aquatic life uses are placed in Category 3b for the current IR cycle.

Despite the results of biological monitoring and the occurrence of a fish kill that suggest “partial support” of the Class B(WW1) aquatic life uses, the results of chemical/physical water quality monitoring at the East Fork of the Des Moines River near St. Joseph (STORET station 10550001) suggest “full support” of the aquatic life uses. Monitoring showed no violations of Class B(WW1) water quality criteria for 36 Ammonia samples (maximum = 1.6 mg/L), 36 pH samples (range = 7.2 to 8.4), 36 Temperature samples (maximum = 24.4°C), 36 Chloride samples (maximum = 100 mg/L), or 36 Sulfate samples (maximum = 130 mg/L) occurred during monitoring from January 2014 to December 2016. One of the 36 samples (3%) analyzed for Dissolved Oxygen (minimum = 4.4 mg/L) violated the Class B(WW1) criteria during the 2014-2016 monitoring period. According to U.S. EPA guidelines (U.S. EPA 1997b, page 3-17) and Iowa DNR's assessment/listing methodology, a violation frequency of significantly greater than 10% for conventional parameters such as Dissolved Oxygen suggests impairment of aquatic life uses. Because the frequency of violations for this parameter is not greater than 10 percent, these results do not suggest impairment of the Class B(WW1) aquatic life uses.

Fish consumption uses remain assessed (evaluated) as “fully supported” based on results of U.S. EPA/DNR fish contaminant (RAFT) monitoring near Algona in 2002 and 2008. The composite samples of fillets from channel catfish and walleye in 2002 had low levels of contaminants. Levels of primary contaminants in the composite sample of channel catfish fillets were as follows: mercury: 0.069 ppm; total PCBs: <0.09 ppm; and technical chlordane: <0.03 ppm. Levels of primary contaminants in the composite sample of walleye fillets were as follows: mercury: 0.154 ppm; total PCBs: <0.09 ppm; and technical chlordane: <0.03 ppm. Follow-up sampling of walleye was conducted in 2008. The level of mercury in the composite sample of walleye fillets in 2008 was 0.14 ppm. The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of the degree to which Iowa’s lakes and rivers support their fish consumption uses. The fish contaminant data generated from the 2002 and 2008 RAFT sampling conducted at this river 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.