Assessment Comments

Assessment is based on: (1) an updated summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau in May 2006 and (2) results of IDNR physical/chemical water quality monitoring conducted at Bloody Run Creek from January 2004 through December 2006 at Site 1 (STORET station 10220003).

Basis for Assessment

[[Note:  Prior to the current (2008) Section 305(b) cycle, this stream segment was designated only for Class B(CW) aquatic life uses.   Due to changes in Iowa’s surface water classification that were approved by U.S.  EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is also now presumptively designated for Class A1 (primary contact recreation) and Class A2 (secondary contact recreation) uses.   This segment remains designated for coldwater aquatic life use (now termed Class B(CW1) uses), and for fish consumption uses (now termed Class HH (human health/fish consumption) uses.   This stream segment also remains identified as an “HQR” (high quality resource) water.]

SUMMARY:  The presumptive Class A1 (primary contact recreation) uses and the presumptive Class A2 (secondary contact recreation) uses are both assessed (monitored) as “fully supported.”  The Class B(CW1) coldwater aquatic life uses are assessed (monitored) as "fully supported" based on (1) a summary of trout reproduction in Iowa streams and (2) results of ambient chemical/physical water quality monitoring conducted from 2004 through 2006.   Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this coldwater stream.   Sources of data for this assessment include (1) an updated summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau in May 2006 and (2) results of IDNR physical/chemical water quality monitoring conducted at Bloody Run Creek from January 2004 through December 2006 at Site 1 (STORET station 10220003).

EXPLANATION:  The Class A1 (primary contact recreation) uses and the Class A2 (secondary contact recreation) uses are both assessed (monitored) as “fully supported.”  Due to recent changes in Iowa’s Water Quality Standards, Iowa’s assessment methodology for indicator bacteria has changed.   Prior to 2003, the Iowa WQ Standards contained a high-flow exemption for the Class A1 criterion for indicator bacteria (fecal coliforms) designed to protect primary contact recreation uses:  the water quality criterion for fecal coliform bacteria (200 orgs/100 ml) did not apply "when the waters [were] materially affected by surface runoff."  Due to a change in the Standards in July 2003, E.  coli is now the indicator bacterium, and the high flow exemption was eliminated and replaced with language stating that the Class A criteria for E.  coli apply when Class A1, A2, or A3 uses “can reasonably be expected to occur.”  Because the IDNR Technical Advisory Committee on WQ Standards could not agree on what flow conditions would define periods when uses would not be reasonably expected to occur, all monitoring data generated for E.  coli during the assessment period, regardless of flow conditions during sample collection, will be considered for determining support of Class A uses for purposes of Section 305(b) assessments and Section 303(d) listings.  

The geometric mean of E.  coli in the 24 samples collected at Bloody Run site 1 during the recreational seasons of 2004 through 2006 was 68 orgs/100 ml.   This geometric mean is well-below the Class A1 criterion of 126 orgs/100 ml.   The geometric mean of the 36 samples collected during calendar years of 2004 through 2006 was 50 orgs/100 ml.   This geometric mean is far below the Class A2 criterion of 630 orgs/100 ml.   Three of the 24 samples (12%) exceeded Iowa’s Class A1 single-sample maximum criterion of 235 orgs/100 ml.; 1 of the 36 samples (3%) exceeded Iowa’s Class A2 single-sample maximum criterion (2,880 orgs/100 ml.).   According to U.S.  EPA guidelines for Section 305(b) reporting and IDNR’s assessment/listing methodology, if the geometric mean of E.  coli is below the applicable state criterion, the primary contact recreation uses should be assessed as "fully supported" (see pgs 3-33 to 3-35of U.S.  EPA 1997b).   Also, according to U.S.  EPA guidelines for Section 305(b) reporting, if less than 10% of samples exceed the single-sample maximum criterion, the primary contact recreation uses should be assessed as "fully supported" (see pgs 3-33 to 3-35of U.S.  EPA 1997b).   According to IDNR’s assessment/listing methodology, the results from Bloody Run site 1 do not indicate that significantly greater than 10% of the samples exceed either the Class A1 or Class A2 single-sample maximum criterions.   Thus, these results suggest that both the Class A1 and Class A2 uses should be assessed as “fully supported.”  

The Class B(CW1) coldwater aquatic life uses are also assessed as “fully supported.”  This assessment is based on the updated summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau in May 2006.   According to this summary, this reach of Bloody Run Creek is in the category of Iowa trout streams that have fairly consistent natural reproduction and are capable of maintaining a viable population for the target trout species without any stocking.   The Class B(CW1) aquatic life uses were also assessed (monitored) as "fully supported" based on results of water quality monitoring at Site 1 on Bloody Run Creek from 2004 through 2006.   None of the 36 samples analyzed for ammonia or pH violated the respective Class B(CW1) aquatic life criteria.  

Fish consumption uses remain "not assessed" due to lack of fish tissue monitoring in this stream reach.