Clear Creek IA 01-UIA-249
mouth (S35 T100N R5W Allamakee Co.) to north line of S15 T100N R5W Allamakee Co.
- Cycle
- 2016
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 5/17/2016 8:22:11 AM
- Updated
- 10/5/2016 12:27:54 PM
The presumptive Class A1 (primary contact recreation) uses and the presumptive Class A2 (secondary contact recreation) uses are both assessed (monitored) as “not supported” (IR 5p) due to levels of indicator bacteria that exceed state water quality criteria. The Class B(CW1) coldwater aquatic life uses are assessed as “fully supporting” (IR 2a) based on results of physical and chemical monitoring from 2012 to 2014 and on the updated trout reproduction summary prepared by the IDNR Fisheries Bureau. Fish consumption (Class HH) uses remain “not assessed” (IR 3a) due to the lack of fish contaminant monitoring in this assessment segment. The sources of data for this assessment are the results of monitoring at Site 28 of the Upper Iowa River Watershed (UIRW) project (STORET No. NEIARCD 190050006) from April 2012 through October 2014 and the January 2016 summary of trout reproduction in Iowa cold water streams prepared by the IDNR Fisheries Bureau.
The presumptive Class A1 (primary contact recreation) uses and the presumptive Class A2 (secondary contact recreation) uses are both assessed 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 21 samples collected during the recreational seasons of 2012 through 2014 at UIRW station 28 were as follows: the 2012 geometric mean was 1,498 orgs/100 ml, the 2013 geometric mean was 4,774 orgs/100 ml and the 2014 geometric mean was 585 orgs/100 ml. All three geometric means exceed the Class A1 criterion of 126 orgs/100 ml, and the 2012 and 2013 geometric means also exceed the Class A2 geometric mean criterion of 630 orgs/100 ml. Seventeen of the 21 samples (81%) exceeded the Class A1 single-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 a recreation season geometric mean exceeds the respective water quality criterion, the contact recreation uses should be assessed as “impaired” (see pgs 3-33 to 3-35 of U.S. EPA 1997b). The Class B(CW1) coldwater aquatic life uses are also assessed (evaluated) as “fully supporting” based on an updated summary of trout reproduction in Iowa streams prepared by the IDNR Fisheries Bureau in January 2016. According to the updated summary, Clear Creek (New Albin) is in the group of Iowa coldwater streams that supports natural reproduction of trout. Based on results of surveys by the IDNR Fisheries Bureau, this stream is placed in the category of Iowa trout streams that exhibit fairly consistent natural reproduction and maintain a viable population of brown trout without any stocking (a Category I stream). The fish consumption uses remain “not assessed” due to the lack of fish contaminant monitoring in this stream segment upon which to base an assessment.
The Class B(CW1) coldwater aquatic life uses are assessed as “fully supporting”. Monitoring from 2012 to 2014 at Upper Iowa River Watershed Site 28 included analysis for ammonia (14 samples), temperature (14 samples), and pH (13 samples). None of these samples collected violated the respective Class B(CW1) criteria. These results suggest “full support” of the Class B(CW1) aquatic life uses.