East Fork Des Moines River IA 04-EDM-971
from Hwy 169 at Devine Access (S26 T94N R29W Kossuth Co.) to County Road B63 (130th) (S23 T94N R29W Kossuth Co)
- Cycle
- 2018
- Release Status
- Final
- Overall IR
- 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
- Trend
- Unknown
- Created
- 7/29/2019 11:42:35 AM
- Updated
- 8/2/2019 8:50:40 AM
The Class A1 (primary contact recreation) uses are assessed (monitored) as "partially supported" due to high levels of indicator bacteria (E. coli). All other designated uses are "not assessed".
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 was placed and remains in IR Category 4a (impaired; TMDL approved). The Class A1 uses are assessed (monitored) as "partially supported" based on results of monitoring for indicator bacteria (E. coli). The geometric means of indicator bacteria (E. coli) in the 24 samples collected during the recreational seasons of 2012 through 2014 at DNR station 10550001 near St. Joseph were as follows: the 2012 geometric mean was 64 orgs/100 ml, the 2013 geometric mean was 394 orgs/100 ml, and the 2014 geometric mean was 231 orgs/100 ml. The 2013 and 2014 geometric means slightly exceed the Class A1 criterion of 126 orgs/100 ml; the 2012 geometric mean is well-below the Class A1 criterion. Ten of the 24 samples (42%) 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 DNR’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). Thus, because at least one recreation season geometric mean exceeded criteria for Class A1 uses, these uses are assessed as “impaired” (partially supported). All historic assessments for the remaining designated uses can be found in the proper upstream segment:https://programs.iowadnr.gov/adbnet/Segments/1882 See the segment notes for further explanation.