Turkey River IA 01-TRK-152
from bridge crossing at Elgin (S13 T94N R7 Fayette Co.) to confluence with Little Turkey R near Eldorado (S18 T95N R8W Fayette Co.).
- Cycle
- 2018
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 5/20/2019 8:37:48 AM
- Updated
- 7/18/2019 10:20:04 AM
The Class A1 (primary contact recreation) uses are assessed (monitored) as "not supported” due to levels of indicator bacteria that exceed Iowa water quality criteria. The Class B(WW1) aquatic life uses are assessed (monitored) as "fully supported" based on results of water quality monitoring from 2012 to 2014. Fish consumption uses are assessed (monitored) as “fully supporting" based on results of fish contaminant monitoring in 2013 and 2014. The sources of data for this assessment include (1) results of monitoring at station TR60 at the Great River Road (STORET station 15330010) from April 2012 to November 2014, (2) results of monitoring at station TR50 at the Great River Road (STORET station 15330011) monitored from April 2012 to November 2014, and (3) results of Iowa DNR fish contaminant monitoring near Clermont in 2013 and 2014.
The Class A1 (primary contact recreation) uses are assessed (monitored) as "not supported" based on levels of indicator bacteria at two monitoring stations that exceed state water quality criteria. The geometric means of indicator bacteria (E. coli) in the 24 samples collected during the recreational seasons of 2012 through 2014 at station TR50 (STORET station 15330010) were as follows: the 2012 geometric mean was 107 orgs/100 ml, the 2013 geometric mean was 2,602 orgs/100 ml, and the 2014 geometric mean was 95 orgs/100 ml. Ten of the 24 samples (42%) exceeded the Class A1 single-sample maximum criterion of 235 orgs/100 ml. The geometric means of indicator bacteria (E. coli) in the 24 samples collected during the recreational seasons 2012 through 2014 at station TR60 (STORET station 15330011) were as follows: the 2012 geometric mean was 287 orgs/100 ml, the 2013 geometric mean was 824 orgs/100 ml, and the 2014 geometric mean was 211 orgs/100 ml. Eleven of the 24 samples (46%) exceeded the Class A1 single-sample maximum criterion of 235 orgs/100 ml. Four of the six recreation season geometric means exceed the Class A1 criterion of 126 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 are 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”. Results of chemical/physical water quality monitoring from 2012 through 2014 do not suggest impairment of the Class B(WW1) aquatic life uses. Monitoring at stations TR50 and TR60 showed no violations of Class B(WW1) water quality criteria for ammonia (total of 28 samples), chloride (33 combined samples), dissolved oxygen (total of 48 samples), pH (total of 45 samples), and temperature (total of 47 samples). Thus, the Class B(WW1) aquatic life uses are assessed (monitored) as “fully supported”. Fish consumption uses are assessed (monitored) as “fully supported” based on results of DNR fish contaminant monitoring in 2013 and 2014. Average levels of mercury in samples of tissue plugs from Smallmouth Bass were below the Iowa threshold for a one meal/week consumption advisory (0.3 ppm). The average level of mercury in the tissue plugs from three Smallmouth Bass in August 2013 was 0.274 ppm, and the average level in the tissue plugs from four Smallmouth Bass in September 2014 was 0.215 ppm. Because both these average levels are below the consumption advisory threshold, the fish consumption uses are assessed as “fully supporting”.