Price Creek IA 02-IOW-6377
from confluence with unnamed trib in NW1/4 S8 T81N R9W Iowa Co. to headwaters in S31 T82N R10W Benton Co.
- Cycle
- 2016
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 8/31/2016 3:28:46 PM
- Updated
- 8/31/2016 3:28:46 PM
The presumptive Class A1 (primary contact recreation) uses are assessed (monitored) as “partially supported” due to levels of indicator bacteria (E. coli that exceed state water quality criteria. The presumptive Class B(WW1) aquatic life uses remain assessed (monitored) as "fully supported” based on results of chemical/physical monitoring from 2005 through 2008. This sources of data for this assessment are the results of IOWATER volunteer water quality monitoring conducted from 2005-2008 and the results of Section 319 monitoring conducted in 2013 and 2014 on Price Creek at the following seven stations (moving from downstream to upstream): (1) Site 7 at T Avenue (STORET IDs 948067 (IOWATER) and 13480007 (319), (2) Site 6 at 110th St. and S Avenue (STORET IDs 948074 (IOWATER) and 13480006 (319), (3) Site 5 at R Avenue (STORET IDs 948058 (IOWATER) and 13480005 (319), (4) Site 4 at 110th St. (STORET IDs 948070 (IOWATER) and 13480004 (319), (5) Site 3 at PP Avenue (STORET IDs 948071 (IOWATER) and 13480003 (319), (6) Site 2 at P Avenue (STORET IDs 948059 (IOWATER) and 13480002 (319), and (7) Site 1 at NN Avenue (STORET IDs 948060 (IOWATER) and 13480001 (319).
Note: Prior to the 2008 Section 305(b) cycle, this stream segment was classified only for general uses. Due to changes in Iowa’s surface water classification that were approved by U.S. EPA in February 2008, this segment is now presumptively designated for Class A1 (primary contact recreation) uses and for Class B(WW1) aquatic life uses. Thus, for the current assessment, the available water quality monitoring data was compared to the applicable Class A1 and Class B(WW1) water quality criteria.] Summary of monitoring for indicator bacteria (E. coli) at Price Creek (assessment segment IA 02-IOW-0176_0) during recreation seasons of 2013 & 2014. Station Description Station Abbrev. STORET Station No. 2013 GM No. of samples in 2013: 2014 GM (11 samples)* No. & percent of the 15 samples with E. coli > 235 orgs/100 ml: Price Cr. At T Ave. Site 7 13480007 1,045 4 726 13; 87% Price Cr. At 100th St. & S Ave Site 6 13480006 344 4 539 12; 80% Price Cr. At R Ave. Site 5 13480005 751 4 617 12; 80% Price Cr. At 110 St. Site 4 13480004 774 4 517 12; 80% Price Cr. At PP Ave. Site 3 13480003 405 3 388 10; 71% Price Cr. At P Ave. Site 2 13480002 633 3 236 9; 64% Price Cr. At NN Ave. Site 1 13480001 424 2 368 8; 62% All seven stations exceed the Class A1 geometric mean criterion of 126 orgs/100 ml. According to U.S. EPA guidelines for Section 305(b) reporting and according to IDNR’s assessment/listing methodology, if the geometric mean level of E. coli is greater than the state criterion, the primary contact recreation uses should be assessed as "impaired" (see pgs 3-33 to 3-35of U.S. EPA 1997b). Thus, the presumptive Class A1 uses are assessed as “partially supported”.
EXPLANATION: The presumptive Class A1 uses are assessed (monitored) as "partially supported" based on results of Section 319 bacteria monitoring from May 2013 to September 2014. From 2 to four samples from each of the seven monitoring stations on Price Creek were analyzed for E. coli during the recreation season of 2013; 11 samples were analyzed at each of the seven station during the 2014 recreation season. Note: According to the data completeness guidelines in Iowa DNR’s assessment/listing methodology, at least seven independent samples per recreation season are needed to calculate a geometric mean appropriate for comparison to the Class A geometric mean criteria. Too few samples (from 2 to 4) were collected at the seven monitoring stations during the 2013 recreation season to allow calculation of a useful geometric mean. During the 2014 recreation season, however, a sufficient number of samples was collected at each of the seven monitoring sites. The geometric mean levels of indicator bacteria (E. coli) at these seven stations and the number of samples exceeding the Class A1 single-sample maximum criterion of 235 orgs/100 ml were as follows (listed from downstream to upstream):
The presumptive Class B(WW1) aquatic life uses remain assessed (monitored) as “fully supporting” based on results of the water quality monitoring in this segment of Price Creek from 2005-2008. (The only supporting parameter with Class B(WW1) criteria that was collected as part of Section 319 monitoring in 2011 was water temperature; none of the combined 69 samples collected at the seven stations violated the Class B(WW2) criterion for water temperature). No parameters with Class B(WW1) criteria were collected during the 2012-2014 monitoring period). The 2005-08 results for dissolved oxygen, and pH showed no violations of Class B(WW1) criteria in the approximately 10 samples collected at each of the seven monitoring stations in this segment and showed no violations of Class B(WW1) criteria for ammonia in the approximately three samples analyzed from each of the seven stations. The lack of violations suggests “full support” of the presumptive Class B(WW1) aquatic life uses. Note: because the pH data were recorded to the nearest whole pH unit, these data were not useful for determining the strongly pH-dependent violations of aquatic life criteria for ammonia. As monitored from 2005-2008, however, levels of ammonia in this segment of Price Creek are low. The maximum level reported in the combined 25 samples analyzed from the seven stations was 0.8 mg/l in the sample collected from Station PC-7 on July 16, 2005. The next-highest ammonia level in the combined dataset was 0.25 mg/l; 15 of 25 samples reported as less than the detection level of 0.05 mg/l. The pH level for the July 16, 2005 sample from Station PC-7 was reported as 8 pH units, and the water temperature was 24.4C. At this temperature and pH, the sample ammonia level of 0.8 mg/l does not violate Iowa’s Class B(WW1) chronic criterion for ammonia (early life stages present). Arbitrarily assuming a pH level of 9 for this sample considerably lowers the chronic criterion (from 5.62 to 0.88 mg/l) but does not result in a violation of the chronic criterion