Williams Creek IA 01-YEL-443

Note: A TMDL for the bacterial impairment for streams in the Yellow River basin was prepared by Iowa DNR in 2012 and approved by U.S. EPA in 2013.  Due to completion of the TMDL, the Integrated Report category for the Class A1 recreational uses is changed from 5p (impaired; TMDL needed) to 4a (impaired; TMDL approved). 

EXPLANATION:  The presumptive Class A1 (primary contact recreation) uses remain assessed (evaluated) as "partially supported" due to violations of Iowa’s water quality criteria for indicator bacteria.  The geometric mean of E. coli in the 38 samples collected at the monitoring station near county road X16 during the recreational seasons of 2006 through 2008 was 826 orgs/100 ml.  Twenty-seven of the 38 samples (71%) exceeded Iowa’s 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 the geometric mean of E. coli is greater than the state criterion of 126 orgs/100 ml., the primary contact recreation uses should be assessed as "impaired" (see pgs 3-33 to 3-35of U.S. EPA 1997b). 

A fish kill occurred in this stream segment on April 29, 2002, and resulted from the discharge of 1,500 gallons of 10-34-0 starter fertilizer from a local dealer of agricultural chemicals.  Approximately 6 miles of this stream was affected; approximately 5,800 fish were killed.  The party responsible for the kill was identified, and restitution was sought.  A fish kill also occurred on this stream in 1995; the kill was attributed to animal waste from a feedlot (see the assessment for the 1998 cycle for more information). 

According to IDNR's assessment/listing methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired.”  If a cause of the kill is identified, and the cause is either known, or suspected, to be a “pollutant,” the assessment type is considered “monitored” and the affected waterbody is a candidate for Section 303(d) listing.  If, however, a consent order has been issued to the party responsible for the kill and monetary restitution has been sought for the fish killed, the affected waterbody will be placed in IR Category 4d (impaired but TMDL not required).  IDNR feels that (1) TMDLs should not be required for kills caused by a one-time illegal or unauthorized release of manure or other toxic substance where enforcement actions were taken and (2) enforcement action is more appropriate, efficient, and effective for addressing a spill-related impairment than is the TMDL process.  IDNR sought and received restitution for the value of the fish killed in the April 2002 kill from the responsible party.  IDNR considers IR 4d fish kill waters with no subsequent kills reported in at least five year subsequent to the kill as appropriate for movement from IR Category 4d to either categories 2b or 3b (i.e., Iowa’s list of waters in need of further investigation).  Thus, this impairment was moved to Category 3b of Iowa’s 2010 Integrated Report and remained in Category 3b of Iowa’s 2012 Integrated Report.  Because an additional five years has elapsed since the movement of the impairment to IR Category 3b, the Class B(WW2) uses are now considered “not assessed” as provided for in IDNR’s assessment/listing methodology.  In the absence of placement in IR Category 3b, the assessment of the Class B(WW2) uses is now based on results of chemical/physical monitoring at state 1503011 from 2004-06 as described in the following paragraph.

The results of IDNR/UHL water quality monitoring at station 15030011 from 2004 to 2006 showed only two violations of the Class B(WW2) criterion for dissolved oxygen (5.0 mg/l) in the 78 samples collected for a violation frequency of 3%.  The minimum dissolved oxygen value was 4.3 mg/l.  According to U.S. EPA guidelines for Section 305(b) reporting, if less than 10% of samples exceed state criteria for conventional parameters such as dissolved oxygen, the aquatic life 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 YRWP site 15030011 do not indicate that significantly greater than 10% of the samples exceed the Class B(WW2) criterion for dissolved oxygen.  Thus, these results suggest that the Class B(WW2) uses should be assessed (monitored) as “fully supported.”