Clear Creek IA 02-IOW-1937

Assessment Comments

Assessment remains based on results of violations of narrative WQ criteria as documented by volunteer monitors.

Basis for Assessment

Note:  Prior to the current (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 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is now presumptively designated for Class A1 (primary contact recreation) uses and for Class B(WW1) aquatic life uses.    According to the Iowa Water Quality Standards, all perennial rivers and streams and all intermittent streams with perennial pools that are not specifically listed in the Iowa surface water classification are designated as Class A1 and Class B(WW1) waters.    Thus, for the current (2008) assessment, perennial flow is presumed, and the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW1) water quality criteria.]  

SUMMARY:  The general uses of this stream are assessed (monitored) as "not supported" due to impacts of poorly-treated and untreated domestic  wastewater discharged to the stream.   In addition, the presumptive Class A1 (primary contact recreation) uses and the presumptive Class B(WW1) aquatic life uses are also assessed as "not supported" based on violations of Iowa's narrative water quality criteria due to discharge of poorly-treated wastewater to this stream segment.   These are new impairments for this stream segment that resulted from the presumptive addition of the Class A1 (primary contact recreation) and Class B(WW1) aquatic life uses to this stream segment in 2008.  

This assessment is based on results of the an IDNR/IOWATER “snapshot” monitoring event in September 2003 that showed presence of toilet paper, floating sewage material, and a strong sewage smell coming from a tile line that discharges to the uppermost reaches of Clear Creek (see IDNR Water Fact Sheet 2005-2:  Snapshot Events; see also Neely et al.    2003.    Old Man’s Creek and Clear Creek, east-central Iowa:  the role of volunteers in a snapshot sampling (available at http://wqm.igsb.uiowa.edu/iowater/SnapshotResults/Oldmans.pdf )).    Subsequent investigations by volunteer (IOWATER) monitors and by IDNR staff have demonstrated that these impact continue to occur.    

EXPLANATION:  The water quality conditions in this segment of Clear Creek as documented by volunteer monitors and by IDNR staff potentially violate several of Iowa's narrative water quality standards designed to protect general uses of Iowa's surface waters.    The following of Iowa's narrative water quality standards are potentially violated in this segment of Clear Creek:

--such waters shall be free from substances from point source dischargers that will settle to form sludge deposits;

--such waters shall be free from floating debris, oil, grease, scum and other materials from wastewater discharges or agricultural practices in amounts sufficient to create a nuisance;

--such waters shall be free from materials from wastewater discharges or agricultural practices producing objectionable color, odor, or other aesthetically objectionable conditions;

CONCLUSION (new):  Based on the documentation of the impacts of poorly and/or untreated domestic wastewater discharged to the this stream segment, the general uses of this stream, as well as the presumptive aquatic life uses and the presumptive primary contact recreation uses of this segment, are assessed as impaired.   This waterbody was assessed as impaired for general aquatic life uses and was added to Iowa’s 2004 list of impaired waters as required by Section 303(d) of the federal Clean Water Act.    This impairment remained on Iowa’s 2006 Section 303(d) list and remains on Iowa's 2008 list.   Due to the February 2008 EPA approval of changes to Iowa Water Quality Standards, this segment is now also impaired for the presumptive Class A1 (primary contact recreation) and Class B(WW1) aquatic life uses.