Heather Branch IA 03-SKU-901

Assessment Comments

Assessment of aquatic life uses is changed to "not assessed" due to age of data (> 10 years).

Basis for Assessment

[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 (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 (2014) 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/EXPLANATION:  The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment.   The assessment of the presumptive Class B(WW1) aquatic life uses is changed from "fully supported/evaluated" to “not assessed” due to the age of the data upon which previous assessments were assessed (greater than 10 years).   The biological data used for previous assessments were collected in 1998.   As water quality data age, they become less able to represent current water quality conditions.   Thus, according to IDNR’s assessment/listing methodology, waterbodies with assessments based on data older than ten years will be considered “not assessed” unless the previous assessment indicated impairment of the assessed use.