ADBNet

Assessment Comments

Assessment remains based on results of a May 1994 IDNR stream use assessment. Support level for aquatic life uses was changed to "partially supporting" only to reflect the need for follow-up monitoring on this stream.

Basis for Assessment

[Note:  Prior to the 2008 Section 305(b) cycle, this stream segment was designated only for Class B(LR) aquatic life 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.   The stream remains designated for aquatic life uses (now termed Class B(WW2) aquatic life uses).   Thus, for the current (2012) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]

SUMMARY:  The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment.   The Class B(WW2) aquatic life uses remain assessed (evaluated) as "partially supported" based on results of biological monitoring and habitat assessment conducted as part of the May 1994 IDNR stream use assessment.   Due to the age of these data, the assessment category is changed from "monitored" (higher-confidence assessment) to "evaluated" (lower-confidence assessment).   Although the data upon which this assessment were originally based have aged well beyond 10 years--and are thus considered too old to characterize current water quality conditions--the indication of a potential impairment suggests that this stream segment should remain assessed (evaluated) as "partially supported" and thus remain in Category 3b of Iowa’s Integrated Report (i.e., on Iowa's list of waters in need of further investigation).  

EXPLANATION:  Continue to use the assessment of the aquatic life uses developed for the 1996, 1998 and 2000 reports that was based on results of the 1994 IDNR stream use assessment.   As stated in the assessment developed for the previous reporting cycles, the number of fish species (=7) and families (=2) collected during the 1994 stream use assessment are relatively low for streams in the Des Moines Lobe subecoregion (47b), and only 5 of the 11 expected fish taxa for Des Moines Lobe streams were present.   Thus, additional sampling with more a more effective gear type is still needed to better determine the status of the aquatic communities.   The field sheet from the 1994 assessment indicates the presence of relatively high quality aquatic habitats, and field notes indicate that effective seining was hindered by rocks and snags.