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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

SUMMARY:  The Class B(LR) aquatic life uses remain assessed (evaluated) as "fully supported / threatened" (minor impacts) 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 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 2006 Integrated Report (I.e., on Iowa's list of waters in need of further investigation).   The assessment developed for the 2004 assessment/listing cycle is included below.   NOTE:  In order to be consistent with the IDNR assessment/listing methodology for identifying IR Category 3b waters, the level of support of the Class B(LR) uses was changed from the previously-used "fully supported/threatened (minor impacts)" to "partially supported" for the 2006 assessment/listing cycle.   This change does not reflect any knowledge of worsening water quality conditions in this stream.

EXPLANATION:  Continue to use the assessment 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.   Because these data are now considered too old (greater than five years) to accurately characterize current water quality conditions, the assessment category is changed from "monitored" (indicating an assessment with relatively high confidence) to "evaluated" (indicating an assessment with relatively low confidence).