Snyder Bend Lake IA 06-WEM-1734

Assessment Comments

Assessment based on surveys by IDNR Wildlife Bureau.

Basis for Assessment

SUMMARY:  The aquatic life uses are assessed (evaluated) as "fully supporting / threatened."  The Class A (primary contact recreation) uses and fish consumption uses remain "not assessed."  EXPLANATION:  The aquatic life uses are assessed as "fully supporting / threatened."  The upgrade in support of the aquatic life uses from "not supporting" (see assessments for previous reports) to "fully supported / threatened" is based on the following information from the Iowa DNR bureaus of Water Quality and Wildlife.   The aquatic life uses of this Missouri River wetland have been assessed as "partially supported" since 1994 due to habitat alterations (water level instability) due to hydrologic modification (degradation) of the Missouri River channel.   This wetland, however, now receives discharge water from the Port Neal Generating Station, which maintains the necessary water level in the wetland.   Therefore, the impairment due to hydrologic modification is no longer applicable to this waterbody.   Based on this information, the impacts from habitat alterations appear to have been adequately mitigated.   Thus, the level of support of the aquatic life uses is upgraded from "partially supported" to "fully supporting / threatened."  The assessment category for this wetland is "evaluated."  In terms of Section 305(b) reporting, "monitored assessments" are based primarily on recent, site-specific ambient monitoring data and thus have relatively high confidence.   "Evaluated assessments" are those based on data older than five years or other than site-specific ambient monitoring data (e.g., desktop models or questionnaire surveys of fish and game biologists [=best professional judgement]) and thus have relatively lower confidence.   The primary contact recreation uses remain "not assessed" due to a lack of water quality information upon which to base an assessment.   Fish consumption uses remain "not assessed."  In general, Iowa wetlands are not managed for recreational fisheries; thus, fish contaminant monitoring is not typically conducted at these waterbodies.