Shrickers Slough IA 01-MAQ-1

Assessment Comments

Monitoring by LTRMP staff, Bellevue station.

Basis for Assessment

[NOTE: For the 2002 report, Shrickers Slough was separated from the assessment for Rock Creek.   In previous reports, both waterbodies had been assessed as one assessment unit.   Thus, the following assessments for Shrickers Slough for the 1996, 1998, and 2000 reports have been developed from the respective assessments originally developed for the combined "Rock Creek/Shrickers Slough" waterbody.   In order to make these assessments specific to Shrickers Slough, several deletions and additions were necessary; however, no substantive changes were made.   For the unedited original assessments developed for the combined Rock Creek/Shrickers Slough waterbody, see assessment information for lower Rock Creek, segment IA 01-MAQ-0010-1).]

In May 1996, Scott Gritters (DNR/LTRMP) informed DNR/EPD about nutrient enrichment of a backwater lake of the Mississippi R.  (Shrickers Slough) that he believes is due to Rock Creek [the primary tributary of Shrickers Slough].   He feels that industries along Rock Creek are contributing these high levels of nutrients that lead to algae blooms and winterkills in Shricker Slough.   Thus, attribute impairment (although based primarily on circumstantial evidence) to high nutrient levels from industrial and agricultural sources.   Recent sampling conducted by Gritters and Gould (DNR, LTRMP, Bellevue) show significantly high levels of nitrite-nitrate (NOX) and ammonia in Rock Creek.   Average NOX in Rock Creek upstream from industries was 6.83 mg/l; dstr=11.27 mg/l.  Ammonia averaged 0.06 mg/l upstream and 1.78 mg/l downstream.  Compared to other tributaries sampled for LTRMP, Rock Creek has considerably higher NOX and ammonia.