Assessment Comments
Two stream use assessments in Clinton County.
Basis for Assessment
Used assessment prepared for the 1994 report. In May 1996, Scott Gritters (DNR/LTRMP) informed DNR/EPD about nutrient enrichment of a backwater lake of the Mississippi R. (Shricker Slough) that he believes is due to Rock Creek. 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. Average NOX 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.
[NOTE: The 1996 assessment refers to the Rock Creek IA 01-MAQ-0010 waterbody as a whole. For the 2002 report, Rock Creek was subdivided into three segments: IA 01-MAQ-0010-1 (lower), IA 01-MAQ-0010-2 (above PCS-Nitrogen), and IA 01-MAQ-0010-3 (headwaters).]
