Don Williams Lake IA 04-UDM-1249

Assessment Comments

Basis for Assessment

Assessment is based on the following information: 1.  BPJ of DNR Fisheries says that lake has WQ problems; (2) monitoring by ISU in 1990 shows that yearly mean levels of total-P and TSS are worse than the overall means + 1SD for the 116 SPOLs sampled from 1990 to 1992; this suggests sources of organic enrichment and sediment to the lake.   Levels of other parameters (chl-a and Secchi) were within 1 SD of the overall means; (3) a summary of point source impacts to SPOLs prepared in January 1993 by DNR/EPD (JRO) shows that the WW lagoons for the city of Pilot Mound discharge to Bluff Creek approx two miles upstream from the lake; this suggests the potential for PS-caused organic enrichment of the lake.   Levels of use for swimming reported by Bachmann et al.  is rel.  high for SPO impoundment; thus, swimmable use assessed as FST.