Clear Lake IA 02-WIN-841

Assessment Comments

Assessment is based on results of water quality monitoring, RAFT tissue sampling, and surveys of the DNR Fisheries Bureau.

Basis for Assessment

Assessment in the 1992 report (PS) changed to FST in the 1994 report for the following reasons: (1) DNR Fisheries believe that the lake should be assessed as FST, (2) results of monitoring in 1990 show that average levels of total-P and chl-a are slightly worse than overall average levels for the 116 SPOLs sampled in 1990 and 1992; the average secchi depth (0.4 m) was approx one-half the overall average (1.08 m) but was within 1 SD +/-; the average level of TSS was worse than the overall mean + 1 SD.  Thus, these data suggest that the lake has slightly poorer water quality than average for SPOLs in Iowa; (3) results of RAFT monitoring in 1993 show no contaminants at levels of concern.  Past assessments have suggested that WQ is impacted by urban runoff from the city of Clear Lake.   Levels of use for fishing and swimming are relatively high for natural SPOLs in Iowa.   Lake threatened by urban runoff and instability of water level.