Big Spirit Lake IA 06-LSR-1655

Assessment Comments

Monitored in 1990 by ISU as part of the Clean Lakes Classifcation study; in 1993 for surveys of Water Supply Reservoirs (Miller & Kennedy 1993).

Basis for Assessment

Assessment based on Bachmann et al.  1994; fishable uses were assessed in 1992 as FST and as FS for the 1994 report for the following reasons:  (1) results of monitoring in 1990 show that that mean levels of secchi, total-P, chl-a, and TSS were better than overall means for the 116 SPOLs sampled in 1990 and 1992; these data show that Big Spirit has some of the best water quality of any Iowa lake; (2) DNR Fisheries staff believe that both swimmable and fishable uses at the lake are fully supported.   Lake was monitored on March 1, 1993 as part of survey of 15 WS reservoirs (Miller and Kennedy 1993).   Samples from inlet and deep area contained only low amounts of atrazine; none of the other six herbicides were detected in either water or sediment.   Data suggest no problem with herbicides in DW; addtional monitoring, however, should be conducted.