Browns Lake IA 06-WEM-1735

Assessment Comments

Monitored in 1992 by ISU as part of the Clean Lakes Classification study (1994).

Basis for Assessment

Both fishable and swimmable uses were assessed as FST for the following reasons:  (1) BPJ of DNR Fisheries; (2) results of monitoring show that average levels of total-P, TSS, and chl-a are better than overall averages for the 116 SPOLs sampled in 1990 and 1992; the average level of secchi depth was worse than the overall average but was within 1 SD; (3) estimates of both fishing in swimming reported by Bachmann et al.  are relativley high for Iowa SPOLs; (4) as expected, the oxbow lake has a rel.  low sedimentation rate (0.5 cm/yr) and moderately long life expectancy (270 years); (5) Harlan et al.  report that channel degradation of the Missouri River has caused water level problems for the lake; thus, lake receives cooling water from a power plant.   Thus, lake is threatened by hydromodification of the Missouri R.  and by natural lack of depth to allow thermal stratification.