Little River Watershed Lake IA 05-GRA-1358

Assessment Comments

Basis for Assessment

Assessment in the 1992 report (PS) was changed to FS for the 1994 report for the following reasons:  (1) DNR Fisheries assessed the lake as FST, (2) results of monitoring in 1992 show that average levels of secchi depth, total-P, chl-a, and TSS are at or better than overall averages for the 116 SPOLs sampled in 1990 and 1992, (3) relatively low sedimenation rate (0.8 cm/yr) and relatively long estimated life (481 years), (4) no problems with fishkills, and (5) 80 % of watershed in approved SC practices; (6) levels of use for fishing and swimming reported by Bachmann et al.  (1994) are relatively high for SPO impoundments in Iowa.   Low sed.  rate and long life expect.  suggest no threat from NPSP.   Lake not desig as Class C but is primary WS for Leon.   Monitored in Feb 93 for 7 ag herbicides.  Only rel low level of atrazine in water (0.14 & 0.12 ug/l) were detected.   Additional monitoring needed during summer.