Cold Springs Lake IA 05-NSH-1420

Assessment Comments

Basis for Assessment

Assessement for the 1992 report (FS) changed to FST for the 1994 report for the following reasons:  results of monitoring in 1990 show that average levels of total-P, chl-a, and TSS are at or slightly worse than overall mean levels for the 116 SPOLs sampled in 1990 and 1992; thus, WQ is good but is typical for SPO impoundments sampled in 1990 and 1992.   Lake does, however, have exceptionally low sedimentation rate (0.3 cm/yr) and exceptionally long life expectancy (796 years) for an SPO impoundment in Iowa; i.e., lake is not impaired or threatened by NPSP.   Level of swimming use reported by Bachmann et al.  (1994) is better than the typical SPO impoundment.   Only threat to full support is naturally-occurring shallowness; i.e., mean depth of 2.1 m suggests a slight problem with resuspension of sediment and nutrients.