Mormon Trail Lake IA 05-NOD-1404

Assessment Comments

Basis for Assessment

Assessment changed from PS in 1992 report to FST due to recommendation from DNR Fisheries.   Average levels of all parameters sampled in 1990 (secchi, NO3, total-P, chl-a, and TSS) within 1 SD of the respective mean for all 96 lakes.  Average levels of secchi, total-P, chl-a, and TSS are much better than average for the 86 SPO impoundments sampled in 1990 and 1992.   Sedimentation rate and life expectancy are also much better than average for SPO impoundments in Iowa.   Level of swimming use reported by Bachmann et al.  (1994) is higher than the typical SPO impoundment in Iowa.   Levels of total-P and chl-a are in the best 10% of the 86 SPO impoundments sampled in 1990 and 1992.   DNR Fisheries report that lake is threatened by siltation from AG NPS.