Arrowhead Pond IA 06-WED-1702

Assessment Comments

Assessment is based on results of (1) ISU Clean Lakes Classification study in 1990 and (2) surveys by IDNR Fisheries Bureau.

Basis for Assessment

Fishable use was assessed as PS based upon the recommendation of DNR Fisheries.   Results of monitoring in 1990 show that average levels of chl-a, total-P, and TSS are better than overall averages for the 116 SPOLs sampled in 1990 and 1992; the average secchi depth, however, was worse than the overall average but was within 1 SD of the overall mean.   Lake does not have problems with fishkills.  Although designated for swimmable uses, the lake does not have a swimming beach and Bachmann et al.  (1994) report swimming use as zero; thus, swimmable uses were not assessed.   Lake is in an area of high rates of soil erosion; thus, sedimentation rate is rel.  high (7.9 cm/yr) and life expectancy of this 14 acre impoundment is relatively short (26 years).   Thus, lake is impaired by sedimentation from agricultural NPS.