Ottumwa Lagoon IA 04-LDM-1014

Assessment Comments

Basis for Assessment

Fishable uses were assessed as PS and swimmable uses were not assessed for the following reasons: (1) BPJ of DNR staff; (2) results of monitoring show that average levels of total-P and chl-a are worse than overall averages +/- 1 SD for the 116 SPOLs sampled in 1990 and 1992; average level of secchi depth is worse than the overall average but is within 1 SD; average level of TSS approx equal to overall average; (3) lake winterkills in one out of ten years; (4) lake supports a moderate amount of fishing; (5) although designated for swimmable uses, Bachmann et al.  report swimming use as zero; thus, swim.  use not assessed.   Lack of thermal stratification is likely the cause of the relatively poor water quality, although contributions of sediment and nutrients from agricultural and urban areas add to problems with water quality.