Trumbull Lake IA 06-LSR-1636

Assessment Comments

Monitored in 1990 by ISU as part of the Clean Lakes Classification Study (1994).

Basis for Assessment

Assessed as PS for the following reasons:   (1) results of monitoring in 1990 show that average levels of secchi depth, total-P, chl-a, and (especially) TSS are worse than overall averages for the 116 SPOLs sampled in 1990 and 1992 +/- 1 SD; i.e., water quality of this lake is poorer than approximately two-thirds of the SPOLs in Iowa; levels of chl-a and TSS were some of the highest in the 1990-1992 data set for Iowa SPOLs; (2) Clean Lakes Classification study (Bachmann et al.  1994) states that the lake winterkills 7 out of 50 years and that 70% of the lake is covered with aquatic vegetation; (3) lake has relatively high sedimentation rate (1.4 cm/yr) and rel short life expect (64 years) for a natural SPOL; (4) level of swimming use reported by Bachmann et al.  (1994) is very low, thus suggesting impairment.   Secchi, total-P, chl-a, TSS, & swim use were in poorest 10% of Iowa natural (SPOL) lakes.