Coralville Reservoir IA 02-IOW-630

Assessment Comments

Assessment is based on water quality monitoring.

Basis for Assessment

Assess support of the Class A primary contact recreation uses as FS:  no violations of WQ criteria for fecal coliform bacteria in the 18 samples collected at the MaHaffey Bridge station during summers of 1996 & 97 (geometric mean=17 orgs/100 ml; max=200 orgs/100 ml).   Sampling at the 3 beaches (W.  Overlook, Sugar Bottom and Sandy) during summers of 95 & 96 showed no levels exceeding 200 orgs/100 ml during the 18 sampling events over the two years.   Class B(WW) aquatic life uses were assessed as FS:  no violations of Class B(WW) WQ criteria for conventional pollutants and ammonia in the 44 samples collected from Oct 1995 to Sep 1997.   In addition, the March/April 1998 Iowa Conservationist notes that Coralville Reservoir provide good to excellent angling opportunities for saugeye, white bass, crappie, channel catfish, flathead catfish, and walleye.   Fish consumption uses were assessed as FS:  levels of organochlorine contaminants (chlordane, dieldrin, heptachlor epoxide, & DDE) and mercury were well below 1/2 of respective FDA action levels in fillet and whole-fish composite samples of carp in 1995 & 96 (no fillet samples or mercury analysis in 96).