Silver Lake IA 06-LSR-1669

Assessment Comments

Assessment is based on results of monitoring in 1990 by ISU as part of the Clean Lakes Classification study (1994); in 1993 & 1995 for surveys of Water Supply Reservoirs (Miller and Kennedy 1993 & 1995) and results of U.S. EPA/IDNR fish tissue monitoring in 1999.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation uses) were "not assessed."  Continued to assess support of the Class B(LW) aquatic life uses as "fully supported / threatened."  The Class C (drinking water) uses remain assessed as "fully supported."  Fish consumption were assessed as "fully supported."  EXPLANATION:  The level of support of Class A (primary contact recreation) uses was changed from "fully supported / threatened" to "not assessed" due to the lack of information on levels of indicator bacteria at this lake.   This change in assessment reflects a changes in the DNR's Section 305(b) assessment methodology and does not reflect any known changes in water quality.   The previous (1998) assessment of support of the Class B(LW) uses ("fully supported / threatened") was reviewed and approved by the DNR Fisheries Bureau in 2000.   Class C (drinking water) uses remained assessed as "fully supported" based on results of water quality monitoring in 1995 (see assessment developed for the 1996 report above).   Fish consumption uses were assessed as "fully supported."  EPA/DNR fish tissue (RAFT) monitoring in October 1999 showed that levels of contaminants in the composite sample of fillets from common carp and walleye were less than ½ of the respective FDA action levels and DNR levels of concern for organochlorine contaminants and mercury [nearly all contaminants in both samples were below their analytical limits of detection].   Thus, fish consumption uses were assessed as "fully supported."