Little River Watershed Lake IA 05-GRA-1358

Assessment Comments

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses were considered "not assessed."  The Class B(LW) aquatic life uses, the Class C (drinking water) uses, and the fish consumption uses all remain assessed as "fully supported."  EXPLANATION:  The Class A (primary contact recreation) uses were considered "not assessed" due to the lack of information on levels of indicator bacteria at this lake.   The previous assessment of support of the Class B(LW) uses ("fully supported") was reviewed and approved by the DNR Fisheries Bureau in 2000.   The assessment of support of the Class C (drinking water) uses was based on (1) the UHL survey of water supply reservoirs in 1995 (Miller and Kennedy 1995) (see assessment developed for the 1996 report above) and (2) the 1998 results of the Novartis "Iowa Voluntary Atrazine Monitoring Program."  This monitoring showed that the time-weighted mean level of atrazine in samples collected from the Leon raw water source from January to December 1998 (1.3 ug/l, N=30, maximum=2.2 ug/l) was below the MCL of 3.0 ug/l.  According to DNR's Section 305(b) assessment methodology, average and maximum contaminant levels below  MCLs suggest "full support" of drinking water uses.   Fish consumption used remained assessed as "fully supported" based on results of the EPA/DNR fish tissue (RAFT) monitoring in 1994 (see assessment for the 1996 report).