Saylorville Reservoir IA 04-UDM-1213

Assessment Comments

Basis for Assessment

Had no violations of the Class A primary contact recreation WQ criterion of 200 fecal coliforms / 100 ml in the 18 samples collected at mid reservoir near the dam during summers of 1996 and 1997 (geometric mean= 3 orgs/100 ml; max = 14 orgs/100 ml).   Sampling at beaches during the same period showed (1) no violations of the Class A WQ criterion in the 51 samples from 17 sampling events at three sites Oak Grove Beach (geometric means of 2, 3, and 3 orgs/100 ml at the three sites; max of 57 orgs/100 ml) and (2) no violations of the Class A WQ criterion in the 51 samples from the three sites at Sandpiper Beach (geometric means of 5 orgs/100 ml at all sites; max of 82 orgs/ 100 ml).   These results suggest full support (FS) of Class A uses.   Only 1 of the 33 samples coll.  between Oct 95 & Sep 97 exceeded a Class B(WW) WQ criterion for conventional parameters or ammonia:  the sample from Aug.  20, 1996 contained 4.71 mg/l of dissolved oxygen, thus violating the Class B(WW) WQ criterion of 5.0 mg/l.   This single violations (3% of samples) does not suggest a WQ impairment; thus, assess support of the Class B(WW) aquatic life uses as FS.   Levels of pesticides in composite samples of 3-yr old whole-fish carp were well below 1/2 of FDA action levels in both the 1996 & 97 samplings; thus, fish consumption uses assessed as FS.   Lake noted for excellent fishing for crappie and channel catfish, as well providing good populations of walleye, largemouth bass and white bass in the Mar/Apr 98 Iowa Conservationist.   Support of the Class B(WW) & Class A uses continues to be threatened by agricultural NPSs.