Cedar River IA 02-CED-455

from Prairie Cr. (SE 1/4 S34 T83N R7W Linn Co.) to confluence with McCloud Run in SW 1/4 S16 T83N R7W Linn Co.

This is a Legacy Assessment. Prior to 2004, assessments were developed under a methodology that pre-dated the Integrated Report guidelines.

Assessment Cycle

1998

Result Period

1994 - 1996

Designations

Assessment Type

Monitored

Integrated Report

Category 0

Legacy ADBCode

IA 02-CED-0030_1

Overall Use Support

Partial

Aquatic Life Use Support

Threatened

Fish Consumption

Not assessed

Primary Contact Recreation

Partial

Drinking Water

Fully

Documentation

Assessment Comments

(All 21 IOWA/DNR): 324035, 324030, 324028, 324015: (stations monitord for UI contract with DAEC.)

Basis for Assessment

Had no violations of Class B(WW) WQ criteria for toxics in the approx 190 samples collected during the Oct 95 to Sep 97 period at the 4 monitoring stations in this reach; at the station downstream from DAEC, had 2 viols. of the Class B(WW) criterion for pH (both=9.1 units) in 48 samples (=4% viol., =FS). Thus, assess support of the Class B(WW) aquatic life uses as FST due to known threats from NPS pollutants. Assess support of Class C (drinking water uses as FS: had 2 viol. of the Class C WQ criterion for nitrate (both in June 96 & both=11 mg/l) in the 72 samples analyzed for NO3 at the station downstream from DAEC (=station 324035) (mean=5.22; median=5.3 mg/l as NO3-N. Also 2 viols. of the Class C WQ criterion for pH in 72 samples (= 3% violation=FS). Support of Class A (primary contact) use assessed as PS due to > 10% of samples (13 to 25%) that exceed 400 orgs/ 100 ml at all 4 stations. Geometric means all < 200 orgs/100ml. Additional study is needed to determine the sources of fecal coliform bacteria seen in the river.