South Fork Chariton River IA 05-CHA-1328
from confluence with Ninemile Cr. (S4 T69N R22W Wayne Co.) to outfall of Bob White Lake in S4 T68N R22W Wayne Co.
Assessment Comments
Stream use assessment.
Basis for Assessment
Continued to use assessment of support of the Class B(LR) aquatic life uses developed for the 1994 report (=FST). Although this river is not designated for Class C drinking water uses, this river is tributary to Rathbun Reservoir, a Class C waterbody. Monitoring conducted in 1997 by the U.S Army Corps of Engineers near Cambria showed that 7 of 10 samples had level of atrazine that exceeded the MCL of 3.0 ug/l. The average level of atrazine was 14.3 ug/l; median was 12.0 ug/l, with a range of 0.4 to 44.2 ug/l. The violations of the atrzine occurred from June 10 through August 20; the four June samples that violated the MCL all had levels of atrzine greater than 16.0 ug/l. Levels of alachlor were all less than the MCL of 2.0 ug/l. Forty percent of the 9 samples excced the MCLG for cyanazine of 1.0 ug/l. Levels of cyanazine ranged from 0.1 to 15.4 ug/l. Because the stream use assessment upon which the assessessment of support of the Class B(LR) aquatic life uses is based is more than 5 years old, the assessment category was downsgraded from "monitored" to "evaluated" as per U.S. EPA's Section 305(b) guidelines.
Assessment Key Dates
Methods
| 330 | Fish surveys |
| 375 | Visual observation-- may not quantify some parameters-- single season-- by prof. |
| 150 | Monitoring data more than 5 years old |
Monitoring Levels
| Biological | 3 |
| Habitat | 3 |
| Physical Chemistry | 0 |
| Toxic | 0 |
| Pathogen Indicators | 0 |
| Other Health Indicators | 0 |
| Other Aquatic Life Indicators | 0 |
| # of Bio Sites | 0 |
| BioIntegrity | N/A |