Is Rkcrk 4 Lake Polluted?
Yes — Rkcrk 4 Lake in Jasper County, Iowa is on the EPA's Clean Water Act 303(d) impaired-waters list (2024 assessment cycle). It is cited for Algal growth, Turbidity. A formal cleanup plan — a Total Maximum Daily Load (TMDL) — has been written. "Impaired" is a legal designation, separate from the lake's A–F water-quality grade: it means at least one designated use (such as swimming, aquatic life, or fish consumption) does not meet state standards for the listed pollutant.
EPA 303(d) Listing
| On 303(d) impaired list | Listed impaired |
| Cleanup plan (TMDL) | Completed |
| Assessment cycle | 2024 |
| EPA IR category | 4A |
| Location | Jasper County, Iowa |
Pollutants Cited
- Algal growth — listed by EPA as exceeding water-quality standards for at least one designated use.
- Turbidity — listed by EPA as exceeding water-quality standards for at least one designated use.
Specific parameters in the EPA record: CHLOROPHYLL-A, TURBIDITY.
What this means for using Rkcrk 4 Lake
Review the EPA assessment and any state advisories before relying on Rkcrk 4 Lake for swimming, fishing, or other uses. An impairment listing does not mean the lake is closed — most impaired lakes remain open for boating and swimming. It means a specific pollutant exceeds a standard for a specific use. Rkcrk 4 Lake carries an overall water-quality grade of F — see the full breakdown on the lake report. The official EPA assessment is available in the ATTAINS waterbody report.