Walnut Creek IA 02-IOW-708
mouth (S31 T82N R12W Benton Co.) to confluence with North Walnut Cr in S7 T81N R13W Poweshiek Co. trib S24T81NR15W Poweshiek Co.
- Cycle
- 2026
- Current Phase
- Public Comment
- Overall IR
- 2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
- Trend
- Improving
- Trend Comment
- Biological data indicate improvement and led to a delisting of a Category 5b Class BWW2 impairment.
- Created
- 10/27/2025 3:09:24 PM
- Updated
- 12/1/2025 3:32:15 PM
| Cycle Added | Class | Cause | Data Source | Rationale |
|---|---|---|---|---|
| 2006 | Class BWW2 | Biological: low aquatic macroinvertebrate IBI | Biological monitoring: Iowa DNR WQMA | New data: recovery of fish/invertebrate community |
The Class BWW2 use was assessed as “fully supported” based on biological sampling data. The previous Class BWW2 Category 5b impairment was delisted. All other designated uses were "not assessed."
Data Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 BIO See Below 359 Walnut Creek Belle Plaine – REMAP
#73 Site ID Date Drainage Area (mi2) Ecoregion Major Drainage BM Sample Gear BMIBI score BMIBI Class 47f BMIBI BIT BMIBI Pass/Fail 359 8/14/24 84.1 47f MS Art Sub 52 Fair 51 Pass 359 8/10/22 84.1 47f MS Art Sub 29 Poor 51 Fail 359 8/24/20 84.1 47f MS Art Sub 52 Fair 51 Pass Site ID Date Drainage Area (mi2) Ecoregion Major Drainage Riffle Stream? FIBI score FIBI Class 47f FIBI BIT FIBI Pass/Fail 359 8/14/24 84.1 47f MS NA 48 Fair 36 Pass 359 8/10/22 84.1 47f MS NA 56 Good 36 Pass 359 8/24/20 84.1 47f MS NA 42 Fair 36 Pass Community Assessment Type Assessment Result Support Level IR Category Reason Benthic
Macroinvertebrates Monitored Pass (2/3) Full Fish Monitored Pass (3/3) Full Assessment was
monitored because the samples used for Overall Monitored Pass Full 1 the assessment were
collected in a recent five year period. Site ID Data Source ID # Days Monitoring (2020) DO Criteria Type # 2020 violations / Violations needed for impairment Violates Annual Significantly >10% Rule? Assessment Type Support Level 24 hr 0/4 No 359 6 13 16 hr 0/4 No Evaluated Full
Presumptive Class A1 – No Data
Class BWW2 - Biological Sampling:
Benthic Macroinvertebrates:
Fish:
Overall:
Class BWW2 - Continuous DO Monitoring: