Twin Springs Creek IA 01-UIA-273
mouth (S17 T98N R8W Winneshiek Co.) to springs in Twin Springs Parks (S20 T98N R8W Winneshiek Co.)
- Assessment Cycle
- 2020
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 10/1/2020 9:36:12 AM
- Updated
- 10/15/2020 10:59:19 AM
Assessment Summary
The presumptive Class A1 use remains assessed as “partially supported” due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The presumptive Class A2 use remains assessed as “fully supported” based on water quality monitoring data. The Class BCW1 use remains assessed as "fully supported" based on the trout reproduction in Iowa streams summary prepared by the DNR Fisheries Bureau and water quality monitoring data. All other designated uses are “not assessed”.
Assessment Explanation
Sources
of Data: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2010-2011 15960030 Dry Run Creek Watershed Site 18 Presumptive
Class A1 - Indicator Bacteria: Historical Site ID Data Source ID # Samples / # Years 2010 Geometric Mean 2011 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 15960030 6 29 / 2 200 361 Yes 13 45% Yes Evaluated Partial Presumptive
Class A2 - Indicator Bacteria: Historical Site ID Data Source ID # Samples / # Years 2010 Geometric Mean 2011 Geometric Mean Annual Geometric Mean Violation # Violations % Violations Significantly >10% Violations Assessment Type Support Level 15960030 6 29 / 2 200 361 No 5 17% No Evaluated Full Class
BCW1 - Conventional Parameters: Historical Site ID Data Source ID Parameter Name # Samples / # Years Minimum Value # Acute / Chronic Violations % Acute/ Chronic Violations Significantly >10% Violations Assessment Type Support Level 15960030 6 Ammonia 30 / 2 NA 0 / 0 0% / 0% No Evaluated Full 15960030 6 Dissolved oxygen 32 / 2 4.2 NA / 2 NA / 6% No Evaluated Full 15960030 6 pH 30 / 2 NA 0 / NA 0% / 0% No Evaluated Full 15960030 6 Temperature 30 / 2 NA 0 / 0 0% / 0% No Evaluated Full Class
BCW1 – Trout Natural Reproduction: Based on the January 2020
trout reproduction in Iowa streams summary prepared by the DNR Fisheries
Bureau, the Class BCW1 coldwater aquatic life use of Twin Springs Creek was
assessed as "fully supported". According to the updated summary, this
stream was placed in Category I: streams that exhibit consistent natural
reproduction and maintain a wild population of one or more trout species without
any stocking. Class
HH - No Data
Assessment Key Dates
4/21/2010 | Fixed Monitoring Start Date |
10/10/2011 | Fixed Monitoring End Date |
1/1/2020 | Biological Monitoring |
Methods
120 | Surveys of fish and game biologists/other professionals |
220 | Non-fixed station physical/chemical monitoring (conventional pollutant only) |
330 | Fish surveys |
420 | Indicator bacteria monitoring |