Unnamed Tributary to Twelvemile Creek IA 05-GRA-6584
from mouth (T73N R30W Sec17 Union Co.) to dam at pond (T73N R30W Sec18 Union Co.)
- Cycle
- 2020
- Release Status
- Final
- Overall IR
- 3 - Insufficient data exist to determine whether any designated uses are met.
- Trend
- Unknown
- Created
- 9/30/2020 2:28:54 PM
- Updated
- 10/9/2020 10:41:37 AM
The presumptive Class BWW1 use remains assessed as “partially supported” due to violations of the dissolved oxygen criterion. All other designated uses were "not assessed". This assessment is considered evaluated (of lower confidence)—and thus not appropriate for Section 303(d) listing—for three reasons: (1) the Iowa DNR IR methodology requires that at least 10 samples be collected over the three-year assessment period in order to develop a “monitored” (i.e., higher confidence) assessment that is appropriate for Section 303(d) listing, (2) all violations of dissolved oxygen criteria occurred in this headwater stream segment in the exceptionally warm and dry mid-to late summer period of 2012, and (3) this stream is fed by a farm pond whose dam is approximately 650 feet upstream from this monitoring location and flow out of this pond in the near drought conditions of summer 2012 was highly unlikely.
Data
Sources: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 WQ CY 2012 13880007 Unnamed Creek at 140 St Site 12m-7 Presumptive
Class A1 - No Data Presumptive
Class BWW1 - Conventional Parameters: Site ID Data Source ID Parameter Name # Samples / # Years Maximum Value Mean Value Median Value # Acute / Chronic Violations % Acute/ Chronic Violations Significantly >10% Violations Assessment Type Support Level 13880007 6 Ammonia 7 / 1 4.7 1.71 1.2 0 / 2 0% / 29% NA Evaluated Full 13880007 6 Dissolved oxygen 8 / 1 8.5 4 3.3 NA / 5 NA / 62% Yes Evaluated Partial 13880007 6 pH 8 / 1 8.5 7.4 7.4 2 / NA 25% / NA NA Evaluated Full 13880007 6 Temperature 8 / 1 27.5 24 24.8 0 / 0 0% / 0% No Evaluated Full