English Creek IA 04-LDM-1057
mo to Long Branch S16T74NR20W MarionCo
- Cycle
- 2020
- Release Status
- Final
- Overall IR
- 5 - Water is impaired or threatened and a TMDL is needed.
- Trend
- Unknown
- Created
- 9/11/2020 9:19:20 AM
- Updated
- 10/16/2020 12:04:38 PM
The Class BWW2 use remains assessed as “not supported” based on biological sampling data. All other designated uses were "not assessed".
Sources of
Data: Data Source Data Source ID Data Type Data Age Site ID Site Name Site Description Iowa DNR 6 BIO See Below 507 English Creek Knoxville – REMAP #160 Presumptive Class A1 - No Data Class
BWW2 - Biological Sampling: Benthic
Macroinvertebrates: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/Thermal BM Sample Gear BMIBI score BMIBI Class 40a BMIBI BIT BMIBI Pass/ Fail 507 8/14/14 74 40a MS/WW ArtSub 24 Poor 41 Fail 507 9/11/13 74 40a MS/WW ArtSub 22 Poor 41 Fail 507 8/1/13 74 40a MS/WW ArtSub 17 Poor 41 Fail Fish: BioNet Site ID Date Drainage Area (mi2) Ecoregion Major Drainage/Thermal Riffle Stream? FIBI score FIBI Class 40a FIBI BIT FIBI Pass/ Fail 507 8/14/14 74 40a MS/WW NA 17 Poor 33 Fail 507 9/11/13 74 40a MS/WW NA 0 Poor 33 Fail Overall: Community Assessment Type Assessment Result Support Level Earned IR Category Actual IR Category Reason Benthic
Macroinvertebrates Evaluated Fail (0/3) Not Fish Evaluated Fail (0/2) Not Overall Evaluated Fail Not 3bc 5bv Assessment
is evaluated because it included samples not collected in the last five years. Class
BWW2 – Continuous Monitoring Assessment: Continuous monitoring data from 2013 and 2014 were examined for DO and stream temperature criteria violations. The lowest DO concentration recorded in 53 days of continuous monitoring was 2.3 mg/L. The daily DO minimum concentration failed to meet the 24-hour DO criterion (4 mg/L) in 4 of 53 days and the 16-hour DO criterion (5 mg/L) in 2 of 53 days. The 2013 and 2014 combined percentage exceeding the 24-hour DO criterion (7.5%) was slightly less than (passing) the 10% impairment threshold used to assess conventional water quality parameters; however, the associated statistical analysis confidence level was not high (<90%). The 2013 and 2014 combined percentage exceeding the 16-hour DO criterion (3.8%) was less than (passing) the 10% impairment threshold; however, the associated statistical analysis confidence level was not high (<90%). The maximum stream temperature recorded during the sensor deployment period was 31.2 degrees (C). The temperature criterion for warmwater interior streams (32 C) was exceeded in 0 of 53 days. The percentage exceeding (0%) was less than (passing) the 10% impairment threshold with high statistical confidence (>90%). Based on these data, the BWW1 aquatic life use was assessed as not impaired by DO and temperature. The DNR’s continuous monitoring assessment methodology specifies that the frequency of violations must exceed the 10% threshold with greater than 90% statistical confidence in order to assess the aquatic life use as impaired. The assessment type is considered as “monitored” because the data meet the minimum requirements of the DNR’s continuous monitoring assessment methodology. Because of the contradictory results showing DO violations in the first year (2013) and not the second year of monitoring (2014), additional continuous monitoring of DO and temperature is strongly recommended.