East Fork Wapsipinicon River IA 01-WPS-412
from confluence with unnamed tributary in NE 1/4 S36 T96N R13 W (Chickasaw Co.) to headwaters in SE 1/4 SE 1/4 S26 T97N R13W Chickasaw Co.
- Cycle
- 2018
- Release Status
- Final
- Overall IR
- 3 - Insufficient data exist to determine whether any designated uses are met.
- Trend
- Unknown
- Created
- 4/25/2019 9:43:08 AM
- Updated
- 4/25/2019 9:46:44 AM
The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment. The presumptive Class B(WW1) aquatic life uses are assessed (evaluated) as “partially supported” based on results of DNR/SHL biological sampling conducted in 2010 and 2014.
The assessment of the presumptive Class B(WW1) aquatic life uses was based on data collected in 2010and 2014 as part of the DNR/SHL stream biocriteria project. A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the biocriteria sampling data. The biological metrics are based on the numbers and types of benthic macroinvertebrate taxa and fish species that were collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (FIBI) and a benthic macroinvertebrate index (BMIBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2010 and 2014 FIBI scores were 54 and 57 (both good). The 2010 and 2014 BMIBI scores were 33 and 41 (both fair). This segment passed the FIBI BIC 2/2 times and passed the BMIBI BIC 0/2 times in the last five years. The aquatic life use support was assessed as partially supporting (=PS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008. The non-riffle habitat FIBI BIC for this ecoregion is 44 and the artificial substrate BMIBI BIC for this ecoregion is 52. Even though this passedthe FIBI BIC and failed the BMIBI BIC, it is uncertain as to whether or not this segment is meeting the aquatic life criteria because it is a small headwater stream and doesn’t fall in the calibrated watershed size.
Prior to the changes in Iowa’s surface water classification that were approved by U.S.EPA in February 2008, this stream was classified only for general uses due to the inability of the stream to support a viable aquatic community at low-flow conditions. DNR’s existing biological assessment protocol, however, was calibrated to aquatic life reference conditions in larger wadeable streams with perennial flow. The aquatic environment of most headwater streams is one of extremes in water quality. Consequently, intermittent headwater streams tend to have biological diversity that is low relative to more stable aquatic environments of larger streams with perennial flow. Thus, the use of biological assessment methods developed for the ecologically more stable and diverse streams will likely overstate the existence of impairment in headwater streams.