East Otter Creek IA 02-CED-515
mouth (S7 T84N R7W Linn Co.) to confluence with unnamed tributary in S16 T85N R7W Linn Co.
- Assessment Cycle
- 2018
- Release Status
- Final
- Data Collection Period
- Overall IR Category
- 2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
- Trend
- Unknown
- Created
- 5/13/2019 12:40:59 PM
- Updated
- 5/13/2019 12:41:59 PM
The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment. The Class B(WW2) aquatic life uses remain assessed (evaluated) as "fully supported" based on results of DNR/SHL biological sampling in 2002.
The Class B(WW2) aquatic life uses remain assessed (evaluated) as "fully supporting" based on data collected in 2002 as part of the DNR/SHL REMAP project. A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the biological 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 2002 FIBI scores were 45 (fair), 56 (good) and the BMIBI score was 78 (excellent). The aquatic life use support was assessed as fully supporting (=FS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004. The non-riffle habitat FIBI BIC for this ecoregion is 44 and the natural substrate BMIBI BIC for this ecoregion is 70. This segment passed the FIBI BIC 2/2 times and passed the BMIBI BIC 1/1 times in 2002. This aquatic life assessment is now considered "evaluated" based on a change in the 2010 DNR assessment methodology. DNR now requires a segment have two or more biological samples collected from the segment in multiple years over a five-year period to be considered “monitored”. This segment had multiple FIBI samples collected in 2002; however, the multiple samples were not collected during a five-year period and were not collected in multiple years. Additionally, because these data are now considered too old (greater than five years) to accurately characterize current water quality conditions, the assessment category is considered “evaluated” (indicating an assessment with relatively lower confidence) as opposed to "monitored" (indicating an assessment with relatively higher confidence). Despite this change in assessment methodology and type, this waterbody remains in IR Category 2a.