ADBNet

The assessment of the Class B(CW1) aquatic life uses was based on data collected in 2007 as part of the DNR/SHL coldwater stream sampling project. A series of biological metrics which reflect coldwater 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 that were collected in the stream sampling reach. The biological metrics were combined to make a coldwater benthic index (CBI). The index ranks the biological integrity of a coldwater stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2007 CBI score was 64.The aquatic life use support was assessed (evaluated) as fully supporting (=FS), based on a comparison of the CBI score with biological impairment criteria (BIC) established for the 2012 Section 305(b) report.The biological impairment criteria were determined from a statistical analysis of data collected at coldwater stream reference sites from 1994-2011.The CW BIC is 60 and this segment passed the CW BIC 1/1 times in 2007.

This aquatic life assessment is 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 asingle sample collected in 2007 and the biological sampling data are greater than five years old.

In addition, based on an updated summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau in January 2019, the Class B(CW1) uses are assessed as "fully supported". According to the updated summary, Smith Creek (aka Trout River) is in the group of Iowa coldwater streams that supports natural reproduction of trout. Based on results of surveys by the DNR Fisheries Bureau, this stream is placed in the category of Iowa trout streams that exhibit fairly consistent natural reproduction and maintain a viable population of brown trout without any stocking (Category I segment) and exhibits some natural reproduction of rainbow trout (Category II segment).

The Class A1 (primary contact recreation) uses, Class A2 (secondary contact recreation) uses and Class HH (fish consumption) uses remain "not assessed" due to the lack of information upon which to base an assessment.