ADBNet

Assessment Comments

Assessment remains based on results of (1) IDNR/UHL biological (REMAP) sampling in 2002 [(evaluated): FIBI = 33 (fair)] and (2) U.S. EPA/IDNR fish tissue (RAFT) monitoring in 2000.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses are “not assessed” due to the lack of monitoring data upon which to base an assessment.   The Class B(WW) aquatic life uses are assessed (evaluated) as “fully supported” based on results of IDNR/UHL biological (REMAP) monitoring in 2002.   Fish consumption uses remain assessed (monitored) as "fully supported" based on results of U.S.  EPA/IDNR fish contaminant (RAFT) monitoring in 2000.  

EXPLANATION:  Routine water quality monitoring is not conducted in this river segment; thus, data upon which to base assessments of the Class A uses are not available.  

The Class B(WW) aquatic life uses are assessed (evaluated) as “fully supported” based on results of IDNR/UHL biological (REMAP) monitoring in 2002.   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 2002 FIBI score was 33 (fair), which is slightly above the reference condition goal of 32 (fair) for non-riffle stream habitats.   The aquatic life uses were assessed (evaluated) as fully supported (=FS), based on a comparison of the FIBI score with biological impairment criteria (BIC) established from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004.   The non-riffle FIBI BIC for this ecoregion is 32.   This assessment is considered evaluated because the drainage area (2229 mi2) above this sampling site was greater than the maximum limit (500 mi2) that was used to calibrate the Iowa wadeable stream impairment criteria.   Even though this site passed the FIBI BIC, it is uncertain as to whether or not this segment is meeting the aquatic life criteria because it doesn’t fall in the calibrated watershed size.   Several game fish species and species considered sensitive to stream degradation were present in the fish survey.

Fish consumption uses were assessed (monitored) as “fully supported” based on results of U.S.EPA/IDNR fish contaminant (RAFT) monitoring near Adel in 2000.   The composite samples of fillets from channel catfish had low levels of contaminants.   The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of the degree to which Iowa’s lakes and rivers support their fish consumption uses.   Prior to 2006, IDNR used action levels published by the U.S Food and Drug Administration to determine whether consumption advisories should be issued for fish caught as part of recreational fishing in Iowa.   In an effort to make Iowa’s consumption more compatible with the various protocols used by adjacent states, the Iowa Department of Public Health, in cooperation with Iowa DNR, developed a risk-based advisory protocol.   This protocol went into effect in January 2006 (see http://www.iowadnr.gov/fish/news/consump.html for more information on Iowa’s revised fish consumption advisory protocol).   Because the revised (2006) protocol is more restrictive than the previous protocol based on FDA action levels; fish contaminant data that previously suggested “full support” may now suggest either a threat to, or impairment of, fish consumption uses.   This scenario, however, does not apply to the fish contaminant data generated from the 2000 RAFT sampling conducted in this segment of the North Raccoon River:  the levels of contaminants do not exceed any of the new (2006) advisory trigger levels, thus suggesting no justification for issuance of a consumption advisory for this waterbody.