Assessment Comments
Assessment remains based on results of routine chemical/physical water quality monitoring conducted at station M646.9X at Gordon’s Bay Landing from January 2002 through June 2006 by staff of the Upper Mississippi River Long-Term Resource Monitoring Program (LTRMP) at the Fayette field office.
Basis for Assessment
SUMMARY: The Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment. The Class B(WW1) aquatic life uses remain assessed (monitored) as "fully supporting" based on results of ambient chemical/physical water quality monitoring. Fish consumption uses remain "not assessed" due to the lack of recent fish contaminant monitoring in this river reach. The source of data used for this assessment is the results of routine chemical/physical water quality monitoring conducted at station M646.9X at Gordon’s Bay Landing from January 2002 through June 2006 by staff of the Upper Mississippi River Long-Term Resource Monitoring Program (LTRMP) at the Fayette field office.
EXPLANATION: The Class A1 uses were not assessed due to lack of information on levels of indicator bacteria in this reach of river.
The Class B(WW1) (aquatic life) uses remain assessed (monitored) as “fully supported” based on results of water quality monitoring from LTRMP station M646.9X at Gordon’s Bay Landing. Results of monitoring from 2002-06 at this station show no violations of Class B(WW1) water quality criteria for dissolved oxygen or for ammonia-nitrogen in the 51 samples collected. Two of the 73 samples (3%) collected violated the Class B(WW1) criterion for pH. The pH in the samples collected on April 23 and May 7, 2004 were both 9.3; these values exceed Iowa’s Class B(WW1) criterion of 9.0 pH units. According to U.S. EPA guidelines (U.S. EPA 1997b, page 3-17), however, a violation frequency of less than 10 % for conventional parameters such as pH does not suggest impairment of aquatic life uses. Thus, the results of water quality monitoring at this station suggest “full support” of the Class B(WW1) aquatic life uses. Notes: monitoring at station M646.9X ended in June 2006.
Fish consumption uses remain "not assessed" due to lack of recent fish tissue monitoring in this river reach.
