Assessment Comments
Assessment is based on results of (1) USGS/NAWQA monitoring of water quality (1998-2001) and (2) occurrence of fish kills in the watershed.
Basis for Assessment
SUMMARY: The Class B(WW) aquatic life uses remain assessed as "fully supported / threatened;" the fish consumption uses are "not assessed." The sources of information for this assessment include (1) results of monitoring conducted on South Fork Iowa River 2 miles northeast of New Providence from October 1998 to September 2001 by USGS as part of the National Water Quality Assessment Program (NAWQA) (eastern Iowa river basins study unit, station 05451210) and (2) the history of fish kills in this watershed (see above). EXPLANATION: The assessment of support of the Class B(WW) uses for the 2002 report is based (1) on The USGS / NAWQA monitoring that showed (1) no violations of Class B(WW) water quality criteria for pH, dissolved oxygen, or ammonia-nitrogen in the 33 samples collected from October 1998 through September 2001and (2) no violations of the Class B(WW) chronic water quality criterion for pesticides in the 33 samples analyzed during this period. Although these results suggest full support of aquatic life uses, the watershed of the South Fork Iowa River has a history of repeated fish kills, often in the upper reaches of the stream. Despite the lack of fish kills in this lower reach of the South Fork Iowa River during October 1999-September 2001 biennial period, fish kills continue to occur in this watershed (for example, a fish kill attributed to animal waste occurred in the headwaters of this stream on September 6, 2001). Thus, based on results of USGS monitoring and on the history of fish kills in this watershed, the Class B(WW) aquatic life uses remain assessed as "fully supported / threatened." Fish consumption uses are not assessed due the lack of recent fish contaminant monitoring in this river segment. The previous assessment of fish consumption uses for this river segment ("fully supported") was based on results of the USGS/NAWQA fish tissue monitoring in September 1995 (see assessment for the 1998 report above). These data are now considered too old (greater than five years) for characterizing current water quality conditions.
