Assessment Comments
Assessment is based on results of (1) USGS/NAWQA water quality monitoring near Powersville from 1996-98, (2) IDNR-UHL ambient monthly monitoring from 2000-02, and (3) information on intermittency of this stream.
Basis for Assessment
SUMMARY: The Class B(LR) aquatic life uses remain assessed (evaluated) as "fully supported / threatened" due to naturally-occurring problems with flow stability (i.e., intermittency). Sources of data for this assessment include results of (1) IDNR/UHL ambient water quality monitoring from 2000 through 2002 and (2) USGS/NAWQA ambient water quality monitoring from 1996 to 1998.
EXPLANATION: The Class B(LR) aquatic life uses are assessed (monitored) as “fully supported” based on information that this stream is prone to intermittency; the causes of this intermittency are believed to be naturally-occurring. Despite this problem, results of ambient water quality monitoring conducted by IDNR/UHL near Greene, Iowa, from October 2000 through December 2002 suggest “full support” of the Class B(LR) aquatic life uses. Due to the intermittency of this stream, only 12 samples were collected during this three-year period. None of the 12 samples collected violated state criteria for dissolved oxygen, temperature, pH, or ammonia-nitrogen; none of the 4samples analyzed for pesticides contained levels above state criteria. Similarly, the results of water quality monitoring conducted on Flood Creek near Powersville (Floyd County) from March 1996 to September 1998 by USGS as part of the National Water Quality Assessment Program (NAWQA) (eastern Iowa river basins study unit, station 05461390) suggest “full support” of the Class B(LR) uses. Results of monitoring conducted near Greene in from October 2000 to September 2001 as part of the IDNR ambient monitoring network (STORET station 10340002) show no violations of Class B(LR) water quality criteria for conventional parameters and ammonia-nitrogen in the seven monthly samples collected or for pesticides in the 4 samples analyzed. Thus, the monitoring conducted by both IDNR and USGS suggest that, when Flood Creek has sufficient water, the water quality is relatively good.
