Iowa DNR
ADBNet

Water Quality Assessments

Impaired Waters List

South Skunk River IA 03-SSK-934

from the Ames Water Works dam in River Valley Park at Ames (S36 T84N R24W Story Co.) to the Co. Rd. at north line of S6 T85 R23W Story Co (approximately 1 mile NNE of Story City)

Assessment Cycle
2002
Result Period
1998 - 2000
Designations
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 03-SSK-0030_2
Overall Use Support
Threatened
Aquatic Life Use Support
Threatened
Fish Consumption
Fully
Documentation
Assessment Comments

Assessment is based on results of (1) IDNR city monitoring in 2000-01, (2) IDNR/UHL biological monitoring in 1997-98, and EPA/IDNR fish tissue monitoring in 1998.

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses remained assessed as "fully supported / threatened."  Fish consumption uses remain assessed as "fully supported."  The sources of data for this assessment include (1) the results of monthly monitoring from October 1999 through September 2001 at the IDNR ambient city monitoring station located upstream from Ames at the Sleepy Hollow canoe access (2) results of IDNR-UHL biological monitoring in 1997 and 1998, and (3) EPA/IDNR fish tissue monitoring in 1998.   EXPLANATION:  The Class B(WW) aquatic life uses remain assessed as "fully supported / threatened."  Monitoring at the IDNR ambient station upstream from Ames showed no violations of Class B(WW) water quality criteria for dissolved oxygen, pH, or ammonia-nitrogen in the 14 samples collected, for toxic metals in the 14 samples collected, and for pesticides and other toxic organic compounds in the six samples analyzed, during the 2000-2001 biennial period.   These results suggest full support of the Class B(WW) aquatic life uses.   Based, however, on the results of biological monitoring conducted by IDNR and UHL in 1997 and 1998, the assessment of the aquatic life uses of this river segment remain "fully supported / threatened" (see assessment developed for the 2000 report above).   Fish consumption remain assessed as "fully supported" based on results of U.S.  EPA/IDNR fish tissue (RAFT) monitoring conducted in 1998 near Story City (see assessment for the 2000 report).

Monitoring and Methods
Assessment Key Dates
9/18/2001 Fixed Monitoring End Date
10/7/1999 Fixed Monitoring Start Date
Methods
330 Fish surveys
380 Quan. measurements of instream parms-- channel morphology-- floodplain-- 1-2 seasons-- by prof
430 Sediment analysis
230 Fixed station physical/chemical (conventional plus toxic pollutants)
242 Non-fixed station physical/chemical (conv + toxicants during key seasons and flows)
260 Fish tissue analysis
315 Regional reference site approach
320 Benthic macroinvertebrate surveys
Monitoring Levels
Biological 4
Habitat 4
Physical Chemistry 4
Toxic 0
Pathogen Indicators 0
Other Health Indicators 0
Other Aquatic Life Indicators 0
# of Bio Sites 1
BioIntegrity Good
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Metals Overall Use Support Not Impairing
  • Municipal Point Sources
  • Not Impairing
Metals Aquatic Life Support Not Impairing
  • Municipal Point Sources
  • Not Impairing
Organic enrichment/Low DO Overall Use Support Not Impairing
  • Municipal Point Sources
  • Not Impairing
Organic enrichment/Low DO Aquatic Life Support Not Impairing
  • Municipal Point Sources
  • Not Impairing
Priority organics Overall Use Support Not Impairing
  • Municipal Point Sources
  • Not Impairing
Priority organics Aquatic Life Support Not Impairing
  • Municipal Point Sources
  • Not Impairing
Unionized Ammonia Overall Use Support Not Impairing
  • Municipal Point Sources
  • Not Impairing
Unionized Ammonia Aquatic Life Support Not Impairing
  • Municipal Point Sources
  • Not Impairing