Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Twelve Mile Creek Lake IA 05-GRA-1367

Union County S12T72NR30W approx 4 mi E of Creston.

Assessment Cycle
1998
Result Period
1994 - 1996
Designations
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 05-GRA-01320-L_0
Overall Use Support
Threatened
Aquatic Life Use Support
Threatened
Fish Consumption
Fully
Primary Contact Recreation
Not assessed
Drinking Water
Threatened
Documentation
Assessment Comments

Basis for Assessment

Used assessments of support developed for the 1994 and 1996 reports for the Class B(LW) aquatic life uses (=FST), and Class C drinking water uses (=FST).   Due to lack of information, continue to not assess support of the Class A primary contact recreation uses.   Based on results of the sampling for the 1996 Regional Ambient Fish Tissue (RAFT) monitoring program, assessed support of fish consumption uses as fully supporting:  levels of all contaminants in the composite samples of fillets of crappie and channel catfish were below 1/2 of the respective FDA action levels.   In the March/April 1998 Iowa Conservationist, Twelvemile Lake was identified as one of the best fishing lakes in southwest Iowa, with excellent populations of bluegill, largemouth bass, walleye/saugeye, and channel catfish.

Monitoring and Methods
Assessment Key Dates
7/14/1996 Biological Monitoring
Methods
340 Primary producer surveys (phytoplankton/periphyton/macrophyton)
120 Surveys of fish and game biologists/other professionals
222 Non-fixed-station monitoring (conventional during key seasons and flows)
260 Fish tissue analysis
270 PWS chemical monitoring (ambient water)
Monitoring Levels
Biological 0
Habitat 0
Physical Chemistry 3
Toxic 0
Pathogen Indicators 0
Other Health Indicators 0
Other Aquatic Life Indicators 0
# of Bio Sites 0
BioIntegrity N/A
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Nutrients Overall Use Support Not Impairing
  • Agriculture
  • Natural Sources
  • Not Impairing
  • Not Impairing
Nutrients Aquatic Life Support Not Impairing
  • Agriculture
  • Natural Sources
  • Not Impairing
  • Not Impairing
Nutrients Primary Contact Recreation Not Impairing
  • Agriculture
  • Natural Sources
  • Not Impairing
  • Not Impairing
Siltation Overall Use Support Not Impairing
  • Agriculture
  • Natural Sources
  • Not Impairing
  • Not Impairing
Siltation Aquatic Life Support Not Impairing
  • Agriculture
  • Natural Sources
  • Not Impairing
  • Not Impairing