Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Arbor Lake IA 03-NSK-864

Poweshiek County S20T80NR16W W edge of Grinnell

Assessment Cycle
2000
Result Period
1996 - 1998
Designations
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 03-NSK-00330-L_0
Overall Use Support
Not supporting
Aquatic Life Use Support
Threatened
Fish Consumption
Not assessed
Primary Contact Recreation
Not supporting
Documentation
Assessment Comments

Assessment is based on results of water quality monitoring and surveys by IDNR Fisheries Bureau.

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation uses) remained assessed as "not supported."  Continued to assess support of the Class B(LW) aquatic life uses as "fully supported / threatened."  Fish consumption uses were "not assessed."  EXPLANATION:  The level of support of the Class A (primary contact recreation) uses remained assessed as "not supporting."  This assessment remains based upon the statement from Bachmann et al.  (1994) that swimming is prohibited at this lake due to poor water quality (see assessment developed for the 1994 report above).   The previous (1998) assessment of support of the Class B(LW) uses ("fully supported / threatened") was reviewed and approved by the DNR Fisheries Bureau in 2000.   The level of support of fish consumption uses was changed from "not supported" to "not assessed" due to the lack of fish contaminant monitoring at this lake.   See accounts in Bachmann et al.  (1980) and Bachmann et al.  (1994) for more information on water quality problems at Arbor Lake.

Monitoring and Methods
Assessment Key Dates
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
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
Algal Grwth/Chlorophyll a Overall Use Support Moderate
  • Internal nutrient cycling (primarily lakes)
  • Moderate
Algal Grwth/Chlorophyll a Primary Contact Recreation Moderate
  • Internal nutrient cycling (primarily lakes)
  • Moderate
Nutrients Overall Use Support Moderate
  • Agriculture
  • Internal nutrient cycling (primarily lakes)
  • Natural Sources
  • Urban Runoff/Storm Sewers
  • Moderate
  • Moderate
  • Slight
  • High
Nutrients Aquatic Life Support Moderate
  • Agriculture
  • Internal nutrient cycling (primarily lakes)
  • Natural Sources
  • Urban Runoff/Storm Sewers
  • Moderate
  • Moderate
  • Slight
  • High
Nutrients Primary Contact Recreation Moderate
  • Agriculture
  • Internal nutrient cycling (primarily lakes)
  • Natural Sources
  • Urban Runoff/Storm Sewers
  • Moderate
  • Moderate
  • Slight
  • High
Siltation Overall Use Support Moderate
  • Agriculture
  • Natural Sources
  • Urban Runoff/Storm Sewers
  • Moderate
  • Slight
  • High
Siltation Aquatic Life Support Moderate
  • Agriculture
  • Natural Sources
  • Urban Runoff/Storm Sewers
  • Moderate
  • Slight
  • High