Arbor Lake IA 03-NSK-864

Poweshiek County S20T80NR16W W edge of Grinnell

This is a Legacy Assessment. Prior to 2004, assessments were developed under a methodology that pre-dated the Integrated Report guidelines.

Assessment Cycle

1998

Result Period

1994 - 1996

Designations

Assessment Type

Monitored

Integrated Report

Category 0

Trophic

Hypereutrophic

Trend

Stable

Legacy ADBCode

IA 03-NSK-00330-L_0

Overall Use Support

Not supporting

Aquatic Life Use Support

Threatened

Fish Consumption

Not supporting

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

Continued to use the assessment of support of the Class A primary contact recreation uses (=NS), the Class B(LW) aquatic life uses (=FST), and the fish consumption uses (=NS) developed for the 1994 report. Previous Section 305(b) assessments were reviewed and approved by the DNR Fisheries Bureau. This list was placed on the 1998 list of Section 303(d) waters at the recommendations of the DNR Fisheries and Water Quality bureaus.

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