Silver Lake IA 01-MAQ-17

Delaware County S16T88NR4W SE edge of Delhi.

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

Evaluated

Integrated Report

Category 0

Trophic

Hypereutrophic

Trend

Degrading

Legacy ADBCode

IA 01-MAQ-00680-L_0

Overall Use Support

Not supporting

Aquatic Life Use Support

Not supporting

Fish Consumption

Not assessed

Primary Contact Recreation

Not assessed

Documentation

Assessment Comments

Monitoring conduced in 1990 by ISU as part of Clean Lakes Classification Study.

Basis for Assessment

As recommended by the DNR Fisheries Bureau, downgraded the level of support of the Class B(LW) aquatic life uses from PS to NS. According to the DNR Fisheries biologist, water quality of this lake has declined over the last ten years due to agricultural and urban nonpoint sources that have led to problems with nuisance growth of aquatic plants. Aquatic life has been severely impaired due to both summer and winter oxygen depletion. Presently, bullheads are the only fish species able to survive.

Monitoring and Methods

Assessment Key Dates

Methods

120	Surveys of fish and game biologists/other professionals

Monitoring Levels

Biological	0
Habitat	0
Physical Chemistry	0
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	High	Agriculture Internal nutrient cycling (primarily lakes) Natural Sources Sediment resuspension Urban Runoff/Storm Sewers	High Moderate Slight Moderate Moderate
Nutrients	Aquatic Life Support	High	Agriculture Internal nutrient cycling (primarily lakes) Natural Sources Sediment resuspension Urban Runoff/Storm Sewers	High Moderate Slight Moderate Moderate
Nutrients	Primary Contact Recreation	High	Agriculture Internal nutrient cycling (primarily lakes) Natural Sources Sediment resuspension Urban Runoff/Storm Sewers	High Moderate Slight Moderate Moderate
Organic enrichment/Low DO	Overall Use Support	High	Agriculture Internal nutrient cycling (primarily lakes) Natural Sources Urban Runoff/Storm Sewers	High Moderate Slight Moderate
Organic enrichment/Low DO	Aquatic Life Support	High	Agriculture Internal nutrient cycling (primarily lakes) Natural Sources Urban Runoff/Storm Sewers	High Moderate Slight Moderate
Algal Grwth/Chlorophyll a	Overall Use Support	Moderate	Internal nutrient cycling (primarily lakes)	Moderate
Algal Grwth/Chlorophyll a	Aquatic Life Support	Moderate	Internal nutrient cycling (primarily lakes)	Moderate
Algal Grwth/Chlorophyll a	Primary Contact Recreation	Moderate	Internal nutrient cycling (primarily lakes)	Moderate
Noxious aquatic plants	Overall Use Support	Moderate	Source Unknown	Moderate
Noxious aquatic plants	Primary Contact Recreation	Moderate	Source Unknown	Moderate
Suspended solids	Primary Contact Recreation	Moderate	Sediment resuspension	Moderate