What is the water quality grade for Big Creek Lake?

Big Creek Lake in Polk County, Wisconsin received a water quality grade of F (Very Poor). Water clarity: 2.6 ft visibility. Chlorophyll-a (algae): 35.7 µg/L. Surface area: 885 acres.

Is Big Creek Lake safe to swim in?

Avoid swimming, very poor water quality, potential algae toxins. Big Creek Lake has an overall water quality grade of F. Algae concentration (chlorophyll-a) is 35.7 µg/L. Always check local health department advisories before swimming.

Big Creek Lake

Polk County, WisconsinEutrophic

Big Creek Lake is a 885-acre productive, nutrient-rich eutrophic lake in Polk County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 11 other monitored lakes in Polk County, Big Creek Lake ranks #5 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-30. Grade methodology: LakeGrade methodology.

Swimming Safety

Avoid swimming, very poor water quality, potential algae toxins

Water Quality Grade: F, Very Poor

Very murky, less than 2.6 ft of visibility. Chlorophyll-a: 35.7 µg/L. Trophic State Index: 64.

Metric	Value	Grade
Water Clarity (Secchi Depth)	2.6 ft	F
Phosphorus	No data
Chlorophyll-a (Algae)	35.7 µg/L	F
Trophic State Index (TSI)	64	Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

Characteristic	Value
Surface Area	885 acres

Location

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County Ranking

Ranked #5 of 12 lakes in Polk County

Cleaner Lakes Within 30 Miles

Big Creek Lake holds Grade F. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Polk County

More Wisconsin Lake Rankings

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Top 25 by overall water quality score

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Grade A/B + low algae filter

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Panfish-rich, public access

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Other Grade F Lakes in Wisconsin

Arrowhead Lake

Pottawattamie County · Clarity: 1.8 ft

White Oak Lake

Mahaska County · Clarity: 1.4 ft

Crystal Lake Max Depth

Hancock County · Clarity: 1.6 ft

Hannen Lake

Benton County · Clarity: 1.2 ft

Briggs Woods Lake

Hamilton County · Clarity: 1.5 ft

Union Grove Lake

Tama County · Clarity: 1.6 ft

Eutrophic Lakes in Wisconsin

Storm Lake Max Depth Lost Island Lake Nodaway Lake Arrowhead Lake

Reservoir Info (USACE NID)

Big Creek Lake is a man-made reservoir impounded by the Big Creek Diversion Dam (completed 1970), built primarily for flood risk reduction on the BIG CREEK; gravity-type dam, 80 ft tall and 1,750 ft long.

Surface area: 885 ac
Normal storage: 7,600 ac-ft
Max storage: 27,500 ac-ft
Drainage area: 76 sq mi
Hazard class: High
Owner: USACE - Rock Island District

Source: USACE National Inventory of Dams, NID ID IA00014 · Operator website

EPA Impairment Status

Big Creek Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Algal growthPathogens (E. coli, fecal)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit IA 04-UDM-1242 · Official waterbody report

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Most recent sample: 2024-09-30

Monitoring stations: 1