What is the water quality grade for Qacmainstdup Lake?

Qacmainstdup Lake in Mercer County, Wisconsin received a water quality grade of B (Good). Phosphorus: 10 µg/L. Chlorophyll-a (algae): 11 µg/L. Surface area: 133000 acres.

Is Qacmainstdup Lake safe to swim in?

Good for swimming, clear water with low algae levels. Qacmainstdup Lake has an overall water quality grade of B. Algae concentration (chlorophyll-a) is 11 µg/L. Always check local health department advisories before swimming.

Qacmainstdup Lake

Mercer County, WisconsinMesotrophic

Qacmainstdup Lake is a 133,000-acre mesotrophic lake in Mercer County, ND. Water quality is graded B based on 2 sampling years through 2020. Compared to the 4 other monitored lakes in Mercer County, Qacmainstdup Lake ranks #4 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2020-10-20. Grade methodology: LakeGrade methodology.

Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

No clarity data. Phosphorus level: 10 µg/L. Chlorophyll-a: 11 µg/L. Trophic State Index: 46.

Metric	Value	Grade
Water Clarity (Secchi Depth)	No data
Phosphorus	10 µg/L	A
Chlorophyll-a (Algae)	11 µg/L	C
Trophic State Index (TSI)	46	Mesotrophic

Moderate nutrients, good water quality

Lake Details

Characteristic	Value
Surface Area	133.0K acres

Location

Loading map…

County Ranking

Ranked #4 of 5 lakes in Mercer County

Cleaner Lakes Within 30 Miles

Qacmainstdup Lake holds Grade B. 3 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Mercer County

More Wisconsin Lake Rankings

Cleanest lakes in Wisconsin

Top 25 by overall water quality score

Best swimming lakes in Wisconsin

Grade A/B + low algae filter

Family fishing lakes in Wisconsin

Panfish-rich, public access

All Wisconsin lakes

Full state directory

Other Grade B Lakes in Wisconsin

Lake Ashtabula

Barnes County · Clarity: 3.4 ft

Lake Ashtabula

Barnes County · Clarity: 6.6 ft

Garlk1481dw Lake

McKenzie County · Clarity: 5.9 ft

Mt Carmel Dam Lake

Cavalier County · Clarity: 7.9 ft

Garlk1445dw Lake

McLean County · Clarity: 11.7 ft

Gordon Center Lake

Rolette County · Clarity: 8.2 ft

Mesotrophic Lakes in Wisconsin

Lake Ashtabula Garlk1481dw Lake Lake Upsilon Red Willow Lake

Reservoir Info (USACE NID)

Qacmainstdup Lake is a man-made reservoir impounded by the Garrison Dam (completed 1953), built primarily for hydroelectric on the MISSOURI RIVER; earth-type dam, 210 ft tall and 11,300 ft long.

Surface area: 133,000 ac
Normal storage: 18,500,000 ac-ft
Max storage: 26,000,000 ac-ft
Drainage area: 180,940 sq mi
Hazard class: High
Owner: USACE - Omaha District

All listed purposes: Hydroelectric;Irrigation;Navigation;Recreation;Flood Risk Reduction.

Source: USACE National Inventory of Dams, NID ID ND00145 · Operator website · Matched by proximity (0.09 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2020-10-20

Monitoring stations: 1