Marlu Lake
Pope County, Minnesota320 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Marlu Lake. Here is what has been measured.
- zebra mussel
- 62 ft max depth
- Limited data
Marlu Lake in Pope County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Surface area: 320 acres.
Marlu Lake is a 320-acre lake in Pope County, Minnesota with an estimated average depth of about 62 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-11. Methodology: how these readings are compared.
What Marlu Lake is good for
From access and monitoring records, not editorial picks.
- Ice seasonIce-out around Apr 10
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Marlu Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Marlu Lake
These are the measurements Minnesota PCA publishes for Marlu Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4 ft. TSI 57.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 57 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Marlu Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Marlu Lake typically sits around 78°F at the surface in August. Summer average is about 75°F. Usually warmest in Aug (about 78°F) and coldest in Jun (about 71°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (71°F) to its warmest (78°F).
Typical surface water temperature by month, from 19 field readings (2010–2025) via the EPA Water Quality Portal. See the full Marlu Lake water temperature breakdown →
Lake Details
Max depth
~62 ft est.
Surface area
320 acres
Public access
No
Listed by Minnesota PCA
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Marlu Lake.
Lake Size & Watershed
Watershed (drainage) area
56 sq mi
HydroLAKES / HydroSHEDS
Shoreline
3.1 mi
HydroLAKES / HydroSHEDS
Elevation
1,319 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Marlu Lake
Compare lakeside cabins, hotels, and vacation rentals near Marlu Lake in Pope County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Marlu Lake
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Fishing Marlu Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving6 years
Ice season
Typical ice-out
Apr 10
Earliest Mar 14, 2024 · Latest May 1, 2018
Typical ice-in
Nov 27
Earliest Nov 1, 2018 · Latest Jan 3, 2024
Most recent ice-out
Apr 7
2025
27 observations · Minnesota PCA ice records
Reservoir Info (USACE NID)
Marlu Lake is a man-made reservoir impounded by the Marlu Mill Pond (completed 1967), built primarily for recreation on the Chippewa River E Branch; earth-type dam, 20 ft tall and 600 ft long.
- Surface area
- 320 ac
- Normal storage
- 995 ac-ft
- Max storage
- 2,184 ac-ft
- Drainage area
- 59 sq mi
- Hazard class
- Low
- Owner
- Morton, John
Source: USACE National Inventory of Dams, NID ID MN00896 · Operator website
Nearby Lakes in Pope County
Frequently asked questions about Marlu Lake
Where is Marlu Lake?
- Marlu Lake is a lake in Pope County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Marlu Lake?
- Marlu Lake in Pope County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4 ft visibility. Surface area: 320 acres.
Is Marlu Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Marlu Lake?
- Marlu Lake typically sits around 78°F at the surface in August, from 19 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Marlu Lake?
- No published bathymetric survey covers Marlu Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 62 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 320 acres.
When does Marlu Lake thaw?
- Marlu Lake typically has ice-out around Apr 10. Ice typically forms around Nov 27. The open water season is approximately 231 days.
Can I fish at Marlu Lake?
- Public access to Marlu Lake is listed as no on the lake record, so confirm before you make the trip. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Marlu Lake across LakeQuality
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Where this data comes from
72 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA72 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate