Lower Orono Lake
Lower Orono Lake in Sherburne County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2.5 ft visibility. Phosphorus: 138 µg/L. Chlorophyll-a (algae): 76 µg/L. Maximum depth: 18 ft. Surface area: 300.5 acres.
- Clarity
- 2.5 ft
- Typical in August
- 70°F
- Max depth
- 18 ft
- Area
- 301 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 11
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Lower Orono Lake →
Next lake in Sherburne County
Lower Orono Lake is a 301-acre highly nutrient-loaded hypereutrophic lake in Sherburne County, Minnesota with a maximum depth of 18 feet (3-foot average). Water quality is graded F based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 18 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 17 other monitored lakes in Sherburne County, Lower Orono Lake ranks #18 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Very murky, less than 2.5 ft of visibility. Phosphorus level: 138 µg/L. Chlorophyll-a: 76 µg/L. Trophic State Index: 71.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.5 ft | Not graded |
| Phosphorus | 138 µg/L | Poor |
| Chlorophyll-a (Algae) | 76 µg/L | Poor |
| Trophic State Index (TSI) | 71 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Lower Orono Lake
Compare lakeside cabins, hotels, and vacation rentals near Lower Orono Lake in Sherburne 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Lower Orono Lake are listed below.
Top-rated places to stay near Lower Orono Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Lower Orono Lake typically sits around 70°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 77°F) and coldest in May (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 10 field readings (2024–2025) via the EPA Water Quality Portal. See the full Lower Orono Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 18 ft |
| Average Depth | 3.1 ft |
| Surface Area | 301 acres |
| Shoreline Length | 12.2 mi |
| Littoral Zone | 94% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Babcock Memorial ParkPublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Lower Orono 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.
DNR Fisheries Survey Summary
5 surveys on file from MN DNR Fisheries. Most recent: 2021-05-03 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Smallmouth Bass | 12.89 | 0.98 lb |
| Black Bullhead | 12.89 | 0.41 lb |
| Yellow Perch | 9.17 | 0.21 lb |
| White Sucker | 5.33 | 1.28 lb |
| Black Crappie | 4.88 | 0.28 lb |
| White Crappie | 4.84 | 0.19 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Smallmouth Bass
Black Bullhead
Yellow Perch
White Sucker
From the 2021-05-03 survey
Orono Lake is a 281-acre reservoir formed by a dam on the Elk River in the City of Elk River in Sherburne County. Orono Lake has a maximum depth of 18 feet and there is a public access on the west side of the lake in a city park. The reservoir has had issues with sediment deposition from the Elk River over the years…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Lower Orono Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OronoFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — OronoFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — OronoPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.078 m/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (6 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2007-03-30 (2007) | 2008-04-17 (2008) |
| Ice-In | 2007-11-27 (2007) | 2006-11-30 (2006) |
Most recent ice-out: 2022-04-10
Reservoir Info (USACE NID)
Lower Orono Lake is a man-made reservoir impounded by the Elk River (completed 1916), built primarily for recreation on the Elk River; gravity-type dam, 23 ft tall and 207 ft long.
- Surface area
- 300 ac
- Normal storage
- 1,600 ac-ft
- Max storage
- 2,800 ac-ft
- Drainage area
- 234 sq mi
- Hazard class
- High
- Owner
- City of Elk River
Source: USACE National Inventory of Dams, NID ID MN00516 · Operator website · Matched by proximity (0.12 km)
EPA Impairment Status
Lower Orono Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN71-0013-02 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Lower Orono Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Elk River WwtpElk River · 1.4 mi away · NPDES MN0020788MajorRecent violation
- Great River EnergyHelen, Township Of · 1.4 mi away · NPDES MN0001988
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #18 of 18 lakes in Sherburne County
Nearby Lakes With Higher Grades
Lower Orono Lake holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Sherburne County
Frequently asked questions about Lower Orono Lake
What is the water quality grade for Lower Orono Lake?
- Lower Orono Lake in Sherburne County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 2.5 ft visibility. Phosphorus: 138 µg/L. Chlorophyll-a (algae): 76 µg/L. Maximum depth: 18 ft. Surface area: 300.5 acres.
Is Lower Orono Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Lower Orono Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 76 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Lower Orono Lake?
- Lower Orono Lake typically sits around 70°F at the surface in August, from 10 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Lower Orono Lake?
- Lower Orono Lake has a maximum depth of 18 feet and an average depth of 3.1 feet. The lake covers 300.5 acres.
What fish are in Lower Orono Lake?
- Fish species found in Lower Orono Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), channel catfish, common carp, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, shorthead redhorse, silver redhorse, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Lower Orono Lake is located in Sherburne County, Minnesota.
When does Lower Orono Lake thaw?
- Lower Orono Lake typically has ice-out around Apr 11.
Are there boat ramps on Lower Orono Lake?
- Lower Orono Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Babcock Memorial Park. Public access is listed as yes.
Explore Lower Orono Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
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Species activity outlook by water temperature and season
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Where this data comes from
40 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
MNPCA40 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate