Locke Lake
Locke Lake in Anoka County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 3 ft visibility. Phosphorus: 97 µg/L. Chlorophyll-a (algae): 20.9 µg/L. Surface area: 23 acres.
- Clarity
- 3 ft
- Typical in August
- 76°F
- Area
- 23 acres
- Type
- Eutrophic
- Trend
- → Stable
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Locke Lake →
Next lake in Anoka County
Locke Lake is a 23-acre productive, nutrient-rich eutrophic lake in Anoka County, Minnesota. Water quality is graded D based on 2 sampling years through 2024. Phosphorus level is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 22 other monitored lakes in Anoka County, Locke Lake ranks #18 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-07. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 3 ft of visibility. Phosphorus level: 97 µg/L. Chlorophyll-a: 20.9 µg/L. Trophic State Index: 64.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | Not graded |
| Phosphorus | 97 µg/L | Poor |
| Chlorophyll-a (Algae) | 20.9 µg/L | Poor |
| Trophic State Index (TSI) | 64 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Locke Lake
Compare lakeside cabins, hotels, and vacation rentals near Locke Lake in Anoka 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 Locke Lake are listed below.
Top-rated places to stay near Locke Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Locke Lake typically sits around 76°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 76°F) and coldest in Sep (about 67°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 22 field readings (2019–2024) via the EPA Water Quality Portal. See the full Locke Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 23 acres |
| Public Access | Yes |
No bathymetric survey has been published for Locke Lake, so its depth is not documented here.
Recreation & Access
- Brooklyn ParkPublic
Fishing Locke 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 Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Locke Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — LockePublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.014 m/yr | 3 |
| Phosphorus | ↑ Improving | -13.75 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +11.15 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Locke Lake is a man-made reservoir impounded by the Locke Lake (completed 1956), built primarily for recreation on the Rice Creek; concrete-type dam, 25 ft tall and 100 ft long.
- Surface area
- 23 ac
- Normal storage
- 200 ac-ft
- Max storage
- 320 ac-ft
- Drainage area
- 200 sq mi
- Hazard class
- Significant
- Owner
- City of Fridley
Source: USACE National Inventory of Dams, NID ID MN00396 · Operator website
EPA Impairment Status
Locke 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 MN02-0075-01 · Official waterbody report · Matched by proximity (2.9 km)
County Ranking
Ranked #18 of 23 lakes in Anoka County
Nearby Lakes With Higher Grades
Locke Lake holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Anoka County
Frequently asked questions about Locke Lake
What is the water quality grade for Locke Lake?
- Locke Lake in Anoka County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 3 ft visibility. Phosphorus: 97 µg/L. Chlorophyll-a (algae): 20.9 µg/L. Surface area: 23 acres.
Is Locke Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Locke Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 20.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Locke Lake?
- Locke Lake typically sits around 76°F at the surface in August, from 22 EPA Water Quality Portal field readings (2019–2024). That is a typical value for the month, not a live reading.
Are there boat ramps on Locke Lake?
- Locke Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Brooklyn Park. Public access is listed as yes.
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Where this data comes from
34 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA34 samples · 2021–2024
Analytical methods
- Field measurement/observation, generic method
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 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
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory