Pool of Lake St Croix
Pool of Lake St Croix in Washington County, Minnesota has a water quality grade of C (Fair). Water clarity: 4.3 ft visibility. Phosphorus: 39.2 µg/L. Maximum depth: 78 ft. Surface area: 8393.04 acres.
Minnesota DNR surveys at Pool of Lake St Croix average 4.97 smallmouth bass per unit of sampling effort (CPUE) across 18 surveys. The most recent is a Standard Survey dated October 21, 2024. Length samples in the latest survey that recorded them ran 5–19 inches. DNR survey details →
- Clarity
- 4.3 ft
- Max depth
- 78 ft
- Area
- 8,393 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
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Pool of Lake St Croix is a 8,393-acre productive, nutrient-rich eutrophic lake in Washington County, Minnesota with a maximum depth of 78 feet. Water quality is graded C based on 1 sampling years through 2024. Overall water quality is declining over recent sampling years. The lake supports 36 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 1 public boat landing. Compared to the 74 other monitored lakes in Washington County, Pool of Lake St Croix ranks #30 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-29. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Murky, only visible to about 4.3 ft. Phosphorus level: 39.2 µg/L. Trophic State Index: 57.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.3 ft | Not graded |
| Phosphorus | 39.2 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 57 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Pool of Lake St Croix
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Minnesota DNR surveys at Pool of Lake St Croix average 4.97 smallmouth bass per unit of sampling effort (CPUE) across 18 surveys. The most recent is a Standard Survey dated October 21, 2024. Length samples in the latest survey that recorded them ran 5–19 inches.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Pool of Lake St Croix C from EPA Water Quality Portal chemistry, and the water-quality trend over 5 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
18 surveys on file from MN DNR Fisheries. Most recent: 2024-10-21 (Standard Survey).
Top Species by Catch Rate
| Species | Avg catch rate (CPUE) | Avg Weight |
|---|---|---|
| Smallmouth Bass | 4.97 | 0.9 lb |
| Common Carp | 4.04 | 4.74 lb |
| Freshwater Drum | 2.99 | 0.61 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE means more abundant in standardized sampling. This is not a weekly bite report.
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
Common Carp
Freshwater Drum
From the 2024-10-21 survey
A gill net survey was conducted on Lake St. Croix in 2024 and sampled 970 fish represented by 28 different species and one hybrid. Over 51% of the fish sampled were considered game fish species (those species which have defined creel limits). Composition of the top five game fish species sampled were 29.8% Yellow…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Pool of Lake St Croix. 2 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — St. CroixFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — St. CroixFish Stocking History · MN DNR LakeFinder
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 78 ft |
| Surface Area | 8,393 acres |
| Shoreline Length | 124.5 mi |
| Public Access | Yes |
Recreation & Access
- Bayport - Lakeside ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Pool of Lake St Croix
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: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.011 m/yr | 5 |
| Phosphorus | ↓ Declining | +6.49 µg/L/yr | 5 |
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Pool of Lake St Croix 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.
- Xcel Energy - Allen S King Generating PlantOak Park Heights · 1 mi away · NPDES MN0000825MajorRecent violation
- Andersen CorpBayport · 0.6 mi away · NPDES MN0001724
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 #30 of 75 lakes in Washington County
Nearby Lakes in Washington County
Frequently asked questions about Pool of Lake St Croix
Where is Pool of Lake St Croix?
- Pool of Lake St Croix is a lake in Washington County, Minnesota. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Pool of Lake St Croix?
- Pool of Lake St Croix in Washington County, Minnesota has a water quality grade of C (Fair). Water clarity: 4.3 ft visibility. Phosphorus: 39.2 µg/L. Maximum depth: 78 ft. Surface area: 8393.04 acres.
Is Pool of Lake St Croix safe to swim in?
- Generally safe for swimming, moderate water quality. Pool of Lake St Croix has a water quality grade of C (Fair). Always check local health department advisories before swimming.
How deep is Pool of Lake St Croix?
- Pool of Lake St Croix has a maximum depth of 78 feet. The lake covers 8393.04 acres.
What fish are in Pool of Lake St Croix?
- Fish species found in Pool of Lake St Croix include bigmouth buffalo, black bullhead, black crappie, bluegill, channel catfish, common carp, flathead catfish, freshwater drum, gizzard shad, golden redhorse, highfin carpsucker, hybrid sunfish, lake sturgeon, largemouth bass, longnose gar, mooneye, muskellunge, northern pike, paddlefish, quillback, river carpsucker, river redhorse, rock bass, sauger, shorthead redhorse, shortnose gar, silver redhorse, smallmouth bass, smallmouth buffalo, spotted sucker, walleye, walleye/sauger, white bass, white crappie, white sucker, yellow perch. Pool of Lake St Croix is located in Washington County, Minnesota.
What did the DNR fisheries survey find at Pool of Lake St Croix?
- Minnesota DNR surveys at Pool of Lake St Croix average 4.97 smallmouth bass per unit of sampling effort (CPUE) across 18 surveys. The most recent is a Standard Survey dated October 21, 2024. Length samples in the latest survey that recorded them ran 5–19 inches. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Pool of Lake St Croix C from EPA Water Quality Portal chemistry, and the water-quality trend over 5 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Pool of Lake St Croix?
- Pool of Lake St Croix has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Bayport - Lakeside Park. Public access is listed as yes.
Explore Pool of Lake St Croix across LakeQuality
Depth, room, public access, and the state wake-sport rules
4 mi away · 45 ft
Fish species and top-graded lakes across Minnesota
Fish species and best lakes in Washington County
Species activity outlook by water temperature and season
Where to stay at Minnesota's top lakes, each with its grade
Lakes in the St. Croix Watershed, ranked by water quality
High nutrients, frequent algae, reduced clarity
Minnesota's cleanest and most-polluted lakes, ranked
More Minnesota Lake Rankings
State Parks Near Pool of Lake St Croix
Other Grade C Lakes in Minnesota
Eutrophic Lakes in Minnesota
Compare Pool of Lake St Croix With Nearby Lakes
Where this data comes from
68 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- National Park Service Water Resources Division
11NPSWRD_WQX68 samples · 2020–2024
Analytical methods
- Secchi Disk
- Alkaline Persulfate Digestion for Total N and P in Water
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory