Split Rock Reservoir
Pipestone County, Minnesota96 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Split Rock Reservoir. Here is what has been measured.
- Hypereutrophic
- 16 ft max depth
- Public access
Split Rock Reservoir in Pipestone County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 241 µg/L. Chlorophyll-a (algae): 47.5 µg/L. Maximum depth: 16 ft. Surface area: 95.79 acres.
Minnesota DNR's Standard Survey on July 7, 2025 caught 1.00 northern pike per gill net at Split Rock Reservoir. DNR survey details →
Split Rock Reservoir is a 96-acre highly nutrient-loaded hypereutrophic lake in Pipestone County, Minnesota with a maximum depth of 16 feet. Overall water quality is improving over recent sampling years. The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-09-11. Methodology: how these readings are compared.
Split Rock Reservoir covers about 96 acres in Pipestone County. Vrbo is where to look for cabins and lake homes around Split Rock Reservoir, and Booking.com and Expedia search hotels near the lake for your dates.
What Split Rock Reservoir is good for
From access and monitoring records, not editorial picks.
- Fishing12 species recorded
Swimming conditions
Readings onlyAlgae risk
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Split Rock Reservoir 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 Split Rock Reservoir
These are the measurements Minnesota PCA publishes for Split Rock Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.3 ft of visibility. Phosphorus 241 µg/L. Chlorophyll-a 47.5 µg/L. TSI 75.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 241µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 47.5µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 75 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Split Rock Reservoir
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Split Rock Reservoir typically sits around 70°F at the surface in September. Summer average is about 74°F. Usually warmest in Jul (about 77°F) and coldest in May (about 53°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (53°F) to its warmest (77°F).
Typical surface water temperature by month, from 38 field readings (2022–2023) via the EPA Water Quality Portal. See the full Split Rock Reservoir water temperature breakdown →
Minnesota DNR's Standard Survey on July 7, 2025 caught 1.00 northern pike per gill net at Split Rock Reservoir.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Split Rock Reservoir’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2025-07-07 (Standard Survey).
9 surveys on file · most recent 2025-07-07 (Standard Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Bullhead | 34.28 | 4–12 in 2025-07-07 | 0.29 lb |
| White Sucker | 21.84 | 4–17 in 2025-07-07 | 1.32 lb |
| Black Crappie | 17.18 | 4–11 in 2025-07-07 | 0.19 lb |
| Common Carp | 11.81 | 8–22 in 2025-07-07 | 1.94 lb |
| Yellow Perch | 6.09 | 6–8 in 2025-07-07 | 0.22 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and 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.
Black Bullhead
White Sucker
Black Crappie
Common Carp
From the 2025-07-07 survey
Split Rock Lake is an impoundment created by a dam on Split Rock Creek constructed in 1938. This reservoir is located entirely within the boundaries of Split Rock State Park near Ihlen in Pipestone County. It has a surface area of 80 acres, a maximum depth of 16 feet, Secchi depth of 2.5 feet, and is a class 42 lake.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Split Rock Reservoir. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Split Rock ReservoirFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — Split Rock ReservoirFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Split Rock ReservoirPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
16 ft
Surface area
96 acres
Shoreline
3.5 mi
Littoral zone
82%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
33 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,621 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Split Rock Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Split Rock Reservoir in Pipestone 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Split Rock Reservoir are listed below.
Top-rated places to stay near Split Rock Reservoir
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
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Fish Species
Click a species to see every lake where it is documented.
Fishing Split Rock Reservoir
- → Split Rock Reservoir fishing: DNR survey catch rates, species & stocking
- → Split Rock Reservoir fishing forecast & best times (species outlook + 14-day solunar calendar)
- → Split Rock Reservoir fishing regulations (limits, seasons, special rules)
- → Is it safe to eat fish from Split Rock Reservoir? (mercury & PFAS guide)
Water quality readings over time
2 seasons of samples on record (2022–2023). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Phosphorus
Worsening+6 µg/L/yr2 years
Chlorophyll-a
Improving-8.9 µg/L/yr2 years
Reservoir Info (USACE NID)
Split Rock Reservoir is a man-made reservoir impounded by the Splitrock Lake (completed 1937), built primarily for recreation on the Split Rock Creek-TR; rockfill-type dam, 35 ft tall and 300 ft long.
- Surface area
- 80 ac
- Normal storage
- 360 ac-ft
- Max storage
- 540 ac-ft
- Drainage area
- 31 sq mi
- Hazard class
- Significant
- Owner
- MNDNR-Parks
Source: USACE National Inventory of Dams, NID ID MN00100 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Split Rock Reservoir under Clean Water Act (NPDES) discharge permits.
- Erik BaustianJasper · 2.3 mi away · NPDES MN0071676
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.
Nearby Lakes in Pipestone County
Frequently asked questions about Split Rock Reservoir
Where is Split Rock Reservoir?
- Split Rock Reservoir is a lake in Pipestone County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Split Rock Reservoir?
- Split Rock Reservoir in Pipestone County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.3 ft visibility. Phosphorus: 241 µg/L. Chlorophyll-a (algae): 47.5 µg/L. Maximum depth: 16 ft. Surface area: 95.79 acres.
Is Split Rock Reservoir 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 Split Rock Reservoir?
- Split Rock Reservoir typically sits around 70°F at the surface in September, from 38 EPA Water Quality Portal field readings (2022–2023). That is a typical value for the month, not a live reading.
How deep is Split Rock Reservoir?
- Split Rock Reservoir has a maximum depth of 16 feet. The lake covers 95.79 acres.
What fish are in Split Rock Reservoir?
- Fish species found in Split Rock Reservoir include black bullhead, black crappie, bluegill, channel catfish, common carp, green sunfish, hybrid sunfish, northern pike, orangespotted sunfish, pumpkinseed, white sucker, yellow perch. Split Rock Reservoir is located in Pipestone County, Minnesota.
What did the DNR fisheries survey find at Split Rock Reservoir?
- Minnesota DNR's Standard Survey on July 7, 2025 caught 1.00 northern pike per gill net at Split Rock Reservoir. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Split Rock Reservoir’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Split Rock Reservoir?
- Public access to Split Rock Reservoir is listed as yes on the lake record. 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 Split Rock Reservoir across LakeQuality
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Species activity outlook by water temperature and season
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Where this data comes from
30 measurements from 2 monitoring stations, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA30 samples · 2022–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder