Split Rock Reservoir
Split Rock Reservoir in Pipestone County, Minnesota has a water quality grade of F (Algae-prone). 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.
- Clarity
- 1.3 ft
- Typical in August
- 75°F
- Max depth
- 16 ft
- Area
- 96 acres
- Type
- Hypereutrophic
- Trend
- ↑ Improving
- Public access
- Yes
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Split Rock Reservoir →
Next lake in Pipestone County
Split Rock Reservoir is a 96-acre highly nutrient-loaded hypereutrophic lake in Pipestone County, Minnesota with a maximum depth of 16 feet. Water quality is graded F based on 2 sampling years through 2023. 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. 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.
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 1.3 ft of visibility. Phosphorus level: 241 µg/L. Chlorophyll-a: 47.5 µg/L. Trophic State Index: 75.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.3 ft | Not graded |
| Phosphorus | 241 µg/L | Poor |
| Chlorophyll-a (Algae) | 47.5 µg/L | Poor |
| Trophic State Index (TSI) | 75 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay 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 grade measures nutrients and algae, not lodging — cabins and rentals around Split Rock Reservoir are listed below.
Top-rated places to stay near Split Rock Reservoir
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Split Rock Reservoir typically sits around 75°F at the surface in August. 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.
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 →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 16 ft |
| Surface Area | 96 acres |
| Shoreline Length | 3.5 mi |
| Littoral Zone | 82% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Split Rock Reservoir
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2025-07-07 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 34.28 | 0.29 lb |
| White Sucker | 21.84 | 1.32 lb |
| OSS | 21.65 | 0.03 lb |
| Black Crappie | 17.18 | 0.19 lb |
| Common Carp | 11.81 | 1.94 lb |
| Yellow Perch | 6.09 | 0.22 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.
Black Bullhead
White Sucker
OSS
Black Crappie
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
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.1 m/yr | 2 |
| Phosphorus | ↓ Declining | +6 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -8.9 µg/L/yr | 2 |
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.
County Ranking
Ranked #1 of 1 lakes in Pipestone County
Nearby Lakes in Pipestone County
Frequently asked questions about Split Rock Reservoir
What is the water quality grade for Split Rock Reservoir?
- Split Rock Reservoir in Pipestone County, Minnesota has a water quality grade of F (Algae-prone). 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?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Split Rock Reservoir has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 47.5 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Split Rock Reservoir?
- Split Rock Reservoir typically sits around 75°F at the surface in August, 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.
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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)
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 size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder