Pierz Lake
Pierz Lake in Morrison County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 18 µg/L. Chlorophyll-a (algae): 5.6 µg/L. Maximum depth: 34 ft. Surface area: 189.21 acres.
- Clarity
- 9.5 ft
- Typical in August
- 76°F
- Max depth
- 34 ft
- Area
- 189 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 15
- Open water
- 224 days
Next lake in Morrison County
Pierz Lake is a 189-acre mesotrophic lake in Morrison County, Minnesota with a maximum depth of 34 feet (20-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 16 documented fish species including bigmouth buffalo, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 7 other monitored lakes in Morrison County, Pierz Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-24. 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 9.5 ft. Phosphorus level: 18 µg/L. Chlorophyll-a: 5.6 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.5 ft | Not graded |
| Phosphorus | 18 µg/L | Good |
| Chlorophyll-a (Algae) | 5.6 µg/L | Good |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Pierz Lake
Compare lakeside cabins, hotels, and vacation rentals near Pierz Lake in Morrison 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.
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Water Temperature
Pierz Lake typically sits around 76°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in Oct (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 35 field readings (2022–2025) via the EPA Water Quality Portal. See the full Pierz Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 34 ft |
| Average Depth | 20 ft |
| Surface Area | 189 acres |
| Shoreline Length | 3.3 mi |
| Littoral Zone | 34% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Pierz LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Pierz Lake
DNR Fisheries Survey Summary
14 surveys on file from MN DNR Fisheries. Most recent: 2022-06-08 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Largemouth Bass | 31.67 | 0.75 lb |
| Bluegill | 20.43 | 0.16 lb |
| Yellow Perch | 13.35 | 0.15 lb |
| Yellow Bass | 4.60 | 0.93 lb |
| Black Crappie | 2.99 | 0.26 lb |
| Walleye | 2.89 | 1.79 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.
Largemouth Bass
Bluegill
Yellow Perch
Yellow Bass
From the 2022-06-08 survey
A targeted survey was completed June 8-14 to assess size structure of Bluegill and Black Crappie. Previous spring trap netting occurred in 2005, 2011 and 2014. In 2020, sampling was canceled due to Covid 19 restrictions. General observations suggest Bluegill and crappie size structure may be increasing as proportions…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Pierz Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — PierzFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Pierz (1929)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — PierzFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — PierzPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.288 m/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (164 observations).
Estimated open water season: 224 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-20 (2012) | 2013-05-07 (2013) |
| Ice-In | 1991-11-04 (1991) | 2015-12-26 (2015) |
Most recent ice-out: 2025-03-29
Reservoir Info (USACE NID)
Pierz Lake is a man-made reservoir impounded by the Pierz Lake (completed 1955), built primarily for fish and wildlife pond on the Platte River-TR; gravity-type dam, 8 ft tall and 118 ft long.
- Surface area
- 189 ac
- Normal storage
- 3,200 ac-ft
- Max storage
- 3,900 ac-ft
- Drainage area
- 4.4 sq mi
- Hazard class
- Low
- Owner
- MNDNR-Fisheries
Source: USACE National Inventory of Dams, NID ID MN00715 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Pierz Lake under Clean Water Act (NPDES) discharge permits.
- Rich Prairie Sewer Treatment FacilityPierz · 3.9 mi away · NPDES MN0063657
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 #7 of 8 lakes in Morrison County
Nearby Lakes in Morrison County
Frequently asked questions about Pierz Lake
What is the water quality grade for Pierz Lake?
- Pierz Lake in Morrison County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.5 ft visibility. Phosphorus: 18 µg/L. Chlorophyll-a (algae): 5.6 µg/L. Maximum depth: 34 ft. Surface area: 189.21 acres.
Is Pierz Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Pierz Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 5.6 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Pierz Lake?
- Pierz Lake typically sits around 76°F at the surface in August, from 35 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Pierz Lake?
- Pierz Lake has a maximum depth of 34 feet and an average depth of 20 feet. The lake covers 189.21 acres.
What fish are in Pierz Lake?
- Fish species found in Pierz Lake include bigmouth buffalo, black crappie, bluegill, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white crappie, white sucker, yellow bullhead, yellow perch. Pierz Lake is located in Morrison County, Minnesota.
When does Pierz Lake thaw?
- Pierz Lake typically has ice-out around Apr 15. Ice typically forms around Nov 25. The open water season is approximately 224 days.
Are there boat ramps on Pierz Lake?
- Pierz Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Pierz Lake. Public access is listed as yes.
Explore Pierz Lake across LakeGrade
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Where this data comes from
41 measurements from 1 monitoring station, 2022–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA41 samples · 2022–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
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 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