Silver Lake
Olmsted County, MinnesotaLimited DataEutrophic
On the LakeGrade rubric Silver Lake fails the cutoffs — a TSI of 67 and persistent algal pressure put it in the bottom tier.
At a TSI of 67, Silver Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Silver Lake is a shallow lake at 11 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. The lake is compact at 50 acres, with 3.0 miles of shoreline and little volume to buffer nutrient inputs. Silver Lake ranks 4 of 5 in Olmsted County — at the lower end of the locally monitored distribution.
No invasive species are currently listed at Silver Lake — the lake remains off the Minnesota infested-waters roster. Bass fishing is part of the appeal: the species list runs to 13, anchored by largemouth and/or smallmouth bass. Public access is available — the lake is on the Minnesota PCA public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-31. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 2 ft of visibility. Trophic State Index: 67.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 67 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 11 ft |
| Average Depth | 2 ft |
| Surface Area | 50.41 acres |
| Shoreline Length | 3 mi |
| Littoral Zone | 100% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Silver Lake (14-day solunar calendar)
→ Is it safe to eat fish from Silver Lake? (mercury & PFAS guide)
→ Silver Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.098 m/yr | 5 |
Location
County Ranking
Ranked #4 of 5 lakes in Olmsted County
Cleaner Lakes Within 30 Miles
Silver Lake holds Grade F. 2 nearby lakes hold higher grades.
Nearby Lakes in Olmsted County
More Minnesota Lake Rankings
State Parks Near Silver Lake
Other Grade F Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
11 surveys on file from MN DNR Fisheries. Most recent: 2007-07-30 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| White Sucker | 48.00 | 0.67 lb |
| Golden Redhorse | 23.57 | 0.68 lb |
| Largemouth Bass | 19.50 | 0.61 lb |
| White Crappie | 15.08 | 0.21 lb |
| CSH | 13.92 | 0.13 lb |
| Black Crappie | 12.76 | 0.19 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.
White Sucker
Golden Redhorse
Largemouth Bass
White Crappie
From the 2007-07-30 survey
Silver Lake is a 34-acre impoundment of the South Fork Zumbro River located within the city of Rochester, MN. The impoundment is created by a dam, owned and operated by Rochester Public Utilities (RPU). Water quality in the reservoir is affected by sediment deposition from upstream sources and urban runoff. Water…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Silver Lake. 2 reports on file.
- —Fisheries Lake Survey — SilverFisheries Lake Survey · MN DNR LakeFinder
- —Public Water Access Sites — SilverPublic Water Access Sites · MN DNR LakeFinder
Reservoir Info (USACE NID)
Silver Lake is a man-made reservoir impounded by the Silver Lake (completed 1935), built primarily for recreation on the Zumbro River South Fork; gravity-type dam, 30 ft tall and 251 ft long.
- Surface area
- 58 ac
- Normal storage
- 215 ac-ft
- Max storage
- 400 ac-ft
- Drainage area
- 234 sq mi
- Hazard class
- Significant
- Owner
- City of Rochester
Source: USACE National Inventory of Dams, NID ID MN00515 · Operator website
EPA Impairment Status
Silver 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 MN55-0003-00 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Most recent sample: 2024-10-31
Monitoring stations: 1