Minnesota lake · tribal assessment record
Perch Lake (South Basin)
Assessment decisions reported by Minnesota Chippewa Tribe, Minnesota (Fond du Lac Band) to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2024 reporting cycle.
- 449
- Assessed acres
- Lake, Wild Rice
- Water type
- Mesotrophic
- Reported trophic class
This waterbody in one line
Perch Lake (South Basin), a lake in Minnesota, is assessed as not supporting one or more designated uses, with one listed impairment cause in the Minnesota Chippewa Tribe (Fond du Lac Band)'s most recent Integrated Report cycle (2024). By assessed acreage it sits among the largest 10% by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (one listed cause vs 23,610 assessed lakes). Aquatic life is assessed as fully supporting.
- Not Supporting
- overall status
- P90
- Assessed size nationally
- P20
- Shorter cause list
- Fully Supporting
- aquatic life
Assessment verdicts are the Minnesota Chippewa Tribe (Fond du Lac Band)'s decisions as reported to EPA ATTAINS; PlainLakes renders them without modification.
A composite of this record's EPA ATTAINS designated-use verdicts, filed impairment count, and assessment currency, weighted and benchmarked against the national corpus of assessed active waterbodies. This is a water-quality standing, not a human-recreation or property-value judgment, and dimensions with no filed verdict drop out rather than count against the score.
How Perch Lake (South Basin) reads against the filed register
Paragraphs are selected by this unit's percentiles and use matrix: different lakes lead with different dimensions. Figures are ATTAINS / portal register arithmetic, not advice.
The signature stat: assessed size
The number that most separates Perch Lake (South Basin) nationally is assessed size: 448.9 acres, larger than 90% of the 38,628 lake-type units with an area on file.
All ruled-on uses pass
The filed use determinations for recreation, aquatic life are all Fully Supporting. Where an overall IR category still flags the unit, look at the cause list and report standing rather than treating the use row as empty.
Overall status: not supporting
The filer's overall status for Perch Lake (South Basin) is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Typical cause-list length
1 listed cause is a middle-tercile list length among assessed lake-type units. Look to IR category and use outcomes for the distinctive reading.
According to the U.S. Environmental Protection Agency's ATTAINS program, Minnesota carries 13,176 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Perch Lake (South Basin) without modification. See our methodology for reporting-unit limits and gauge linking rules.
The record
Designated-use assessments
Fully Supporting and Not Supporting are the Minnesota Chippewa Tribe (Fond du Lac Band)'s definitive verdicts; other entries mean the use was not conclusively assessed in this cycle. The latest monitoring the Minnesota Chippewa Tribe (Fond du Lac Band) filed against this record runs through 2024. For the definitive verdicts on this record, the Minnesota Chippewa Tribe (Fond du Lac Band) filed the assessment basis as Monitored Data. Those are EPA's own words, not PlainLakes' summary of them.
| Designated use | Group | Verdict |
|---|---|---|
| Aquatic Life: Warm Water Fisheries | Aquatic-life or related | Fully Supporting |
| Cultural: Wild Rice Areas | Cultural use | Fully Supporting |
| Recreation: Primary Contact Recreational | Recreation | Fully Supporting |
| Wildlife | Other | Not Supporting |
The record
Listed impairment causes
Causes the Minnesota Chippewa Tribe (Fond du Lac Band) listed as impairing designated uses of this lake, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Mercury | Wildlife | 2016 | TMDL priority: High |
Reading the record
Cleanup queue for Perch Lake (South Basin)
1 listed cause ranked High in the TMDL queue, still without a plan
The Minnesota Chippewa Tribe (Fond du Lac Band) ranked Mercury high in its TMDL development queue, and no cleanup plan is on file for that listing yet. That queue rank is the Minnesota Chippewa Tribe (Fond du Lac Band)'s own scheduling signal, not an EPA national rule.
A High ranking names a position in the state's plan-writing queue; it is not a measure of how impaired the water is. How listing and cleanup work.
Scale and rank
Perch Lake (South Basin) is one of 13,176 lake-type waterbodies reported to EPA from Minnesota, and one of 1,939 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 449 assessed acres it ranks 4,003rd by assessed size among the 38,628 lakes the dataset carries an area for, counting a state’s repeated filings of one water once, behind 4,002 lakes with a larger one.
Still unfiled
The Minnesota Chippewa Tribe (Fond du Lac Band) has not yet filed a definitive fish-consumption verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
Reported trophic class
Mesotrophic is the trophic class the filing agency reported to EPA ATTAINS for this assessment unit. It describes nutrient enrichment, not whether the water is safe, and it is not a PlainLakes inference. What the trophic scale measures.
In context
Where Perch Lake (South Basin) sits nationally
Assessed size among U.S. lakes
Distribution of assessed acreage across ATTAINS lakes filed with an area, counting a state’s repeated filings of one water once
449 Top 10% larger than 90% of 38,628 lakes
lakes the dataset carries an area for, counting a state’s repeated filings of one water once, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
Listed causes vs waterbodies carrying a verdict
How many impairment causes U.S. waterbodies with a reported verdict carry
1 Longer than most more listed causes than 49% of 23,610 waterbodies carrying a verdict
named waterbodies carrying a verdict, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
In both charts each bar is a band and taller bars hold more waterbodies; the dashed line and filled bar mark Perch Lake (South Basin). Hover or tap any bar for its full count and share.
In context
Minnesota context
ATTAINS carries 13,176 lake-type waterbodies in Minnesota, 1,798 assessed as not supporting at least one use and 1,566 fully supporting. Among the 1,939 indexed units there, Perch Lake (South Basin) ranks 784th by listed-cause count (one listed cause) and 595th by assessed size among the 1,930 with an area filed; it sits in the not-supporting set (1,798 statewide) . Its listed causes (Mercury) sit outside Minnesota's top-five list, which is led by Mercury in Fish Tissue.
| Other large assessed lakes in Minnesota | Assessed acres |
|---|---|
| Superior Not Supporting | 13,182,720 |
| Lake of the Woods Not Supporting | 301,348 |
| Red (Lower Red) Not reported | 164,699 |
| Lower Red Lake Fully Supporting | 164,689 |
| Mille Lacs Not Supporting | 128,076 |
| Red (Upper Red) Not Supporting | 119,279 |
Peers near Perch Lake (South Basin)'s size or cause load
Similar assessed acres
Nearest filed extents (449 acres here).
- Lake Mcleod · 449 acres · FL
- Friends Lake · 449 acres · NY
- Lake Maitland · 449 acres · FL
- Newcomb Lake · 450 acres · NY
Similar cause load
Nearest listed-cause counts (1 here). Peers already in the acreage column are omitted.
- Aaron River Reservoir · 1 causes · MA
- Abbotts Creek (including Lexington-Thomasville Water Supply Reservoir at normal reservoir elevation, Tom-A-Lex Lake) · 1 causes · NC
- Abeniki Lake · 1 causes · NH
- Academy Brook II Dam · 1 causes · NH
What to do with this record
- Assessment verdicts are cycle-based, not real-time. For fish-consumption decisions, your state advisory program is the binding source. Consumption status guide
- Impairment listings follow the Clean Water Act 303(d) process; a listing is a regulatory finding, not a closure notice. 303(d) explained
PlainLakes renders state assessment decisions and federal gauge observations without modification. It does not issue advisories.
Assessment decisions on this page are rendered directly from state Integrated Report records in EPA's ATTAINS system; gauge figures are daily-value observations from the USGS National Water Information System, no number is typed in by an editor. Overall status, use verdicts, and causes are the Minnesota Chippewa Tribe (Fond du Lac Band)'s reported decisions for assessment unit FDL_114B. Counts and percentiles are computed across all lake-type records PlainLakes ingests from ATTAINS. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-08-17. Primary sources: EPA ATTAINS and USGS National Water Information System.