Minnesota lake · state assessment record
Trillium
Assessment decisions reported by Minnesota to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2015 reporting cycle.
- 150
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Trillium, a lake in Minnesota, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2015). By assessed acreage it sits in the upper quartile by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (one listed cause vs 23,610 assessed lakes). Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P77
- Assessed size nationally
- P20
- Shorter cause list
- Not Supporting
- fish consumption
Assessment verdicts are the state agency'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 Trillium 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 Trillium nationally is assessed size: 150 acres, larger than 77% of the 38,628 lake-type units with an area on file.
The uses disagree
This record splits: Not Supporting on fish consumption, Fully Supporting on recreation. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Trillium: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Trillium. The remaining work is implementation and tracking, read the cleanup-standing and cause rows for what the state already committed to address.
Overall status: not supporting
The filer's overall status for Trillium 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 Trillium 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 state's definitive verdicts; other entries mean the use was not conclusively assessed in this cycle.
| Designated use | Group | Verdict |
|---|---|---|
| Aquatic Consumption | Fish-consumption or fishery | Not Supporting |
| Aquatic Recreation | Recreation | Fully Supporting |
The record
Listed impairment causes
Causes the state 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 in Fish Tissue | Aquatic Consumption | 2002 | TMDL approved |
Reading the record
Trillium: Category 4A reading
4A Category 4A: impaired, TMDL completed
Minnesota filed this assessment unit as Category 4A: impaired, with a pollutant-budget TMDL already completed under 303(d). The listing remains an impairment finding; the plan is on file rather than still awaiting write-up.
Scale and rank
Trillium 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 150 assessed acres it ranks 8,916th 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 8,915 lakes with a larger one.
Not yet on record
The state has not yet filed a definitive aquatic-life verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
In context
Where Trillium 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
150 Top 23% larger than 77% 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 Trillium. 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, Trillium ranks 1,243rd by listed-cause count (one listed cause) and 1,284th by assessed size among the 1,930 with an area filed; it sits in the not-supporting set (1,798 statewide) . Its listed causes include Mercury in Fish Tissue, which also appears among Minnesota's most-filed impairment causes (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 Trillium's size or cause load
Similar assessed acres
Nearest filed extents (150 acres here).
- Loomis Lake · 150 acres · WA
- TAR RIVER (including lower portion of the City of Rocky Mount Reservoir below highwater elevation 130 feet MSL) · 150 acres · NC
- Adams Lake · 150 acres · OK
- Beaver Dam Pond · 150 acres · NE
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
- The fish-consumption use is assessed as not supporting. Before eating fish from this lake, check your state fish-advisory program for species-specific meal limits. 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 state's reported decisions for assessment unit MN11-0270-00. 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.