Wisconsin reservoir · state assessment record
Spirit River Flowage
In Lincoln County. Assessment decisions reported by Wisconsin to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle.
- 1,220
- Assessed acres
- Reservoir
- Water type
This waterbody in one line
Spirit River Flowage, a reservoir in Wisconsin, is assessed as not supporting one or more designated uses, with 2 listed impairment causes in the state's most recent Integrated Report cycle (2026). By assessed acreage it sits among the largest 5% by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (2 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting. Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P95
- Assessed size nationally
- P10
- Shorter cause list
- Not Supporting
- aquatic life
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.
Reading Spirit River Flowage's filed record
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: in-state cause rank
Inside Wisconsin, cause-list rank is the local separator: Spirit River Flowage is 23 of 1,219 indexed units by listed-cause count, toward the top of that state's filed lists.
Large assessed unit
At 1,220 acres, Spirit River Flowage clears the upper tercile of assessed lake-type units with an area on file (1,971 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
No ruled-on use clears the bar
On the uses this filer ruled on, fish consumption, recreation, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Spirit River Flowage: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Spirit River Flowage. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Large within Wisconsin
Among Wisconsin's 1,170 indexed units with an area, Spirit River Flowage ranks 78 by assessed size, toward the large end of that state file.
According to the U.S. Environmental Protection Agency's ATTAINS program, Wisconsin carries 19,871 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Spirit River Flowage 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. The latest monitoring Wisconsin filed against this record runs through 2025. For the definitive verdicts on this record, Wisconsin filed the assessment basis as Monitored Data. Those are EPA's own words, not PlainLakes' summary of them. Wisconsin filed its own confidence on the 2 definitive verdicts it rated: Low and Good. That rating is the filer's, in EPA's own field, and EPA publishes no definition of the four words it offers.
| Designated use | Group | Verdict |
|---|---|---|
| Fish Consumption | Fish-consumption or fishery | Not Supporting |
| Fish and Aquatic Life | Aquatic-life or related | Not Supporting Filer confidence: Low on biological; Good on physical/chemical |
| Recreation | Recreation | Not Supporting Filer confidence: Good |
| Public Health and Welfare | Recreation | Not Assessed |
| Wildlife | Aquatic-life or related | Not Assessed |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this reservoir, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Mercury | Fish Consumption | 1998 | TMDL priority: Low |
| Phosphorus, Total | Fish and Aquatic Life; Recreation | 2012 | TMDL priority: High |
Probable sources named by the state
Each source below is listed under the cause the state filed it against, and carries the word the state filed with it — confirmed, or suspected.
- Mercury
- Atmospheric Deposition - Toxics (confirmed)
- Phosphorus, Total
- Non-Point Source (suspected)
Reading the record
Cleanup queue for Spirit River Flowage
1 listed cause ranked High in the TMDL queue, still without a plan
Wisconsin ranked Phosphorus, Total high in its TMDL development queue, and no cleanup plan is on file for that listing yet. That queue rank is the state'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
Spirit River Flowage is one of 19,871 lake-type waterbodies reported to EPA from Wisconsin, and one of 1,219 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 1,220 assessed acres it ranks 1,972nd 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 1,971 lakes with a larger one.
In context
Where Spirit River Flowage 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
1,220 Top 5% larger than 95% 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
2 Longer than most more listed causes than 80% 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 Spirit River Flowage. Hover or tap any bar for its full count and share.
In context
Wisconsin context
ATTAINS carries 19,871 lake-type waterbodies in Wisconsin, 493 assessed as not supporting at least one use and 4,225 fully supporting. Among the 1,219 indexed units there, Spirit River Flowage ranks 23rd by listed-cause count (2 listed causes) and 78th by assessed size among the 1,170 with an area filed; it sits in the not-supporting set (493 statewide) . Its listed causes include Mercury; and Phosphorus, Total, which also appear among Wisconsin's most-filed impairment causes (led by Phosphorus, Total).
| Other large assessed lakes in Wisconsin | Assessed acres |
|---|---|
| Lake Winnebago Not Supporting | 131,942 |
| Lake Pepin Not Supporting | 25,503 |
| Petenwell Lake Not Supporting | 23,001 |
| Lake Poygan Not Supporting | 14,024 |
| Lake Chippewa Fully Supporting | 13,616 |
| Turtle Flambeau Flowage Not Supporting | 12,943 |
Peers near Spirit River Flowage's size or cause load
Similar assessed acres
Nearest filed extents (1,220 acres here).
- Lake Clinch · 1,219 acres · FL
- Walter E. Long Lake · 1,219 acres · TX
- Philpott Reservoir (Smith River) · 1,221 acres · VA
- Roosevelt - South · 1,218 acres · MN
Similar cause load
Nearest listed-cause counts (2 here). Peers already in the acreage column are omitted.
- 12th St. Beach · 2 causes · IL
- 31st St. Beach · 2 causes · IL
- 49th St. Beach · 2 causes · IL
- 57th St. Beach · 2 causes · IL
What to do with this record
- The fish-consumption use is assessed as not supporting. Before eating fish from this reservoir, 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 WI10007188. 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.