Rhode Island lake · state assessment record
Tiogue Lake
Assessment decisions reported by Rhode Island to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2024 reporting cycle.
- 234
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Tiogue Lake, a lake in Rhode Island, is assessed as not supporting one or more designated uses, with 2 listed impairment causes in the state's most recent Integrated Report cycle (2024). By assessed acreage it sits in the upper quartile 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 fully supporting.
- Not Supporting
- overall status
- P83
- 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.
Where Tiogue Lake stands in 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 Tiogue Lake nationally is assessed size: 233.9 acres, larger than 83% of the 38,628 lake-type units with an area on file.
Not one verdict, several
This record splits: Not Supporting on aquatic life, Fully Supporting on fish consumption, recreation. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Tiogue Lake: Category 4C reading
Category 4C marks impairment from pollution that is not a pollutant (for example habitat or flow alteration) on Tiogue Lake. A classic TMDL load model often does not apply; the cause list should name the non-pollutant stressor.
Longer than most cause lists
2 listed causes puts this unit above 80% of assessed lake-type records by list length. Treat that as a coding-and-sampling signal: states that split pollutants finely mint longer lists without proving worse water.
Overall status: not supporting
The filer's overall status for Tiogue Lake is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
According to the U.S. Environmental Protection Agency's ATTAINS program, Rhode Island carries 233 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Tiogue Lake 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. Rhode Island filed its own confidence on the 4 definitive verdicts it rated: Excellent. 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 | Fully Supporting Filer confidence: Excellent |
| Fish and Wildlife Habitat | Aquatic-life or related | Not Supporting Filer confidence: Excellent |
| Primary Contact Recreation | Recreation | Fully Supporting Filer confidence: Excellent |
| Secondary Contact Recreation | Recreation | Fully Supporting Filer confidence: Excellent |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this lake, with the cycle each was first listed. None is a pollutant, so none carries a TMDL cleanup plan.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Non-Native Aquatic Plants | Fish and Wildlife Habitat | 2008 | Not applicable (non-pollutant) |
| Non-Native Fish/Shellfish/Zooplankton | Fish and Wildlife Habitat | 2008 | Not applicable (non-pollutant) |
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.
- Non-Native Aquatic Plants
- Introduction of Non-Native Organisms (Accidental or Intentional) (suspected)
- Non-Native Fish/Shellfish/Zooplankton
- Introduction of Non-Native Organisms (Accidental or Intentional) (suspected)
Reading the record
Tiogue Lake: Category 4C reading
4C Category 4C: impaired by a non-pollutant; TMDL programme does not apply
Rhode Island filed this assessment unit as Category 4C: the impairment is not caused by a pollutant, so the Clean Water Act 303(d) cleanup-plan (TMDL) programme, which allocates pollutant loads, does not apply here.
A 4C listing is still an impairment finding about designated uses; it is not a clean bill of health. How listing and cleanup work.
Scale and rank
Tiogue Lake is one of 233 lake-type waterbodies reported to EPA from Rhode Island, and one of 126 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 234 assessed acres it ranks 6,420th 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 6,419 lakes with a larger one.
Reported trophic class
Rhode Island carried the trophic field for this assessment unit and filed it as unclassified, which records that no class was determined rather than that the water is unenriched. What the trophic scale measures.
Why no water-level record
Tiogue Lake has no daily USGS water-level or reservoir-storage series on this page because NWIS lists a lake monitoring site named for the waterbody, but the site is not active, and PlainLakes ingests only the active inventory, so there is no series to attach. How PlainLakes links gauges.
In context
Where Tiogue Lake 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
234 Top 17% larger than 83% 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 Tiogue Lake. Hover or tap any bar for its full count and share.
In context
Rhode Island context
ATTAINS carries 233 lake-type waterbodies in Rhode Island, 119 assessed as not supporting at least one use and 21 fully supporting. Among the 126 indexed units there, Tiogue Lake ranks 34th by listed-cause count (2 listed causes) and 10th by assessed size among the 126 with an area filed; it sits in the not-supporting set (119 statewide) . Its listed causes include Non-Native Aquatic Plants, which also appears among Rhode Island's most-filed impairment causes (led by Non-Native Aquatic Plants). It also lists Non-Native Fish/Shellfish/Zooplankton, outside that top-five list.
| Other large assessed lakes in Rhode Island | Assessed acres |
|---|---|
| Scituate Reservoir Fully Supporting | 3,277 |
| Worden Pond Not Supporting | 1,051 |
| Flat River Reservoir (Johnson Pond) Not Supporting | 647 |
| Watchaug Pond Not Supporting | 568 |
| Stafford Pond Not Supporting | 480 |
| Watson Reservoir Not Supporting | 371 |
Peers near Tiogue Lake's size or cause load
Similar assessed acres
Nearest filed extents (234 acres here).
- Catherine Lake · 234 acres · AR
- East Caroga Lake · 234 acres · NY
- Mud · 234 acres · MN
- North Bend Lake · 234 acres · WV
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
- 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 state's reported decisions for assessment unit RI0006014L-02. 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.