Rhode Island lake · state assessment record
Ponagansett Reservoir
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.
- 220
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Ponagansett Reservoir, a lake in Rhode Island, is assessed as fully supporting its designated uses, with no impairment causes listed 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 shorter than on half of assessed lakes (0 listed causes). Aquatic life is assessed as fully supporting.
- Fully Supporting
- overall status
- P83
- Assessed size nationally
- P51
- Shorter cause list
- Fully 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.
How Ponagansett Reservoir 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: cause-list length
The standout filed fact is a short cause list: 0 causes, shorter than 51% of assessed lake-type units. A short list can mean a focused impairment, or a shallow assessment.
Every ruled-on use is fully supporting
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.
Large assessed unit
At 220 acres, Ponagansett Reservoir clears the upper tercile of assessed lake-type units with an area on file (6,702 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
Large within Rhode Island
Among Rhode Island's 126 indexed units with an area, Ponagansett Reservoir ranks 11 by assessed size, toward the large end of that state file.
IR category in the supporting band
EPA's Integrated Report category for Ponagansett Reservoir is 2. In ATTAINS that band means the assessed uses are supporting (or supporting with other waters in the unit), so the narrative weight shifts to how deep the assessment went and whether monitoring is current, not to a restoration plan.
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 Ponagansett Reservoir 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 3 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 and Wildlife Habitat | Aquatic-life or related | Fully Supporting Filer confidence: Excellent |
| Primary Contact Recreation | Recreation | Fully Supporting Filer confidence: Excellent |
| Secondary Contact Recreation | Recreation | Fully Supporting Filer confidence: Excellent |
| Fish Consumption | Fish-consumption or fishery | Not Assessed |
| Public Drinking Water Supply | Drinking-water supply designation | Not Assessed |
The record
Listed impairment causes
The state's reported assessment lists no impairment causes for this lake.
Reading the record
Ponagansett Reservoir: Category 2 reading
2 Category 2: some uses supported, others not assessed
Rhode Island filed this assessment unit as Category 2: some designated uses are supported and others were not assessed in this cycle. Absence of a failing verdict is not the same as a full Category 1 finding.
Scale and rank
Ponagansett Reservoir 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 220 assessed acres it ranks 6,703rd 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 6,702 lakes with a larger one.
What this record holds
Rhode Island completed an assessment here and listed no impairment cause, so the record holds a verdict and its supporting use rows but no pollutant to track over time. The state 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
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.
In context
Where Ponagansett Reservoir 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
220 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
0 Among the shortest cause lists fewer listed causes than 51% 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 Ponagansett Reservoir. 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, Ponagansett Reservoir ranks 120th by listed-cause count (no listed causes) and 11th by assessed size among the 126 with an area filed; it is one of the 21 fully-supporting indexed records in the state .
| 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 Ponagansett Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (220 acres here).
- Iowa · 220 acres · MN
- Long Lake · 220 acres · ND
- Buffalo Creek Lake · 220 acres · NE
- Contoocook River - Hopkinton Flood Control Dam · 220 acres · NH
Similar cause load
Nearest listed-cause counts (0 here). Peers already in the acreage column are omitted.
- 31st Street Harbor · 0 causes · IL
- 42nd Avenue East Beach · 0 causes · MN
- 59th Street Harbor · 0 causes · IL
- 657 Dunleavy (Beach) · 0 causes · MI
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 RI0006015L-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.