Rhode Island lake · state assessment record
Quidnick 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.
- 173
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Quidnick Reservoir, a lake in Rhode Island, is assessed as not supporting one or more designated uses, with one listed impairment cause 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 (one listed cause vs 23,610 assessed lakes). Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P79
- 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 Quidnick 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: assessed size
The number that most separates Quidnick Reservoir nationally is assessed size: 173.4 acres, larger than 79% of the 38,628 lake-type units with an area on file.
Not one verdict, several
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.
Quidnick Reservoir: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Quidnick Reservoir. 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 Quidnick Reservoir 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, Rhode Island carries 233 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Quidnick 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 Consumption | Fish-consumption or fishery | Not Supporting Filer confidence: Excellent |
| Primary Contact Recreation | Recreation | Fully Supporting Filer confidence: Excellent |
| Secondary Contact Recreation | Recreation | Fully Supporting Filer confidence: Excellent |
| Fish and Wildlife Habitat | Aquatic-life or related | Not Assessed |
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 | Fish Consumption | 2000 | TMDL approved |
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 in Fish Tissue
- Atmospheric Deposition - Toxics (confirmed)
Reading the record
Quidnick Reservoir: Category 4A reading
4A Category 4A: impaired, TMDL completed
Rhode Island 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
Quidnick 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 173 assessed acres it ranks 8,058th 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 8,057 lakes with a larger one.
Awaiting a filing
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.
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 Quidnick 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
173 Top 21% larger than 79% 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 Quidnick 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, Quidnick Reservoir ranks 75th by listed-cause count (one listed cause) and 16th by assessed size among the 126 with an area filed; it sits in the not-supporting set (119 statewide) . Its listed causes include Mercury in Fish Tissue, which also appears among Rhode Island's most-filed impairment causes (led by Non-Native Aquatic Plants).
| 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 Quidnick Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (173 acres here).
- River · 173 acres · MN
- Attica Water Supply Reservoir · 173 acres · NY
- Lower Spunk · 173 acres · MN
- Lincoln Lake · 173 acres · MI
Similar cause load
Nearest listed-cause counts (1 here). Peers already in the acreage column are omitted.
- Aaron · 1 causes · MN
- 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
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 RI0006013L-04. 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.