Rhode Island lake · state assessment record
Lawton Valley 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.
- 81
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Lawton Valley Reservoir, a lake in Rhode Island, is assessed as not supporting one or more designated uses, with 3 listed impairment causes in the state's most recent Integrated Report cycle (2024). By assessed acreage it sits above the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (3 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P66
- Assessed size nationally
- P5
- 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.
Lawton Valley Reservoir against the ATTAINS 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 cause-list length: 3 listed impairment causes, a longer list than 90% of assessed lake-type units (n=23,610). List length tracks how states sample and code, not a severity score.
Every filed use falls short
On the uses this filer ruled on, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Lawton Valley Reservoir: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Lawton Valley 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 Lawton Valley Reservoir is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Large assessed unit
At 81.4 acres, Lawton Valley Reservoir clears the upper tercile of assessed lake-type units with an area on file (13,359 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
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 Lawton Valley 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 2 definitive verdicts it rated: Fair, Good and 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 | Not Supporting Filer confidence: Fair on other public health indicators; Excellent on physical/chemical |
| Public Drinking Water Supply | Drinking-water supply designation | Not Supporting Filer confidence: Good on physical/chemical; Excellent on other public health indicators |
| Fish Consumption | Fish-consumption or fishery | Not Assessed |
| Primary Contact Recreation | Recreation | Insufficient Information Filer confidence: Excellent |
| Secondary Contact Recreation | Recreation | Insufficient Information 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 and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Flow Regime Modification | Fish and Wildlife Habitat | 2008 | None reported |
| Phosphorus, Total | Fish and Wildlife Habitat | 2014 | TMDL approved |
| Total Organic Carbon (TOC) | Public Drinking Water Supply | 2014 | 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.
- Flow Regime Modification
- Impacts From Hydrostructure Flow Regulation/Modification (suspected) Water Diversions (suspected)
- Phosphorus, Total
- Agriculture (confirmed) On-Site Treatment Systems (Septic Systems and Similar Decentralized Systems) (confirmed) Loss of Riparian Habitat (confirmed) Internal Nutrient Recycling (confirmed) Waterfowl (confirmed) Natural Sources (confirmed) Urban Runoff/Storm Sewers (confirmed)
- Total Organic Carbon (TOC)
- Agriculture (confirmed) On-Site Treatment Systems (Septic Systems and Similar Decentralized Systems) (confirmed) Loss of Riparian Habitat (confirmed) Internal Nutrient Recycling (confirmed) Waterfowl (confirmed) Natural Sources (confirmed) Urban Runoff/Storm Sewers (confirmed)
Reading the record
Lawton Valley 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
Lawton Valley 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 81 assessed acres it ranks 13,360th 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 13,359 lakes with a larger one.
Still unfiled
The state has not yet filed a definitive fish-consumption verdict and a definitive recreation verdict for this record; those fields populate when it reports them 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 Lawton Valley 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
81 Top 34% larger than 66% 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
3 Longer than most more listed causes than 90% 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 Lawton Valley 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, Lawton Valley Reservoir ranks 20th by listed-cause count (3 listed causes) and 47th by assessed size among the 126 with an area filed; it sits in the not-supporting set (119 statewide) . Its listed causes include Phosphorus, Total, which also appears among Rhode Island's most-filed impairment causes (led by Non-Native Aquatic Plants). It also lists Flow Regime Modification and Total Organic Carbon (TOC), 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 Lawton Valley Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (81 acres here).
- Gregory, Lake · 81 acres · CA
- Lake Washington · 81 acres · WA
- Lake Lariat · 81 acres · MD
- Little Dan Hole Pond · 81 acres · NH
Similar cause load
Nearest listed-cause counts (3 here). Peers already in the acreage column are omitted.
- 67th St. Beach · 3 causes · IL
- Abiquiu Reservoir · 3 causes · NM
- Absecon Creek (AC Reserviors) (gage to SB) · 3 causes · NJ
- Absecon Creek (below gage) · 3 causes · NJ
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 RI0007035L-06. 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.