Massachusetts lake · state assessment record
Jenks Reservoir
Assessment decisions reported by Massachusetts to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2020 reporting cycle.
- 26
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Jenks Reservoir, a lake in Massachusetts, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2020). By assessed acreage it sits below the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (one listed cause vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P39
- Assessed size nationally
- P20
- 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 Jenks Reservoir 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: in-state cause rank
Inside Massachusetts, this unit sits toward the short-list end: cause-list rank 543 of 678 indexed units.
Every ruled-on use is not supporting
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.
Jenks Reservoir: Category 4C reading
Category 4C marks impairment from pollution that is not a pollutant (for example habitat or flow alteration) on Jenks Reservoir. A classic TMDL load model often does not apply; the cause list should name the non-pollutant stressor.
Overall status: not supporting
The filer's overall status for Jenks Reservoir is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Mid-pack inside Massachusetts
Size rank 437 of 678 inside Massachusetts is mid-pack; the national percentile is the better scale comparison for this unit.
According to the U.S. Environmental Protection Agency's ATTAINS program, Massachusetts carries 1,191 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Jenks 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. For the one definitive verdict on this record, Massachusetts filed the assessment basis as Monitored Data. Those are EPA's own words, not PlainLakes' summary of them.
| Designated use | Group | Verdict |
|---|---|---|
| Fish, Other Aquatic Life and Wildlife | Aquatic-life or related | Not Supporting |
| Aesthetic | Other | Not Assessed |
| Fish Consumption | Fish-consumption or fishery | Not Assessed |
| Primary Contact Recreation | Recreation | Not Assessed |
| Secondary Contact Recreation | Recreation | 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. None is a pollutant, so none carries a TMDL cleanup plan.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Non-Native Aquatic Plants | Fish, Other Aquatic Life and Wildlife | 1996 | 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) (confirmed)
Reading the record
Jenks Reservoir: Category 4C reading
4C Category 4C: impaired by a non-pollutant; TMDL programme does not apply
Massachusetts 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
Jenks Reservoir is one of 1,191 lake-type waterbodies reported to EPA from Massachusetts, and one of 678 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 26 assessed acres it ranks 23,674th 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 23,673 lakes with a larger one.
Open in the register
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.
In context
Where Jenks 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
26 Top 61% larger than 39% 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 Jenks Reservoir. Hover or tap any bar for its full count and share.
In context
Massachusetts context
ATTAINS carries 1,191 lake-type waterbodies in Massachusetts, 678 assessed as not supporting at least one use and 40 fully supporting. Among the 678 indexed units there, Jenks Reservoir ranks 543rd by listed-cause count (one listed cause) and 437th by assessed size among the 678 with an area filed; it sits in the not-supporting set (678 statewide) . Its listed causes include Non-Native Aquatic Plants, which also appears among Massachusetts's most-filed impairment causes (led by Mercury in Fish Tissue).
| Other large assessed lakes in Massachusetts | Assessed acres |
|---|---|
| Quabbin Reservoir Not Supporting | 24,010 |
| Wachusett Reservoir Not Supporting | 3,962 |
| Assawompset Pond Not Assessed | 2,034 |
| North Watuppa Pond Not Supporting | 1,728 |
| Long Pond Not Supporting | 1,728 |
| South Watuppa Pond Not Supporting | 1,473 |
Peers near Jenks Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (26 acres here).
- Avenue · 26 acres · MN
- Bond · 26 acres · IL
- Bowling Lake · 26 acres · NE
- Busseron Lake No. G-4 · 26 acres · IN
Similar cause load
Nearest listed-cause counts (1 here). Peers already in the acreage column are omitted.
- Aaron · 1 causes · MN
- Abbotts Creek (including Lexington-Thomasville Water Supply Reservoir at normal reservoir elevation, Tom-A-Lex Lake) · 1 causes · NC
- Abeniki Lake · 1 causes · NH
- Academy Brook II Dam · 1 causes · NH
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 MA51075. 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.