Massachusetts lake · state assessment record
Lake Shirley
Assessment decisions reported by Massachusetts to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle, a cycle that is open for public comment.
- 360
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Lake Shirley, a lake in Massachusetts, is assessed as not supporting one or more designated uses, with 8 listed impairment causes in the state's most recent Integrated Report cycle (2026), a cycle that is open for public comment. By assessed acreage it sits in the upper quartile by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (8 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting. Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P88
- Assessed size nationally
- P0
- 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.
Reading Lake Shirley's filed record
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, cause-list rank is the local separator: Lake Shirley is 4 of 678 indexed units by listed-cause count, toward the top of that state's filed lists.
Longer than most cause lists
8 listed causes puts this unit above 99% 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.
Every ruled-on use is not supporting
On the uses this filer ruled on, fish consumption, recreation, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Lake Shirley: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Lake Shirley. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Large assessed unit
At 360 acres, Lake Shirley clears the upper tercile of assessed lake-type units with an area on file (4,694 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, Massachusetts carries 1,191 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Lake Shirley 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 definitive verdicts 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 |
|---|---|---|
| Aesthetic | Other | Not Supporting |
| Fish Consumption | Fish-consumption or fishery | Not Supporting |
| Fish, Other Aquatic Life and Wildlife | Aquatic-life or related | Not Supporting |
| Primary Contact Recreation | Recreation | Not Supporting |
| Secondary Contact Recreation | Recreation | Not Supporting |
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 |
|---|---|---|---|
| Turbidity | Aesthetic, Primary Contact Recreation, Secondary Contact Recreation | 2002 | TMDL priority: Low |
| Mercury in Fish Tissue | Fish Consumption | 2012 | TMDL approved |
| Brittle Naiad, Najas Minor | Fish, Other Aquatic Life and Wildlife | 2020 | None reported |
| Dissolved Oxygen | Fish, Other Aquatic Life and Wildlife | 2020 | TMDL priority: Low |
| Eurasian Water Milfoil, Myriophyllum Spicatum | Fish, Other Aquatic Life and Wildlife | 2020 | None reported |
| Fanwort | Fish, Other Aquatic Life and Wildlife | 2020 | None reported |
| Harmful Algal Blooms | Fish, Other Aquatic Life and Wildlife; Aesthetic; Primary Contact Recreation; Secondary Contact Recreation | 2020 | TMDL priority: Low |
| Non-Native Aquatic Plants | Fish, Other Aquatic Life and Wildlife | 2020 | None reported |
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 (confirmed)
- Brittle Naiad, Najas Minor
- Introduction of Non-Native Organisms (Accidental or Intentional) (confirmed)
- Eurasian Water Milfoil, Myriophyllum Spicatum
- Introduction of Non-Native Organisms (Accidental or Intentional) (confirmed)
- Fanwort
- Introduction of Non-Native Organisms (Accidental or Intentional) (confirmed)
- Non-Native Aquatic Plants
- Introduction of Non-Native Organisms (Accidental or Intentional) (confirmed)
Massachusetts also recorded the source of at least one listing here as unknown, including for Turbidity, Mercury in Fish Tissue, Dissolved Oxygen, and Harmful Algal Blooms.
Reading the record
Where Lake Shirley sits among peers
80% of Massachusetts's lakes assessed this deeply also had no use supported
Massachusetts ruled definitively on 5 designated uses at Lake Shirley and found none of them supported. The dataset shows 61 Massachusetts lakes judged to that same depth.
Massachusetts's assessed lakes are most often judged on 1 use; this one was judged on 5.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 15 | 14 | 11 | 0 | 0 |
| Mixed | Not possible | 5 | 19 | 31 | 12 |
| None supported | 283 | 60 | 91 | 128 | 49 (this record) |
Ringed cell: Lake Shirley. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Lake Shirley 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 360 assessed acres it ranks 4,695th 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 4,694 lakes with a larger one.
In context
Where Lake Shirley 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
360 Top 12% larger than 88% 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
8 Longer than most more listed causes than 99% 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 Lake Shirley. 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, Lake Shirley ranks 4th by listed-cause count (8 listed causes) and 32nd by assessed size among the 678 with an area filed; it sits in the not-supporting set (678 statewide) . Its listed causes include Mercury in Fish Tissue, Dissolved Oxygen, Fanwort, and Non-Native Aquatic Plants, which also appear among Massachusetts's most-filed impairment causes (led by Mercury in Fish Tissue). It also lists Turbidity; Brittle Naiad, Najas Minor; Eurasian Water Milfoil, Myriophyllum Spicatum; and Harmful Algal Blooms, outside that top-five list.
| 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 Lake Shirley's size or cause load
Similar assessed acres
Nearest filed extents (360 acres here).
- Lake Charles · 360 acres · FL
- Augur Lake · 360 acres · NY
- Portage · 360 acres · MN
- Stingy · 360 acres · MN
Similar cause load
Nearest listed-cause counts (8 here). Peers already in the acreage column are omitted.
- Ashuelot River - Fisk Mill Hydro · 8 causes · NH
- Brownlee Reservoir, Upper (Weiser to Porters Flat) · 8 causes · ID
- Calumet · 8 causes · IL
- Chingarora Creek to Thorns Creek · 8 causes · NJ
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 MA81122. 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.