Vermont lake · state assessment record
Memphremagog (5,660 acres)
Assessment decisions reported by Vermont to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2020 reporting cycle.
- 5,660
- Assessed acres
- Lake, Freshwater
- Water type
- Mesotrophic
- Reported trophic class
This waterbody in one line
Memphremagog, a lake in Vermont, is assessed as not supporting one or more designated uses, with 2 listed impairment causes in the state's most recent Integrated Report cycle (2020). By assessed acreage it sits among the largest 1% of assessed lakes nationally (38,628 lakes with a filed area); its impairment list is among the longest nationally (2 listed causes vs 23,610 assessed lakes). Vermont rules it not supporting for aquatic habitat to support aquatic biota, wildlife, or plant life, while other aquatic-life uses are supported. Fish consumption is assessed as fully supporting.
- Not Supporting
- overall status
- P99
- Assessed size nationally
- P10
- Shorter cause list
- Not Supporting
- aquatic-life or related
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 Memphremagog 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: assessed size
The number that most separates Memphremagog nationally is assessed size: 5,660 acres, larger than 99% of the 38,628 lake-type units with an area on file.
Mixed use determinations
This record splits: Not Supporting on recreation, aquatic life, Fully Supporting on fish consumption. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Memphremagog: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Memphremagog. The remaining work is implementation and tracking, read the cleanup-standing and cause rows for what the state already committed to address.
Longer than most cause lists
2 listed causes puts this unit above 80% 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.
Overall status: not supporting
The filer's overall status for Memphremagog is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
According to the U.S. Environmental Protection Agency's ATTAINS program, Vermont carries 712 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Memphremagog 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.
| Designated use | Group | Verdict |
|---|---|---|
| Aquatic Biota and Wildlife That May Utilize or Are Present in the Waters | Aquatic-life or related | Fully Supporting |
| Aquatic Habitat to Support Aquatic Biota, Wildlife, or Plant Life | Aquatic-life or related | Not Supporting |
| Fish Consumption | Fish-consumption or fishery | Fully Supporting |
| The Use of Waters for Boating and Related Recreational Uses | Recreation | Fully Supporting |
| The Use of Waters for Fishing and Related Recreational Uses | Recreation | Fully Supporting |
| The Use of Waters for Swimming and Other Primary Contact Recreation | Recreation | Not Supporting |
| The Use of Waters for the Enjoyment of Aesthetic Conditions | Other | Not Supporting |
| The Use of Water for Irrigation of Crops and Other Agricultural Uses | Other | Not Assessed |
| The Use of the Water for Public Water Source | Drinking-water supply designation | 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 |
|---|---|---|---|
| Phosphorus | The Use of Waters for the Enjoyment of Aesthetic Conditions; The Use of Waters for Swimming and Other Primary Contact Recreation | 2006 | TMDL approved |
| Flow Regime Modification | Aquatic Habitat to Support Aquatic Biota, Wildlife, or Plant Life | Not reported | TMDL priority: Low |
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.
- Phosphorus
- Non-Point Source (suspected)
Reading the record
Memphremagog: Category 4A reading
4A Category 4A: impaired, TMDL completed
Vermont 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
Memphremagog is one of 712 lake-type waterbodies reported to EPA from Vermont, and one of 712 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 5,660 assessed acres it ranks 553rd 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 552 lakes with a larger one.
Reported trophic class
Mesotrophic is the trophic class the filing agency reported to EPA ATTAINS for this assessment unit. It describes nutrient enrichment, not whether the water is safe, and it is not a PlainLakes inference. What the trophic scale measures.
In context
Where Memphremagog 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
5,660 Top 1% larger than 99% 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
2 Longer than most more listed causes than 80% 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 Memphremagog. Hover or tap any bar for its full count and share.
In context
Vermont context
ATTAINS carries 712 lake-type waterbodies in Vermont, 154 assessed as not supporting at least one use and 558 fully supporting. Among the 712 indexed units there, Memphremagog ranks 50th by listed-cause count (2 listed causes) and 7th by assessed size among the 712 with an area filed; it sits in the not-supporting set (154 statewide) . Its listed causes include Phosphorus, which also appears among Vermont's most-filed impairment causes (led by Eurasian Water Milfoil, Myriophyllum Spicatum). It also lists Flow Regime Modification, outside that top-five list.
| Other large assessed lakes in Vermont | Assessed acres |
|---|---|
| Champ-Northeast Arm Not Supporting | 57,022 |
| Champ-Main Lake Not Supporting | 37,809 |
| Champ-Isle La Motte Not Supporting | 20,962 |
| Champ-Malletts Bay Not Supporting | 12,049 |
| Champ-Port Henry Not Supporting | 8,372 |
| Champ-Missisquoi Bay Not Supporting | 6,398 |
Peers near Memphremagog's size or cause load
Similar assessed acres
Nearest filed extents (5,660 acres here).
- Melton Hill Reservoir · 5,690 acres · TN
- Miltona · 5,690 acres · MN
- Dead River · 5,691 acres · ME
- McClure Reservoir (Mariposa County) · 5,691 acres · CA
Similar cause load
Nearest listed-cause counts (2 here). Peers already in the acreage column are omitted.
- 12th St. Beach · 2 causes · IL
- 31st St. Beach · 2 causes · IL
- 49th St. Beach · 2 causes · IL
- 57th St. Beach · 2 causes · IL
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 VT17-01L01_01. 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.