Mississippi reservoir · state assessment record
Grenada Lake (6,011 acres)
Assessment decisions reported by Mississippi to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2018 reporting cycle.
- 6,011
- Assessed acres
- Lake / Reservoir / Pond
- Water type
This waterbody in one line
Grenada Lake, a reservoir in Mississippi, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2018). 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 (one listed cause vs 23,610 assessed lakes). Aquatic life is assessed as fully supporting. Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P99
- Assessed size nationally
- P20
- Shorter cause list
- Fully 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.
How Grenada Lake 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 Grenada Lake nationally is assessed size: 6,011 acres, larger than 99% of the 38,628 lake-type units with an area on file.
The uses disagree
This record splits: Not Supporting on fish consumption, Fully Supporting on aquatic life. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Grenada Lake: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Grenada Lake. 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 Grenada Lake 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, Mississippi carries 114 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Grenada Lake 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 Life Support | Aquatic-life or related | Fully Supporting |
| Fish Consumption | Fish-consumption or fishery | Not Supporting |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this reservoir, 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 | 1998 | TMDL approved |
Probable sources
Mississippi listed the source of the impairment as unknown. That is the state's own filed value, not a gap in this record: the cause has been identified, the origin has not.
Reading the record
Grenada Lake: Category 4A reading
4A Category 4A: impaired, TMDL completed
Mississippi 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
Grenada Lake is one of 114 lake-type waterbodies reported to EPA from Mississippi, and one of 14 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 6,011 assessed acres it ranks 523rd 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 522 lakes with a larger one.
Awaiting a filing
The state has not yet filed a definitive recreation verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
In context
Where Grenada Lake 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
6,011 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
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 Grenada Lake. Hover or tap any bar for its full count and share.
In context
Mississippi context
ATTAINS carries 114 lake-type waterbodies in Mississippi, 14 assessed as not supporting at least one use and 84 fully supporting. Among the 14 indexed units there, Grenada Lake ranks 5th by listed-cause count (one listed cause) and 1st by assessed size among the 14 with an area filed; it sits in the not-supporting set (14 statewide) . Its listed causes include Mercury in Fish Tissue, which also appears among Mississippi's most-filed impairment causes (led by Mercury in Fish Tissue).
| Other large assessed lakes in Mississippi | Assessed acres |
|---|---|
| Ross Barnett Reservoir Assessment unit MS507511 Fully Supporting | 20,737 |
| Sardis Lake Fully Supporting | 15,277 |
| Grenada Lake Fully Supporting | 9,927 |
| Arkabutla Lake Fully Supporting | 6,279 |
| Ross Barnett Reservoir Assessment unit MS507412 Fully Supporting | 5,483 |
| Enid Lake Fully Supporting | 4,741 |
Peers near Grenada Lake's size or cause load
Similar assessed acres
Nearest filed extents (6,011 acres here).
- Wright Patman Lake · 6,014 acres · TX
- Island Lake Rsvr(W.Basin) · 6,020 acres · MN
- Nolin Lake · 6,024 acres · KY
- Ute Reservoir · 5,988 acres · NM
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 reservoir, 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 MS915811. 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.