Louisiana lake · state assessment record
Catahoula Lake
Assessment decisions reported by Louisiana to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle. The cleanup plan below was established by EPA rather than by Louisiana.
- 16,509
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Catahoula Lake, a lake in Louisiana, is assessed as not supporting one or more designated uses, with 3 listed impairment causes in the state's most recent Integrated Report cycle (2026). 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 (3 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P100
- 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.
Where Catahoula Lake 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 Catahoula Lake nationally is assessed size: 16,509 acres, larger than 100% of the 38,628 lake-type units with an area on file.
Not one verdict, several
This record splits: Not Supporting on aquatic life, Fully Supporting on recreation. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Longer than most cause lists
3 listed causes puts this unit above 90% 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.
Catahoula Lake: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Catahoula Lake. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Overall status: not supporting
The filer's overall status for Catahoula Lake 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, Louisiana carries 76 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Catahoula 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. The latest monitoring Louisiana filed against this record runs through 2024. For the definitive verdicts on this record, Louisiana filed the assessment basis as Monitored Data. Those are EPA's own words, not PlainLakes' summary of them. Louisiana filed its own confidence on the 3 definitive verdicts it rated: Fair and Good. 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 Propagation | Aquatic-life or related | Not Supporting Filer confidence: Fair on physical/chemical; Good on toxicological |
| Primary Contact Recreation | Recreation | Fully Supporting Filer confidence: Fair |
| Secondary Contact Recreation | Recreation | Fully Supporting Filer confidence: Fair |
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 |
|---|---|---|---|
| Mercury - Fish Consumption Advisory | Fish and Wildlife Propagation | 2000 | TMDL established by EPA |
| Dissolved Oxygen | Fish and Wildlife Propagation | 2002 | TMDL priority: Low |
| Turbidity | Fish and Wildlife Propagation | 2006 | 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.
- Mercury - Fish Consumption Advisory
- Atmospheric Deposition - Toxics (suspected)
- Dissolved Oxygen
- Natural Sources (suspected)
- Turbidity
- Agriculture (suspected)
Louisiana also recorded the source of at least one listing here as unknown, including for Mercury - Fish Consumption Advisory.
Reading the record
EPA plan standing on Catahoula Lake
1 cleanup plan EPA established here
EPA, not Louisiana, established that plan.
Scale and rank
Catahoula Lake is one of 76 lake-type waterbodies reported to EPA from Louisiana, and one of 74 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 16,509 assessed acres it ranks 186th 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 185 lakes with a larger one.
Awaiting a filing
The state has not yet filed a definitive fish-consumption verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
Reported trophic class
Louisiana 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 Catahoula 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
16,509 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
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 Catahoula Lake. Hover or tap any bar for its full count and share.
In context
Louisiana context
ATTAINS carries 76 lake-type waterbodies in Louisiana, 64 assessed as not supporting at least one use and 11 fully supporting. Among the 74 indexed units there, Catahoula Lake ranks 11th by listed-cause count (3 listed causes) and 6th by assessed size among the 74 with an area filed; it sits in the not-supporting set (64 statewide) . Its listed causes include Mercury - Fish Consumption Advisory, Dissolved Oxygen, and Turbidity, which also appear among Louisiana's most-filed impairment causes (led by Mercury - Fish Consumption Advisory).
| Other large assessed lakes in Louisiana | Assessed acres |
|---|---|
| Toledo Bend Reservoir-From Texas-Louisiana state line to Toledo Bend Dam Not Supporting | 165,487 |
| White Lake Not Supporting | 56,487 |
| Lake Salvador Not Supporting | 49,477 |
| Grand Lake Not Supporting | 47,869 |
| Lac Des Allemands Not Supporting | 16,596 |
| Lake Fausse Point and Dauterive Lake Not Supporting | 16,495 |
Peers near Catahoula Lake's size or cause load
Similar assessed acres
Nearest filed extents (16,509 acres here).
- Tellico Reservoir · 16,500 acres · TN
- Barkley Reservoir · 16,541 acres · TN
- Eufaula Lake, Canadian River Deep Fork · 16,453 acres · OK
- Lake Audubon · 16,610 acres · ND
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 LA081603_00. 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.