Louisiana lake · state assessment record
Devil's Swamp Lake and Bayou Baton Rouge
Assessment decisions reported by Louisiana to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle.
- 64
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Devil's Swamp Lake and Bayou Baton Rouge, a lake in Louisiana, is assessed as not supporting one or more designated uses, with 13 listed impairment causes in the state's most recent Integrated Report cycle (2026). By assessed acreage it sits above the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (13 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P60
- 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.
How Devil's Swamp Lake and Bayou Baton Rouge 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: cause-list length
The standout filed fact is cause-list length: 13 listed impairment causes, a longer list than 100% of assessed lake-type units (n=23,610). List length tracks how states sample and code, not a severity score.
Every filed use falls short
On the uses this filer ruled on, 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.
Devil's Swamp Lake and Bayou Baton Rouge: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Devil's Swamp Lake and Bayou Baton Rouge. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Small within Louisiana
State size rank 70 of 74 puts Devil's Swamp Lake and Bayou Baton Rouge toward the small end of Louisiana's indexed lake-type units with an area.
Overall status: not supporting
The filer's overall status for Devil's Swamp Lake and Bayou Baton Rouge 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 Devil's Swamp Lake and Bayou Baton Rouge 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 | Not Supporting Filer confidence: Fair on physical/chemical and pathogen indicators; Good on other public health indicators |
| 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 |
|---|---|---|---|
| Hexachlorobenzene | Primary Contact Recreation | 1998 | Action recorded (type not published) |
| Hexachlorobutadiene | Primary Contact Recreation | 1998 | Action recorded (type not published) |
| Dissolved Oxygen | Fish and Wildlife Propagation | 2000 | TMDL priority: Low |
| Lead | Primary Contact Recreation | 2000 | Action recorded (type not published) |
| PCBs - Fish Consumption Advisory | Fish and Wildlife Propagation | 2000 | Action recorded (type not published) |
| Fecal Coliform | Primary Contact Recreation | 2002 | TMDL priority: Low |
| Turbidity | Fish and Wildlife Propagation | 2002 | TMDL priority: Low |
| Nitrate/Nitrite (Nitrite + Nitrate as N) | Fish and Wildlife Propagation | 2004 | TMDL priority: Low |
| Phosphorus, Total | Fish and Wildlife Propagation | 2004 | TMDL priority: Low |
| Arsenic | Primary Contact Recreation | 2008 | Action recorded (type not published) |
| Mercury - Fish Consumption Advisory | Fish and Wildlife Propagation | 2008 | Action recorded (type not published) |
| Mercury | Primary Contact Recreation | 2016 | Action recorded (type not published) |
| Ammonia | Fish and Wildlife Propagation | 2026 | 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.
- Hexachlorobenzene
- Contaminated Sediments (suspected)
- Hexachlorobutadiene
- Contaminated Sediments (suspected)
- Dissolved Oxygen
- On-Site Treatment Systems (Septic Systems and Similar Decentralized Systems) (suspected)
- Lead
- Contaminated Sediments (suspected)
- PCBs - Fish Consumption Advisory
- Contaminated Sediments (suspected)
- Fecal Coliform
- On-Site Treatment Systems (Septic Systems and Similar Decentralized Systems) (suspected)
- Nitrate/Nitrite (Nitrite + Nitrate as N)
- On-Site Treatment Systems (Septic Systems and Similar Decentralized Systems) (suspected)
- Phosphorus, Total
- On-Site Treatment Systems (Septic Systems and Similar Decentralized Systems) (suspected)
- Arsenic
- Contaminated Sediments (suspected)
- Mercury - Fish Consumption Advisory
- Atmospheric Deposition - Toxics (suspected)
- Mercury
- Contaminated Sediments (suspected)
Louisiana also recorded the source of at least one listing here as unknown, including for Turbidity, Mercury - Fish Consumption Advisory, and Ammonia.
Reading the record
Where Devil's Swamp Lake and Bayou Baton Rouge sits among peers
79% of Louisiana's lakes assessed this deeply also came out mixed
Louisiana ruled definitively on 3 designated uses at Devil's Swamp Lake and Bayou Baton Rouge and found 2 of 3 not supported. The dataset shows 39 Louisiana lakes judged to that same depth.
Louisiana's assessed lakes are most often judged on 3 uses, as this one was.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 1 | 0 | 8 | 2 | 0 |
| Mixed | Not possible | 4 | 31 (this record) | 11 | 6 |
| None supported | 12 | 0 | 0 | 0 | 0 |
Ringed cell: Devil's Swamp Lake and Bayou Baton Rouge. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Devil's Swamp Lake and Bayou Baton Rouge 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 64 assessed acres it ranks 15,324th 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 15,323 lakes with a larger one.
Not yet on record
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 Devil's Swamp Lake and Bayou Baton Rouge 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
64 Top 40% larger than 60% 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
13 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 Devil's Swamp Lake and Bayou Baton Rouge. 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, Devil's Swamp Lake and Bayou Baton Rouge ranks 1st by listed-cause count (13 listed causes) and 70th by assessed size among the 74 with an area filed; it sits in the not-supporting set (64 statewide) . Its listed causes include Dissolved Oxygen, Turbidity, and Mercury - Fish Consumption Advisory, which also appear among Louisiana's most-filed impairment causes (led by Mercury - Fish Consumption Advisory). It also lists Hexachlorobenzene; Hexachlorobutadiene; Lead; PCBs - Fish Consumption Advisory; Fecal Coliform; Nitrate/Nitrite (Nitrite + Nitrate as N); Phosphorus, Total; Arsenic; Mercury; and Ammonia, outside that top-five list.
| 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 |
| Catahoula Lake Not Supporting | 16,509 |
Peers near Devil's Swamp Lake and Bayou Baton Rouge's size or cause load
Similar assessed acres
Nearest filed extents (64 acres here).
- Cohansey R (Greenwich to 75d17m50s) · 64 acres · NJ
- East Pine Pond · 64 acres · NY
- North Pond · 64 acres · NY
- Trout Brook · 64 acres · NJ
Similar cause load
Nearest listed-cause counts (13 here). Peers already in the acreage column are omitted.
- Morses Creek / Piles Creek · 13 causes · NJ
- Passaic R Lwr (Saddle R to Dundee Dam) · 13 causes · NJ
- Lake Union / Lake Washington Ship Canal · 12 causes · WA
- Branchport Creek · 11 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 LA070203_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.