Louisiana lake · state assessment record
Clear Lake and Smithport Lake; includes old Edwards Lake
Assessment decisions reported by Louisiana to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2022 reporting cycle.
- 2,752
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Clear Lake and Smithport Lake; includes old Edwards Lake, a lake in Louisiana, is assessed as not supporting one or more designated uses, with 4 listed impairment causes in the state's most recent Integrated Report cycle (2022). By assessed acreage it sits among the largest 5% by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (4 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P97
- Assessed size nationally
- P3
- 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.
Clear Lake and Smithport Lake; includes old Edwards Lake against the ATTAINS 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: monitoring lag
The signature tension is currency: the reporting cycle is 2022 while monitoring evidence runs through 2016, a 6-year gap. Cycle year and last-monitored year move independently in ATTAINS; this page shows both.
Large assessed unit
At 2,752 acres, Clear Lake and Smithport Lake; includes old Edwards Lake clears the upper tercile of assessed lake-type units with an area on file (1,062 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
Longer than most cause lists
4 listed causes puts this unit above 95% 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.
No ruled-on use clears the bar
On the uses this filer ruled on, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Clear Lake and Smithport Lake; includes old Edwards Lake: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Clear Lake and Smithport Lake; includes old Edwards Lake. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
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 Clear Lake and Smithport Lake; includes old Edwards 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 2016. 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 2 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 |
|---|---|---|
| Agriculture | Other | Fully Supporting Filer confidence: Fair |
| Fish and Wildlife Propagation | Aquatic-life or related | Not Supporting Filer confidence: Fair on physical/chemical; Good on toxicological |
| Primary Contact Recreation | Recreation | Insufficient Information Filer confidence: Fair |
| Secondary Contact Recreation | Recreation | Insufficient Information 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 |
|---|---|---|---|
| Dissolved Oxygen | None; the one use assessed against it was met | 2000 | TMDL approved |
| Mercury - Fish Consumption Advisory | Fish and Wildlife Propagation | 2002 | TMDL priority: Low |
| Nitrate/Nitrite (Nitrite + Nitrate as N) | None; the one use assessed against it was met | 2004 | TMDL approved |
| Phosphorus, Total | None; the one use assessed against it was met | 2004 | TMDL approved |
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.
- Dissolved Oxygen
- Natural Sources (suspected)
- Mercury - Fish Consumption Advisory
- Atmospheric Deposition - Toxics (suspected)
- Nitrate/Nitrite (Nitrite + Nitrate as N)
- Natural Sources (suspected)
- Phosphorus, Total
- Natural Sources (suspected)
Louisiana also recorded the source of at least one listing here as unknown, including for Mercury - Fish Consumption Advisory.
Reading the record
How current is Clear Lake and Smithport Lake; includes old Edwards Lake's evidence?
6 years between the 2022 reporting cycle and monitoring through 2016
The latest monitoring Louisiana filed against this record runs through 2016. 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.
The cycle is when the state reported; the monitoring year, where filed, is when it measured. How to read assessment currency.
Scale and rank
Clear Lake and Smithport Lake; includes old Edwards 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 2,752 assessed acres it ranks 1,063rd 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 1,062 lakes with a larger one.
Open in the register
The state has not yet filed a definitive fish-consumption verdict and a definitive recreation verdict for this record; those fields populate when it reports them 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 Clear Lake and Smithport Lake; includes old Edwards 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
2,752 Top 3% larger than 97% 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
4 Longer than most more listed causes than 95% 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 Clear Lake and Smithport Lake; includes old Edwards 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, Clear Lake and Smithport Lake; includes old Edwards Lake ranks 5th by listed-cause count (4 listed causes) and 29th 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 and Mercury - Fish Consumption Advisory, which also appear among Louisiana's most-filed impairment causes (led by Mercury - Fish Consumption Advisory). It also lists Nitrate/Nitrite (Nitrite + Nitrate as N); and Phosphorus, Total, 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 Clear Lake and Smithport Lake; includes old Edwards Lake's size or cause load
Similar assessed acres
Nearest filed extents (2,752 acres here).
- Gay Stamp Sands Area of Impact · 2,752 acres · MI
- Lake Lavon · 2,750 acres · TX
- Cabinet Gorge Reservoir · 2,756 acres · MT
- Little Tallapoosa River (R L Harris Lake) · 2,747 acres · AL
Similar cause load
Nearest listed-cause counts (4 here). Peers already in the acreage column are omitted.
- Agency Lake · 4 causes · OR
- Alachua Sink · 4 causes · FL
- Aldrich Pond · 4 causes · MA
- American Falls Reservoir (Snake River) · 4 causes · ID
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 LA100605_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.