Oklahoma lake · state assessment record
American Horse Lake
Assessment decisions reported by Oklahoma to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2018 reporting cycle.
- 100
- Assessed acres
- Lake, Freshwater
- Water type
- Mesotrophic
- Reported trophic class
This waterbody in one line
American Horse Lake, a lake in Oklahoma, is assessed as fully supporting its designated uses, with no impairment causes listed in the state's most recent Integrated Report cycle (2018). By assessed acreage it sits above the national median by assessed acreage (38,628 lakes); its impairment list is shorter than on half of assessed lakes (0 listed causes).
- Fully Supporting
- overall status
- P70
- Assessed size nationally
- P51
- Shorter cause list
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.
Reading American Horse Lake's filed record
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 2018 while monitoring evidence runs through 2008, a 10-year gap. Cycle year and last-monitored year move independently in ATTAINS; this page shows both.
Shorter than most cause lists
Only 0 causes on file, shorter than 51% of assessed lake-type units. Pair the short list with the use matrix: a single Not Supporting use can still be the whole story.
Every ruled-on use is fully supporting
The filed use determinations for recreation are all Fully Supporting. Where an overall IR category still flags the unit, look at the cause list and report standing rather than treating the use row as empty.
IR category in the supporting band
EPA's Integrated Report category for American Horse Lake is 2. In ATTAINS that band means the assessed uses are supporting (or supporting with other waters in the unit), so the narrative weight shifts to how deep the assessment went and whether monitoring is current, not to a restoration plan.
Overall status: fully supporting
Overall status is Fully Supporting. If an IR category or cause row still appears, it usually reflects a prior listing path or a use the overall rollup does not collapse, read those sections rather than stopping at the tile.
According to the U.S. Environmental Protection Agency's ATTAINS program, Oklahoma carries 456 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to American Horse 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 Oklahoma filed against this record runs through 2008. Oklahoma filed its own confidence on the 3 definitive verdicts it rated: 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 |
|---|---|---|
| Aesthetic | Other | Fully Supporting Filer confidence: Good |
| Agriculture | Other | Fully Supporting Filer confidence: Good |
| Primary Body Contact Recreation | Recreation | Fully Supporting Filer confidence: Good |
| Fish Consumption | Fish-consumption or fishery | Not Assessed |
| Fish and Wildlife Propagation-Warm Water Aquatic Community Subcategory | Aquatic-life or related | Insufficient Information Filer confidence: Good |
The record
Listed impairment causes
The state's reported assessment lists no impairment causes for this lake.
Reading the record
American Horse Lake: Category 2 reading
2 Category 2: some uses supported, others not assessed
Oklahoma filed this assessment unit as Category 2: some designated uses are supported and others were not assessed in this cycle. Absence of a failing verdict is not the same as a full Category 1 finding.
Scale and rank
American Horse Lake is one of 456 lake-type waterbodies reported to EPA from Oklahoma. It is not among the 173 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 100 assessed acres it ranks 11,704th 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 11,703 lakes with a larger one.
What this record holds
Oklahoma completed an assessment here and listed no impairment cause, so the record holds a verdict and its supporting use rows but no pollutant to track over time. The state has not yet filed a definitive fish-consumption verdict and a definitive aquatic-life verdict for this record; those fields populate when it reports them in a future Integrated Report cycle.
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.
Why no water-level record
American Horse Lake has no daily USGS water-level or reservoir-storage series on this page because NWIS lists a lake monitoring site named for the waterbody, but the site is not active, and PlainLakes ingests only the active inventory, so there is no series to attach. How PlainLakes links gauges.
In context
Where American Horse 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
100 Top 30% larger than 70% 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
0 Among the shortest cause lists fewer listed causes than 51% 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 American Horse Lake. Hover or tap any bar for its full count and share.
In context
Oklahoma context
ATTAINS carries 456 lake-type waterbodies in Oklahoma, 153 assessed as not supporting at least one use and 45 fully supporting.
| Other large assessed lakes in Oklahoma | Assessed acres |
|---|---|
| Grand Lake Site 12 Not Supporting | 46,500 |
| Grand Lake Site 13 Not Supporting | 46,500 |
| Grand Lake Site 14 Fully Supporting | 46,500 |
| Grand Lake Site 15 Fully Supporting | 46,500 |
| Robert S. Kerr Lake Not Supporting | 43,380 |
| Texoma Lake, Red River Arm, Lower Not Supporting | 31,081 |
Peers near American Horse Lake's size or cause load
Similar assessed acres
Nearest filed extents (100 acres here).
- Androscoggin River - D. C. Power Dam · 100 acres · NH
- Beeds Lake · 100 acres · IA
- Catherine Lake · 100 acres · AR
- Delaney Lake · 100 acres · MO
Similar cause load
Nearest listed-cause counts (0 here). Peers already in the acreage column are omitted.
- 31st Street Harbor · 0 causes · IL
- 42nd Avenue East Beach · 0 causes · MN
- 59th Street Harbor · 0 causes · IL
- 657 Dunleavy (Beach) · 0 causes · MI
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 OK520620010100_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.