Oklahoma lake · state assessment record
Oologah Lake
Assessment decisions reported by Oklahoma to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2024 reporting cycle.
- 29,460
- Assessed acres
- Lake, Freshwater
- Water type
- Eutrophic
- Reported trophic class
This waterbody in one line
Oologah Lake, a lake in Oklahoma, is assessed as not supporting one or more designated uses, with 2 listed impairment causes in the state's most recent Integrated Report cycle (2024). 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 (2 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting.
- Not Supporting
- overall status
- P100
- Assessed size nationally
- P10
- 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 Oologah 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 Oologah Lake nationally is assessed size: 29,460 acres, larger than 100% of the 38,628 lake-type units with an area on file.
Mixed use determinations
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.
Oologah Lake: Category 4A reading
Category 4A means a TMDL (or equivalent) is already approved for the impairment on Oologah Lake. The remaining work is implementation and tracking, read the cleanup-standing and cause rows for what the state already committed to address.
Longer than most cause lists
2 listed causes puts this unit above 80% 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.
Overall status: not supporting
The filer's overall status for Oologah 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, Oklahoma carries 456 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Oologah 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 2023. Oklahoma filed its own confidence on the 5 definitive verdicts it rated: Good and Excellent. 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 on other public health indicators; Excellent on physical/chemical |
| Agriculture | Other | Fully Supporting Filer confidence: Excellent |
| Fish and Wildlife Propagation-Warm Water Aquatic Community Subcategory | Aquatic-life or related | Not Supporting Filer confidence: Good on biological; Excellent on physical/chemical |
| Navigation | Other | Fully Supporting Filer confidence: Good |
| Primary Body Contact Recreation | Recreation | Fully Supporting Filer confidence: Good on physical/chemical; Excellent on pathogen indicators |
| Fish Consumption | Fish-consumption or fishery | Insufficient Information Filer confidence: Excellent |
| Public and Private Water Supply | Drinking-water supply designation | Insufficient Information Filer confidence: Good on pathogen indicators; Excellent on physical/chemical |
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 |
|---|---|---|---|
| Turbidity | Fish and Wildlife Propagation-Warm Water Aquatic Community Subcategory | 1998 | TMDL approved |
| Dissolved Oxygen | Fish and Wildlife Propagation-Warm Water Aquatic Community Subcategory | 2004 | TMDL approved |
Probable sources
Oklahoma 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
Oologah Lake: Category 4A reading
4A Category 4A: impaired, TMDL completed
Oklahoma 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
Oologah Lake is one of 456 lake-type waterbodies reported to EPA from Oklahoma, and one of 173 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 29,460 assessed acres it ranks 106th 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 105 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
Eutrophic 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
Oologah 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 Oologah 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
29,460 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
2 Longer than most more listed causes than 80% 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 Oologah 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. Among the 173 indexed units there, Oologah Lake ranks 38th by listed-cause count (2 listed causes) and 7th by assessed size among the 170 with an area filed; it sits in the not-supporting set (153 statewide) . Its listed causes include Turbidity and Dissolved Oxygen, which also appear among Oklahoma's most-filed impairment causes (led by Mercury).
| 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 Oologah Lake's size or cause load
Similar assessed acres
Nearest filed extents (29,460 acres here).
- Millwood Lake · 29,500 acres · AR
- Searles Lake · 29,632 acres · CA
- Klamath River HU, Lost River HA, Clear Lake, Boles HSAs · 29,220 acres · CA
- Walter F. George Lake · 29,890 acres · GA
Similar cause load
Nearest listed-cause counts (2 here). Peers already in the acreage column are omitted.
- 12th St. Beach · 2 causes · IL
- 31st St. Beach · 2 causes · IL
- 49th St. Beach · 2 causes · IL
- 57th St. Beach · 2 causes · IL
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 OK121510010020_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.