Arizona lake · state assessment record
Tunnel Reservoir
The assessment record reported by Arizona to EPA under Clean Water Act sections 303(d) and 305(b), filed in the 2026 reporting cycle.
- 35
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Tunnel Reservoir, a lake in Arizona, was reported but not assessed in the state's most recent Integrated Report cycle (2026). By assessed acreage it sits below the national median by assessed acreage (38,628 lakes).
- Not Assessed
- overall status
- P46
- Assessed size nationally
Assessment verdicts are the state agency's decisions as reported to EPA ATTAINS; PlainLakes renders them without modification.
Tunnel Reservoir 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: assessed size
Assessed size is not the extreme here: 35.2 acres sits near the middle of the 38,628 units with an area filed (percentile 46).
IR category 3 on Tunnel Reservoir
The Integrated Report category filed for Tunnel Reservoir is 3. PlainLakes renders EPA's code without remapping it into a consumer grade.
Overall status: Not Assessed
ATTAINS overall status on this unit is “Not Assessed”. PlainLakes does not rewrite that vocabulary into a consumer score.
According to the U.S. Environmental Protection Agency's ATTAINS program, Arizona carries 78 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Tunnel Reservoir 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.
| Designated use | Group | Verdict |
|---|---|---|
| Agricultural Irrigation | Other | Insufficient Information |
| Agricultural Livestock Watering | Other | Insufficient Information |
| Aquatic and Wildlife (Coldwater Fishery) | Aquatic-life or related | Insufficient Information |
| Fish Consumption | Fish-consumption or fishery | Insufficient Information |
| Full Body Contact | Recreation | Insufficient Information |
The record
Listed impairment causes
The state reported this lake in its 2026 Integrated Report cycle but reached no assessment determination, so no causes are listed. The unit is recorded under EPA integrated-reporting Category 3: reviewed, with insufficient information to determine whether it meets water-quality standards. An undetermined waterbody is neither confirmed clean nor confirmed impaired.
Reading the record
What Tunnel Reservoir's record holds
Scale and rank
Tunnel Reservoir is one of 78 lake-type waterbodies reported to EPA from Arizona. It is not among the 44 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 35 assessed acres it ranks 20,799th 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 20,798 lakes with a larger one.
What this record holds
Arizona filed this lake in its 2026 Integrated Report cycle but reached no determination, so the record holds that filing and its use rows, but no verdict, and with nothing judged, no impairment cause to track over time. The state has not yet filed a definitive fish-consumption verdict, a definitive recreation verdict, a definitive aquatic-life verdict, and 1 other for this record; those fields populate when it reports them in a future Integrated Report cycle.
In context
Where Tunnel Reservoir 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
35 Top 54% larger than 46% 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
In both charts each bar is a band and taller bars hold more waterbodies; the dashed line and filled bar mark Tunnel Reservoir. Hover or tap any bar for its full count and share.
In context
Arizona context
ATTAINS carries 78 lake-type waterbodies in Arizona, 34 assessed as not supporting at least one use and 20 fully supporting.
| Other large assessed lakes in Arizona | Assessed acres |
|---|---|
| Lake Mohave Not Supporting | 27,044 |
| Lake Havasu Not Supporting | 19,780 |
| Roosevelt Lake Not Supporting | 18,345 |
| Lake Powell Not Supporting | 9,770 |
| Lake Pleasant Not Supporting | 8,000 |
| Topock Marsh Not Assessed | 4,870 |
Lakes near Tunnel Reservoir's assessed acres
Similar assessed acres
Nearest filed extents (35 acres here).
- Fountain Lake · 35 acres · WI
- Lake Kabau · 35 acres · NY
- Long · 35 acres · MN
- Smith Lake (aka Lodi Lake, San Juaquin County) · 35 acres · CA
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 AZL15020001-1550_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.