New Mexico reservoir · state assessment record
Heron Reservoir
Assessment decisions reported by New Mexico to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle.
- 4,497
- Assessed acres
- Reservoir
- Water type
This waterbody in one line
Heron Reservoir, a reservoir in New Mexico, is assessed as not supporting one or more designated uses, with 3 listed impairment causes in the state's most recent Integrated Report cycle (2026). By assessed acreage it sits among the largest 5% by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (3 listed causes vs 23,610 assessed lakes). New Mexico rules it not supporting for coldwater aquatic life, while other aquatic-life uses are supported.
- Not Supporting
- overall status
- P98
- Assessed size nationally
- P5
- Shorter cause list
- Not Supporting
- aquatic-life or related
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 Heron Reservoir 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: in-state cause rank
Inside New Mexico, cause-list rank is the local separator: Heron Reservoir is 1 of 58 indexed units by listed-cause count, toward the top of that state's filed lists.
Large assessed unit
At 4,497 acres, Heron Reservoir clears the upper tercile of assessed lake-type units with an area on file (683 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
Not one verdict, several
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.
Longer than most cause lists
3 listed causes puts this unit above 90% 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.
Heron Reservoir: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Heron Reservoir. 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, New Mexico carries 176 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Heron 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 |
|---|---|---|
| Coldwater Aquatic Life | Aquatic-life or related | Not Supporting |
| Irrigation Storage | Other | Fully Supporting |
| Livestock Watering | Other | Fully Supporting |
| Primary Contact | Recreation | Fully Supporting |
| Wildlife Habitat | Aquatic-life or related | Fully Supporting |
| Public Water Supply | Drinking-water supply designation | Not Assessed |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this reservoir, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Temperature | Coldwater Aquatic Life | 2014 | TMDL priority: High |
| Mercury - Fish Consumption Advisory | Coldwater Aquatic Life | 2026 | TMDL priority: Low |
| Nutrients | Coldwater Aquatic Life | 2026 | TMDL priority: High |
Reading the record
Cleanup queue for Heron Reservoir
2 listed causes ranked High in the TMDL queue, still without a plan
New Mexico ranked 2 listed causes high in its TMDL development queue, and no cleanup plan is on file for those listings yet. That queue rank is the state's own scheduling signal, not an EPA national rule.
A High ranking names a position in the state's plan-writing queue; it is not a measure of how impaired the water is. How listing and cleanup work.
Scale and rank
Heron Reservoir is one of 176 lake-type waterbodies reported to EPA from New Mexico, and one of 58 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 4,497 assessed acres it ranks 684th 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 683 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.
Why no water-level record
Heron Reservoir 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 Heron 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
4,497 Top 2% larger than 98% 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
3 Longer than most more listed causes than 90% 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 Heron Reservoir. Hover or tap any bar for its full count and share.
In context
New Mexico context
ATTAINS carries 176 lake-type waterbodies in New Mexico, 46 assessed as not supporting at least one use and 28 fully supporting. Among the 58 indexed units there, Heron Reservoir ranks 1st by listed-cause count (3 listed causes) and 4th by assessed size among the 58 with an area filed; it sits in the not-supporting set (46 statewide) . Its listed causes include Temperature, Mercury - Fish Consumption Advisory, and Nutrients, which also appear among New Mexico's most-filed impairment causes (led by Nutrients).
| Other large assessed lakes in New Mexico | Assessed acres |
|---|---|
| Navajo Reservoir Not Supporting | 12,680 |
| Elephant Butte Reservoir Not Supporting | 10,909 |
| South Lordsburg Playa Not Assessed | 7,412 |
| Ute Reservoir Not Supporting | 5,988 |
| Laguna del Pero Fully Supporting | 4,477 |
| Caballo Reservoir Not Supporting | 4,441 |
Peers near Heron Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (4,497 acres here).
- Enid Lake · 4,499 acres · MS
- Allegheny River/Reservoir · 4,488 acres · NY
- Lower Fire Lake · 4,480 acres · AK
- Columbia River · 4,515 acres · OR
Similar cause load
Nearest listed-cause counts (3 here). Peers already in the acreage column are omitted.
- 67th St. Beach · 3 causes · IL
- Absecon Creek (AC Reserviors) (gage to SB) · 3 causes · NJ
- Absecon Creek (below gage) · 3 causes · NJ
- Agate Reservoir · 3 causes · OR
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 NM-2117_10. 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.