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LakeQuality

Lake Roberts

Grant County, New Mexico61 acresView mapDirections

NR
Not rated

Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.

Water temp
No reading
No gauge
Clarity
5.7 ft
Secchi · sampled 2019
Level
No reading
No gauge
Trend
Stable
2 years of samples
  • Impaired · Mercury
  • Limited data

Lake Roberts in Grant County, New Mexico is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5.7 ft visibility. Chlorophyll-a (algae): 41.1 µg/L. Surface area: 61.2 acres.

Clarity
5.7 ft
Area
61 acres
Chlorophyll-a
41.1 µg/L
Trend
Stable
Loading map…

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Stays near Lake Roberts

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Watch Lake Roberts’s letter

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Why Lake Roberts has no grade

We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Lake Roberts, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity and algae (chlorophyll-a), but not phosphorus.

Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.

Sampling is run by NMED and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

Lake Roberts is a 61-acre lake in Grant County, New Mexico. Water clarity is declining over recent sampling years.

Source: EPA Water Quality Portal sampling records, NMED, last sampled 2019-10-02. Grade methodology: LakeQuality methodology.

Swimming Safety

Not rated

Limited data

The letter is not a swimming clearance. Lake Roberts is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), temperature. Check local advisories before you swim.

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Water quality measurements for Lake Roberts

These readings exist but are not enough for an A–F grade — see why.

Murky, only visible to about 5.7 ft. Chlorophyll-a 41.1 µg/L. TSI 59.

MetricValueGrade
Water Clarity (Secchi Depth)5.7 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)41.1 µg/LNot graded
Trophic State Index (TSI)59Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Surface Area61 acres

No bathymetric survey has been published for Lake Roberts, so its depth is not documented here.

Fishing Lake Roberts

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.625 m/yr2
Chlorophyll-a Improving-1.75 µg/L/yr2

Reservoir Info (USACE NID)

Lake Roberts is a man-made reservoir impounded by the Lake Roberts Dam (completed 1963), built primarily for recreation on the Sapillo Creek; earth-type dam, 64 ft tall and 401 ft long.

Surface area
61.2 ac
Normal storage
748.3 ac-ft
Max storage
2,982 ac-ft
Drainage area
89 sq mi
Hazard class
High
Owner
NEW MEXICO DEPARTMENT OF GAME AND FISH

Source: USACE National Inventory of Dams, NID ID NM00273 · Operator website

EPA Impairment Status

Lake Roberts is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)Temperature

Source: EPA ATTAINS assessment unit NM-2504_20 · Official waterbody report

Graded lakes near Lake Roberts

Lake Roberts has no grade, but these lakes within a short drive do.

Nearby Lakes in Grant County

Frequently asked questions about Lake Roberts

Where is Lake Roberts?

Lake Roberts is a lake in Grant County, New Mexico. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).

What is the water quality grade for Lake Roberts?

Lake Roberts in Grant County, New Mexico is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5.7 ft visibility. Chlorophyll-a (algae): 41.1 µg/L. Surface area: 61.2 acres.

Is Lake Roberts safe to swim in?

The letter is not a swimming clearance. Lake Roberts is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), temperature. Check local advisories before you swim.

Where this data comes from

4 measurements from 1 monitoring station, 2019. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • NM Environmental Dept./SWQB21NMEX_WQX4 samples · 2019

Analytical methods

  • 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (1)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Impairment status from EPA ATTAINS 303(d) database