
Oligotrophic Lakes in New Mexico
6 oligotrophic lakes in New Mexico. Low nutrients, clear water, excellent for swimming.
An oligotrophic lake is what most people picture when they think of pristine northern lake country: clarity to depth, no algal scum, cold water that holds dissolved oxygen all the way to the bottom even in August. Across New Mexico, 6 lakes register as oligotrophic — 0% of them break 50 feet of depth, which is the structural condition that underwrites the trophic class. Without depth and a low-nutrient watershed, oligotrophy is hard to sustain.
Oligotrophic lakes almost always carry the lowest phosphorus and chlorophyll-a readings on record, since the same low-nutrient conditions produce both the trophic class and the clear water.
| # | Lake | County | Clarity | Depth | TSI |
|---|---|---|---|---|---|
| 1 | Heron Lake Deep Dam | Rio Arriba | 3.7 ft | - | 49 |
| 2 | Grindstone Canyon Reservoir Deep | Lincoln | 9 ft | - | 46 |
| 3 | Mescalero Lake Deep | Otero | - | - | 46 |
| 4 | Mescalero Lake Shallow | Otero | - | - | 48 |
| 5 | Silver Lake Deep | Otero | - | - | 47 |
| 6 | Silver Lake Shallow | Otero | - | - | 49 |
Source: EPA National Aquatic Resource Surveys, 2026.