Rio Grande Floodway at San Marcial streamflow

Page Note: Rio Grande at San Marcial - Critical Low Flow

Status: Critically Low

The Rio Grande is flowing at zero discharge at San Marcial — a complete cessation of flow. This represents a 100% decline from the 5-year median of 345 ft³/s and a catastrophic drop from 11 ft³/s year-over-year.

Key Observations:

• Current flow: 0 ft³/s (as of July 7, 2026)
• vs. 5-yr median: 345 ft³/s — the river is running completely dry
• Year-over-year decline: 11 → 0 ft³/s — 100% reduction in one year

Implications: This zero-flow condition at San Marcial indicates severe water stress in the Rio Grande basin. The San Marcial gauge is a critical monitoring point below Elephant Butte Reservoir; zero flow here suggests either:

1. Upstream demand consuming all available water
2. Extended drought conditions limiting snowmelt and precipitation contributions
3. Reservoir releases insufficient to meet downstream commitments

Historical Context: At a median of 345 ft³/s, this location typically has substantial flow year-round. Zero discharge is an extreme condition that affects:

• Riparian ecosystems along the lower Rio Grande
• Agricultural water availability downstream
• Potential compact delivery obligations under the Rio Grande Compact

This warrants close monitoring and coordination with water management agencies.