SSAVE THE SOUTHWEST← Evidence Library
RESEARCH 01 — COLORADO RIVER & RESERVOIRS

Start with the condition of the system.

Before testing a solution, establish the problem with primary evidence. This page separates reservoir status, hydrology and water-use accounting so unlike measurements are not presented as one simple equation.

Research rule:These facts establish the water-system challenge. They do not, by themselves, prove that 3 MAF/year is the right target or that desalination is the right solution.
FACT 01
Historic lowsLake Mead + Lake Powell
Supported

Combined reservoir storage is lower than at any point since before Lake Powell began filling in 1963.

In its 2026 decision documents, the U.S. Bureau of Reclamation states that after a record-low 2025–26 snowpack, combined storage in Lake Mead and Lake Powell fell below any level seen since before Lake Powell began filling in 1963. Reclamation also reports that both reservoirs reached record-low elevations in August 2026.

Primary sourceU.S. Bureau of ReclamationData period: 2026
What it means

The Colorado River system's two largest storage reservoirs have a much smaller buffer for future dry periods.

What it does not prove

Low storage alone does not establish how much new water should be created or which supply strategy should be chosen.

View original source ↗Post-2026 source library ↗
FACT 02
14.9 → 12.5MAF/year averages
Supported

Recent natural flow at Lees Ferry has averaged below the longer historical average.

14.9 MAF/yr1906–2006 average
→
12.5 MAF/yr2000–2023 average

Reclamation's Post-2026 scoping presentation shows observed annual natural flow at Lees Ferry and highlights these two averages. The difference is about 2.4 MAF/year, roughly 16% below the earlier-period average.

What it means

The recent multi-decade period has delivered less natural flow, on average, than the longer historical period shown by Reclamation.

What it does not mean

It does not prove the river has permanently “lost” 2.4 MAF/year or that every future year will resemble 2000–2023.

View Reclamation presentation ↗View natural-flow data ↗
FACT 03
Measured differentlyUse, losses & returns
Supported

Colorado River water use is officially tracked — but not by one single interchangeable dataset.

Reclamation publishes separate Water Accounting, Consumptive Uses and Losses, and Evapotranspiration/Evaporation reports. The agency explicitly notes that these reports are standalone products with differing definitions and methodologies.

Why this matters to our model

We should not subtract a “demand” number from a “supply” number unless the periods and definitions are genuinely comparable. Research must show exactly what each dataset measures.

Water Accounting

Measured diversions, returns and consumptive use for users on the Lower Colorado River mainstem.

Consumptive Uses & Losses

Broader estimates of anthropogenic uses and losses across the Colorado River System, organized by use, tributary and state.

Lower Basin Water Accounting ↗Consumptive Uses & Losses ↗
FACT 04
Storage mattersOperational resilience
Supported

Reservoir storage is an operating buffer, not just a visual measure of drought.

Reclamation's Post-2026 process coordinates operations of Lake Powell and Lake Mead because reservoir elevations affect water deliveries, critical federal infrastructure and the system's ability to respond to prolonged drought and hydrologic uncertainty.

What it means

Rebuilding storage can increase operating flexibility and the ability to withstand future dry periods.

How we use it

Save the Southwest treats reducing Colorado River withdrawals and helping rebuild reservoir storage as a system objective, not proof of a specific engineering solution.

Post-2026 operations ↗Final EIS source library ↗
SOURCE LIBRARY

Verify the evidence yourself.

These are the primary federal source collections used on this page. Links open the original publisher rather than a Save the Southwest summary.

Future Colorado River Operations — Decision DocumentsU.S. Bureau of Reclamation2026Open ↗
Post-2026 EIS Scoping PresentationU.S. Bureau of ReclamationHydrology through 2023Open PDF ↗
Colorado River Natural Flow & Salt DataU.S. Bureau of ReclamationProvisional through 2024Open ↗
Upper Colorado Consumptive Uses & LossesU.S. Bureau of ReclamationData through 2024 / reports updated 2025Open ↗
Lower Colorado Water AccountingU.S. Bureau of Reclamation2025 report availableOpen ↗
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