Colorado Water Officials Warn of Near-Term Risks to Lake Powell as 2007 Rules Expire

Amy Ustick, Section Chief for Interstate, Federal, and Water Information at the Colorado Water Conservation Board, told the Boulder Water Resources Advisory Board on June 15 that the legal and operational framework for the Colorado River remains anchored in the Colorado River Compact of 1922 and the 2007 interim guidelines.

Ustick said the compact is not being renegotiated and described the 2007 guidelines as ‘‘interim’’ rules meant to be revisited in 2026. She said those guidelines have tended to operate in a demand-driven way—releases from Lake Powell increase when Lake Mead draws down due to lower-basin use—rather than being strictly supply-driven by inflows.

Why it matters: The 2007 framework’s demand-driven mechanics have contributed to releases that in some years far exceeded Powell’s inflows, leaving Powell’s storage vulnerable. Ustick said Reclamation is close to issuing a final environmental impact statement and a record of decision; the federal agency’s preferred approach will shape how releases are timed and whether Powell’s levels can be stabilized.

What officials proposed and warned Ustick described the Upper Basin states’ negotiating priorities: a shift toward supply-driven operations (so Powell does not consistently release more water than flows into it), mechanisms to rebuild storage, and voluntary contribution programs that would pay water users to leave water in the system. She said the Upper Basin has submitted a formal alternative to Reclamation and that the agency has discussed a ‘‘preliminary preferred alternative’’ as part of the NEPA process.

On litigation risk, Ustick said one Lower Basin state, Arizona, has threatened litigation and that differences in compact interpretation complicate matters. She noted a legal dispute over whether the Upper Basin’s non-depletion obligation (commonly framed as 75 million acre-feet over a 10-year period) should be augmented in some analyses to about 82.5 million acre-feet by including half of the Mexican treaty obligation — an interpretation she said the basins disagree on and that could shape future court arguments.

Forecasts and uncertainty When board members asked for a quantified risk that Lake Powell could drop below power pool or go to deadpool, Ustick cited recent 24-month studies and hydrology-dependent forecasts that place the probability of dropping below power pool near the midrange (she cited roughly a 50% path in current projections). She said outcomes will depend heavily on near-term inflows and operational choices (including releases from upstream initial units such as Flaming Gorge).

On causation, Ustick said the drivers include reservoir operations, how strictly Upper Basin states have curtailed uses in dry years, and climate-related reductions in flows; she said causation questions are legally and scientifically complex and contested between the basins.

Tribal participation and contribution programs Ustick said Reclamation is consulting tribes on a separate but parallel track and that Colorado wants to explore how tribal undeveloped apportionments might participate in contribution programs. She described earlier pilot efforts (such as system-conservation pilots) that produced limited volumes, and said Colorado would like federal funding and clear Reclamation accounting rules for conserved water to enable a scaled contribution program.

What’s next Ustick told the board she expects Reclamation to publish a final EIS and record of decision in the coming weeks and months and emphasized that whatever approach Reclamation adopts will shape operations for the immediate post-2026 period. She urged continued coordination among the Upper Basin states and engagement on voluntary contribution mechanisms rather than assuming a single legal or technical fix.

The Colorado River update was presented as an information item; no formal action was taken by the Water Resources Advisory Board at the June 15 meeting.