Addressing the over-appropriation of the Colorado River requires the Bureau of Reclamation to evolve in its role as “watermaster.”  Understandably, the focus over the past decades has been administration of existing water delivery contracts, improved “system operations” and, since the early 2000s, short-term administration of water shortages.  Acknowledgement of “long-term” challenges requires “long-term” responses.  A three-pronged approach may prove the recipe for success.

Humility.  Our predecessors were mistaken about the availability of Colorado River water when devising the 1922 Colorado River Compact.  Are we confident that we can predict the future?  Hydrowonk is not.  The future is inherently uncertain.  Therefore, prudent planning must consider the underlying uncertainty of future hydrologic and economic conditions.  Since the 1990s, the Bureau has made significant progress in developing tools to assess the uncertainty of hydrologic conditions.  Time to integrate the underlying uncertainty of economic conditions into the toolbox.  Machine learning and, eventually AI, should become part of the tools the Bureau and Colorado River water users employ for planning and assessment of transactional opportunities.

Flexibility.  The prudent use of Colorado River water in the future must adapt to changing future hydrologic and economic circumstances.  Hardwiring future Colorado River water use to assumed future conditions as of today will miss the mark.  Relative to today’s expectations, the timing, magnitude and duration of “unexpected” future conditions will require flexibility in the future allocation of Colorado River water.  Responsible water resource planning must find the optimal mix of short-term versus long-term arrangements governing the use of Colorado River water.

Predictability.  The effectiveness of planning and development of transactional opportunities will be enhanced by predictability of the “rules of the road.”  Our predecessors wisely stated entitlements in terms of consumptive use rather than diversions.  The Bureau has developed the tools for measuring consumptive use of Colorado River water for its annual report to the U.S. Supreme Court on Arizona v. California.  What are the environmental consequences and the impact on reliability of Colorado River water for water right holders of moving consumptive use and storage of the Colorado River water “up” or “down” river and across the Upper and the Lower basin?

The experience of California during the 1990-91 drought is worth considering.  The California Department of Water Resources (“DWR”) administered a “Drought Water Bank” between willing sellers and buyers of water.  A major portion of the water was made available by groundwater substitution in the Sacramento Valley where senior water right holders of Sacramento River surface water reduced their diversions from the river and increased groundwater pumping.  A key issue was the inter-connectiveness of groundwater and the Sacramento River.

After the drought, DWR developed “rebuttable” presumptions of the portion of pumped groundwater that was presumed to be connected to the Sacramento River depending on the distance of groundwater pumping from the Sacramento River.  This rule provided a guidepost for anticipating DWR approval of transactions based on switching from using Sacramento River water to increased groundwater pumping.  The presumption was “rebuttable” in the sense that DWR would consider evidence challenging the accuracy of DWR’s quantification for the specific circumstances of a proposed transaction.

DWR’s rebuttable presumptions established guideposts for reviewing disputes among parties in contested hearings.   While the approach does not eliminate the potential uncertainty of regulatory review of proposed transactions, it does provide the framework for regulatory review.  That is, while one cannot eliminate regulatory uncertainty, one can reduce it.  What else can one expect?

In the blink of an eye in Water World, it will be midnight, December 31, 2026.  How the water community focuses its efforts will have a bearing on the prospect of successfully addressing the over-appropriation of the Colorado River.  Managing the river for the future requires embracing the uncertainty of hydrologic and economic conditions and thinking in terms of risk management.

Time to manage the Colorado River as an integrated system.  Cooperative agreements among Colorado River water users across states, across sovereign nations, across basins, and across borders with humility, flexibility and regulatory predictability will be a legacy worth leaving.

It is time for us to step up, bring creativity, imagination, and innovation to the table.  It is time that we act like we believe that the Colorado River is a unique and socially valuable resource worthy of sustainable management for generations.

In Part 5, Hydrowonk presents further data on the impact of COVID-19 on the economies of each Colorado River Basin state to provide a starting context for thinking about how to address the Colorado River Basin as one integrated system.