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Blog Post · November 5, 2018

A Water Budget for the Environment

California’s freshwater ecosystems—and many native species that rely on them—are in decline and becoming increasingly vulnerable to drought. Allocating water to these ecosystems is contentious because it often conflicts with urban and agricultural uses. There may be a way to meet environmental needs that reduces conflict.

My recent presentation before the Delta Science Program outlined an alternative approach to managing water for the environment that is detailed in a 2017 PPIC report. 

Currently, state and federal regulators rely heavily on minimum flow and water quality standards to protect the environment. These flows are often set to meet the needs of one or more endangered species. This approach has failed to reverse the decline in native species and their ecosystems for many reasons—simply bumping up minimum flows is unlikely to improve conditions.

Instead, our report recommends establishing ecosystem water budgets. These budgets would specify a volume of water to be made available to support a range of ecosystem functions to which native species are adapted. The amounts would vary in accordance with the type of water year (e.g., wet, average, dry) but each amount would be fixed for a number of years. The volume to start with would be the water currently allocated to meet minimum flow and water quality standards. Mechanisms would be needed to increase this volume where necessary through purchases or leases.

To be effective, the budget should be flexibly managed, much like a water right—preferably by an ecosystem trustee vested with the authority to trade and store water. These budgets would focus on improving overall ecosystem conditions rather than protecting individual species.

Ecosystem water budgets are a better approach for three reasons. First, the flexible allocation of water allows environmental managers to use water more efficiently by responding to changing conditions (such as droughts, storms, and heatwaves) and delivering water to habitat in areas that are likely to have the highest ecological benefit.

Second, having a budget that can be flexibly managed makes the environment a partner in water management, not just a constraint. The ecosystem trustee would sit at the table with water managers and participate in the trading, storage, and planning that goes on in a watershed.

Finally, a budget with a set term makes the amount of water that will be allocated to the environment clear to all water users. This addresses one of the most common complaints about environmental water management: urban and agricultural users face uncertainty over regulatory actions that transfer water from economic to environmental uses.

Ecosystem water budgets would be an advance over traditional minimum flow and water quality standards, but they are unlikely to succeed without major improvements in both ecosystem planning and water accounting. Robust, watershed-scale plans are needed to set budget objectives and priorities for action. We recommend annual watering plans—vetted with local stakeholders—that preview actions to be taken every year, depending on hydrologic conditions. Equally important, California must improve accounting for water use and availability, because it’s not possible to manage what you don’t measure.

The current approach to freshwater ecosystem management is not working for anyone. The three reforms described here—ecosystem water budgets, ecosystem plans, and improved accounting—are likely to produce better outcomes for native species and result in more efficient use of environmental water. They also have the potential to increase certainty about environmental water allocation and reduce controversy. Making the environment a partner in water management is a novel, effective way to address one of the big challenges in California water.


Drought Freshwater Ecosystems Water Supply Water, Land & Air