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Blog Post · July 26, 2021

What It Means to Store Water for the Environment

photo - shorebird

It’s no secret that California’s ecosystems suffer during droughts. In times of water scarcity, environmental uses are often low priority, leading to fish die-offs and other negative outcomes. For the next year, Professor Sarah Null of Utah State University will be working with a diverse team of experts to study how to better manage water stored for the environment, to better protect vulnerable ecosystems during a time of biodiversity loss and accelerating climate change. Null, an expert in environmental water management and water systems modeling, is a PPIC CalTrout Ecosystem Fellow.

photo - Sarah Null

What does it mean to store water for the environment, and why is it important?

It means exactly what it sounds like: storing water, either in surface reservoirs or as groundwater, for the environment. However, we’re interested in expanding the options for flexibly managing that water. We are thinking about storage as a way to manage water, so that it could be traded, stored for later use, exchanged with other users, or released to support ecosystem function.

What’s our biggest challenge with storing water for the environment right now?

Our team has identified three big challenges; the first is infrastructure. Reservoirs were built for other uses, like water supply, hydropower, or flood protection. We have to think about how storing water for the environment could impact those other uses. Another big challenge is governance—who would manage water for the environment? The last challenge is legal opportunities and constraints—how could water be stored for flexible use within existing laws? Those three are the big challenges, although there are likely other challenges also.

What are you learning about how to manage environmental water for maximum environmental benefit?

Environmental regulatory requirements are needed to maintain ecosystems. However, they are not very good at rehabilitating ecosystems. We need environmental water allocations that can be managed flexibly if we are going to build resilience. This could enable more proactive water management during droughts for ecosystems, and better integration with urban and agricultural water uses.

How good are our models for predicting climate change’s effects on hydrology, water quality, and aquatic habitats?

We are very confident that the climate is warming; there is uncertainty around how much the climate is warming. Precipitation is a whole other ball of wax. We don’t really understand whether climate change will make California’s climate grow wetter or drier. Both might happen, with wetter winters and drier summers. And because of warming, more precipitation will fall as rain instead of snow, leading to what I call “flashier” rivers, with lots of runoff over short periods and very dry summers. Those conditions are hard to manage, and there’s a good deal of uncertainty around them. For climate and hydrological modeling, we simulate a whole bunch of alternatives so we can really understand where the bounds of uncertainty lie.

What’s making you particularly excited about this work right now?

This project is exciting because it’s really novel. We know that the status quo isn’t working for ecosystems. This is an opportunity to be bold and think about how to do things differently. Ecosystems and environmental water management bear a lot of risk from hydrologic and system uncertainty, which adds urgency and makes this project very timely.

We have a great team on this project, and I’m excited to lead it. I specialize in environmental water management and systems modeling, and our team has another systems modeler, water lawyers, a geomorphologist, and ecologists. It’s not new to bring together many disciplines to work on water management, but it’s always the smartest way to get things done.


climate change Drought Floods Freshwater Ecosystems Water, Land & Air