From the slopes of the Sierra Nevada mountains to the Central Valley farmlands, the Cosumnes River flows through a diverse range of California terrain. The gold-rich river was once a hotspot for miners who ventured west in search of wealth during the 1800s. The glitter of the gold rush subsided long ago and more recently years of drought have caused stretches of the Cosumnes River to run dry.
“The Cosumnes River is one of only a few undammed rivers left in the state of California, and its natural flow regime is absolutely critical to the ecological and human communities in the region,” said Erin Donley Marineau, Ph.D. and California programs director at The Freshwater Trust, a conservation non-profit.
The river is critical to farmers, wildlife, and also to a huge portion of the state’s population. The Cosumnes contributes to the San Francisco Bay and Sacramento–San Joaquin River Delta Estuary (Bay Delta)—the largest natural estuary on the western coast of North and South America. The Bay Delta water resources are vitally important to the people and environment of California. This water is also an essential economic resource and is used by companies across every industry including Amazon Web Services (AWS).
“At AWS, we are committed to ensuring we have a positive impact on water resources in Northern California and other regions where we operate.” said Will Hewes, AWS Water Sustainability Lead. “While we rely on water from the Bay Delta to cool some of our Northern California data centers, we are also working with local governments, public utilities, and nonprofits to recharge groundwater and invest in recycled water infrastructure to help solve water challenges in the region.”
AWS committed to be water positive by 2030. That means AWS will return more water to communities and the environment than it uses in its direct operations. One way AWS will meet this goal is by investing in water replenishment projects in the communities where it operates.
In Northern CA, one example of how AWS is replenishing water is by recharging groundwater along the Consumnes River in partnership with The Freshwater Trust and the Omochumne-Hartnell Water District. Groundwater is water found underground in the cracks and spaces in soil, sand, and rock. Even though it's underground, it still helps keep rivers flowing during the dry months when it seeps back into the river channel. Decades of excessive groundwater use along the Cosumnes has contributed to diminishing surface water levels, which is raising concerns for wildlife, farmers, and the surrounding communities. Replenishing groundwater increases its supply, which in turn increases surface water levels in the Cosumnes River.
“Our droughts are likely to become more frequent, so we can't continue withdrawing groundwater without a plan to replenish it. We must return water to the system when conditions allow, otherwise we won’t have the same access to these resources in the future,” said Dave Pfuhler, environmental scientist at The Freshwater Trust.
To recharge groundwater, the Omochumne-Hartnell Water District is applying excess water from winter storms to two vineyards adjacent to the Cosumnes in the winter months. The absorption of the water into the underlying groundwater reservoir will help the local deficit and contribute to surface water flow during drier summer and fall months. It may also lower the temperature of the river, improve wildlife habitat, and increase the amount of water deposited into the Bay-Delta, helping to decrease the risk that California communities and farmers will have to do without water from this critical source.
“When we take steps like these to improve groundwater replenishment, it's good for the environment and humans. This particular project provides an example of the type of work that can be scaled to many different locations,” said Marineau. “And if it is done at scale, it can have a very large impact.”
As part of the water positive commitment, AWS is also working with other conservation groups, non-profits, and local utilities to recharge and replenish groundwater in Oregon, Brazil, the United Kingdom, and other places around the world.
