The U.S. Bureau of Reclamation's and CA Department of Water Resource's $58 million Yolo Bypass Salmonid Habitat Restoration and Fish Passage ("Big Notch") Project came online last December. It shows that riparian habitat restoration doesn’t have to mean disruption and how smart, carefully engineered projects can work with the water systems we already depend on. (Just to clarify - the nonprofit Fresno Aquarium project is not government-funded like this project).

The Big Notch project allows winter floodwaters from the Sacramento River to be intentionally directed onto the existing Yolo Bypass floodplain in a more controlled manner than before and over a more extended period of time. For juvenile salmon, these shallow, slow-moving wetlands act like biological accelerators — rich in food, warmer than the main river channel, and proven to help fish grow faster and survive their journey to the ocean.

But extending floodplain flows doesn’t just benefit salmon. Many of California’s native fishes evolved with seasonal flooding and are built to take advantage of these brief, food-rich windows — species like splittail, suckers, and juvenile native minnows all benefit from the shallow, warm, highly productive conditions floodplains create.

At the same time, these restored environments don’t give non-native predators any advantage. Floodplains are temporary, turbid, and dynamic — exactly the opposite of the stable, deep, permanent habitats favored by many invasive species. Non-natives aren’t eliminated, but they are put at a disadvantage, while native fish gain a growth and survival edge that helps rebalance the system toward the species that belong here.

Just as important, seasonal wetlands do real work for people. When floodwaters spread out across a floodplain, they slow down and soak into the soil, recharging groundwater aquifers instead of racing straight downstream. In a state where groundwater sustainability is front and center, floodplains are part of the solution — not a relic of the past.

The Yolo Bypass Big Notch (named for the Big Notch it cut into the existing 100+ year old Fremont Weir) is upstream of the Delta shipping channel and well away from the deep-draft navigation corridor used by oceangoing vessels.

This kind of floodplain reconnection happens off to the side, during high-flow winter periods, without interfering with shipping, commerce, or the infrastructure Californians rely on every day. It’s restoration designed to coexist with flood protection and water management, not compete with them.

And that also brings the lesson home to the San Joaquin River.

We don’t have to choose between salmon and sensible water management. We can build projects that behave like floodplains again—on purpose, in the right places, in the right seasons—while keeping our farms productive and our cities supplied.

The Yolo Bypass shows what’s possible when science, engineering, and practicality line up. For communities along the San Joaquin River, it offers something we don’t get often enough in California water conversations — a working example that cooperation, not conflict, is how we move forward.

For more information and to watch a movie of the Big Notch in operation, visit:
https://water.ca.gov/News/Blog/2026/Jan-2026/Video-Fremont-Weir-overtops-for-the-first-time-with-Big-Notch-Fish-Passage-Facility