San Joaquin River Restoration Program
The Dos Rios Ranch and the San Joaquin River NWR projects link recovery actions in the Sacramento/San Joaquin Delta with the target restoration reaches of the San Joaquin River Restoration Program, sitting 26 river miles north of the Restoration Program, and bordering the legal Delta. The proposed boundary expansion for the San Joaquin River National Wildlife Refuge would improve connectivity amongst these initiatives even further.
When the SJR Restoration Program reaches its target of reconnecting previously dry stretches of the San Joaquin River with the Delta, restored salmon populations will pass through this area twice in their lives: once when returning to natal spawning areas from the sea as adults, and again as juveniles out-migrating to the sea. Juvenile salmon face many threats during outmigration including predation by non-native fishes (sport fish such as striped bass and large mouth bass), getting lost in dead-end canals and diversions, or being taken by pumps used to divert river water for human use. This project will provide opportunities for out-migrating juvenile salmon to forage on seasonally inundated floodplains – floodplains that harbor fewer predatory fish, and greater quantities of fish food. Studies from the Yolo Bypass (Knagg’s Ranch) and Cosumnes River Preserve show that fish allowed access to seasonally inundated floodplains grow much larger much faster than fish forced to rear in the river’s channel. Bigger fish can avoid predation and have a higher likelihood of making it to the ocean.
The San Joaquin River boasts the most southerly inland anadromous fish run in North America, which historically was dominated by spring-run type. Spring-run salmon migrate in from the sea during the spring snowmelt period (March – May) and hold over in deep pools during the warm summer months to spawn in the fall and winter. Spring snowmelt floods flush juveniles back out to sea. Floodplain reconnection during this spring snowmelt period is crucial for salmon recovery, but also coincides with the growing season for all agricultural products in the region. This project capitalizes on opportunities to compromise between ag production and fish production as lands that are very expensive to farm are converted to high-quality fish nurseries, and water supply reliability for regional agriculture is enhanced.
While the quantity of floodplain restoration needed to recover a self-sustaining population of spring-run Chinook salmon is widely debated, multiple-benefit flood protection projects like this one likely provide the most politically feasible progress towards salmon recovery with the greatest public benefit. We promote the development of multiple-benefit flood control projects that will bolster overlapping conservation initiatives while enhancing water supply reliability, recreation, environmental quality and regional economic sustainability.