California Code, Water Code - WAT § 85003

(a) Originally, the Delta was a shallow wetland with water covering the area for many months of the year. Natural levees, created by deposits of sediment, allowed some islands to emerge during the dry summer months. Salinity would fluctuate, depending on the season and the amount of precipitation in any one year, and the species that comprised the Delta ecosystem had evolved and adapted to this unique, dynamic system.

(b) Delta property ownership developed pursuant to the federal Swamp Land Act of 1850, and state legislation enacted in 1861, and as a result of the construction of levees to keep previously seasonal wetlands dry throughout the year. That property ownership, and the exercise of associated rights, continue to depend on the landowners' maintenance of those nonproject levees and do not include any right to state funding of levee maintenance or repair.

(c) In 1933, the Legislature approved the California Central Valley Project Act, which relied upon the transfer of Sacramento River water south through the Delta and maintenance of a more constant salinity regime by using upstream reservoir releases of freshwater to create a hydraulic salinity barrier. As a result of the operations of state and federal water projects, the natural salinity variations in the Delta have been altered. Restoring a healthy estuarine ecosystem in the Delta may require developing a more natural salinity regime in parts of the Delta.