Authorizes the Secretary and agency heads to work with State agencies in conducting a comprehensive assessment of California water demands and resources that take into consideration State, regional, and local circumstances. Requires the Secretary to: (1) recommend additional California water supply projects and activities; (2) develop and implement a related grant program; (3) establish a competitive loan and grant program to assist State and local agencies in financing projects not included in the Bay-Delta program; (4) recommend appropriate funding levels to implement chosen projects and activities; and (5) coordinate and manage activities consistently with the California ecosystem program, the Bay-Delta program, and the water supply program.