California's Sacramento-San Joaquin Delta is formed at the confluence of the southward flowing Sacramento River and the northward flowing San Joaquin River where the waters join to flow into the Pacific Ocean via San Francisco Bay. Both the federal Central Valley Project and the State Water Project store water in the Sacramento River system and export it southward from the Delta. Water quality maintenance (salinity control) in the Bay-Delta system is accomplished by a hydraulic barrier sustained with reservoir releases in the otherwise low-flow (rainless) summer and fall periods. Water allocated to this purpose flows into the Bay and Pacific Ocean; it cannot be exported. This study presents the historic, social, economic, legal, institutional and engineering conflicts that surround these two competing water uses.