BY BRADEN CARRTWRIGHTDaily Post Staff Writer Palo Alto officials say the San Francisco Public Utilities Commission is hoarding water based on unrealistic drought projections, driving up rates and killing salmon. “This is a very serious problem. Very serious,” Councilman Ed Lauing said last Monday. “If it’s not stopped, this could cause severe rate hikes in water, and that is not what this council wants.” Utsav Gupta, a member of the city’s Utili…