Human Modifications (historical, modern) Altered Processes that Stress Ecosystem Function (physical, biological, chemical) Indicators of Poor Ecosystem Function (physical, biological, chemical)
Historic Habitats (high variability) Modern Habitats (low variability)
Extensive and Dynamic Floodplain- Marsh Interface Managed Floodplain, Small and Static Marsh Interface YOLO BYPASS
From Many Branching Dead-End Channels to… (high variability) …Fewer Channels and Fully Connected Loops (low variability) Constructed Channels
2 Billion Cubic Yards Washed Downstream
Flow Regulation, Sediment Capture, Water Temperature, Habitat Access Loss (reduces variability) Shasta Dam and Lake
Storage, Diversions, Exports, Agriculture (reduces variability) Sacramento River Basin Component San Joaquin River Basin Component Million Acre Feet (MAF) Million Acres Total Reservoir Capacity
Harmful Invasives: More Will Come (most thrive in low variability) Striped Bass Largemouth Bass Asian Clam Brazilian Waterweed
Discharges: Point Source (Urban, Agriculture, Industrial), Non-Point Source
1873TODAY Flow and Gradients to Bay (High System Variability) Flow and Gradients Strongly to Pumps (Low System Variability)
Net Delta Outflow (Million Acre Feet per Month) Unimpaired Delta Outflow Historical Delta Outflow Diversions & Exports Decrease Delta Outflow Releases Increased Fall Delta Outflow (Reduces Variability)
Steep slope Levee/ Hard Shoreline Sea Level Rise T2T1T2T1 Gentle slope Ample Limited None Shoreline Type Estuarine Transgression and Sea Level Rise Sea Level Rise Accommodation
Understanding “how” and “why” = tools for Delta Plan Variability is key – foundation of all native estuarine species evolution Our challenge is tackling historical changes and modern threats (habitats + processes + stressors) THANK YOU ! Browns Island Oct 2003 Photo: S. Siegel
Subsidence The “Deep” Delta Levee Protection Agricultural Salinity Needs Greenhouse Gases
Lots of Tides + Controlled Rivers + Export Flows to Pumps = LOW VARIABILITY