Gravel Augmentation Update Recreation and Park Commission Lilly Allen 5/25/16
Overview • Why Gravel Projects? • Past Projects • 2016 Project • Questions? • If interested & time allows: – Underlying Science – Beyond 2016
Declining Fish Habitat Central Valley dams have drastically reduced habitat.
Overview • Why Gravel Projects? • Past Projects • 2016 Project • Questions? • If interested & time allows: – Underlying Science – Beyond 2016
2008 2011 Upper Sailor Bar Upper Sunrise Downstream 2010 Upper Sunrise Side Channel 2014 Nimbus Basin Lower Sailor Bar 2012 2009 Upper Sailor Bar 2013 Upstream River Bend 7 Sites ranging from 0.7 – 5 acres
2014 Nimbus Basin
Before 2014 Site – Nimbus Basin Lower American Gravel Augmentation and Side Channel Creation
After 2014 Site – Nimbus Basin Lower American Gravel Augmentation and Side Channel Creation
Nimbus Basin Before After
Overview • Why Gravel Projects? • Past Projects & Results • 2016 Project • Questions? • If interested & time allows: – Underlying Science – Beyond 2016
Sacramento Bar 2016
Current Condition
Proposed Changes 18.6 acres
Public Outreach: Mailers & Signs
Disturbance
Woody Material Placement
Questions?
Overview • Why Gravel Projects? • Past Projects & Results • 2016 Project • Questions? • If interested & time allows: – Underlying Science – Beyond 2016
American River Specific Habitat Suitability Criteria 1. Velocity 2. Depth 3. Gravel Size
2010 Site – Upper Sunrise
A New (additional) Design Criterion 1. Depth 4. Hyporheic Flow (Froude Number)
New Horizons in Design Calculating hyporheic flow using Froude numbers / Fr V gD Helps indicate Gravity boundary between Inertia = ------------ turbulent and Fr = Froude Number V = Water Velocity laminar flow g = Gravity conditions D = Hydraulic Depth We can use this to better predict where salmon will spawn
After Before Density = 3.25 per m 2 1m Density = 0.10 per m 2 1m <3 juvenile fish per 25 m 2 >82 juvenile salmon per 25 m 2
Overview • Why Gravel Projects? • Past Projects & Results • 2016 Project • Questions? • If interested & time allows: – Underlying Science – Beyond 2016
What do they need? General salmon life cycle 2) Adult Spawning 3) Embryo and Alevin Incubation 1) Adult Immigration and holding 4) Juvenile Rearing 5) Juvenile Emigration
Juvenile Rearing Complex side channel habitat
Questions?
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