Port of Hood River Waterfront Recreation Committee Hood River Delta Historical Overview Existing Conditions Future Changes
Historic Perspective Sand Bar was present before Bonneville Speed of Hood River is faster than Columbia Delta is caused by Hood River meeting Columbia Several sand moving forces exist
1930
1935
1967
Wind River 35
Cascade Locks 1935
Rock Creek 1930
Patterns Changes to river system caused by: –Railroad construction –Bonneville Dam –Control dikes –Freeway construction –Dam Pool management Similar patterns exist along river
Current Conditions Sand bar has existed for many years Bar slowing increasing in size Major Hood River flow events cause significant change –Flood of ’96 –Flood of ’06 High Columbia flows erode/change bar
2005
2007
Comparison
Current Conditions
Animation
Process Details Friction-dominated deltas are associated with high bed friction and shear stress. These stresses cause the flow to slow down rapidly and deposit sediment with a wider lateral extent than the inertia- dominated deltas. The river/basin setting for this type of situation is more common. It consists of a shallow water level where the river flow and basin meet. This shallow area is a major factor in producing a friction-dominated delta. Features associated with this type of delta include subaqueous levees, middle ground bars (fining seaward), and bifurcated channels.
Friction-Dominated Delta
Future Delta is searching for Equilibrium Equilibrium is not static Public impact is possible with “equilibrium” Meteorological event frequency hard to predict
Quantities Additional Sand on existing bar –Estimated at 8 ft average = 750,000cy Additional Sand Bar area 26 acres –Additional sand volume = 750,000 cy Removal cost/yard varies by method
Hood River Profile
Issues Recreation –Opportunities –Separation –Uses –Safety Commerce –Tour boat dock access –Event Site impact