Assessment of the Hood River Delta Hood River, Oregon Pacific Northwest Waterways Association Annual Meeting October 13, 2010 Michael McElwee, Executive Director Port of Hood River
Overview U.S. Army Corps of Engineers (Portland District) Planning Assistance to States (PAS) Program Conducted Jan. 2007- July 2010 Study Elements: Delta Evolution & Modeling Economic Impacts Habitat Assessment Intervention Strategies
Port of Hood River
Port of Hood River Mission: Economic Growth and Quality of Life in the Columbia Gorge Interstate Bridge Recreation Sites Marina Ken Jernstedt Airport
Port of Hood River Light Industrial Properties Hood River Waterfront 2010
Port of Hood River
November 7, 2006
November 7, 2006
Assessment Methodology Delta Evolution Hood River Watershed November 2006 Event Predictive Modeling
Delta Evolution Pre-1938 - Before Bonneville Steep, alpine tributary entering active Columbia Two dams upstream of Hood River on Columbia River or major tributaries Impacts - Significant, sustained freshet - Deposition creates elongated bars/islands downstream
1930
1935
1938 through 1970s Bonneville Dam/37 upstream dams Steep tributary entering calm water body - the Bonneville Pool Impacts - Reduction in magnitude of freshet - Changed temporal variation in flow - Sediment deposited in fan shape--a delta forms
1948 Columbia River @ 1,000,000 ft3/s
1950 Hood River Waterfront looking southwest
1960s and 1970s Extensive Waterfront fill Control Structures Built Impacts - Limits lateral variation in Hood River - Mouth moves 600 meters northward - Deposition shifts northward toward navigation channel
1967
2005
2007
1934-2008
Hood River Watershed
Sediment Sources Columbia River Hood River Basin West, Middle, and East Forks Average daily sediment discharge (Q s ) of Hood River 280 tons/day at 1500-1600 ft 3 /s (Ref: USGS, 1914) and average annual sediment discharge - 40,000 tons/year (Ref: USAE, 1937) December through March High sediment discharge associated with floods
Sediment Sources (cont.) Lahars* or glacial outburst floods Coe, Eliot, Ladd, and Newton-Clark Glaciers Previous 100 years, 20-25 lahars triggered by glacial outburst floods Initiated by volcanic activity Coe Glacier/ Coe Branch 1963 Ladd Glacier/Ladd Creek 1961 Induced by hydrologic events Polallie Creek 1980 Eliot Glacier/Eliot Branch of Middle Fork 1999 Eliot Glacier/Eliot Branch of Middle Fork 2006 * A water saturated mass of rock and sediment- appearing like wet cement - that flows down a glacial outwash valley
Sediment Sources (cont.) Glacier retreat and hydrologic induced debris flows Nearly all glaciers in Cascades are retreating Two Mount Hood glaciers have retreated significantly since 1901 the Ladd and Eliot Glaciers Glacial retreat and hydrologic events increase number of debris flows North of Mount Rainier rapid snowmelt in mid summer South of Mount Adams - heavy rainfall in late fall and early winter before much snow accumulation
November 2006 6 to 8 November heavy rainfall, snow on ground at higher elevations of basin, pre-winter conditions 7 November early morning - glacial outburst flood initiated by collapse of upper section of west lateral moraine of Eliot Glacier, debris moved downslope 25-30 km/hr 7 November - 0730-0800 a.m.- peak of outburst flood recorded at USGS Gage at Tucker Bridge
Eliot Glacier (July 2005) Eliot Glacier (December 2006)
20000 USGS Gage 1412000; Hood River @ Tucker Bridge 18000 16000 14000 12000 Flow (cfs) 10000 8000 6000 4000 2000 0 5 6 7 8 9 Elapsed Time, hours Nov2006 TUCKER BRIDGE OBS FLOW
1% rainfall 20 10 Maximum Rainfall Frequency Curves for Hood River Experimental Station Period of Record 1928-2005 Rainfall Totals for Storm Period, inches 5 2 1 0.5 November 2006 November 2006 Rainfall Duration 1-day Rain 3-day Rain February 1996 February 1996 0.2 99.90 99.50 98.00 90.00 70.00 50.00 30.00 10.00 2.00 0.50 0.10 0.01 Percent Chance Exceedance
Discharge, ft3/s 26,000 24,000 22,000 20,000 18,000 16,000 Nov-2006 14,000 Feb-1996 Nov-1995 12,000 10,000 8,000 6,000 4,000 2,000 0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 Hydrographs for Alternative Flow Conditions
Modeling Hydrodynamic simulations of flow in Hood River and Columbia River using 2-D finite element models RMA-2, ADH Tracking sediment (transport and fate) the Particle Tracking Model PTM
Model Domain (plan)
Model Domain (perspective 5x vertical exaggeration)
Conditions Simulated Hood River low frequency of occurrence flows (e.g. February 1996) low frequency of occurrence flows with glacial outburst flood (e.g. November 2006) high-average flow (December-March) average flow May and June Columbia River freshet (May and June flows) average flow in November and December average flow December-March
Sediment Transport Conditions Simulated Hood River Sediment concentrations during floods (C s = 1000 to 5000 p.p.m.) Very high concentrations during glacial outburst flood (C s = 100, 000 to 200,000 p.p.m.) Average concentrations (Dec-Mar) (C s = 60-100 p.p.m.) Columbia River C s = 0.0 p.p.m.
Freshet - (hydrodynamics)
High Flow and Outburst Flood (hydrodynamics)
High Flow and Outburst Flood (sediment tracking)
Deposition: High Flow/Average Sediment
Deposition: Glacial Outburst
Conclusions - Overall Glacial retreat means increase debris flows initiated by hydrologic events For Hood River Basin - heavy rainfall in November and December Likely flow path is the Eliot Branch of the Middle Fork 15 km (9 mile) debris flow impacts is not valid But, November event was rare, system changing event with respect to both volume of sediment that slid in the outwash valley and distance transported
Debris Flows will continue Immediate and significant deposition at Hood River Probability of reoccurrence can not be determined Aggradation will continue through average sediment discharges during seasonal high flow and increased sediment discharges during floods Probability of event recurring in the future can be determined Future conditions at the Delta can be estimated - deposition volume and patterns
Conclusions - Delta Moderate erosion will occur on northern and eastern (upstream) edge No impact to shipping channel even in future debris flow scenarios Limited erosion will occur at the western (downstream) edge Increase in sediment levels will mean riparian plant growth
Conclusions - Port Facilities No action required to maintain Marina access Nichols Basin/Cruise Ship Dock permanently blocked without significant, ongoing dredging Event Site constriction will increase Jetty construction would favorably alter flow conditions.. but potential for increased navigation hazards
May 2009
Comparison 1/07 to 5/09
Delta Management - Safety - Access - Recreation - Habitat
Credits (USACE Portland District) Col. Steven R. Miles, P.E., Commander Kevin Brice, P.E., PMP, Deputy District Engineer for Project Management Jeremy Weber, Project Officer Kathleen A. Warner, Project Officer James D. Crain, P.E., Geo-morphologist (Special Thanks to Col. Thomas E. O Donovan, P.E. Commander ) Consultants Andrew Jansky, P.E., Flowing Solutions Inc. Port Staff Laurie Borton, Operations Manager