US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

U.S. Army Corps of Engineers Coastal Processes Modeling for

the Alaskan Coast

By Bruce Ebersole and Dr. Robert Jensen

Flood and Storm Protection Division

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

Overview

Wave Climate- Chukcki Sea to Aleutians

Wave Climate- Bering Straits to North Slope

Storm Water Level Climate – West and North Alaskan Coasts

Circulation Model of Cook Inlet

Storm Vulnerability and Shore Protection Design

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

Wave Climate - Chukchi Sea to the

Aleutians

• Hindcast done 1999-2001 using the WAM model

• Design of improved Delong Mountain Terminal

• 1985-2002 wave hindcast (June thru November each year)

• Time-varying ice cover considered • 15 Storms 1954-1983• Validated with buoy deployed 2000 and

2001 off DMT; NDBC buoy 46035 in Bering Sea for entire hindcast

Delong Mt Terminal

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

Wave Climate – Bering Straits to North Slope

Barrow

• Hindcast done 2003-2004 using WAM• Design of storm damage reduction

project at Barrow• 1982-2003 wave climate (June thru

December each year)• Time-varying ice cover considered • 30 Storms 1954-1981• Validated with Shell Oil buoy data; Sep-

Oct 1983 and Aug-Sep 1984• Validated with Corps shallow water

wave gage off Barrow - 2003 (have 2004 wave data)

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

North and West Coast of Alaska Storm Water Levels

Beaufort and Chukchi Sea Domain

North Pacific Domain• Storm water level hindcast done 2004-2005 using the ADCIRC model (tide plus wind surge)

• Design of Barrow project and vulnerability of western Alaskan native communities

• Approx 25 storms each domain, 6 overlapping• Storms from 1950s to 2003• Time-varying ice cover considered• Validation to tidal constituents and measured water

levels• Data saved for entire domain• Stage-frequency curves for combined tide and surge

at key sites

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

Storm Vulnerability Assessment and Shore Protection Project

Design (Barrow)• Wave and water level hindcast data as input• Shallow water wave transformation (STWAVE)• Set-up, run-up, erosion computed with SBEACH• Frequency of extreme coastal water levels

Special Output Locations from WAM - to STWAVE

October 1963 storm

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

Tidal Circulation Model of Cook Inlet/Port of Anchorage• Modeling work done in 2002-2004• ADCIRC model applied in 2D-DI mode• Circulation patterns as cause for excessive shoaling at Port

of Anchorage• Extensive validation using NOAA water level and ADCP data

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

Ideas for Partnering in Technology Transfer/Product Development

• Create web-accessible 20-yr wave climatology for northern and western coasts of Alaska + tools to meet stakeholder needs

• Extend to full year hindcast for western Alaskan coast, and expand to include southern Alaskan coast

• Create web-accessible 50-yr storm wave and water level climate database; with frequency-of-occurrence relationships + tools to meet stakeholder needs

• Annual climate and storm updates to the database• Extend hindcast looking back in time (improve look for patterns, cycles?)• Conduct threat assessment at native Alaskan communities using storm

wave and water level database + tools• Assessment done using simple wave transformation, set-up and run-up

computations or nearshore modeling approach (e.g. Barrow)• Provide web-based tools and guidance for conducting threat

assessments and evaluating shore protection design options

US Army Corpsof Engineers Coastal and Hydraulics Laboratory - ERDC

Ideas for Interagency/Academia R&D Collaboration

• Repeat hindcast with future estimates of changing ice cover to examine changing storm damage threat

• Examine potential for changing storm frequency to alter the storm damage threat

• Delve into the hindcast wave climate- knowledge “sleeps” in the data

• Impact of increased sediment loads into Cook Inlet, other inlets and estuaries

• Collaborate on technology advancement• joint wave, surge/circulation, sedimentation, beach erosion

model development• wave generation in rapidly turning wind fields• wind momentum transfer into waves and 3-D circulation,

with and without partial ice cover, arctic air/sea temp conditions

• beach erosion for gravel beaches, sandy cliffs, cliffs with permafrost

• terrain effects on winds, waves and circulation