LUMMI NATION MULTI-HAZARD MITIGATION PLAN 2020 UPDATE Prepared For: Lummi Indian Business Council (LIBC) Funded By: U.S. Environmental Protection Agency Performance Partnership Grant (Grant No. BG-01J57901-0) Prepared By: Water Resources Division Lummi Natural Resources Department Contributors: Kara Kuhlman CFM, Water Resources Manager Andy Ross, LG, LHg, CFM, Water Resources Specialist III/Hydrologist Gerald Gabrisch GISP, GIS Manager Adopted by the Lummi Indian Business Council: September 15, 2020 Approved by the Federal Emergency Management Agency: October 1, 2020 This project has been funded wholly or in part by the United States Environmental Protection Agency under Assistance Agreement BG-01J57901-0 to the Lummi Nation. The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. TABLE OF CONTENTS 1. Introduction ......................................................................................................................... 9 1.1. Goals and Objectives .....................................................................................................10 1.2. Sections .........................................................................................................................11 2. Planning Process ...............................................................................................................13 2.1. Plan Preparation ............................................................................................................13 2.1.1. Plan Preparation 2007 Update .................................................................................14 2.1.2. Plan Preparation 2010 Update .................................................................................14 2.1.3. Plan Preparation 2015 Update .................................................................................14 2.1.4 Plan Preparation 2020 Update …………………………………………………………...15 2.2. Public Participation Process ...........................................................................................15 2.3. Existing Documents Review ...........................................................................................15 2.4. Plan Update Process ......................................................................................................17 2.4.1. 2007 Update ............................................................................................................17 2.4.2. 2010 Update ............................................................................................................19 2.4.3. 2015 Update ............................................................................................................21 2.4.4. 2020 Update ............................................................................................................23 3. LIBC Adoption ...................................................................................................................27 4. Description of the Lummi Reservation ...............................................................................29 4.1. Lummi Nation Government .............................................................................................29 4.2. Land Use and Socioeconomic Conditions ......................................................................29 4.2.1. Historical Land Use ..................................................................................................31 4.2.2. Current Land Use .....................................................................................................32 4.2.3. Future Land Use ......................................................................................................35 4.2.4. Population ................................................................................................................37 4.2.5. Socioeconomic Conditions .......................................................................................37 4.2.6. Utilities .....................................................................................................................42 4.2.7. Emergency Services ................................................................................................43 4.3. Topography ....................................................................................................................44 4.4. Climate ...........................................................................................................................45 4.5. Hydrogeology .................................................................................................................46 4.5.1. Hydrologic Soil Groups.............................................................................................48 4.6. Reservation Watersheds ................................................................................................49 4.7. Surface Water Resources ..............................................................................................49 4.7.1. Rivers, Sloughs, Streams, and Ditches ....................................................................49 4.7.2. Springs and Wetlands ..............................................................................................52 4.7.3. Estuarine and Marine Waters ...................................................................................55 5. Natural Hazard Risk Assessment ......................................................................................57 5.1. Assessment Areas .........................................................................................................57 5.1.1. Lummi Peninsula Assessment Area .........................................................................58 5.1.2. Floodplain Assessment Area ....................................................................................59 5.1.3. Northwest Upland Assessment Area ........................................................................59 5.1.4. Portage Island Assessment Area .............................................................................59 5.1.5. Sandy Point Peninsula Assessment Area.................................................................60 5.1.6. Gooseberry Point Assessment Area .........................................................................60 5.2. Cultural Resources .........................................................................................................66 5.3. Hazard Identification and Vulnerability Assessment .......................................................66 5.4. Floods ............................................................................................................................68 5.4.1. Profiles of Flood Hazards .........................................................................................68 5.4.1.1. Nooksack River Floods ......................................................................................69 Lummi Nation Multi-Hazard Mitigation Plan i 2020 Update 5.4.1.2. Sequence of Nooksack River Flooding ..............................................................70 5.4.1.3. Coastal Floods ...................................................................................................76 5.4.2. Effects of Past Flood Events ....................................................................................76 5.4.2.1. Effects of Nooksack River Floods ......................................................................76 5.4.2.2. Effects of Coastal Floods ...................................................................................80 5.4.3. Flood Vulnerability Assessment ...............................................................................84 5.4.3.1. FEMA Flood Zones ............................................................................................84 5.4.3.2. Nooksack River Flood Vulnerabilities .................................................................84 5.4.3.3. Coastal Floods Vulnerabilities ............................................................................87 5.4.4. Potential Flood Losses .............................................................................................88 5.4.4.1. Nooksack River Floods Losses ..........................................................................89 5.4.4.2. Coastal Floods Losses ......................................................................................89 5.5. Earthquakes ...................................................................................................................90 5.5.1. Profiles of Earthquake Hazards ................................................................................90 5.5.1.1. Types of Earthquake Hazards ...........................................................................90 5.5.1.2. Measurement Scales of Earthquakes and Earthquake Damages ......................91 5.5.1.3. Types of Earthquakes ........................................................................................94 5.5.2. Effects of Past Earthquake Events ...........................................................................95 5.5.2.1. Subduction Zone Earthquakes ...........................................................................95 5.5.2.2. Intraplate Earthquakes .......................................................................................98 5.5.2.3. Crustal Earthquakes ..........................................................................................99