Butte County Flood Mitigation Plan Butte County January 2006 Prepared by: BUTTE COUNTY FLOOD MITIGATION PLA N January 2006 Prepared by: TABLE OF CONTENTS EXECUTIVE SUMMARY ......................................................................................................... ix SECTION 1.0 INTRODUCTION............................................................................................ 1-1 BACKGROUND ......................................................................................................................... 1-1 Climate ................................................................................................................................. 1-1 Physical Features................................................................................................................. 1-1 Population and Economy ..................................................................................................... 1-1 Watersheds ........................................................................................................................... 1-1 GOALS OF THE FLOOD MITIGATION PLAN ............................................................................... 1-3 BUTTE COUNTY WATERSHEDS OVERVIEW ............................................................................. 1-4 Big Chico Creek Watershed ................................................................................................. 1-4 Butte Creek Watershed ........................................................................................................ 1-4 Cherokee Watershed ............................................................................................................ 1-4 Feather River/Lower Honcut Creek Watershed .................................................................. 1-4 Lake Oroville/Upper Feather River Watershed ................................................................... 1-5 Little Chico Creek Watershed .............................................................................................. 1-5 Pine Creek Watershed.......................................................................................................... 1-5 EXISTING BUTTE COUNTY FLOOD REGULATIONS ................................................................... 1-6 SECTION 2.0 PLANNING PROCESS ................................................................................... 2-1 PUBLIC INVOLVEMENT ............................................................................................................ 2-1 AGENCY COORDINATION ........................................................................................................ 2-2 LOCAL CAPABILITY ASSESSMENT ........................................................................................... 2-2 SECTION 3.0 RISK ASSESSMENT ...................................................................................... 3-1 BIG CHICO CREEK WATERSHED ............................................................................................. 3-2 BUTTE CREEK WATERSHED .................................................................................................... 3-4 CHEROKEE WATERSHED ......................................................................................................... 3-5 FEATHER RIVER/LOWER HONCUT CREEK WATERSHED .......................................................... 3-7 LAKE OROVILLE/UPPER FEATHER RIVER WATERSHED .......................................................... 3-9 ii Table of Contents January 2006 LITTLE CHICO CREEK WATERSHED ...................................................................................... 3-10 PINE CREEK WATERSHED ..................................................................................................... 3-11 OTHER FLOOD-RELATED HAZARDS: BRIDGES ..................................................................... 3-12 OTHER FLOOD-RELATED HAZARDS: LAND USE PLANNING ................................................. 3-13 OTHER FLOOD-RELATED HAZARDS: LOCAL DRAINAGE ...................................................... 3-15 ASSESSING VULNERABILITY: IDENTIFYING ASSETS ............................................................. 3-16 Critical Facilities ............................................................................................................... 3-16 Improvements Parcel Assets .............................................................................................. 3-17 ASSESSING VULNERABILITY: ESTIMATING POTENTIAL LOSSES ........................................... 3-48 Flood Insurance Premiums and Claims ............................................................................ 3-48 Repetitive Losses ................................................................................................................ 3-48 Damage Survey Reports ..................................................................................................... 3-51 Potential Losses Estimate .................................................................................................. 3-51 MULTI-JURISDICTIONAL RISK ASSESSMENT ......................................................................... 3-52 SECTION 4.0 MITIGATION MEASURES........................................................................... 4-1 BIG CHICO CREEK WATERSHED: LINDO CHANNEL DIVERSION .............................................. 4-2 BIG CHICO CREEK WATERSHED: SYCAMORE CREEK .............................................................. 4-3 BIG CHICO CREEK WATERSHED: ROCK CREEK-KEEFER SLOUGH SPLIT ................................... 4-4 BIG CHICO CREEK WATERSHED: CONFLUENCE OF BIG CHICO CREEK AND LINDO CHANNEL 4-5 BIG CHICO CREEK WATERSHED: ROCK CREEK ...................................................................... 4-6 BIG CHICO CREEK WATERSHED: SACRAMENTO RIVER .......................................................... 4-7 BUTTE CREEK WATERSHED: BUTTE CREEK LEVEES .............................................................. 4-8 CHEROKEE WATERSHED: CHEROKEE CANAL ......................................................................... 4-9 CHEROKEE WATERSHED: CHEMICAL FACILITIES STORAGE IN THE FEMA SFHA ................ 4-10 FEATHER RIVER/LOWER HONCUT CREEK WATERSHED: NORTH FORK OF DRY CREEK ........ 4-11 FEATHER RIVER/LOWER HONCUT CREEK WATERSHED: DRY CREEK TRIBUTARIES CONFLUENCE ........................................................................................................................ 4-12 iii Table of Contents January 2006 FEATHER RIVER/LOWER HONCUT CREEK WATERSHED: FEATHER RIVER ............................ 4-13 FEATHER RIVER/LOWER HONCUT CREEK WATERSHED: CITY OF OROVILLE STORMWATER DRAINAGE ............................................................................................................................ 4-14 FEATHE RIVER/LOWER HONCUT CREEK WATERSHED: WYMAN RAVINE .............................. 4-15 LAKE OROVILLE/UPPER FEATHER RIVER WATERSHED: CONCOW CREEK AND CIRBY CREEK ................................................................................................................................... 4-16 LITTLE CHICO CREEK WATERSHED: VEGETATION IN LITTLE CHICO CREEK ........................ 4-17 LITTLE CHICO CREEK WATERSHED: DEAD HORSE SLOUGH ................................................. 4-18 LITTLE CHICO CREEK WATERSHED: DRAINAGE IN LITTLE CHICO CREEK ............................ 4-19 LITTLE CHICO CREEK WATERSHED: UNCERTIFIED LEVEE .................................................... 4-20 PINE CREEK WATERSHED: PINE CREEK AND SINGER CREEK ................................................ 4-21 EMERGENCY PREPAREDNESS AND EVACUATION PLAN ......................................................... 4-22 Flood Threat Recognition .................................................................................................. 4-22 Flood Response .................................................................................................................. 4-32 Critical Facilities ............................................................................................................... 4-32 Shelters ............................................................................................................................... 4-32 Evacuation Routes ............................................................................................................. 4-35 Re-Entry to Evacuated Area .............................................................................................. 4-35 Post-Disaster Recovery and Mitigation ............................................................................. 4-35 COUNTYWIDE MITIGATION MEASURES: PUBLIC EDUCATION AND AWARENESS ................... 4-36 Map Information ................................................................................................................ 4-36 Outreach Projects and Educational Programs.................................................................. 4-36 Real Estate Disclosure ....................................................................................................... 4-37 Library ............................................................................................................................... 4-37 Technical Assistance .......................................................................................................... 4-37 COUNTYWIDE MITIGATION MEASURES: LAND USE PLANNING ............................................ 4-38 Butte County and Incorporated Cities General