▸ 6:00 : Doors Open ▸ 6:10 : Presentation ▸ 6:40 – 8:00 : Open House 1
Update of King County Communities’ FEMA Flood Insurance Rate Map Open House March 21, 2018 2
Agenda • Background of the National Flood Insurance Program • Flood Study Map Update • Process and Schedule • Open House Layout 3
King County Communities Background of the National Flood Insurance Program 4
Purpose of the National Flood Insurance Program (NFIP) The NFIP is a Federal program enabling property owners in participating communities to purchase insurance as a protection against flood losses in exchange for State and community floodplain management regulations that reduce future flood damages . ...If a community adopts and enforces a floodplain management ordinance to reduce future flood risk to new construction in floodplains , the Federal Government will make flood insurance available within the community as a financial protection against flood losses. Program started in 1968. 5
Purpose of the National Flood Insurance Program (NFIP) 6
Basis for Floodplain Mapping 1% Annual Chance Flood (“100 - year”) Standard 1,125,000 Miles of River are mapped for the NFIP – on average 11,250 miles of river are seeing the 1% flood or greater every year. 42,500 Miles of Coastline are mapped – on average 425 miles of coastline are seeing the 1% flood or greater every year. 7
Purpose of the National Flood Insurance Program Reduce duce economic onomic loss ss cause sed d by flood ood events ents • Between 1980 and 2013, the United States suffered more than $260 billion in flood- related damages. • Flooding accounts for approximately 85% of all disaster declarations. • On average, more people die annually from flooding than any other natural hazard. Graphs from http://www.nws.noaa.gov/hic/ With adjustment for katrina 8
Purpose of the National Flood Insurance Program Reduce uce economic omic loss ss caused d by flood d events ts 9
King County Flood Insurance Claims 1977-Present Community Claims Paid Building Contents Total Auburn 6 $ 44,223.24 $ - $ 44,223.24 Bellevue 35 $ 642,502.31 $ 119,102.93 $ 761,605.24 Burien 10 $ 75,323.02 $ 8,730.57 $ 84,053.59 Carnation 21 $ 634,440.21 $ 122,206.47 $ 786,646.68 Des Moines 5 $ 216,514.76 $ 4,237.18 $ 220,751.94 Duvall 4 $ 136,708.84 $ 9,802.75 $ 146,511.59 Enumclaw 3 $ 56,801.50 $ 12,699.15 $ 69,500.65 Federal Way 3 $ 17,532.90 $ 2,132.60 $ 19,665.50 Issaquah 125 $ 3,089,181.06 $ 892,651.36 $ 3,981,832.42 Kenmore 1 $ 14,697.30 $ - $ 14,697.30 Kent 15 $ 148,628.44 $ 1,205.06 $ 149,833.50 Unincorporated King County 1000 $ 18,654,592.46 $ 3,045,796.34 $ 21,818,494.17 Kirkland 4 $ 40,083.87 $ 4,434.97 $ 44,518.84 Lake Forest Park 1 $ 1,886.44 $ - $ 1,886.44 Mercer Island 2 $ 20,830.35 $ - $ 20,830.35 Milton 4 $ 70,379.73 $ - $ 70,379.73 Normandy Park 3 $ 13,978.43 $ - $ 13,978.43 North Bend 61 $ 826,087.52 $ 159,679.81 $ 985,767.33 Pacific 35 $ 579,145.56 $ 19,864.30 $ 599,009.86 Redmond 5 $ 22,290.75 $ - $ 22,290.75 Renton 10 $ 71,134.89 $ 13,840.03 $ 84,974.92 Sammamish 2 $ 41,996.22 $ - $ 41,996.22 SeaTac 1 $ 1,319.24 $ - $ 1,319.24 Seattle 122 $ 1,692,480.66 $ 358,460.87 $ 2,050,941.53 Shoreline 1 $ 4,021.74 $ - $ 4,021.74 Skykomish 23 $ 362,992.17 $ 11,247.47 $ 374,239.64 Snoqualmie 872 $ 15,570,635.09 $ 2,300,850.94 $ 18,114,839.26 10 Tukwila 1 $ 1,309.89 $ - $ 1,309.89 Total 2375 $ 43,051,718.59 $ 7,086,942.80 $ 50,530,119.99
Flood Definition From FloodSmart.com: A flood is a general and temporary condition where two or more acres of normally dry land or two or more properties are inundated by water or mudflow. 11
Mandatory Purchase Requirement Two federal statutes mandate purchase of flood insurance • The Flood Disaster Protection Act of 1973 • The National Flood Insurance Reform Act of 1994 ▸ Applies to properties in the 1% Chance Floodplain • Insurance is a prerequisite to receive a loan from Federally regulated and insured lenders. • The requirement is triggered when a loan is: Made Increased Renewed Extended • The insurance must be in effect for the life of the loan. • Monetary penalties on lenders for non-compliance, requires escrow accounts for other insurance purposes, and requires that lenders review flood maps and map changes. 12
How the National Flood Insurance Program (NFIP) Works Three disciplines of the NFIP: Mapp pping ng – • Fl Floo ood d Studi dies Regulations lations • Ins nsuran rance ce • 13
King County Communities Review of the Flood Study Map Update 14
Map Modernization Process ▸ New maps are digital county-wide ▸ Follows a USGS Quad layout – countywide coverage with no city “cut - outs” ▸ Re-delineation of flooding sources where better topography was available ▸ Vertical Datum change (NGVD 1929 to NAVD 1988) 15
What’s new Vertical tical Da Datum tum Chang ange ▸ NGVD 29 • Based on a mean sea level from 21 tidal stations in the US & 5 stations in Canada ▸ NAVD 88 • Based on the density of the Earth instead of varying values of sea heights • More accurate ▸ Conver versio sion n for King Count nty y Varies ies • NGVD + (vertical adjustment’) = NAVD • Conversion factor for County for FIS ranges from 3.5 to 4.1 feet 16
Digital Flood Insurance Rate Maps Vertical Datum and FIRMs (e.g. uses 3.8’ conversion) NGVD D 29 NA NAVD VD 88 15 15 15 15 10 10 10 10 5 BFE E = 2 2 ft ft BFE E = 5 5.8 ft 5 0 0 17
King County DFIRM Timeline Hi History • Scoping Meeting – July 27, 2005 Discuss proposed scope of work, identify available data and update needs, 25 Attendees • Levee Certification Documentation Needs Identified – April 2006 • Preliminary Map Release – September 2007 • King County Appeal – February 2008 • Revised Preliminary Map Release – November 8, 2010 • FEMA Letter to Senators on Levee Policy – March 2011 18
King County DFIRM Study Timeline Hi History y 19
Seclusion (2017) Seclusion and appealable areas 38 map panels 20
Riverine Floodplain and Floodway Definitions 100 YEAR FLOODPLAIN FLOODWAY FLOODWAY FRINGE SURCHARGE FLOODWAY + FLOODWAY FRINGE = 100 YEAR FLOODPLAIN SURCHARGE NOT TO EXCEED 1.0 FEET 21
Survey Collection • Collected by Minister Glaeser Surveying in 2006 • 42 bridges • 282 cross sections • 40.5 miles of stream LiDAR Survey 22
Hydrologic Methods Frequency EXCEEDANCE FREQUENCY IN PERCENT 99.0 98.0 95.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 5.0 2.0 1.0 0.5 0.2 0.1 1,000,000 9 8 7 6 5 4 F 3 2 l DISCHARGE (cfs) 100,000 9 8 7 o 6 5 4 3 w 2 10,000 SKAGIT RIVER NEAR CONCRETE HEC-FFA COMPUTED CURVE USGS #12194000 EXPECTED PROBABILITY ADJUSTMENT UNREGULATED PEAK FLOWS 5% CONFIDENCE LIMITS DERIVED FROM PEAK VERSUS 1DAY REGRESSION 95% CONFIDENCE LIMITS CORPS OF ENGINEERS, SEATTLE DISTRICT MEDIAN PLOTTING POSITIONS 28 APR 1998 LOG TRANSFORM BASIN AREA= 2737 SQ MI SYSTEMATIC STATISTICS NUMBER OF EVENTS WATER YEARS OF RECORD HISTORIC EVENTS= 1898, 1909, 1917, 1921 MEAN= 4.9744 HISTORIC EVENTS= 4 ST. DEV.= 0.1744 HIGH OUTLIERS= 0 RECORDED EVENTS= 1925, 1944-1991, 1994-1996 COMPUTED SKEW= 0.6973 LOW OUTLIERS= 0 CONSTRUCTED BY: APPROVED BY: REGIONAL SKEW= 0.0000 ZERO OR MISSING= 0 ADOPTED SKEW= 0.5000 SYSTEMATIC EVENTS= 52 HISTORIC RECORD= 99 YRS ____________________________________ C. FITZGERALD, E.I.T. 23
Hydraulic Methods Method Description • Steady State HEC-RAS model • Roughness is examined closely (calibrated to gages) • High water mark data were collected by nhc and MGS for Detailed (Zone AE) the high flow events of January 7, 2006, November 11, 2006, and March 25, 2007 • Floodway Analysis 24
Green River Scope of Work (2010) 25
Why Modify our Current Approach? ▸ Throughout Map Modernization, stakeholders expressed concern on the “without - levee” procedures used to map non-accredited levees ▸ In February 2011, a group of U.S. Representatives and Senators wrote to FEMA requesting a revision to the current practice of mapping levees and their associated flood risk. ▸ Stakeholders and Congress felt the historical mapping approach did not reflect the hazard reduction that some non-accredited levees may still afford. 26
Levee Policy Process ▸ Th The e King County ty Fl Flood d Insur surance ance Stu tudy y has s bee een on ho hold as i s it t waits ts for r FEMA A to to f finalize alize a ne new appro roach ach in sh showin ing g floodp oodplains lains on th the landwa ward rd si side of leve vees es th that t are re not t accre redit ited ed to to pr prote tect t against nst the th e 1% f flood. ood. 27
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