FEMA Region VIII Reducing Losses through Higher Regulatory Standards 2013 Colorado Floods Case Study...

FEMA Region VIII

Reducing Losses through Higher Regulatory Standards

2013 Colorado Floods

Case StudyMay 2015

HMTAP HSFEHQ-09-D-1129 / 14-J-0003

2Reducing Losses Through Higher Regulatory Standards

Overview

• Losses Avoided Study• Comparison of two damage scenarios

• The losses before and the losses after a regulation was enacted

A losses avoided study strives to answer the question:What would have happened if this measure wasn’t implemented?

Can a dollar value be put on the savings?

• Best Practices Report• Mitigation measures effective in reducing flood

damages and economic losses


Summary of the 2013 Colorado Floods

• Widespread notable event

• NOAA determined that the event was a maximum 1,000-year rainfall event

• Unprecedented rainfall resulted in catastrophic flooding

• In four days, more than 17 inches of rainfall was recorded in Boulder County

Rainfall amounts across the impacted area, majority of intense rainfall was in the three study counties – Boulder, Larimer, and Weld


Reducing Losses Through Higher Regulatory Standards

Loss Summaries – SBA, IA and NFIP

• Total 2013 Colorado event losses determined from Federal assistance programs

• National Flood Insurance Program (NFIP)

• Individual Assistance (IA) Program

• Small Business Administration (SBA)

• Includes verified program losses for Boulder, Larimer and Weld counties

SBA

NFIP

IA

$200 millionBoulder, Larimer and Weld Counties

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Loss Summaries – IA Losses in Basements


Boulder

Larimer

$12 million

Weld

• Total basement only losses • Includes losses in properties

that reported a flood high water mark in the basement

• More than 6,500 properties

• IA claims• 51% of the applications were for

basement only losses• Basement only losses are 22%

of the total IA losses

• More than 93% of basement only claims were located outside of the SFHA

Boulder, Larimer and Weld Counties

Loss Summaries – Erosion


• Can the losses due to erosion be quantified?• Aerial imagery was used to identify structures

• 34 found• Most were located in Jamestown (Boulder County)• Total FEMA IA verified losses were $1.48 million

Erosion damage in Jamestown, Colorado

Loss Summaries – Letter of Map Change


• Were LOMA, LOMR-F, and LOMC structures impacted?

• LOMCs effectively remove the requirement for flood insurance for the structure

• LOMA: Letter of Map Amendment

• LOMR-F: Letter of Map Revision Based on Fill

• LOMC: Letter of Map Change

• Boulder, Larimer, and Weld had structures with LOMAs and LOMR-Fs that had IA, SBA, and/or NFIP claims

• Average losses of structures with LOMCs are relatively low when compared to structures without LOMCs

Summary of the 2013 Colorado Floods – Types of Flooding

Reducing Losses Through Higher Regulatory Standards 9

• Alluvial fans - formed in mountainous regions by floodwater that fans out when it reaches the valley

• Flash flooding - fast moving, deep floodwaters with potential to cause channel migration

• Riverine - floodwaters overflow stream channel banks, which may cause erosion and scour

Riverine Flooding - Example of Scour

Alluvial Fan Flooding - Example of Debris

Flash Flooding - Example of Channel Migration

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Summary of 2013 Colorado Floods - What’s Unique About This Study?

• The nature of the event and the impacted communities provided ample data to look at a range of floodplain management practices

• Differences in floodplain management practices among communities provided an opportunity to compare and contrast effectiveness of the practices

Channel Migration in Longmont, CO


Regulatory Losses Avoided Study (LAS) – Phase I: Study Area Selection


• 3 counties selected (Boulder, Larimer, Weld) and 43 jurisdictions

CO Losses Avoided Data Summary (Boulder, Larimer, Weld)

IA: 21,442 applicants, $56M FVLNFIP: 1,769 claims, $51MSBA: 1,832 applicants, $91MStructure Points (363K)• Building Area/Value• Year Built• Foundation Type• Num Stories, etc

HWMs, event and regulatory depth grids, soil erosion/deposition

Flood Extent Depth Grid Creation and Loss Estimation

Data

• LiDAR• High Water Marks• Post-Event Imagery

Analysis

• Event and Regulatory Depth Grids

Losses

• Event losses (IA, NFIP, SBA)• Model scenarios using GIS

and Hazus


Regulatory Losses Avoided Study (LAS) – Phase I: Project Development

• Select regulatory standards to evaluate• Define scenarios

Regulation Scenario

Floodplain development No development allowed in SFHA

Floodway development No development allowed

Critical facility siting No development allowed in SFHA

Freeboard 1) Implemented earlier2) Not implemented at

all3) Higher or lower

freeboard

Erosion setback No development allowed Freeboard

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• Created geospatial modeling tools to prepare, analyze, and export the data

• Data Preparation Tool• Data Export Tool• Data Analysis Tool

Data Preparation Tool: prepares the data for analysis and if structure data are incomplete, utilizes assumptions to estimate values for foundation type and building square footage

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Data Analysis Tool: runs scenarios using 100-year flood and 2013 flood event data plus regulatory information to estimate regulatory losses avoided

General

Building

Contents

Displacement

Loss of function

Social and Environmental

Mental stress and anxiety

Loss of productivity

Environmental



• Define general and social and environmental benefits to use to quantify losses

• Assign benefits to scenarios

Benefits EvaluatedBenefit Cost Variables

Building Occupancy

Type

Depth Damage

Functions

Number of Occupants

Benefit Factors

Scenario: Freeboard


• Regulation• Freeboard

• Three freeboard scenarios

1. Freeboard regulated earlier

2. Freeboard not regulated

3. Freeboard regulated to a higher or lesser standard

• Criteria• SFHA structures

Freeboard Concept

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Scenario: What if No Freeboard IN THE 2013 FLOOD EVENT


• Damage reductions from existing freeboard regulations in the 2013 event:

• $136 million in Boulder County• $1.8 million in Larimer County• $0.9 million in Weld County

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Scenario: Freeboard Increased by 2 FeetIN THE 2013 FLOOD EVENT


• If freeboard was increased by 2 feet, there would be a decrease in estimated losses of over 74% in Boulder, Larimer and Weld Counties in the 2013 flood event

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Scenario: No Freeboard IN THE 100-YEAR FLOOD EVENT


• Damage reductions from existing freeboard regulations in the 100-year event:

• $1.5 billion in Boulder County• $71 million in Larimer County• $73 million in Weld County


Elevation with Freeboard and Stream Setbacks• Estes Park has proactive

standards that provided protection in the 2013 floods• Required freeboard of 1 foot

with recommended freeboard of 2 to 3 feet above 100-year flood

• Stream setbacks in land use code

• Floodplain development restrictions

Case Study

Left - Estes Park business owner next to his building that was not damaged in the 2013 flooding due to elevating the structure. Right - View behind elevated structure looking at the Big Thompson River during the 2013 flood.

Best Practice - Freeboard

Scenario: Floodplain Development Restrictions - Best Practices

Channel Improvements

• Longmont, Left Hand Creek Channel Improvement Project

• Pre-Disaster Mitigation (PDM) project

• Improved channel design:• Reduced the size of the

SFHA• Removed more than 100 homes from the SFHA

• Project cost = $5.7 million• Total losses avoided in

2013 event = $22 million• ROI = 3.91

23

Case Study

Left Hand Creek Channel Improvement Project in Longmont, Colorado


Scenario: Floodway Development Restrictions

• Regulation • No development permitted in the floodway

• Criteria • Structures located in the floodway


County Total number of floodway structures

Boulder 523

Larimer 444

Weld 90

Typical Riverine Floodplain Cross Section Showing the Floodway

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Scenario: No Floodway Development IN THE 100-YEAR FLOOD EVENT


• Most (59%) of the total losses avoided are in Larimer ($64 million)

• Larimer has the greatest number of impacted floodway structures, with twice as many acres considered floodway parcels than Boulder or Weld

Regulatory LAS Summary - Floodway


Floodway Development Restrictions • Poudre River Acquisition and Open

Space Preservation in Fort Collins’ 100-year floodplain• 55 acres of parks• 924 acres of natural areas• 979 acres out of 1,485 of floodplain

acres preserved within city limits• Two-thirds (66%) of the 100-year

floodplain preserved as open space

• Very minor damage in Fort Collins from 2013 flood (50-year RI event)

Case Study

Open Space preserved in McMurry Natural Area and Legacy Park along the Poudre River in Fort Collins reduced flood impacts in the September 2013 event.

Best Practice Scenario: Outreach Projects

• Communities that participate in the NFIP’s Community Rating System (CRS) can qualify for insurance premium discounts

• Reviewed outreach score of Community Rating System (CRS) communities in study area to determine any correlation between NFIP policies, claims, and CRS score for outreach projects (c330 score)

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CRS Communities

Boulder County – CRS Class 7 City of Louisville – CRS Class 8

City of Boulder – CRS Class 5 City of Fort Collins – CRS Class 4

City of Longmont – CRS Class 8 City of Loveland – CRS Class 7


Best Practice Scenario: Outreach Projects - Key Findings

• Communities with higher outreach scores tend to have more NFIP policy holders and reduced average claims

• Successes and challenges• Success influenced by

variety of factors• Increased awareness of

flood risk• City of Boulder and Fort

Collins particularly successful



Summary – Best Practices

• Adding two feet of freeboard yields the highest benefits

• Offers the largest general category benefits

• Floodplain development restrictions yields the second highest benefits

• Offers the largest social and environmental benefits


QUESTIONS AND ANSWERS

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FEMA Region VIII Reducing Losses through Higher Regulatory Standards 2013 Colorado Floods Case Study...

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