Arid Regions Policy Committee
Agenda
March 1, 2011
9:00 – 10:00 AM Pacific Time
The call in number is 218-936-4700 access code is 27376 .
1. Introductions and Welcome – additional agenda items.
2. Solicitation of a volunteer to take summary notes and post them on the Arid Regions
page.
3. Status of Alluvial Fan Discussion Paper – Discussion Paper has been delivered to FEMA
for consideration.
4. Comments/Discussion on the draft Erosion Zone White Paper (attached)
5. Solicitation of one Arid Regions focused presentation for ASFPM session at Louisville.
6. Planning for next Arid Regions conference, proposed for 2013, hosting chapter to be
determined .
7. Participation by other Arid Regions Chapters
8. Identify Action Items
9. Next meeting date
Riverine Erosion Hazards & Floodplain Management: A White Paper
ASFPM Arid Regions Committee
Lead Author: Jon Fuller/ JE Fuller/Hydrology & Geomorphology, Inc.
Introduction
Riverine erosion is a significant, but unstudied, flood risk for many NFIP communities. In 1999, FEMA
reported that “approximately one-third of the nation’s streams experience severe erosion problems”
resulting in $450 million dollars of erosion-related damages, over half of which occurs in the arid
southwest and in the northwest.1 Riverine erosion may be even more hazardous than flood inundation
for the following reasons:



Riverine erosion can damage homes elevated well above the regulatory water surface elevation
– homes outside the regulatory floodplain can be destroyed when the river banks migrate
laterally.
Property damaged by flood inundation can sometimes be considered a total loss, but property
damaged by riverine erosion is not only destroyed, the land itself may be completely washed
away leaving no chance to rebuild, let alone recover any property contents.
Riverine erosion can occur progressively during floods smaller than the 100-year flood, resulting
in significant cumulative river migration which destroys homes and property.
Despite these very real, extreme hazards, riverine erosion hazard zones are currently not shown on the
FIRM, flood insurance does not cover riverine erosion damage, and risk of erosion is not considered in
the determination of flood insurance rates. Furthermore, despite NFIP directives that communities
should be managing erosion hazard areas, clear guidance from FEMA is lacking on how such flood risks
are to be managed. The goals of this white paper is to encourage ASFPM member communities and
FEMA to improve tools for delineating and managing riverine erosion hazard areas.
Background
a. National Flood Insurance Act, 1968 – Creates NFIP
b. Upton-Jones Amendment, 1988 – Authorized FEMA to provide insurance for structures
subject to imminent collapse due to erosion. Designed for coastal areas, but didn’t
exclude riverine.
c. Riverine Erosion Hazard Analysis (REHA) Feasibility Study
1
1998 dollars. FEMA, 1999, Riverine Erosion Hazard Area Mapping Feasibility Study.
i. Done in response to National Flood Insurance Reform Act (1994), Section 577
(technical feasibility of mapping REHA)
ii. Conclusion: Mapping Riverine Erosion Hazards is Feasible
d. NFIP – 44 CFR
i. Part 60.10
ii. Part 60.24
Problem Statement





Insurance Available for Erosion Damage?
Property Lost, Not Just Damaged
Damage Occurs Outside Regulatory Floodplain
Damage Occurs at Flows Less Than 1% Peak
Case Histories
o St. George, Utah 2005 Flood
o City of Tucson, 1983 Flood
o Salt Lake City, 1980’s Floods
Current Practice


Actions by Local Communities
o City of Austin, Texas
o King County, Washington
o Maricopa County, Arizona
o Pima County, Arizona
o Salt Lake County
o Washington County, Utah (St George, Santa Clara)
o State of Vermont
o State of New Hampshire
o State of Arizona
o AMAFCA, New Mexico
Local Riverine Erosion Management Strategies
o Development Setbacks
o Erosion Hazard Zones
o Meander Corridors
Opportunities




Clarification of existing NFIP regulations
Consistency with coastal erosion NFIP policies
Coordination with existing State & Local programs
RiskMAP framework
o Multi-hazard delineations
o More comprehensive depiction of flood risk
Recommendations







Clarify NFIP regulations with respect to management of erosion hazard zones.
Specifically include riverine erosion as a flood hazard to be managed by NFIP communities
Add direction for riverine erosion hazard delineation in FEMA Guidelines & Specifications
o Consistent standard required everywhere
o FEMA must be big brother, require delineations
o Methodology: not one size fits all
Develop management recommendations for NFIP communities
o FIRM Zones
o Zone ER – Riverine Erosion Zone
o LOMR rules for ER
Make insurance available for riverine erosion
Methodology
o Numerical Methods to Quantify Hazard
o Engineering Guidelines for Analysis of Structural Measures
o Review Checklist
Training – Identification, Analysis, Review
o Agency
o Consultants