Assessing and increasing mitigation time
through non-structural actions
Floodplain Management Association Conference
Sacramento, California
September 9, 2016
Presented by:
Sami Nall, PE
Water Resources Engineer
CA Department of Water Resources
Co-author:
[email protected]
Nathan Pingel, PE
916-574-1432
Vice President
David Ford Consulting Engineers, Inc. Boone Lek, PE
[email protected]
Sr. Water Resources Engineer
916-840-5201
CA Department of Water Resources
[email protected]
916-574-2633
1
A Stressed System, the Need for Action
• Central Valley people, property and assets at risk
• Current flood risk management path unsustainable
• Lack of funding for capital works and for ongoing operations
and maintenance of existing infrastructure
• In 2008, the Legislature enacted the Central Valley Flood
Protection Act, which authorized and required development
of the Central Valley Flood Protection Plan (CVFPP) to
address these issues
2
2017 Update to the CVFPP
• CVFPP is a dynamic, programmatic plan,
updated in five year cycles – CVFPP first
adopted in 2012, first “Update” in 2017
• 2017 Update: same goals as 2012 CVFPP
• The planning horizon is the 30 years
• Refines and updates the State Systemwide
Investment Approach (SSIA)
• Adds specifics about recommended near and
longer-term investment and financing approach
• Provides broad guidance about more resilient risk
management
• Coordinated and aligned with other major flood
management efforts
3
Technical Work to Support CVFPP Goals
• Technical analyses
informing a reasonable,
balanced and costeffective approach
• Emphasis on sustainable,
integrated flood
management
• Diverse array of actions to
improve flood protection
• CVFPP Public Draft
December 2016
4
Today’s Discussion
CVFPP Technical Work:
Assessing and increasing
mitigation time through
non-structural actions
5
Today’s Discussion
•What are the components of a flood warning
system, and how are they determined?
•How are mitigation times used in the Basin-Wide
Feasibility Study (BWFS) baseline condition?
•What non-structural measures are being
considered as part of the BWFS?
•How do we evaluate the benefits of an enhanced
flood response and emergency preparedness
(EFREP)?
6
Flood warning timeline
Goal of flood warning system is to increase the mitigation
time for floodplain communities, allowing more time to
mitigate flood losses.
© David Ford Consulting
Engineers, Inc.
7
Baseline forecast lead times
• Time between threat
recognition and
threshold exceedence.
• Baseline forecast lead
times developed by
DWR and NWS
forecasters.
© David Ford
Consulting
Engineers, Inc.
8
Baseline notification & decision-making times
• Based on completeness of existing local flood response plans.
• Baseline times developed by DWR and NWS forecasters.
Status of flood-preparedness components in Sacramento Basin
Operational area
(1)
Evacuation and mass
care component
(2)
Temporary protection
component
(3)


Sacramento City


Sacramento County


Yolo County


Colusa County


Glenn County


Tehama County


Sutter County


Yuba City


Butte County


Shasta County


Yuba County
Status of flood-preparedness components in San Joaquin Basin
Operational Area
(1)
Evacuation and mass
care component
(2)
Temporary protection
component
(3)

Fresno County

Madera County

Merced County

San Joaquin County

Stanislaus County
 = component exists and is complete
 = component exists, but is partially complete or out-of-date
 = component does not exist or whereabouts unknown





Vital services maint.
component
(4)
Public information
component
(5)
Post-flood recovery
component
(6)

































Vital services maint.
component
(4)
Public information
component
(5)
Post-flood recovery
component
(6)















9
Baseline mitigation times
• Computed as difference between forecast lead and
notification/decision-making times.
• If notification/decision-making time is > than the forecast lead time,
mitigation = 0.
• Need to consider the effectiveness of the flood warning system.
© David Ford
Consulting
Engineers, Inc.
10
Flood warning efficiency factor
eff = Frw x Fw x Fc
• Frw = fraction of public that receives warning (determined using
Sorensen & Mileti equations).
Mitigation times used here.
• Fw = fraction of public that is willing to respond. A value of 1.0 was
used, derived from EFREP expert elicitation.
• Fc = fraction of public that knows how to respond effectively and is
capable of responding. A value of 0.70 was used, derived from
EFREP expert elicitation.
11
Adjusted mitigation times
• Adjusted mitigation times = mitigation time x eff
12
BWFS mitigation times
Mitigation times used to:
− Adjust persons-per-structure values (life risk).
− Reduce vehicle inventory (vehicle Expected Annual
Damage (EAD)).
− Reduce residential content damage (residential
EAD).
13
Adjust Persons-Per-Structure (PPS) values
PPS values adjusted to account for fraction of floodplain
occupants who will respond effectively and evacuate.
PPSadj = (1-eff) x PPS
• eff = efficiency of flood warning system.
• PPS = unadjusted persons-per-structure value.
• PPSadj = adjusted persons-per-structure value.
14
Reduce vehicle inventory
Adjusted mitigation times used to determine % of vehicles
that evacuate.
15
Reduce content damage
• Adjusted mitigation times used to select residential content
depth-damage function (DDF).
• EFREP developed DDF for various mitigation times.
70
60
Damage, in %
50
40
30
No w arning time
1-hr warning
6-hr warning
12-hr w arning
24-hr w arning
36-hr w arning
48-hr w arning
20
10
0
-5
0
5
10
15
20
Depth, in ft
16
One of BWFS goals: non-structural measures
• Identify non-structural
measures that can, in
concert with structural
improvements, be
used to reduce overall
flood risk.
• DWR and NWS
estimated with-project
condition forecast lead
and notification/
decision-making times
for all impact areas.
© David
Ford
Consulting
Engineers,
Inc.
17
Non-structural EFREP measures
18
How do we evaluate the benefit of these
non-structural measures?
Baseline
mitigation times
eff
Adjust PPS
© David Ford
Consulting
Engineers, Inc.
Adjusted
mitigation times
Adjust total # of
vehicles
Baseline asset
inventory
Modify res.
structure occ.
type
Baseline HECFDA model
Recall how we used baseline
mitigation times in the risk analysis.
Compute
stage-damage
Compute
baseline EAD
& life risk
19
Evaluate with-project mitigation times
Baseline asset
inventory
Baseline HECFDA model
1. Make a copy of the baseline asset
inventory file and HEC-FDA model.
20
Evaluate with-project mitigation times
With-project
mitigation times
eff
Adjusted
mitigation times
2. Recompute eff and adjusted
mitigation times using with-project
mitigation times.
21
Evaluate with-project mitigation times
With-project
mitigation times
eff
Adjusted
mitigation times
Adjust PPS
Adjust total # of
vehicles
Modify res.
structure occ.
type
3. Adjust PPS, # of vehicles,
and residential structure
occupancy types.
22
Evaluate with-project mitigation times
With-project
mitigation times
eff
Adjust PPS
© David Ford
Consulting
Engineers, Inc.
Adjusted
mitigation times
Adjust total # of
vehicles
With-project
asset inventory
Modify res.
structure occ.
type
With-project
HEC-FDA
model
4. Import with-project asset inventory file
into with-project HEC-FDA model.
5. Compute stage-damage, EAD, and
life risk.
6. Compare to baseline EAD & life risk.
Compute
stage-damage
Compute withproject EAD &
life risk
23
Summary
• Mitigation time can be increased or
improved through non-structural
actions like EFREP
• 2017 Update will refine the 2012 CVFPP and provides a
holistic path forward to a different approach
• The refined SSIA enables the State to
integrate and prioritize investments in multi-benefit flood risk
reduction projects
• CVFPP will take 30 years to implement
24
THANK YOU!
For More Information
Central Valley Flood Management
Planning (CVFMP) Program website
www.water.ca.gov/cvfpm
[email protected]
25
Anticipated 2017 CVFPP Update Schedule
October 2016
•
Stakeholder Draft Released
•
Public Draft Released/Delivered to the Central Valley
Flood Protection Board
•
Public Comment Period Begins
•
Joint 2017 Update and Supplemental Programmatic
Environmental Impact Report (SPEIR) Public
Meetings
•
Anticipated SPEIR Certification
•
Anticipated Board Adoption of the 2017 Update and
SPEIR Findings
December 2016
January 2017
May 2017
June 2017
26
Key Outcome of CVFPP
State Systemwide Investment Approach
• Reasonable, balanced and costeffective approach
• Emphasis on sustainable,
integrated flood management
• Diverse array of actions to
improve flood protection for
•
•
•
•
Urban areas
Small Communities
Rural/Agricultural areas
Systemwide
• Recognized need for residual
risk management
27