HomeMy WebLinkAbout200304 CC Wksn PresentationFlood Risk Reduction –Draft Strategy Review
City Council and task force work session
March 4, 2020
Task Force
Framework
Strategy
Examples at 4 scales of action PAST to FUTURE
Next steps
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Outline
Members / Introductions
•12 Meetings, 9 months
Value to Staff
•Gaps; Service expectations vs.
reality
•Value and values
•Shared language
•Common problem, leading the
conversation
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Task Force
Technical analysis
What is valuable, when?
What matters, where, to whom?
What is flooding?
How we view risk
Drivers of increasing flood risk
Areas of work
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Framework
Surface water
Groundwater
Sanitary backflow
Pathways to structural flood risk
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Climate / Natural
Environment
Varies in time
•Short term weather
•mid-term season
•long term climate
Varies in place
•Uphill / slopes / low area
•Near creek, wetland, lake
How we view risk
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Flood Exposure
•Degree to which
property, homes,
buildings, infrastructure
and other asset come
into contact with flood
water
•Depends on runoff, flow,
storage, drainage,
groundwater, and soils.
Varies spatially, some
area near low areas and
flow paths are exposed
How we view risk
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Flood Vulnerability
•The degree to which
exposed assets are
unable to resist flooding
and are damaged by
floods
•Depends on the extent
of assets on the land,
both public and private,
and how well it can
resist flooding, or limit
damage when flooded
How we view risk
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How we view risk
Key equation
Flood risk = climate x exposure x vulnerability
Applied at varying scales; system, class, component
City Example: Sanitary system, sanitary sewer lift station, electrical components
Personal Example: Dwelling, foundation/basement, individual window well
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Areas of Work
Technical analysis / quick wins
•Infrastructure
•Regulation
•Emergency Services
•Outreach and Engagement
Task Force Discussions
•What we expect vs. what we get and future vision
•Shared view of risk, what we value and personal values
•Potential actions / prioritization
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Drivers of increasing risk
Leading drivers
TOP –Climate change has already, and will expose more assets to flooding in the future.
This driver is predicted to overwhelm the other drivers in terms of scale.
SECOND –Private and public asset and infrastructure are both exposed and vulnerable.
Public infrastructure can define flood exposure for different points in the landscape, and
serve as a pathway for private risk
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Drivers of increasing risk
Other drivers
THIRD –Most of the land use decisions have already been made, and cannot be unmade,
we choose to drain the landscape, connect it to the waters, and develop over waters.
There is additional demand for drainage that can reduce vulnerability, but marginally affects
flood exposure downstream.
FOURTH –There is increasing demand for use of land, imperviousness drives runoff in
small storms and marginally affects flood exposure in large storms
How we view risk
Areas of work
Drivers of increasing flood risk
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Framework
Comprehensively reduce the risk of flooding throughout the community
In our work with the community we will;
•make flood information available to all and promote flood awareness
•work to help people stay safe in floods
•help people protect their properties from flooding and the affects of floods
•plan public streets and parks to accept and transmit flood waters to reduce the risk
and disruption of related city services
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Strategy
Comprehensively reduce the risk of flooding throughout the community
In our areas of work;
•Infrastructure: We will renew our infrastructure and operate it to reduce risk
•Regulation: We acknowledge competing demands of land use and addressing
drainage, groundwater and surface water issues. We help people solve issues
without harming another
•Outreach and engagement: We make flood information available and give people
tools for flood resilience
•Emergency Services: We help people prepare for floods, remove people from harm
during floods, and recover after floods.
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Strategy
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FUTURE
How we view risk
•Systems, awareness, dynamic
•Climate x exposure x vulnerability
Areas of work
•Infrastructure, regulation, outreach &
engagement, emergency services
•Risk management
Key Trends
•Climate change, aging infrastructure
PAST
How we view risk
•Reactive, static
•probability x consequence
Areas of work
•Infrastructure and emergency
response
•Bigger pipes, risk transfers, rescue
Key Trends
•Drainage, land development
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Framework
FUTURE
•Freeways shut down, sewers back up,
flooded basements, less?
•Staff reallocated to call center, provide
safety advice only
•Emergency response plan brings
resources to problems faster
•Predictive pumping make a little extra
room based on forecasts
•Capital plan is proactive and prioritized,
no need for reactive change
PAST
•Freeways shut down, sewer
backups, flooded basements
•Call center overwhelmed
•After action, look to blame, solve
‘problem areas’ that flooded by
transferring risk downstream
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’87 style flood response
FUTURE
•Add storage in streets and right of
way (lower streets, tree trenches, etc)
•Add new curb and gutter, plan
emergency flow paths
•Rebuild catch basins, add needed inlets
•Review pipe sizes, repair and upsize
only where we make room with
storage downstream
PAST
•Add new sump drainage pipe
•Add new curb and gutter
•Rebuild catch basins
Neighborhood and parks
reconstruction
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FUTURE
•Erosion and stormwater standards
•Regional and local flood elevation
standards, grading and drainage review
•Impervious limit
•Technical assistance available
•People are flood aware, help others
•People with exposure have taken
actions to reduce vulnerability
•Most critical at-risk structures
removed or redeveloped
PAST
•Erosion control standards
•Regional flood elevation standards
•No impervious limit
•No technical assistance
Residential redevelopment,
individual home drainage issue
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FUTURE
•once per five year proactive
inspection and preventative
maintenance
•Preventative debris removal
•Adopt-a-drain, community cleanups
•Enhanced street sweeping
•Trouble spot retrofits
•Smart infrastructure, remote level
awareness, predictive pumping control
PAST
•Reactive maintenance, run-to-failure
•Clear clogs
•2 per year street sweeping
Stormwater infrastructure,
operations and maintenance
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FUTURE
•Risk Management
•Comprehensive areas, service based
•Policy and program
•Adaptation, design for future based on
increasing risk of climate change
•Community focus, build capacity for
resilience
•$xx.xx?
PAST
•Problem solving
•Focus area, complaint based
•Reactive
•Design for past, assume future looks
the same
•Expert focused, technical
•Storm Utility fee $37.59/quarter
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Water resources paradigm
Indirect
•Impervious Surface Planning Commission
Proposal
•Climate Action Plan
•2020-21 Budget workplan
•2021-26 Capital Improvement Plan (CIP)
•2022-23 Budget
Direct
•Finalize framework and strategy for
Council consideration
•Order major amendment to
Comprehensive Water Resources
Management Plan, align policy with
strategy and do tactical planning for water
resource program expansion
•Create first comprehensive flood risk
reduction plan with public engagement
ahead of Morningside 2022-23
reconstruction projects and Weber park
development
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Next Steps