SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer 11 Upper Islais Creek Watershed Approach
April 2022 Commission Update
Greg Norby, AGM, Wastewater Enterprise
Sarah Minick, Urban Watershed Planning Manager, Wastewater Enterprise Steve Robinson, Director of Wastewater Capital Planning, Infrastructure Bureau SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Agenda
1. Alemany flooding challenge & Commission request
2. Watershed-scale approach
3. Preliminary findings
4. Equity & community engagement
5. Preliminary street reconfiguration concepts
6. Questions & discussion
Sensitive
Flood Extent 5-yr 3-hr
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer SFPUC Commission feedback
• Think big
• Be creative, all ideas on the table
• Play the long game
• Learn from the past, think about the future, change course if it makes sense • Create policy framework to guide planning & design on the surface • This alternative analysis should take a public pol icy lens and pose the question:
As this is a large investment, can we deliver more long-term flood resilience, and more ancillary benefits to more San Franciscans?
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Approach Capture and convey stormwater in a pipe Use distributed, multi-benefit green infrastructure and urban design projects to manage stormwater
Project
Stage
Conceptual engineering (refinement of alignment,
10% design, easements, environmental, traffic,
geotechnical)
Watershed planning, alternatives development
& evaluation, feasibility, costing, community
engagement, advanced capital planning
SFPUC Stormwater Management Approaches
Lower Alemany Area
Stormwater Improvement Project
Upper Islais Creek Watershed Alternatives
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Why a watershed approach?
• Transforming the surface of our city to be more flood r
esilient can deliver multiple benefits to more
San Franciscans.
• Green infrastructure and flood resilient streets and
bui
ldings are better suited to adapting to a changing
climate.
• A watershed planning process can engage neighborhood
r
esidents in finding solutions that solve problems that
matter to them.
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Progress to date
INTERDICIPLINARY TEAM
City & watershed planners, urban designers, modelers, civil & traffic engineers
PRECEDENT STUDIES
Flood resilient urban design, voluntary buy out programs
SPATIAL ANALYSIS
Land use, ownership, connectivity, equity, alignment
HYDROLOGIC & HYDRAULIC ANALYSIS
Causes of flooding, flow & direction, flood areas, system capacity, outcomes under multiple alternatives
COMMUNITY NEEDS & PREFERENCES
Identifying synergies with neighborhood needs with neighborhood participation SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer 5-Year Storm Flood Extent – Land Use Analysis
Flood Depth – 5yr, 3hr
2 - 6”
6 - 12”
>12”
Total Area of Flood Extent
Caltrans / Right-of-Way
Commercial/Industrial
Open Space
Residential
Mixed Use
Institutional
61%
Right-of-Way
10%
6%
3% 3%
78%
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer
SOAK IT UP
Rain garden
Green roof
Swale
Permeable paving
Green street
PROTECT
Floodproofing
Elevate buildings
Berm, levee, wall
Flood resilient streets
Floodable spaces
Land use changes
SLOW IT DOWN
Tree well storage
Detention basin
Underground storage
Floodable park
Urban creeks & canals
Flood Resilient Neighborhoods
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer SOAK IT UP Preliminary Findings
Parcel Retrofits / Lafayette Elementary
Green Streets / Mission-Valencia Green Gateway
Large-Scale Infiltration/Reuse / Hunters View
SOAK IT UP
• Manage 200 acres using
green infrastructure
• Retrofit 14 schools, 9
parks, large parcels, ~100
blocks of green streets
• 20% reduction in flood
volume
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer SLOW IT DOWN Preliminary Findings
SLOW IT DOWN
• Optimal location near conveyance constraint
• Five suitable sites with good performance identified
• 1 gallon storage = 1/2 to 2/3 gallon flood volume
reduction
• Example scenario of 4M gallons of storage reduces
floodwater from 4.5MG to 1.8MG, a
60% reduction
Subsurface Storage / example rendering
Surface Conveyance / Roombeek, Netherlands
Multi-Purpose Surface Detention / Manassas Park, VA
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer PROTECT Preliminary Findings
PROTECT
• Street re-design keeps remaining 20% of flows away from properties, sidewalks, & neighborhood streets while
integrating measures that address community traffic speed, noise, & safety concerns.
• Building floodproofing provides additional protection.
Signage on floodwall
Marlborough Primary School, UK
Floodwall with seating
Longsdale Street Danenong, Australia
Pocket patio, possible floodwall
823 Congress, Austin
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Environmental Justice Communities
Community quality-of-life priorities
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Alemany Blvd Existing Conditions
ExistingExisting
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Alemany Blvd Potential Section - Conceptual
Existing
Potential Concept
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer San Francisco Boulevard Examples
Residential Shared Street Octavia Blvd, Hayes Valley Residential Street Sunset Boulevard Residential Shared Street // Octavia Blvd, Hayes Valley Residential Street Park Presidio Boulevard and 14th Ave. 14th Ave
Park Presidio Blvd.
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Alemany Blvd Potential Section - Conceptual Rendering
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer 191919
Capital Improvement Project – Lower Alemany
Area Stormwater Improvement Project
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer
1. ~6,000 LF auxiliary 10-ft diameter sewer tunnel
2. Connecting to existing sewer upstream/downstream to capture excess runoff
Objective
1. Addresses SSIP level of service (LOS) of managing stormwater in Lower Alemany area during 5-year 3-hour storm
a) Provides a freeboard of minimum 2-feet in the sewer
b) Combined sewer will not flow on street surface
Other Predicted Benefits
Modeling predicts stormwater in Cayuga Area managed in 25-year, 3- hour storm
Project Milestones
1. Dec 2022 – Final Conceptual Engineering Report
2. Jul 2024 – Forecast Design Completion
3. Mar 2028 – Forecast Construction Completion
AUXILIARY SEWER TUNNEL
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Next Steps
August 2022
• Refined mu lti-benefit alternatives
• Feasibility & costing
• Preliminary alignment with City partners
• Additional community outreach and engagement
O
ctober 2022
• SFPUC evaluation of watershed approach
SAN FRANCISCO PUBLIC UTILITIES COMMISSION | Water Power Sewer Thank You!