Patricia Gonzales, Graduate Student in Civil & Environmental Engineering at Stanford University Sustainable Urban Systems Symposium Stanford University, June 2016

1. SUMMARY
Traditional urban water supply portfolios have proven to be unreliable under the uncertainties associated
with growth and long-term climate variability, particularly in arid and semi-arid regions already facing water
shortages. Introducing alternative water supplies such as recycled water, captured runoff, desalination, as
well as demand management strategies such as conservation and efficiency measures, has been widely
proposed to address the long-term reliability and resilience of urban water resources. Collaborative efforts
have the potential to achieve this goal through more efficient use of common pool resources and access to
funding opportunities for supply diversification projects. However, this collaborative approach requires a
paradigm shift towards holistic solutions that address the complexity of hydrologic, socio-economic and
governance dynamics surrounding water management issues. The objective of this work is to develop an
integrative framework for the assessment of water resource reliability from the perspective of various
spatially interrelated water resources and institutions. We define the reliability of an urban water provider as
the ability to access adequate supplies to consistently satisfy current needs, manage demand, and have the
capacity to adapt to future scenarios. This framework introduces a systematic, context-sensitive
assessment to help regional managers direct the implementation of strategies to progress reliability,
including innovative metrics to assess supply diversity, based on local criteria and preferences. We
demonstrate the application of this framework to the Hetch Hetchy Regional Water System in the San
Francisco Bay Area of California. Our framework demonstrates how water service providers that share
common water supplies can establish integrative regional management partnerships in order to achieve
individual and collective short-term and long-term benefits.
Re-Inventing the Nation’s Urban Water Infrastructure (ReNUWIt)
Patricia Gonzales1, Newsha Ajami1
1Stanford University
A Regional Integrative Framework for Reliable and Resilient Water Supplies
Systems Integration and Institutions- Visioning, assessment and implementation tools for regional and municipal planning
RESEARCH APPROACH
CASE STUDY: HETCH HETCHY REGIONAL WATER SYSTEM
DISCUSSION AND IMPLICATIONS
BAWSCA Annual Survey – FY 2012-13
BAWSCA Overview April 2014
5
BAWSCA Members Map
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25
24
23
22
21
20
19
18
18
17
16
15
14
13
12
12
11
9
10
8
7
6
5
5
4c
4b
4b
4a
4a
4a
3
2
1
Calaveras
Reservoir
San Antonio
Reservoir
San
Andreas
Reservoir
Pilarcitos
Reservoir
Crystal
Springs
Reservoir
Half
Moon
Bay
Palo
Alto
San
Jose
San
Mateo
Hayward
Daly
City
Alameda County
San Mateo County
Santa Clara County
San Francisco
SFO
San Francisco Bay
Pacific Ocean
Legend
1 Alameda County Water District
2 City of Brisbane
3 City of Burlingame
4a CWS – Bear Gulch
4b CWS – Mid-Peninsula
4c CWS – South San Francisco
5 Coastside County Water District
6 City of Daly City
7 City of East Palo Alto
8 Estero Municipal Improvement District
9 Guadalupe Valley MID
10 City of Hayward
11 Town of Hillsborough
12 City of Menlo Park
13 Mid-Peninsula Water District
14 City of Millbrae
15 City of Milpitas
16 City of Mountain View
17 North Coast County Water District
18 City of Palo Alto
19 Purissima Hills Water District
20 City of Redwood City
21 City of San Bruno
22 San Jose Municipal Water System
23 City of Santa Clara
24 Stanford University
25 City of Sunnyvale
26 Westborough Water District
Sources: BAWSCA, San Mateo County General Plan
Annual Survey
FY 2012-13
April 2014
The Bay Area Water Supply and Conservation Agency (BAWSCA) represents the interests of
24 cities and water districts, an investor-owned utility, and a university that purchase water on a
wholesale basis from the San Francisco Regional Water System (SF RWS). These entities
represent a diverse group of service areas that provide water to 1.7 million people, businesses
and community organizations in Alameda, Santa Clara and San Mateo counties.
LOCAL RELIABILITY PERFORMANCE
OPPORTUNITIES FOR ENHANCED RELIABILITY
BAWSCA Overview April 2014
BAWSCA Members Map
26
25
24
23
22
21
20
19
18
18
17
16
15
14
13
12
12
11
9
10
8
7
6
5
5
4c
4b
4b
4a
4a
4a
3
2
1
Calaveras
Reservoir
San Antonio
Reservoir
San
Andreas
Reservoir
Pilarcitos
Reservoir
Crystal
Springs
Reservoir
Half
Moon
Bay
Palo
Alto
San
Jose
San
Mateo
Hayward
Daly
City
Alameda County
San Mateo County
Santa Clara County
San Francisco
SFO
San Francisco Bay
Pacific Ocean
Legend
1 Alameda County Water District
2 City of Brisbane
3 City of Burlingame
4a CWS – Bear Gulch
4b CWS – Mid-Peninsula
4c CWS – South San Francisco
5 Coastside County Water District
6 City of Daly City
7 City of East Palo Alto
8 Estero Municipal Improvement District
9 Guadalupe Valley MID
10 City of Hayward
11 Town of Hillsborough
12 City of Menlo Park
13 Mid-Peninsula Water District
14 City of Millbrae
15 City of Milpitas
16 City of Mountain View
17 North Coast County Water District
18 City of Palo Alto
19 Purissima Hills Water District
20 City of Redwood City
21 City of San Bruno
22 San Jose Municipal Water System
23 City of Santa Clara
24 Stanford University
25 City of Sunnyvale
26 Westborough Water District
Sources: BAWSCA, San Mateo County General Plan
BAWSCA Overview April 2014
BAWSCA Members Map
26
25
24
23
22
21
20
19
18
18
17
16
15
14
13
12
12
11
9
10
8
7
6
5
5
4c
4b
4b
4a
4a
4a
3
2
1
Calaveras
Reservoir
San Antonio
Reservoir
San
Andreas
Reservoir
Pilarcitos
Reservoir
Crystal
Springs
Reservoir
Half
Moon
Bay
Palo
Alto
San
Jose
San
Mateo
Hayward
Daly
City
Alameda County
San Mateo County
Santa Clara County
San Francisco
SFO
San Francisco Bay
Pacific Ocean
Legend
1 Alameda County Water District
2 City of Brisbane
3 City of Burlingame
4a CWS – Bear Gulch
4b CWS – Mid-Peninsula
4c CWS – South San Francisco
5 Coastside County Water District
6 City of Daly City
7 City of East Palo Alto
8 Estero Municipal Improvement District
9 Guadalupe Valley MID
10 City of Hayward
11 Town of Hillsborough
12 City of Menlo Park
13 Mid-Peninsula Water District
14 City of Millbrae
15 City of Milpitas
16 City of Mountain View
17 North Coast County Water District
18 City of Palo Alto
19 Purissima Hills Water District
20 City of Redwood City
21 City of San Bruno
22 San Jose Municipal Water System
23 City of Santa Clara
24 Stanford University
25 City of Sunnyvale
26 Westborough Water District
Sources: BAWSCA, San Mateo County General Plan
Describe
current
state of
the water
system
Analyze
factors
affecting
water supply
and demand
reliability
Evaluate
flexibility
points for
enhanced
reliability
Design
flexible tools
to enhance
reliability
under
uncertainty
• Greater supply diversity is needed to address the uncertainties of future water shortages.
• Local socio-economic factors and demand portfolios, pricing structures, water reuse and recycling
potential, conservation measures, land use patterns, and existing governance structures are all
opportunities that can lead to enhanced flexibility, resiliency, and risk management in the region.
• Agencies may be hesitant to develop new supplies due to the financial risks and the hydrologic
uncertainties that influence the potential outcomes of such an investment. Under more
collaborative dynamics, these risks could be reduced by sharing costs and benefits of these
projects among several agencies, since the benefits of increased reliability would be extended to
the regional level.
• Future research should investigate how the hydro-socio-economic framework in a region could
support more effective allocations of risks and benefits, and how stakeholder dynamics could be
leveraged to develop the necessary financing strategies for enhanced reliability.
• BUILDING UP ON EXISTING AGENCY INTERCONNECTIONS
• Enhancing regional coordination
• Network and risk sharing
• CONSERVATION POTENTIAL
• Targeted socio-economic drivers
• Water use efficiency innovation
• SUPPLY AUGMENTATION AND SHARING
• Pooling of shared supplies
• Efficient land use for the development of new supplies
• TARGETING DEMAND DIVERSITY
• Tailoring water supplies to different water quality needs
Example: The existing infrastructure of the Hetch Hetchy RWS is an opportunity for sharing
both existing and new water supplies.
Reliable urban
water supplies
Residential
Commercial/Industrial
Government/ Institutional
Irrigation
Resiliency
Sustainability
Flexibility
Risk Management
Ability to access
adequate supplies to
consistently satisfy
current needs, make
responsible use of
supplies, and have the
capacity to adapt to
future scenarios
DEFINING RELIABILITY
2013 2013 20132013
MEASURING RELIABILITY
REGIONAL RELIABILITY PERFORMANCE
Scenario SUSi
No adaptive capacity (shown) 34.79
Adding local projects only 46.67
Adding local + regional projects 51.19
FUTURE WORK
VIRTUAL WATER TRADING AS A RELIABILITY ENHANCEMENT MECHANISM
• Indicators are normalized to a
1-10 scale.
• index is calculated using the
geometric mean to address
the challenge of assigning
specific weights to each
criterion. This approach allows
us to weight all criteria as non-
substitutable while giving
implicit weighing to the
indicators with worse
performance.
• Supply diversity is an
important aspect of reliability,
commonly overlooked. We
propose the use of the Gini-
Simpson index as a diversity
metric, which considers both
the number of sources
available and their relative
abundance:
Supply diversity =
Ongoing research focuses on modeling the potential impacts of enabling flexible sharing of
supplies at the regional level for users relying on a common supply pool. Under virtual trading
dynamics, access to a given amount of a resource is exchanged (rather than a physical resource).
This way, if a utility decides to introduce an alternative supply to their system, such as using
recycled water for industrial purposes, this additional supply would provide leverage for negotiating
their existing allocations from the common pool with utilities that do not have such a capacity.
Therefore, virtual trading could promote the diversification of water supply portfolios and lead to
more resilient regional supplies. For this to be realistic in the urban water sector, we need to
understand the existing governance and hydro-economic network, assess the economic and
reliability benefits, and identify barriers to be addressed.
USE OF INFORMATION TECHNOLOGY TO FACILITATE REGIONAL COORDINATION
Innovative decision support tools are needed that
allow for open, flexible, and transparent
interactions among the multiple stakeholders
involved in water management. Introducing these
attributes through the use of information
technology, such as a smart coordination
platform, will allow a connection between social
and hydrological realities when defining the
regional scope of new supply projects, help
identify cost-effective investments for supply
diversification, and match available resources to
such investment opportunities, thus making more
efficient use of common supply pools, and
enhancing reliability and resilience at local and
regional scales.
Reliability indicator
values and overall
index by agency
as of Fiscal Year
2013-14.
Supply reliability
and adaptive
capacity measures
show greater
variability than
demand
management
among BAWSCA
member agencies.
Reliability index
(overall index in parenthesis)