welcome to the asce 2016 convention€¦ · gi/lid features (best management practices) added to...
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WELCOME TO THE ASCE 2016 CONVENTION
Engineering Optimal Financial, Social, and Environmental Returns
Marty Janowitz MES ENV SP
Vice President Sustainable Development
Stantec Consulting
The Implementation of the BCE, AutoCASE™ and Envision™ on Behalf of
Stormwater Projects in Arid Regions
The Rationale – AutoCASE™ and Envision™ • To make sensible comparisons between green infrastructure/low impact
development and traditional grey infrastructure
• Through a common metric
• To value the risk & benefits of sustainable projects
• Integrating engineering methods and economic methods to price options for decision-making.
• Identify optimal outcomes
• So that the project is done right and the right project is done.
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Premise
• In more humid parts of the country GI/LID practices are cost-effective by enhancing the potential for reducing or eliminating the risk of sewer overflows.
• Potential contaminant migration in stormwater tends to be more limited in arid environments as water bodies are few and groundwater is deep.
• Stormwater management important because use of stormwater can offset the need for potable water.
• Vegetation watered with stormwater has potential to decrease energy use and improve the quality of life by mitigating effects from the urban heat island.
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Background
• The Pima County Regional Flood Control District and the City of Tucson, have been creating a Low Impact Development and Green Infrastructure Guidance Manual to facilitate the adoption of GI/LID practices in Pima County and the City of Tucson with the Pima Association of Governments
• They completed a joint Water-Wastewater (2010) Infrastructure, Supply and Planning Study • Goal 5: Increase the use of rainwater and stormwater to reduce demands on
potable supplies”
• Subgoal 5.1: Develop design guidelines
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Background 2
• Despite efficient water use, best practices in stormwater management, and water re-use, the population in Pima County is growing and renewable water resources are diminishing due to drought across the Colorado River Basin.
• Together, a working group developed a Guidance Manual to facilitate the adoption of GI/LID practices in Pima County and the City of Tucson.
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Unique Regional Aspects
• The Tucson region does not have combined sanitary sewers/storm sewer systems and so does not suffer from combined sewer overflow problems that give other regions cause to implement GI/LID;
• The desert environment does experience monsoons with potential for severe flooding and also seeks the beneficial use of stormwater for irrigation.
• AutoCASE™ was made more useful to desert regions by calculating the cost and benefit based on these conditions common to the arid Southwest.
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Scenarios
• The goal of this Beta Testing project is to evaluate GI/LID benefits in the Pima County environment. AutoCASETM uses economic and risk analysis to evaluate costs and multi-benefits using AutoCAD Civil3D files of GI/LID practices. Because the motivating factors for use of GI/LID are different in Pima County, there is a need to evaluate the costs and multi-benefits of these features in that environment.
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GI/LID
• One reason for developing the GI/LID Guidance Manual was to provide a tool for public and private sector professional designers, including engineers, landscape architects, planners, developers and non-profit organizations, to utilize and better understand design configurations and the benefits of GI/LID.
• This comparison then provides a framework for how our community can plan and adapt to become more resilient utilizing GI/LID in stormwater-management.
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Deliverables
• Deliverable 1: A beta version of AutoCASE TM software with initial parameters for GI/LID practices.
• Deliverable 2: Evaluation of two clustered GI/LID scenarios (commercial site and transportation corridor) considering a series of individual practices
• Deliverable 3: List of factors that are most important and contribute most to the two different scenarios to calculate effectiveness of the GI/LID practices with the associated probabilities.
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Deliverables
• Deliverable 4: Costs and multi-benefits of each of the individual GI/LID practices (described in the LID/GI Guidance Manual) in the County’s and City’s environment.
• Deliverable 5: Evaluation of the economic and environmental returns from investing in GI/LID practices in the arid west that can be incorporated into the LID/GI Guidance Manual.
• Deliverable 6: Summary report
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Objectives
• To evaluate the cost and multi-benefits of these individual GI/LID practices to determine how GI/LID creates value for the arid west
• e.g. recreational benefits, air pollution reduction, carbon reduction, water quality improvements, lower urban heat island mortality rate etc.
• To create a reference document that documents the sustainable return of relevant infrastructure projects.
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GI/LID Features Evaluated
Eight green infrastructure (GI) features evaluated
Features also combined in two sites:
- A commercial site
- A roadway reach
Economic analysis used to determine which GI features provide the greatest benefits in Tucson and how they can be used to comply with:
- Commercial rainwater harvesting ordinance
- Green streets guidelines
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GI/LID Practices Evaluated
Water Harvesting Basins
Bio Retention Basins
Xeriscape Swales
Cisterns
Infiltration Trenches
Detention Basins (or Extended Detention Basins)
Pervious Pavers
Curb Extensions, new & retrofit chicanes, medians, road diets with inlets to gather street water runoff, traffic circles)
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Costs, Benefits and Outcomes
• A distribution of costs, benefits and possible outcomes as described by the following factors. • Direct Financial Return on Investment
• Sustainable Return on Investment
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Cost-Benefit Considerations
• Water Costs (assumed to be water costs associated with irrigation reduction/potable water savings, and water pumping costs)
• Energy Savings (especially energy reduction from shading)
• Operation & Maintenance (assumed to include maintenance required for continued functionality of GI).
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Methodology
• Risk Analysis Approach • Reflecting the range of uncertainty about inputs as well as their most likely
values.
• A probability distribution representing the outcome of future events, based on limited information.
• Input into a Monte Carlo risk analysis following a cost-benefit approach.
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Outcomes
• Evaluation of usability and usefulness of the AutoCASE™ and applicability of the data used. • A description of Envision scoring of GI/LID features to articulate the link between
GI/LID and Envision.
• An evaluation on the possible use by the City and County for the Envision™ System to assess GI/LID practices.
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Findings
GI/LID features (best management practices) added to the conventional design provide multiple high impact social benefits on both sites analyzed
- Commercial Site
- Road Re-Design
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Envision Results – Road Re-Design Site
Quality of Life
Leadership Resource Allocation
Natural World
Climate
Other
Envision Category Breakdown of Value – Road Re-Design
“…most of the value is attributed to increased pedestrian safety due to traffic calming (Quality of Life), reduced heat mortality (Quality of Life), reduced social cost of water (Natural World), and lower carbon and air pollution (Climate).” -AutoCASE Beta Testing Project, Final Report
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Road Re-Design Results
Summary Results Net Present Value of
Benefits - Silverbell Road Capital Expenditures -$42,125 O&M Costs -$3,897 Reduced Electricity Costs $20,331 Reduced Natural Gas Costs $57 Direct Financial NPV -$26,634 Reduced Flood Risk $25,645 Change in Property Values $1,592 Reduced Heat Stress Mortality $84,634 Value of Reduced CO2 Emissions $12,095 Value of Reduced Air Pollution $17,588 Reduced Direct Costs of Water $43,823 Reduced Marginal Social Costs of Water Use $39,868 Increased Pavement Longevity Benefit $1,763 Traffic Calming - Roundabouts and Curb
Extension $117,737
Other Benefits $3,412 Sustainable NPV $322,523
0%
10%
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50%
60%
70%
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90%
100%
-$2,000 -$1,000 $0 $1,000 $2,000 $3,000
Pro
bab
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of
No
t Ex
ceed
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Net Present Value of Net Benefits (Benefits - Costs)
Thousands
Base Case - DirectFinancial NPV
Base Case -Sustainable NPV
Direct Financial NPV(Includes GI/LIDFeatures)
Total SustainableNPV (Includes GI/LIDFeatures)
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Net Present Value of Net Benefits (Benefits
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Road Re-Design Benefits
Reduced Electricity Costs 6%
Reduced Flood Risk 7%
Reduced Heat Stress Mortality
23%
Value of Reduced CO2 Emissions
3% Value of Reduced
Air Pollution 5%
Reduced Direct
Costs of Water 12%
Reduced Marginal Social Costs of Water Use
11%
Traffic Calming - Roundabouts and Curb
Extension 32%
Other Benefits 1%
Net Present Value of Benefits – Road Re-Design
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Road Re-Design Benefits
Direct Financial Value 9%
Government or Taxpayer 20%
User / Target-Beneficiary or Customer Service
1%
Economic or Business Activity
22%
Environmental 10%
Community or Other 38%
Stakeholder Breakdown of Value – Road Re-Design
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GI/LID Results Net Present Values – Median (50th Percentile) Costs Benefits
CapEx Cost O&M Costs Flood Risk Reduction Property Value
Uplift Heat Mortality Risk
Reduction Reduced CO2 Emissions Reduced Other
Costs Direct Financial NPV Total SNPV
Bioretention -$2,096 -$377 $169 $49 $515 $0 $0 -$2,473 -$1,740
Pervious Pavers,
relative to asphalt -$2,496 -$834 $168 $51 $513 $0 $0 -$3,330 -$2,597
Detention Basin /
Extended Detention-$1,215 -$194 $234 $50 $514 $0 $0 -$1,409 -$612
Water Harvesting
Basin* -$132 -$7 $200 $52 $518 $0 $0 -$139 $631
Cistern -$2,685 $0 $95 $0 $0 $0 $448 -$2,685 -$2,142
Xeriscape Swale -$383 -$173 $159 $51 $512 $0 $0 -$556 $167
Infiltration Trench -$701 -$167 $200 $50 $515 $0 $0 -$868 -$102
Pavement -$10,817 $0 -$424 $0 $0 $0 $0 -$10,817 -$11,241 Concrete -$14,106 $0 -$379 $0 $0 -$1,346 $0 -$14,106 -$15,831 *Entered as Infiltration Basin
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GI/LID Results
0%
10%
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30%
40%
50%
60%
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90%
100%
-$18,000 -$13,000 -$8,000 -$3,000 $2,000
Pro
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of
No
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Net Present Value of Net Benefits (Benefits - Costs)
Bioretention
Pervious Pavers/PorousPavement
Detention Basin
Water Harvesting Basin
Cistern
Xeriscape Swale
Infiltration Trench
Pavement/Ashphalt
Concrete
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Highlights • Benefits of GI/LID features quantified and
monetized:
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
$(1,000) $(500) $- $500 $1,000 $1,500 $2,000 $2,500 $3,000
Pro
bab
ility
of
No
t Ex
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din
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Net Present Value of Net Benefits (Benefits - Costs)
Thousands
Commercial Site DirectNPV - No GI/LID
Commercial Site SNPV -GI/LID Included
"Road Re-Design DriectNPV - No GI/LID"
Road Re-Design SNPV -GI/LID Included
• Adding GI/LID features to the commercial and road re-design sites provides net benefits to the Tucson region
• Largest benefits: heat related mortality, traffic calming, flooding, reduced water costs and reduced air pollution
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Net Present Value of Net Benefits (Benefits
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GI/LID features have a payback to governments, the environment, the economy and the community
This approach allows all stakeholder groups to understand how they are affected by a project
- “What’s in it for me?”
Ignoring benefits of GI/LID features can lead to incorrect decisions
Overall Findings Stormwater Pilot Project
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Recommendations
The City of Tucson, Pima County, should continue to use this approach to demonstrate the full value of its GI/LID initiatives
This information should be used to help make the best decisions as projects are planned and designs are modified
The Tucson region should consider the use of Envision to communicate project benefits to outside stakeholders
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THANK YOU FOR ATTENDING ASCE 2016!
Reminder: WE LOOK FORWARD TO SEEING YOU NEXT
YEAR AT ASCE 2017 IN NEW ORLEANS, LOUISIANA!