Siting, and Cost Effectiveness Analysis City-Wide Green Stormwater Infrastructure Sizing, Siting, and Cost Effectiveness Analysis Mike Blackhurst, PhD, PE (TX) Research Scientist Heinz Endowments University of Pittsburgh 28-FEB-17

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Hydrologic and hydraulic modeling Integrating sewershed and GI modeling contexts involved interdisciplinarity. Hydrologic and hydraulic modeling Sizing and Engineering + siting + economic + analysis analysis Policy analysis Achieved by Green Infrastructure Overflow Reductions Implementation opportunity Current Deployments Technically Realistic Cost Feasible Potential Optimal Policy Enabled Context for our project

Gray and green model results can be integrated using total cost curves. 1. Cost of compliance with gray when green = 0 ($3B-$5B) Total minimum cost* TOTAL COST INFLOWS REDUCED 2. Cost of compliance less than total minimum technology cost. Significant cost efficiencies realized by green infrastructure. 3. Cost of compliance exceeds total minimum technology. Moderate cost efficiencies realized by green infrastructure. 4. Compliance met with all gray solution because cost of gray + green exceeds cost of gray when green = 0

Our approach is Estimate the cost and inflow performance of select GI for each parcel in Pittsburgh, PA Prepare marginal and total cost curves for GI Develop extensible methods to accommodate future changes Publish the results in an open and extensible format Network results and future work with others

A summary of methods (1) Characterize land use by parcel using best available data (2) Apply sizing and siting criteria to identify all feasible installations of Rain gardens Downspout disconnects Green roofs Pervious pavement (3) Run hydrologic models for each feasible installations (4) Estimate cost effectiveness of each installation (5) (Publish results and hope for more!)

Step 1. Land use. Harmonize land use layers.

Step 1. Land use. Harmonize land use layers.

Step 2. Divide surface by parcel and building buffer.

Step 3. Land use. Associated proximity to right-of-way

Step 4. Attribute each subdivided land with topographical information.

See example retrofits on project website http://sb.ucsur.pitt.edu/green-infrastructure/

Process Flow Preparation of Geospatial Data (ArcMAP) Not currently extensible Land use shapefile Apply sizing and siting criteria to Identify GI locations Tabular data for SWMM Preparation and simulation of SWMM (Python + SWMM) Extensible, run-time 30 days Table of SWMM hydrologic results Cost estimation Publish to map (R) Extensible, run-time 1 hr Extensible, run-time 36 hrs

Mil gal overflows reduced Summary statistics of results Collection Area ALCOSAN Priority Sewersheds Mil gal inflow reduced Mil gal overflows reduced million sq for 2003 precop Net Present Value ($M) for 2003 precip CE in $ / gal Overflow GI ft count mean (range) mean (min + 2 sd) Disconnect 11.6 11,600 35 (20 - 10) 3.5 (2.5 - 5.8) 6 (3-12) 0.9 (0.6-1.5) 0.2 (0.01 -0.3) Building to rain garden 14.9 22,200 100 (60 - 140) 113 (11 - 180) 32 (20 - 46) 44 (30 - 10) 1 (0.3 - 6) Surface to rain garden 18.5 23,100 65 (35 - 110) 130 (90 - 210) 20 (11-33) 54 (31-86) 2.5 (0.1 -5) Permeable pavement 96.8 12,100 920 (180 - 1060) 1,100 (940 - 1,280) 220 (180 - 260) 350 (310 - 430) 1.6 (0.1 - 2.5) Green roof 13.3 3,100 61 (55-80) 2,110 (1,480 - 2,930) 10 (8 - 12) 410 (280 -510) 35 (20 - 55) totals 215 139,000 1,200 (950 - 1,500) 3500 (2,600 - 4,600) 290 (230 - 360) 860 (660 - 1,150) - An overall 5.5% (4%-1%) reduction in inflows for year 2003 design storm

Exemplary Product: Marginal GI Cost Curves

Published in an open, extensible manner Explore resources on project website. http://sb.ucsur.pitt.edu/green-infrastructure/

Gray and green model results can be integrated using total cost curves. 1. Cost of compliance with gray when green = 0 Total minimum cost* TOTAL COST INFLOWS REDUCED 2. Cost of compliance less than total minimum technology cost. Significant cost efficiencies realized by green infrastructure. 3. Cost of compliance exceeds total minimum technology. Moderate cost efficiencies realized by green infrastructure. 4. Compliance met with all gray solution because cost of gray + green exceeds cost of gray when green = 0

Acknowledgements Sponsored by Mascaro Center for Sustainable Innovation at University of Pittsburgh Heinz Endowments