Tools and Case Studies forGreen-Gray Lifecycle Cost Analysis
ASCE Spring Seminar April 2018Justin Kerns
ms consultants
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis 2
EPA National Stormwater Calculator
Low Impact Development (LID) Controls
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Included LID Controls• Disconnection (rooftop downspouts)• Rain Harvesting (rain barrel or cistern)• Rain Gardens• Green Roofs• Street Planters• Infiltration Basins• Permeable Pavement
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Low Impact Development (LID) Controls
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Included LID Controls• Disconnection (rooftop downspouts)• Rain Harvesting (rain barrel or cistern)• Rain Gardens• Green Roofs• Street Planters• Infiltration Basins• Permeable Pavement
Modeling Capabilities• Hydrologic Analysis• Cost Analysis• Climate Scenarios
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Location and Project Information
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• Site Name• Search for Site Location• Site Area
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Soil Type
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• NRCS Web Soil Survey• Defined by Hydrologic
Soil Group• Group A – Sand• Group B – Sandy Loam• Group C – Clay Loam• Group D – Clay
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Soil Drainage
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• NRCS Web Soil Survey• Saturated Hydraulic
Conductivity
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Topography
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• NRCS Web Soil Survey• Surface Slope
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Precipitation
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• Measured at nearbyNational WeatherService rain gage
• Average annual rainfallbased on long-termhistorical data
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Evaporation
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• Measured at nearbyNational WeatherService weather station
• Monthly evaporationrates calculated fromlong-term historical data
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Climate Scenarios
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• Climate projectionsproduced by the WorldClimate ResearchProgramme (WCRP)
• Scenarios model futurechanges in temperatureand precipitation
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Climate Scenarios
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• Climate projections affect the average monthly rainfall• Three scenarios• Two time periods
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Climate Scenarios
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• Climate projections affect the average monthly rainfall• Three scenarios• Two time periods
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Climate Scenarios
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• Climate projections affect the average monthly rainfall• Three scenarios• Two time periods
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Land Cover
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Select the percent of sitearea covered by:
• Forest• Meadow• Lawn• Desert• Impervious
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Low Impact Development (LID) Controls
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Select percent ofimpervious area to betreated by each LID type
Enter design storm to beused for LID sizing
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
LID Controls
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Rain Gardens• Ponding Height• Soil Media Thickness• Soil Media Conductivity• % Capture Ratio
(ratio of LID area todesired captured area)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
LID Controls
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Street Planter• Ponding Height• Soil Media Thickness• Soil Media Conductivity• Gravel Bed Thickness• % Capture Ratio
(ratio of LID area todesired captured area)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
LID Controls
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Permeable Pavement• Pavement Thickness• Gravel Layer Thickness• % Capture Ratio
(ratio of LID area todesired captured area)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
LID Controls
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Site Suitability• Physical Obstructions• Utility Conflicts• Ease of Access
Impacts• Construction Cost• Maintenance Cost
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
LID Controls
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Select cost region
Impacts• Construction Cost• Maintenance Cost
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
LID Controls
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Select cost region
Impacts• Construction Cost• Maintenance Cost
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
LID Controls
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Select cost region
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Model Options
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• Select number of yearsto analyze
• Enter event threshold• Consecutive Days
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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• Compare multiplescenarios at once
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Site Description
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Summary
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Rainfall / RunoffEvents
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Rainfall / RunoffFrequency
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Rainfall / RetentionFrequency
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Runoff by RainfallPercentile
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Extreme EventRainfall / Runoff
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Capital Cost(tabular)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Capital Cost(graphical)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Maintenance Cost(tabular)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Results
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Maintenance Cost(graphical)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Quantifying Costs
Traditional Costs• Capital Costs• Maintenance Costs
Indirect Costs• R/W Acquisition Costs• Treatment Plant Costs• Snow removal• Water Re-Use• Energy Savings• Tax Incentives / Utility Fees
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Quantifying Costs
Traditional Costs• Capital Costs• Maintenance Costs
Indirect Costs• R/W Acquisition Costs• Treatment Plant Costs• Snow removal• Water Re-Use• Energy Savings• Tax Incentives / Utility Fees
Non-Monetary Costs• Air Quality• Water Quality• Habitat Quality
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Franklin County Correctional Facility
23 Acre SiteBuildingParking LotLandscaping
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Lifecycle Cost AnalysisTraditional Stormwater Gray Infrastructure• Asphalt Parking Lot• Storm Sewer• Catch Basins• Detention Basin• Maintenance (30 Years)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Lifecycle Cost AnalysisTraditional Stormwater Gray Infrastructure• Asphalt Parking Lot• Storm Sewer• Catch Basins• Detention Basin• Maintenance (30 Years)
Low Impact Development Green Infrastructure• Permeable Pavers• Storm Sewer• Catch Basins• Detention Basin• Maintenance (30 Years)
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Lifecycle Cost AnalysisTraditional Stormwater GrayInfrastructure• Capital Cost = $1,350,000• Maintenance Cost (30 years) = $430,000• Total = $1,780,000
Low Impact Development GreenInfrastructure• Capital Cost = $1,710,000• Maintenance Cost (30 years) = $380,000• Total = $2,090,000
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Lifecycle Cost AnalysisCity of Columbus StormwaterUtility Fee• Based on property’s contribution to
stormwater runoff• 2,000 SF Impervious Area = 1 ERU
(Equivalent Residential Unit)• 23 Acres Impervious = 500 ERU• Annual Stormwater Fee = $27,040• 30 Year Fee = $811,200• GI used to meet all water quality and
quantity requirements = 100% credit
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
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Lifecycle Cost AnalysisTraditional Stormwater GrayInfrastructure• Capital Cost = $1,350,000• Maintenance Cost (30 years) = $430,000• Stormwater Fee (30 years) = $811,000• Total = $2,590,000
Low Impact Development GreenInfrastructure• Capital Cost = $1,710,000• Maintenance Cost (30 years) = $380,000• Total = $2,090,000
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis
Questions?
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Justin Kernsms consultants, inc.2221 Schrock Rd,
Columbus, OH 43229614-898-7100
April 2018 ASCE Spring Seminar | Green-Gray Cost Analysis