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Green Infrastructure / Low Impact Development LID Design Tool and Lifecycle Costing NWWBI Stormwater Task Force Robert Muir City of Markham

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National Water and Wastewater Benchmarking Initiative Stormwater Task Force Fall Workshop, Richmond Hill, Ontario, Canada
by Robert J. Muir, M.A.Sc., P.Eng.
Manager, Stormwater, City of Markham
Presentation reviews the history of low impact development best management practices in Ontario, York Region and the City of Markham. Application of Analytical Probabilistic Models to assess LID performance and capacity for cost-effective design is reviewed. Lifecycle costs of distributed and centralized green infrastructure LID features are compared with conventional grey infrastructure stormwater management approaches. Normalized unit costs of various LID technologies are compared including annualized capital depreciation and operation and maintenance costs. Recent Ontario green infrastructure LID BMP implementation costs for bioswales, infiltration trenches, rain gardens and permeable pavement are summarized. City of Markham North Markham's LID servicing strategy is reviewed including impact of new development LID servicing on tax rates or stormwater utility fees.

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Green Infrastructure / Low Impact Development LID Design Tool and Lifecycle Costing NWWBI Stormwater Task Force Robert Muir City of Markham

  1. 1. National Water & Wastewater Benchmarking Initiative Stormwater Task Force LID Design Tool & Lifecycle Costing Robert J. Muir. M.A.Sc., P.Eng. Manager, Stormwater Richmond Hill, Ontario October 26, 2017 1
  2. 2. • Background – LID Target Evolution – Markham & Local Experience • Analytical Probability Design Tool – Capacity vs Performance • MOECC Draft LID Targets • Capital & Lifecycle Cost Considerations – Comparison with Traditional Design – Unit Costs for Completed LID Projects – North Markham Lifecycle Costs Analysis 2 Outline
  3. 3. Background on LID / Green Infrastructure • LIDs / GI can help replicate the natural hydrologic cycle and mitigate groundwater and surface water system impacts of development. Improves quantity and quality management. 3
  4. 4. Background on Policy and Targets • 1991 Ontario interim guidelines to mitigate new development impacts by managing stormwater “at source”, promotes infiltration, vegetated BMPs. • 1994 & 2003 Ontario design guidelines include targets for sizing quality ponds but not sizing LIDs • LID criteria set based on local needs: – 1995 OPA 118 match recharge on ORM – 2006 Toronto 5 mm for water quality control (Wet Weather Flow Management) – 2010 Markham target for Eckhart Creek = 10 mm for erosion control – 2012 TRCA 5 mm for erosion (to retain on-site per Criteria Document) 4
  5. 5. Markham Implementation of LIDs • First LID features for meeting water balance goals approved 10 years ago: • Kylemore Subdivision Recharge Basin & Biofilters • Retrofits completed on an opportunity basis (combined with other works): • Grencrest Park Raingarden • Demonstration projects to test new technologies / approaches: • Green Road at South East Community Centre 5 Glencrest Park Raingarden Markham Green Road Pilot
  6. 6. Markham Implementation of LIDs 6 Kylemore Forested Wetland for Water Balance
  7. 7. York Region Implementation • “Etobicoke Exfiltration System” for meeting Oak Ridges Moraine MESP water balance goals approved / built 20 years ago: – Richmond Hill OPA 118 Ph.4 • Lake Simcoe Protection Act 2008 targets for urban phosphorus management. • Clean Water Act polices to maintain WHPA Q1/Q2 recharge. • Municipal pilot projects: – W-Stouffville Community Park – Newmarket Residential Road – Aurora Recreation Complex – E.Gwillimbury Municipal Office 7 Richmond Hill OPA 118 (1997)
  8. 8. Analytical Probabilistic Models (APMs) • Research in early 1980’s at the University of Toronto • Alternative to continuous period simulation for analysis of urban drainage systems • Comparative studies have validated APM results • Many applications for the planning of urban runoff quantity/quality control systems
  9. 9. How APMs Work • Characterize rainfall statistics based on past records: • Mathematically transform stats into hydrologic & hydraulic performance: Storage Catchment ‘Treated’ Outflow (e.g., infiltration) Bypass (‘spill’)Runoff
  10. 10. APMs for LID Measure Design & Assessment • Dr. Yiping Guo at the McMaster University in Hamilton, Ontario develops LID evaluation models. Page 10
  11. 11. LID Target Volume Cost Effectiveness 11 Diminishing Volume Controlled Higher Volume Targets Have Lower Incremental Benefits
  12. 12. MOECC Proposed Minimum LID Targets (Draft) • Pressure to advance LID implementation (Environmental Commissioner of Ontario 2014) as part of extreme weather adaptation. • Ministry of Environment and Climate Change (MOECC) issues interpretation bulletin relaxing implementation constraints (promote LIDs in tight soils). • 2017 Draft LID Guidance sets aggressive, high stormwater retention/capture & release targets of 27 - 28 mm across Markham area & York Region. 12 LID Volume Targets
  13. 13. Capital Cost Impacts of Draft MOECC Targets • Cost for LID higher than conventional technologies. 13Draft – City of Barrie (LID Cost Analysis.xlsx) Grey / Central Green / Distributed
  14. 14. Lifecycle Cost Impacts of Draft MOECC Targets • Present Value of LID lifecycle costs 4-5 times higher than conventional technologies (initial capital, O&M, replacement). 14Draft – City of Barrie (LID Cost Analysis.xlsx) Grey / Central Green / Distributed
  15. 15. Unit Costs of LID and Traditional SWM • ‘Normalized’ cost (annual cost per hectare served) needed for alternative evaluation & system planning or budgeting. • Past studies have not normalized costs in comparisons. 15 POND LIDs Non-normalized O&M Costs
  16. 16. 0 2000 4000 6000 8000 10000 12000 14000 16000 Bioretention Permeable Pavement Infiltration Trench / Chamber Enhanced Grass Swale Markham Wet Pond Average Annual Maintenance + Depreciation Cost per Impervious Area ($ / ha / year) Depreciation Maintenance Unit Costs of LID and Traditional SWM • Annual ‘normalized’ cost of ponds less than LIDs. 16 POND LIDs Normalized O&M + Depreciation Costs
  17. 17. Completed LID Project Costs 17 City / Town LID Type (Project Name) Capital + Soft Cost ($) Service Area (ha) Cost / Hectare * Markham Bioswale & Infiltration Trench (Green Road) $ 783,602 1.90 $412,422 + Markham Rain Garden (Glencrest Park) $216,000 1.6 ** $135,000 Brampton Bioswale (County Court SNAP) $130, 514 0.2 $652,570 + Whitchurch- Stouffville Various Measures (Coultic Park & CC Parking Lot) $103,026 0.11 $936,600 Ottawa Bioretention (Sunnyside / Road) $282,887 0.464 $609,670 Ottawa Bioswale (Stewart / Road) $363,452 2.010 $180,821 Ajax Rain Garden (Lake Driveway) $350,000 0.14 $2,500,000 Mississauga Bioswale & Pavers (Elm Drive) $226,000 0.633 $357,030 Mississauga Bioswale (Lakeview) $420,900 1.6 $363,063 Median Unit Cost = $412,000 / ha * Range similar to TRIECA 2017 examples ** No impervious hectares
  18. 18. MOECC LID Target Policies for City Activities 1) Linear Development shall maintain pre- development water balance for whole site or net increase in impervious area. • Road reconstruction / widening • Markham “Green Road” example added cost $1.35M / km • Barrie lifecycle impact 4-5 times cost of conventional SWM design • Ottawa estimates 30% added cost 2) Linear Infrastructure with restrictions meet 75% of target, no cost constraint allowed. • Flood Control Program sewer upgrades would add 15% cost 3) Roadway mill and overlay exempt but ”encouraged to undertake SWM retrofits to the activities Maximum Extent Possible” • Ottawa estimates 300% more cost 18
  19. 19. Impacts of LID Targets on Future Development • LID targets shall apply to development to meet pre- development water balance goal including : – New Development (new lot, change in use, building construction requiring Planning Act approval), – Redevelopment (full/partial building demolition), – Intensification (infill, increased density or units). • Governance for LID O&M on private sites being considered by MOECC can have implications on various City departments: – Data management / inventory – Easement & subdivision / site-plan agreements – Monitoring requirements – Compliance inspection / enforcement 19
  20. 20. Impacts of MOECC LID Targets in Markham • Local need unclear given decades of rising baseflows*, including Rouge River. – Are LID controls needed in all catchments ? • Area-wide targets are set in comprehensive local subwatershed studies – Are MOECC 27-28 mm targets needed given North Markham 2-10 mm recharge targets? 20 North Markham Baseflows Increasing for 50 years * TMIG baseflow study report 2010 link Urbanization and baseflow resiliency review link
  21. 21. North Markham LID Lifecycle Costs • North Markham, Future Urban Area (FUA) has many new features compared to conventional developments. • New services are evaluated for long-term lifecycle costs, including O&M and replacement. • Analysis allows sustainable funding to be secured up front for Muti-Use Paths, Low Impact Development features, etc. 21 North Markham 1288 ha
  22. 22. North Markham LID Unit Costs • Groups of LID features were assessed for O&M costs and replacement costs to derive unit costs scaled to whole 1288 hectare development. • Sources of maintenance tasks and costs included: – TRCA 2013 STEP Life Cycle Costs – City of Barrie LID Lifecycle Analysis – CVC Permeable Paver O&M Cleaning Costs – Markham Operations, Engineering, Environmental Services Staff – Checking with ASCE 2010 publication, consultant cost estimates • Added activities included: – Administration (GIS, records management, etc.) – Design, Contract Admin, Project Management – Replacement for measures with > 50 year service life – Labour payroll burden, equipment, travel time (indirect costs) 22 Sources: TRCA 2013, ASCE 2010
  23. 23. Indirect O&M Costs Related to Activities 23 15-20% Indirect Costs, Truck ($60/hr), Payroll Burden (benefits etc.) 15-20%
  24. 24. North Markham LID Groups 24 (A) Bioretenion / Rain Gardens (B) Infiltration Galleries (C) Stormwater Planters (D) Permeable Pavement (E) Rain Cisterns
  25. 25. LID Unit Costs – Infiltration Gallery O&M 25 Normalized O&M Cost $2,211 / impervious ha / year DRAFT
  26. 26. LID Unit Costs – Infiltration Gallery Depreciation 26 Normalized Depreciation Cost $6,410 / impervious ha / yearDRAFT
  27. 27. LID Unit Costs – Infiltration Gallery Total Costs 27 DRAFT
  28. 28. LID Scenarios – Total North Markham Costs 28
  29. 29. LID Cost Funding Impacts – Utility Fees 29 Scenario Annual O&M Cost Annual Depreciation Total Cost % of Stormwater Fee Budget $234 M 1 $1.97 M $ 0.36 M $ 2.33 M 30 % 2 $ 0.42 M $ 1.21 M $ 1.63 M 21 % 3 $ 0.82 $ 0. 99 M $ 1.81 M 23 % City-wide fee increase (permanent)
  30. 30. LID Cost Funding Impacts – Total Budget 30 Scenario Annual O&M Cost Annual Depreciation Total Cost % of 2017 Capital and Operating Budget $283 M 1 $1.97 M $ 0.36 M $ 2.33 M 0.82 % 2 $ 0.42 M $ 1.21 M $ 1.63 M 0.58 % 3 $ 0.82 $ 0. 99 M $ 1.81 M 0.64 %
  31. 31. LID Cost Funding Impacts – Tax Rate 31 Scenario Annual O&M Cost Annual Depreciation Total Cost % of Tax Funded Programs 1 $1.97 M $ 0.36 M $ 2.33 M 1.6 % 2 $ 0.42 M $ 1.21 M $ 1.63 M 1.1 % 3 $ 0.82 $ 0. 99 M $ 1.81 M 1.2 % City-wide tax increase (permanent)
  32. 32. Conclusions • Many tools available for designing LIDs: – spreadsheets for York Region designs 20+ years ago – analytical probabilistic models for efficient ‘what if’ sensitivity analysis and design – advanced simulations (SWMM-based) • System-wide planning needed to identify cost-effective targets to meet local goals (e.g., subwatershed studies) • Costing evaluations have not always considered normalized costs, full lifecycle replacement costs, or system-wide O&M and ‘depreciation’ costs for sustainable financial planning. • LID O&M and depreciation costs for one large development block can have a tangible impact on city-wide finances (tax rate, utility fees, etc.) 32
  33. 33. Thank You 33

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