Moving from Pilots to a Program: Seattle s Green Infrastructure Program: September 20, 2012

Transcription

1 Moving from Pilots to a Program: Seattle s Green Infrastructure Program: September 20, 2012

2 Overview Brief History: Getting Started to Now GSI Program: What s Working? GSI Program: What needs Improvement? GSI Program: What s new?

3 The Beginning SEA Streets, Seattle Portland

4 Porous Pavement High Point

5 Growing the Program: Building GSI Experience and Knowledge Project SEA Street #1 Carkeek Cascade Broadview Natural Drainage System Pinehurst Natural Drainage System High Point Thornton Creek Water Quality Project Ballard Roadside Rain Gardens Swale on Yale Project Drainage Area 2 acres 28 acres 32 acres 49 acres 129 acres 660 acres 3 acres 435 acres

6 GSI is a viable tool in the retrofit toolbox for multiple various business areas

7 Creek Goals

8 CSO Reduction Goals

9 Water Quality Improvement Goals

10 GSI Projects Primary Driver Project Water Quality Flow SEA Street #1 Carkeek 110th Broadview NDS Pinehurst NDS High Point Thornton Creek Water Quality Project (primary biofiltration) Ballard Roadside Rain Gardens (2-year) maximize (1-2 year) (1-2 year) Delay (6-month storm) (1 year) Swale on Yale (primary biofiltration) For systems designed for Flow control, you still get WQ treatment

11 Cost Effectiveness(NPV) based on TSS Removal

12 What s Working?

13 Seattle s Stormwater Code Requires GSI

14 Modeling and pre-sizing 35% 30% 25% 20% 15% 10% 5% 26 sf 50 sf 74 sf Native soil Infiltration rate (in /hr) 0.25" 1" 0% 25-year LOS creek protection (2-yr to pasture). 98.6% volume infiltration CSO reduction. 95% volume infiltration water quality. 91% volume infiltration water quality (w/ underdrain)

15 Pre-approved approaches

16 Voluntary Installations - RainWise SPU RainWise Program Voluntary Incentive/rebate system on Private Property $3.5/sf Mitigated 2 Practices: Residential Rain Gardens Cisterns Overflow to street or side sewer (next adding trees & greenroofs)

17 RainWise 2012 Incentives 12,000 residences Eligible Feasibility analysis estimated participation (due to technical and interest): 12% What we are finding: Higher % of roof area captured on a given sites roof than anticipated

18 RainWise Basins, Planned

19 RainWise

20 Regulatory and NGO support

21 What s Needs Improvement?

22 Ballard Roadside Rain Gardens Pilot Lessons Learned

23 Reevaluate safety standards

24 GSI O&M Procedures and cost Efficiencies Frequency Year 1 Year 2 and 3 Year Site Maintenance Weekly Every 2 weeks Every 2 weeks Watering Weekly Weekly None Cost/sq.ft. of landscape area $2.86-$3.98 $2.74-$3.07 $0.60-$1.40 Typical Block $6K-$9K $6K-$7K $1K-$3K Per acre of landscaped area Seattle s footprint of GSI for CSO (8 acres) $125K-$174K $119K-$134K $26K-$61K $1.2K-$1.4M $944K-$1.3M $207K-$603K

25 Policy Support: Is natural hydrology a supportive objective?

26 Natural Hydrology performance target =?

27 Need to move project planning beyond the silo and Integrating Multiple benefits Spot flooding SSOs Sidewalks Transportation Action Agenda Climate Action Plan 2020 agenda

28 Integrating Multiple objectives

29 Quantifying the Value of GSI Many benefits beyond better water quality New small-business opportunities; Flexible responses to adapt to climate change; Groundwater recharge; Improved neighborhood streetscapes Opportunity for residents and businesses to help through actions

30 Green Infrastructure Benefits go beyond the primary project goal 1.5 MG CV reduction 7.6 Acres of Rain Gardens 40+ MG stormwater prevented from entering our treatment plants, system and pumps

31 Green Infrastructure has potential to add Resiliency Against Impacts of Climate Change Potential Climate Change Represented by 6% increase in precipitation Climate Change Model 135 conduits completely surcharged 24% increase over Existing Conditions hours cumulative surcharge 61% increase over Existing Conditions Climate Change Model with GSI 65% and 69% decrease in potential impacts of climate change in extent and duration of surcharging, respectively Surcharged Pipes in Climate Change Model

32 How to compare Value not just Cost

33 Green Infrastructure Valuation

34 6 5 4 Design smarter more work to optimize effectiveness of GSI for CSO Reduction Infrequent/Short Duration Overflows 0.26 MG Overflow w/o GSI MG Overflow w/ 30% Impervious Mitigated ==> 0.32 gal/sf mitigated 3 2 Frequent/Long Duration Overflows 0.82 MG Overflow w/o GSI 0.32 MG Overflow w/ 30% Impervious Mitigated ==> 0.63 gal/sf mitigated Flow 1 30% Reduction Close to Compliance Capacity Far From Compliance Capacity

35 GI Effectiveness (gal CV removed/sf to practice) Basin Scale Optimization: Practice Specific Performance Basin 150 Basin Cisterns Alleys Raingardens Total

36 NPV ($M) CSO: Cost Premium for GSI in Right-of-Way (NPV) $100.0 $90.0 $88.8 $92.7 $84.0 $80.0 $70.0 $71.6 $60.0 $53.6 $56.5 $50.0 Gray Cost Gray + Green $40.0 $30.0 $20.0 $10.0 $5.4 $5.0 $0.0 North Union Bay (NUB) Montlake Delridge Ballard

37 If we value all the silos collectively, GSI anticipated to be highly cost effective

38 Whats New?

39 What is our approach to solutions? Fix It, First Sewer System Improvements Keep Stormwater Out Natural Drainage Solutions Store What s Left Underground Storage

40 CSO reduction goals - Areas considered for GSI

41 Seven GSI Projects planned

42 GSI Program Resources! GSI Program Management RFP GSI Project Implementation RFP (Proposals Due 10/2/12)

43 Questions? Tracy Tackett GSI Program Manager City of Seattle Seattle Public Utilities Ray Hoffman, Director

44 Green Infrastructure Siting & Informed Concent

45 Project Timeline for Ballard & Delridge projects in initial contract(s)