1 / 34

Public Works Advisory Board (PWAB) Meeting April 15, 2013

Horizon West Town Center Low Impact Development Manual Project Overview. Public Works Advisory Board (PWAB) Meeting April 15, 2013. Mark Ellard, PE, CFM, D.WRE Geosyntec Consultants – Lake Mary, Florida. Outline. Introduction Town Center Overview What is LID? Regulatory Drivers

more
Download Presentation

Public Works Advisory Board (PWAB) Meeting April 15, 2013

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Horizon West Town Center Low Impact Development Manual Project Overview Public Works Advisory Board (PWAB) Meeting April 15, 2013 Mark Ellard, PE, CFM, D.WRE Geosyntec Consultants – Lake Mary, Florida

  2. Outline • Introduction • Town Center Overview • What is LID? • Regulatory Drivers • Selected LID Practices • Cost Impacts • Next Steps

  3. Introduction What Are We Trying to Accomplish? • Accommodate higher density/intensity development • Utilize land resources efficiently • Maintain and improve water quality in receiving water bodies • Provide options to structural stormwater facilities • Develop experience/expertise with construction and maintenance of LID practices

  4. Town Center Overview Horizon West Area

  5. Town Center Overview Horizon West Town Center • Employment and commercial hub • Higher density urban environment: • Connected/walkable streets and blocks • Integrated mixed use districts • Compact urban places • Town Center development program: • 3,500 acres • 6,000 housing units • 1,200 hotel rooms • ~8,000,000 sq. ft. of commercial and office uses

  6. Town Center Overview Town Center Town Center Code • Phase I – adopted 01/29/2013 • Administration • Streets and blocks • Land use • Placemaking • Phase II – Green Infrastructure: • LID Manual/practices • Stormwater master planning • Open space component

  7. Town Center Overview Why LID Manual for the Town Center? • Close to 30% of Town Center will function as some form/type of open space, which presents an opportunity to create a more sustainable stormwater management system. • The County is in the process of developing the Town Center Code. • Town Center could serve as a pilot LID program before enabling implementation for a larger area or throughout the unincorporated portion of Orange County.

  8. What is LID? Definitions • Low Impact Development (LID) is an approach to land development that works with nature to manage stormwater as close to its source as possible. • EPA Definition (Coffman, 2000) • LID is a site design strategy with a goal of maintaining or replicating the predevelopment hydrologic regime through the use of design techniques to create a functionally equivalent hydrologic landscape.

  9. What is LID? Definitions (cont.) • LID practices • Stormwater facilities that more closely mimic natural conditions by: • Reducing the size and extent of structural facilities (impervious area) • Promoting infiltration (groundwater recharge) • Lengthening runoff flow paths • Capturing stormwater in close proximity to the source of runoff • Distributing runoff storage (retention and/or detention) • Improving water quality

  10. What is LID? LID Applications • New Development • Green Initiatives • Sustainability • Urban Retrofits • Meet New Regulatory Objectives • NPDES • TMDLs • Water Conservation

  11. What is LID? Benefits of LID • Enhanced water quality protection and restoration; • Improved groundwater recharge; • Reduced wetland and upland habitat impacts; • Reduced downstream erosion; • Improved site aesthetics; • Potential increase in property values; • Potential development cost savings.

  12. What is LID? Challenges of LID • Effective integration with traditional stormwater management practices; • Lack of familiarity of local contractors with construction (i.e., certifications, etc.); • Lack of familiarity by county engineers and other local/regional permitting authorities of performance and effectiveness; • Lack of experience with maintenance procedures and associated costs.

  13. What is LID? Goals of the Orange County LID Manual • Promote the use of structural LID practices; • Educate landowners, developers, engineers, planners and permitting authorities; • Provide guidance and design information to developers and engineers as they consider LID practices.

  14. What is LID? Where else in Florida ? • Manuals • Sarasota (Draft) • Jacksonville / Duval County (Draft) • Alachua County (Draft) • Ordinances / Comp Plan • Dunnellon • Oldsmar • St. Pete • Melbourne

  15. Regulatory Drivers • Orange County Mayor’s Sustainability Initiative • Promote sustainability • Orange County Comprehensive Plan • Meet policy directives • NPDES / TMDLs • Promote green infrastructure • Impaired waters (Lake Jesup, Wekiva, Econ, Lake Apopka, etc.) • Statewide Stormwater Quality Rule • In limbo, but coming back?

  16. Regulatory Drivers Orange County Policies Supporting LID • Orange County Comprehensive Plan 2010-2030 • Policies FLU6.6.5, FLU8.9.1, FLU8.9.2, UD1.5.5, AR1.1.14, SM1.2.1, SM1.6.2, SM1.6.5, SM1.6.6, SM1.7.4 • Examples: FLU8.9.2 Orange County will develop Low Impact Development (LID) strategies in conjunction with the State Water Management Districts to reduce impacts to water quality and manage water quantity concerns…. SM1.6.2Orange County shall actively participate in the development of innovative stormwater management programs that protect and conserve the County’s water resources. This shall include, but not be limited to, the use of Low Impact Design (LID) technology such as swales and porous pavement in parking lots…

  17. Regulatory Drivers Coordination with Water Management Districts • Goals • To familiarize permitting staff; • To use acceptable flood criteria; • To use acceptable water quality criteria. • Two meetings conducted to date • At least one additional meeting

  18. Regulatory Drivers • Flood Attenuation – Water Quantity Management • Current Regulations • Detention: attenuate 25 Year Storm (Post < Pre) • Landlocked w/no positive outfall: store 100 Year Storm • Typically addressed with detention or retention pond – exfiltration if suitable soils • LID Approach • Meet detention/retention volume with distributed practices • Multiple infiltration opportunities to promote evapotranspiration • May still need pond, but much smaller

  19. Regulatory Drivers Water Quality – Cumulative Impacts of Development • Current stormwater regulations limit discharge rate (cubic feet per second Post <Pre) • Stormwatermanagement facilities (i.e., Ponds) Treat pollutants, but do not reduce 100% (TP ~60-70%, TN ~40-50%) • Increases in impervious area = more volume of runoff (cubic feet Post > Pre) • More runoff volume typically results in more pollutant mass discharged over the long term

  20. Selected LID Practices Pervious Pavement • Applications • Non-residential: (commercial/office) parking areas; • Residential: driveways and sidewalks; • Low-volume, low-speed areas; • Open space area: sidewalks or bike paths. Typical pervious concrete paver cross section (Source: Interlocking Concrete Pavement Institute) Typical pervious asphalt cross section (Source: Public Works Magazine) Grass pave (Source: Stone Age Pavers) Interlocking concrete pavers(Source: CT DEP) Gravel-pave (Source: NDS Inc.)

  21. Selected LID Practices Bioretention Areas/Bioswales • Applications • Non-residential: commercial/office; • Residential: parking areas, street edges, rooftop runoff, adjacent to sidewalks and walking paths; • Urban: parking areas, rooftop runoff; • Street: within existing roadway ditch, curb cuts to bioswale, roadway median. Bioretention area in parking lot(Source: City of Santa Barbara Manual) Not to scale Bioretention swale adjacent to roadway (Source: NRCS) Plan view illustrating a shallow bioretention system (Source: Sarasota LID Manual) Cross section view of a shallow bioretention system (Source: Sarasota LID Manual)

  22. Selected LID Practices Rain Gardens • Applications • Non-residential: (commercial/office) and residential: adjacent to parking areas, driveways, sidewalks, walking paths and rooftops; • Streets: adjacent to parking spaces; • Urban: rooftop drainage; • Open space: adjacent to parking areas and walking paths. Typical cross section of a raingarden(not to scale) (Source: Adapted from Oregon Environmental Council) Raingarden installed on a residential lot (Source: Geosyntec) organic (mulch) layer

  23. Planter box designed to capture and treat rooftop runoff(Source: Geosyntec) Illustration of typical planter box cross section (Source: Bayou Land RC&D BMP Guidance Manual) Selected LID Practices Planter Box • Applications • Adjacent to non-residential (commercial/office) and residential buildings.

  24. Illustration of tree box filter cross section (Source: Contech, Inc.) Illustration of typical tree box filter cross section (Source: Filterra) Treebox filter along road edge (Source: Geosyntec) Selected LID Practices Tree Box Filters • Applications • Non-residential: commercial/office; • Residential/Urban: parking areas, street edges, sidewalks; • Open space: walking paths.

  25. Curb cut along road isproviding drainage to raingarden (Source: Geosyntec) Curb cuts and inverted median along four lane road (Source: City of Arlington Virginia) Selected LID Practices (Source: North Central Texas) (Source: NRCS) (Source: US EPA) (Source: State of Massachusetts) Curb Cuts & Inverted Medians • Applications • Non-residential (commercial/office): parking decks and rooftops; • Streets.

  26. Stormwater harvesting system adjacent to a children’s museum(Source: Geosyntec) Selected LID Practices Stormwater Harvesting - Cisterns • Applications • Non-residential (commercial/office): parking decks and rooftops; • Residential rooftops. Above ground cistern used for irrigation purposes(Source: Duke University) Schematic of an underground cistern supplying adjacent building with grey water (Source: All Things Rainwater)

  27. Cost Impacts • Capital Costs • Reduced infrastructure (↓) • Potentially smaller ponds (↓) • More vegetation/plantings (↑) • Contractor certifications (↑) • Maintenance Costs • Training/certifications for personnel (↑) • Replace typical landscaping – offset overall BMP maintenance area (↓) • Infiltration/media testing (↑)

  28. Phase II: Example Project • Purpose • Show LID techniques can accommodate equivalent density/intensity development as traditional methods; • Provide alternatives to structural stormwater facilities; • Provide additional opportunities for infiltration; and • Illustrate that water quality, water quantity, and nutrient loading criteria can be met or exceeded using LID practices. • Project Site (29.09 acres): portion of Hamlin PD • Commercial: -Grocery store – 54,000 sq. ft. • Bank (Outparcel) – 4,500 sq. ft. • Retail – 4,500 sq. ft. • Residential: - 168 MF units (7 buildings at 24 units/building)

  29. Phase II: Example Project

  30. Phase II: Example Project

  31. Phase II: Example Project • Comparison Results • The LID Concept provides the same commercial and residential square footage and parking while utilizing 25.15 acres of the original 29.09 acres – a reduction of 3.78 acres (13%). • The LID concept plan meets or exceeds the Traditional concept plan in all stormwater management criteria.

  32. Next Steps….. • Phase II: Example Project • Capital costs comparison • Maintenance requirements • Phase III: Maintenance Cost Estimation • Develop maintenance cost projection spreadsheets • Project maintenance costs for each LID practice • Compare to national data • Outreach Program

  33. Questions?

  34. Mark Ellard, PE, CFM, D.WRE - mellard@geosyntec.com 3525 West Lake Mary Boulevard, Suite 306 Lake Mary, Florida 32746 407-321-7030 Thank You !

More Related