Realizing District Ecological Infrastructure: From Vision to Site Implementation in Cities SUN-A04

Transcription

1 Realizing District Ecological Infrastructure: From Vision to Site Implementation in Cities SUN-A04 Session Marketing Statement Implementing district scale ecological infrastructure continues to be a difficult puzzle in American cities, where property owners, regulators, and market forces can determine the success or failure of a bold vision. This session will describe examples of phased site development infrastructure solutions in recent projects by Biohabitats, Mithun and Sasaki. Learning Objectives 1. Understand the evolution of Eco-District planning concept and innovations in urban ecological infrastructure. 2. Appreciate the market and regulatory forces that are influencing implementation of ecological infrastructure. 3. Understand a conceptual framework for phased implementation of district infrastructure. 4. Examine creative approaches to phased site development through recent project examples. Overview of topics to be covered in the panel. Definition of urban ecological infrastructure. Overview of district scale planning and its benefits. Christian Runge, ASLA, Mithun I. Define ecological infrastructure in the urban context. The term ecological takes on a new definition when applied in an urban context where restoration to the pre-development condition may be impossible. This talk will focus on the methods that practitioners can use to positively impact local urban and larger regional ecosystems and specifically discuss the challenges of multi-phase, multijurisdictional urban projects. What is Ecological Infrastructure for the purpose of this presentation? i. Hydrology- Stormwater management = improving local and regional water quality by reducing non-point source pollution and replicating natural hydrologic flow regimes through green or gray systems ii. Habitat/biodiversity/resilience-Designers can dramatically effect these elements in the urban environment by building diversity in planting design. Street trees and associated plantings are a primary means of connectivity in dense urban environment, especially for flying species. Green roofs and other on-structure systems. iii. Climate adaptation- in planting design and in maintenance plan iv. Energy/waste- Reduce building energy use through passive design, plant material, trees. Water reuse, blackwater treatment.

2 v. Equity, client and community acceptance- Aesthetics and equitable distribution of green infrastructure as well as stakeholder engagement are critical to long term sustainability of these strategies II. III. IV. Define district-scale planning and its benefits- Parcel by parcel development significantly diminishes the possibilities for sustainable ecological infrastructure while large scale city design can be impractical and unwieldy. For this discussion, we will be specifically referencing district scale development in American cities due to their unique spatial and political qualities. a. Benefits of District Scale planning i. Building Efficiency ii. District energy generation and waste treatment iii. Flexibility in implementing ecological infrastructure (distributed v. centralized bioretention) iv. Bundling parking, transit v. Scale of governance and process is critical (eco-district approach) b. Early conceptual model: Lloyd Crossing, Mithun i. Establishing baseline condition metrics for energy, stormwater, biodiversity ii. Establishing targets iii. Using integrated design of site and building to meet targets iv. Being honest about what can and should do in cities. c. The low hanging fruit: district implementation at Seattle University i. The university is the perfect laboratory for district scale planning. 1. Single land owner allows master plan to be 2. Already doing district energy 3. Innovative as brand 4. Site opportunities, substantial public realm Conceptual framework for district scale implementation of ecological infrastructure in cities a. Phased-Interim parcel condition, future condition b. Nested-Start in building, move out to parcel boundary, then to ROW c. Modular- replicable system across the campus or district d. Connected- Efficient treatment train from building systems to site. e. Bundled systems, in the public realm Describe forces that are influencing district implementation a. Demographics- people want to reside in living cities (biophilia) b. Tenant demand- organizations like Weyerhauser, Amazon, State of MD are moving to cities and want healthy green design for their workforce c. Developers are following this market demand. Some are ahead of the curve, and some are behind it. d. Regulators can incentivize, stall or block phased district implementation (to be discussed in depth with case studies) e. Designers provide the vision, but also facilitate and educate consultants, regulators and clients. f. Using the ROW in cities (Taylor 28, 14 Ave, Bell street) All three of these projects reconfigure the automobile lane alignments in order to create usable open space for public realm and green infrastructure. g. Power line ROW work. Ecological restoration for pollinator species and climate adaptation. Mithun is currently working with artist Sarah Bergmann, ecologists from Seattle City Light, and entomologists from Xerces Society to create guidelines for pollinator habitat design in utility corridors.

3 h. Green infrastructure and equity- City of New Orleans is piloting several projects that seek to build green infrastructure in under-served neighborhoods which often have the worst drainage problems. i. Ecodistricts, concerned with process rather than prescription: collaborative governance, creating a political and metrics driven roadmap. A unique suite of metrics are developed for each district. V. Challenges to district implementation- Mini case study of Mariposa Housing Redevelopment, Denver a. Varied funding sources effect timing/ coordination and quality of construction b. Master plan and design and construction completed by different firms c. Difficult to get all city departments on the same page therefore stormwater and parking were completed in a piecemeal fashion. PERMITTING AND IMPLEMENTING A MASTERPLAN S GREEN INFRASTRUCTURE UNDER MARYLAND S ENVIRONMENTAL SITE DESIGN CRITERIA Brian Chilcott, Associate ASLA, Sasaki Associates Project Overview: The Blairs is a 24.4 acre district redevelopment masterplan in downtown Silver Springs, Maryland. The masterplan, completed in 2012, divides the site into 5 implementation phases. Phases 1 and 2 were carried through design development simultaneously and construction documentation for phase 1 was completed in August The entire project aims for LEED Gold Certification for New Construction. Site Overview: The site is part of the headwaters of the Lower Rock Creek watershed and drains into Rock Creek Park, an ecologically sensitive, geomorphically unique and biologically rich segment of Rock Creek administered by the National Park Service. Rock Creek is a tributary of the Potomac, which drains into the Chesapeake Bay. The site is a sloped escarpment transitional between the Northern Piedmont and Coastal Plain ecoregions and shows an extremely heterogeneous soil profile including a quite variable depth to bedrock. In downtown Silver Springs, its existing urban condition is 85% impervious and includes large asphalt surface parking, aging retail and residential buildings. The Regulatory Framework: Maryland Stormwater Act of 2007 Environmental Site Design to the Maximum Extent Practicable (ESD to the MEP) o Small-scale stormwater management practices, nonstructural techniques, and better site planning to mimic natural hydrologic runoff characteristics and minimize impact of land development on water resources Optimize conservation of natural features Minimize impervious surfaces Manage runoff o Benchmark hydrology = woods in good condition Detailed Objectives: 1. Prevent soil erosion from development projects 2. Prevent increases in nonpoint pollution (namely phosphorus)

4 3. Restore, enhance, and maintain chemical, physical and biological integrity of receiving waters to protect public health and enhance domestic, municipal, recreational, industrial and other uses of water as specified by MDE 4. Maintain 100% of the average annual predevelopment groundwater recharge volume 5. Capture and treat stormwater runoff to remove pollutants 6. Implement a channel protection strategy to protect receiving streams 7. Prevent increases in the frequency and magnitude of out-of-bank flooding from large, less frequent storms 8. Protect public safety through the proper design and operation of stormwater management facilities Treatments Considered: 1. Green Roofs still considered impervious surface but counts towards treated volumes. 2. Permeable pavement (infiltration considered pervious) 3. Rainwater harvesting 4. Submerged gravel wetlands 5. Landscape infiltration 6. Infiltration berms 7. Drywells 8. Micro-bioretention 9. Rain gardens 10. Swales 11. Enhanced filters Enforcement: Montgomery County Department of Permitting Services 1. Concept 2. Site Development 3. Final (As-Built) District Stormwater Treatment Target: Project received a waiver from MCDPS due to site limitations on infiltration (shallow bedrock) Target PE = 2.2 ( 24.4 acre drainage area, 85% area impervious, Hydrologic Soil Group B) Translation: ESD facilities would have to treat 2.2 of rainfall from acres of impervious surfaces in order to mimic woods in good condition o 3 Primary ESD Treatments: 8 Green Roofs (media depth required as part of waiver conditions) Micro-biofiltration box planters Underground structural volume-based filter o Underdrained surface swales along Eastern Ave. on the D.C. side of property (does not count towards MD ESD). Only treats Eastern Ave. street runoff. Phase 1 & 2 Site Solutions, Phasing Challenges & Missed Opportunities Planting Design

5 o 9 spaced 5 landscape plugs (100% MD native species) across entire planted ground. Dense ground plantings will absorb more rainwater and greatly reduce runoff; however, these benefits do not qualify as ESD treatment. This design also will increase irrigation needs during drought. o Maximized urban canopy. MCDPS required total number of mitigation trees to compensate for those being removed (21); however, our design quadruples the urban canopy of the site (101 trees in Phase 1). A single mature deciduous tree can capture 100 gallons of rainwater on its surfaces and evaporate it after the storm. Urban canopy (and total site leaf area index) greatly reduces runoff but these benefits are not easily quantified and do not count towards ESD treatment. Trees in the micro-biofiltration box planters will absorb considerable stormwater but these benefits also are not considered in ESD calculations. o Temporary park (Phase 4 site) serves as on-site tree nursery for Phase 2 and 3 trees (still Schematic not permitted yet). o Rainwater harvesting & gray water reuse represent big missed opportunities that the client now is interested in incorporating into later phases. Irrigation was essential to our rooftop gardens; we therefore only achieved 2 of 4 possible LEED points for Water Conservation. If we could have irrigated with gray water, those points would have been within reach. o o Leaf mulch in all upland planting beds striving for woods in good condition Resilience through biodiversity == about 42,000 plants across 160 different species! Fig. 1 Blairs Master Plan

6 Fig. 2 Blairs Rendering Hassalo on 8 th Water Street and NORM The Lloyd District, Portland, OR Erin English, PE LEED AP, Biohabitats VI. VII. VIII. Brief Overview of the Living Infrastructure Guide from EcoDistricts. a. New guidebook available for use for planners, designers, engineers. b. Collaboration with Mithun and others. c. Review main topic areas briefly. Review water & habitat-related strategies in the context of living infrastructure for district scale projects. a. Opportunities & Challenges at the district scale. b. The need to aim for adaptation and flexibility to best address local, project/district specific needs. Hassalo on 8 th : Water Street and NORM a. Case study of an early ecodistrict or district scale project in Portland, OR, with a focus on the integrated water strategies employed across the site for managing wastewater, stormwater and rainwater. b. Review the Water Street concept of designating the two-block central pedestrian corridor as the place for living infrastructure to process, filter and store water in a way that is visible to the public and that creates green space in the urban hardscape.

7 c. Meet N.O.R.M. the natural organic recycling machine that processes all of the wastewater in the street while providing reclaimed water to meet 100% of the toilet flushing demand, cooling demand and landscape irrigation. d. Discuss wastewater process, flows, schematic and layout on the site. e. Discuss integration with landscape architects, architects, structural engineers, MEP engineers, civil engineers and contractor during the design and construction. f. the social media persona Biohabitats created to educate the public about wastewater. Fig. 3 Hassalo on 8 th Natural Treatment System