Pathway To Net Positive Urban Watershed The SW Ecodistrict s 10th Street Stormwater Infrastructure Study

Transcription

1 Charles Kelley ZGF Architects LLC, Portland, OR Ed Clark ZGF Architects LLC, Seattle, WA Pathway To Net Positive Urban Watershed The SW Ecodistrict s 10th Street Stormwater Infrastructure Study Introduction The SW Ecodistrict is in Washington, DC where 21st Century urban planning is being invented. It includes an innovative design strategy where cutting-edge green infrastructure and community inspiration are integrated in a beautiful setting; this leverages the interface between high-performance, stormwater strategies and people. With engaged neighbors, public support, feasible investment, shared development opportunities, and alignment with public policy the SW Ecodistrict is an example of a district-scaled approach to achieve an adaptable green infrastructure that uses surface water and ground water resources to achieve a water balance for an intensely-developed neighborhood. The SW Ecodistrict develops a Net Positive water system as it transforms an office precinct in to a vital mixed-use district. In-depth analysis was completed to understand the carrying capacity through scrutinizing water sources and uses across the project. The conditions are created through a plan that is intended to transform an office precinct into a vital, urban and mixeduse community as a biophilic amenity for nearby communities. The unique water system is feasible because it brings together diverse communities and user groups through the creation of equitable gathering spaces and places of respite that expose, enhance, and celebrate the hydrologic process.

2 To achieve its Net Positive goals for water and energy, an aggressive integration of natural and built systems are proposed to leverage a new sense of beauty and improved experience in the SW Ecodistrict. Located between the National Mall and the Basin in the Southwest Rectangle in Washington, DC it was historically an area redeveloped as a signature urban renewal district in the 1960s that displaced many poor communities to form a stateof-the-art office precinct for federal workers. Due to its single purpose and lack of outdoor vitality, it has become a homogenous, sterile, office environment. It is often joked that is the only place in DC where you can idle a tour bus and no one would complain. The goal of the SW Ecodistrict Plan was to significantly revitalize the open space system and achieve the highest efficiencies in energy use and water processes while minimizing waste generation. This plan provided a road map for private interests to redevelop new facilities on behalf of the federal government along SW 10th Street. As architects, urban designers, and sustainability specialists, the SW Ecodistrict has served as an a inspiration for other projects. We have uncovered the importance of planning for innovative districts using advanced sustainable design systems to create a sense of purpose and beauty for communities. This is done first, by setting audacious goals to create cost neutral solutions that generate resource positive outcomes. Second, by delivering services through the cost neutral design configurations for urban neighborhoods that are functional and extraordinarily beautiful. Third, by establishing agreements and governance structures to pay for and operate facilities. The benefits found in one transformed neighborhood experience due to use of green instrasture has fundamentally built a strong partnership to move it forward. The SW Ecodistrict Taskforce developed the plan and was led by the National Capital Planning Commission. The taskforce was comprised of Federal and District Stakeholders who worked together to conform the district to current planning objectives and achieve a Net Zero energy goal as measured by carbon and other resource goals determined by the Taskforce. The Taskforce pioneered a pathway to a Net Positive water system through leveraging jurisdictional opportunities and providing an enhanced experience. In part, this was due to a new stormwater management plan that DC tested in the SW Ecodistrict Plan and then adopted and implemented. Not only did the configuration of this new neighborhood treat stormwater (with the capital investment supported by a very short return on investment) it did so with a profound sense of beauty. It employed biophilic design tenets, establishing a new precedent where stormwater management reinforces the benefits of green infrastructure to support the outdoor settings of urban lifestyles.

3 Key Take Away Through the work of the stakeholders, aggressive quantitative goals for water, energy, and waste are achieved through the transformation of the SW Ecodistrict. The quality of the spaces between buildings support the performance of building systems to make a unique and variable neighborhood. The future of this district is dependent on the cohesion amongst its partners. The sense of beauty of the place and wonder in the application of technology generated a new dimension in urbanism that could be supported by the City, the Federal Government, adjacent communities, property owners and tenants. Together they can coordinate their individual inclination to achieve a collective benefit for themselves and future communities. This paper analyzes the following: 1. Vision Plan: How vision plans for urban neighborhoods can make the business case for comprehensive water systems that achieve broader economic and ecological goals. 2. Challenges and Opportunities: How political and regulatory barriers influence the success of the water system concept. 3. Using Stormwater Credits: How using stormwater credits with other onsite resources at the district scale, such as water treatment, waste management, and energy systems can increase development feasibility and transform neighborhood beauty. 4. Cost Sharing: How the SW Ecodistrict use a cost sharing agreement between public and private entities to leverage beauty in open space system through stormwater improvements. The SW Ecodistrict develops provides a rich amenity for everyone to emjoy.

4 1. Vision Plan The SW Ecodistrict Initiative, and the adoption of the SW Ecodistrict Plan and related efforts, is a comprehensive and forward looking approach to transform an isolated federal precinct in the nation s capital into a highly sustainable workplace and livable neighborhood. It reconciles the Monumental Core Framework Plan, which proposed using federal lands more efficiently and locating new cultural sites and museums in the area south of the National Mall to catalyze economic development with Executive Order 13514: Federal Leadership in Environmental, Energy and Economic Performance, signed by President Obama in The Order sets targets for energy, water, and greenhouse gas reductions for federal buildings. The SW Ecodistrict Initiative seeks to accomplish the following goals in the targeted area: A revitalized mixed-use neighborhood and cultural destination A well-connected community A high-performance environmental showcase An economically successful partnership These goals were in alignment with a new kind of integrated open space design concept connecting buildings and open spaces together using plant and water systems to reduce heating and cooling demands and cultivate a unique live and work place. This initiated a vision process to find a nurturing and enduring environment that creates a nature-rich and unique urban experience. In this, there is the recognition that heterogeneity and diversity are key to creating a robust natural and built ecosystems that promote a lasting connection with district residents and visitors. The SW Ecodistrict would consider how to knit together high-performance building with district infrastructure to support a multiplicity of use and appeal to numerous stakeholders. The aggressive integration of natural and built systems were proposed to leverage a new sense of beauty in the SW Ecodistrict. A quantitative model and substantive evaluation of proposed stormwater strategies was the basis for qualitative analysis of spaces for occupant activities. The model also provided a palette of design opportunities that provide performative and ecological benefits as well as spatial and experiential variability. This process recognized the layered values and importance of green infrastructure. Of the five scenario considered, one assumes the Ecodistrict buys stormwater credits rather than builds green infrastructure. Other scenarios use green infrastructure to create and sell stormwater credits to finance increasingly sophisticated water systems. When considered against the credits they could generate, it was clear that the credits generated and the resources and associated cots avoided could finance a significant reduction in potable water demand. Complex modeling fueled by historic precipitation data was utilized to make the best use of stormwater resource and optimize collection surfaces. Every square foot of ground plane and roof area was modeled to understand how the stormwater resource could best be leveraged to assist with meeting retention goals and to quantify funding district improvements through the DC stormwater credits systems. The stormwater systems were crafted not only to capture and slow discharge, but to provide solutions that would provide experiential improvements, habit and localized evaporative cooling. The modeling of the water system balanced the mix of occupant activities with the supply of water that naturally occurs due to seasonal climate conditions. It also takes into account the supply of resources that passes by the site through the public water supply a wastewater system.

5 Design strategies were leveraged in the project through the use of green infrastructure to manage stormwater and organize outdoor spaces to leverage the innate human desire to be connected to natural systems, commonly referred to as biophilia. Microclimate improvements provide comfortable outdoor settings during warmer weather, including a variety of settings and scales with enclosures for seclusion as well as visual connections. The variety of views and experiences allow moments of quiet contemplation as well as opportunities for planned or serendipitous social interaction. Multiplicity of use across the open space varies daily and seasonally supporting different social and cultural uses. 1 2 Independence Ave Virginia Ave 1. View south from Independence Avenue SW. Exposed conveyance daylights the stormwater system to create a meandering rivulet that cascade down 10th Street and terminates in Benjamin Banneker Park. Maryland Ave 2. View between Virginia and Maryland Ave. SW. L Enfant Plaza 3 3. View from L Enfant Plaza toward Riverfront 4 Banneker Overlook 10th Street SW Conceptual Design Diagram 4. View at Banneker Overlook

6 2. Challenges And Opportunities Consideration was given to several systems to separate water for the appropriate purpose of use. A prominent conclusion of the study was based on concerns within the SW Ecodistrict Taskforce that recognized the barriers to regulatory approval for the treatment of black water (or grey water) for direct potable water use. The following systems were considered: A system to separately collect, treat, and store grey water from black water is an additional cost that was not considered in this study. In this study, wastewater also known as black water would be collected, (inclusive of grey waters) treated and reused in combination with an aquifer storage and recovery system as a part of an indirect water reuse concept. DC would require water management legislation around an aquifer storage and recovery system. Collection of rainwater and condensate water would require regulatory approval for use as potable water. Though, with further study and policy changes it is hypothetically possible to reuse. Collection of condensate water would require regulatory approval for use as potable water. Like rainwater in Washington, DC further study is required but it is hypothetically possible to reuse. Condensate has a relatively low temperature that can contribute to cooling in the area through heat exchange. Collection of stormwater off-site including 9th Avenue Storm Sewer contains tidal waters of the Potomac. This source contains both stormwater (stormwater credit generator) and river water. This source of water is onsite at 9th Street and E Avenue. This water would require treatment. Also, Constitution Avenue contained dewatering, stormwater, and some combined sewer overflow from the approximate location of the Tiber Creek. To capture this water, a 1,200 long pipe and pump would be required, which is quite expensive. This water would require treatment. Collection of intercepted wastewater from nearby sewage lines conveying wastewater to the Blue Plains Advanced Wastewater Treatment Plant. Wastewater is prevalent on the site due to a large main located in Maine Avenue. This water could be used for non-potable water uses after treatment. To implement this innovative water system at a district scale, an entity will be required to plan, build, and maintain the system. This could be the role of government, a utility, a water service company or a local business improvement district. In each case, a business plan could be devised to finance the cost of capital improvements through repayment in the fees paid by district subscribers. It could evolve over time through successive development. Each building would need to be purple pipe ready. Each block should be able to connect to the district water collection and supply system. The cisterns would be sized, divided, and ultimately connected for each development area such as DOE, L Enfant Plaza, Freeway Lid, and Overlook.

7 OTHER WATER RESOURCES GAL / DAY CAPITAL COST OPERATING COST STORMWATER CREDITS AVOIDED COSTS ON SITE On Site Rainwater Potential SS $ $ +++ $$$ (Impervious Area, SW Discount, SW Retention Credit, Municpal Water) Well Water*** (Aquifer) SSS $$$ $$$** Potential $$ (Municpal Water and Waste Water) Gray, Storm and Condensate Water SSS $$$$ $$$ Potential $$ (Municpal Water and Waste Water) OFF SITE 9 th Street*** Potomac and Stormwater Constitution Ave*** Dewater and Stormwater Treated Waste Water*** SSS $$$ $$$** + SS $$$$ $$$ + SSS $$$ $$$$ $$ (Municpal Water and Waste Water) $$ (Municpal Water and Waste Water) $$ (Municpal Water and Waste Water) NOTE: S= Volume; $=Cost; + = Credit ** Replacing Non Waste Waters, ***Permitting Risks DOE L Enfant Plaza Overlook Freeway Lid Onsite capture and reuse system contained enough resources to meet development activity demand.

8 3. Using Stormwater Credits The SW Ecodistrict has an aggressive plan to reduce water, waste, and energy by 2030 (in order to meet Executive Order 13514). The configuration and performance of this planned neighborhood is to achieve such goals in a national showcase of sustainability. The design of the SW Ecodistrict Plan provides a pragmatic framework to accomplish these goals through redevelopment using existing technologies in advanced ways. The SW Ecodistrict Stormwater Infrastructure Study, published in December 2014, analyzes the configuration of a new kind of district stormwater system which has the potential to meet U.S. Environmental and Protection Agency (EPA) regulations, as administered through the District of Columbia Department of Environment, while contributing to the transformation of the area. In this mix of policies and site features, the SW Ecodistrict Taskforce considered how nearby utilities, development, and stormwater became resources for both water and energy efficiency. Once stormwater requirements were taken into account and the requirements (modeling to meet City stormwater requirements) to use green infrastructure were implemented, the problem statement and goal of the project pivoted to an integrated water and energy proposition. While the overriding force was to meet the executive order and establish a Net Zero energy district, as measured by carbon, a Net Positive water system was simultaneously established. The processing of water (with heat in the district) demonstrated how urban development could be reconfigured as an urban system to make a cost effective environmentally responsive place. Zero Net Energy as Measured by Carbon Challenge To accomplish this, the district needed to reduce total energy demand through conservation, share and reuse byproducts of energy generation and then decarbonize the energy and power sources. In looking at such a proposition, we recognized that the existing steam heating system would need to be exchanged with a low temperature heating and cooling system. This system required that heat throughout the district would be conveyed through a hydronic, water-based system between buildings and across the district. The potential to store heat in surface water features, sub-surface water storage, and aquifer storage would be all connected to the flow of water through the site. This was not limited to potable water, but included wastewater, and stormwater flows, with the potential to convey both a water resource and energy. Washington, DC Stormwater Requirements DC Water entered into a consent decree in 2005 to control combined sewer overflows into the Anacostia River and Potomac Rivers. DC water is currently engaged in implementing a Long Term Control Plan (LTCP) - called the Clean Rivers Project. In addition to the physical improvement required to be made in the public conveyance, collection, and treatment infrastructure, the City also stipulated through its stormwater management plan that private properties also contribute to reductions in stormwater that enters the combined sewer overflow (CSO) systems across the City. This included a stormwater management charge in order to support larger system improvements, an impervious area charge to stimulate a reduction

9 in unmanaged stormwater flows from existing properties, and stormwater credits for retaining stormwater onsite through redevelopment which could be sold to other property owners without the ability to manage stormwater onsite. This system was being considered at the same time as NCPC SW Ecodistrict Task force was developing the SW Ecodistrict Plan. Consequently there were synergies between these two processes that helped the SW Ecodistrict expand from Net Zero Energy to include a Net Positive water system. Current and future SW 10th Street. The future encompasses stormwater improvements that organize active transportation and multimodal movements while creating a setting for community activities for a supporting a mix of uses.

10 Revealed Value of Stormwater The stormwater credit system helped pay for the SW Ecodistrict water system and parts of the energy system. These two systems, as designed into the public open space system, resulted in a new setting that supported desired street level activity and a pro forma that provided a cost positive benefit in the in DC real-estate market. To achieve credits you needed to exceed the minimum retainage of rainfall on your property in a 80 percentile storm event (1.2 per 24 hour rainfall). You could be given a credit for retaining stormwater for each gallon, dependent on the intensity of redevelopment and if stormwater originated from public or private lands. The following four scenarios discuss the stormwater requirements and the potential for credit generation for various building/site redevelopments. Major Improvement on Private Sites For a major improvement on a private site the minimum stormwater requirement is for a property to retain up to the 1.2 storm event in 24 hours. Retention of stormwater between the 1.2 storm event and the 1.7 in 24 hours generates stormwater credits that can be sold. Voluntary Stormwater Management on Private Sites When no site improvements are made on private sites and voluntary stormwater management occurs, all stormwater that is treated and reused is creditable up to the 1.7 storm event. Voluntary Stormwater Management of Public Areas on Private Sites Private sites can manage stormwater runoff from public areas or other private sites. All stormwater runoff from public areas that is treated and reused is creditable up to the 1.7 storm event. Significantly more credits for stormwater can be generated via treatment of voluntary public and voluntary private lands. The stormwater credits create a revenue stream to finance the needed capital improvements for the stormwater management systems. Substantial Improvement on Private Sites For a substantial improvement on a private site the minimum stormwater requirement is for a property to retain up to the.8 storm event in 24 hours. Retention of stormwater between the 1.2 storm event and the 1.7 in 24 hours generates stormwater credits that can be sold. ANNUAL FEE FOR IMPERVIOUS AREAS Impervious Area Charge RATE / YEAR 10 YEAR PROJECTED INCREASE $144/1,000gsf 200 to 300% Stormwater Fee $32/1,000gsf 100 to 200% STORM EVENT MAJOR IMPROVEMENT SUBSTANTIAL IMPROVEMENT POTENTIAL TO AVOID FEE 4% (with treatment above storm event) 55% (with treatment above storm event) VOLUNTEER IMPROVEMENT 0.8 Storm Event Stormwater management required Stormwater management required Credits generated up to 0.8 volume The avoided costs and potential credits that would offset the infrastructure improvements. 1.2 Storm Event 1.7 Storm Event Stormwater management required Credits generated up to 0.5 volume Credits generated up to 0.4 volume Credits generated up to 0.9 volume Credits generated up to 1.2 volume Credits generated up to 1.7 volume

11 Rainwater Resource A water balance was conceivable if the demand for treated stormwater exceeded the collected supply. In most cases, the naturally occurring water supply in the summer exceeded the demand from toilet flushes and makeup water for cooling systems, and other non-potable uses. When considering the addition of condensate, this became particularly challenging in areas of the district that had low soil infiltration rates. The SW Ecodistrict Plan pooled building scaled investments at the district scale, allowing all buildings within the district to reuse collected roof runoff and treated stormwater from distributed storage locations. SW Ecodistrict collection area, with over 65 total acres and approximately 57% of the area in streets and public space, could generate up to 2.2 million Stormwater Retention Credits annually. Due to the high intensity of potential treated stormwater use, the distribution of collected rainwater to the potential 26,000 subscribers in the district was a meaningful way to consume the stored water supply. The boundary of the catchment area was determined by the buildings and open spaces that logically had the potential to capture and share captured roof and stormwater in a reuse system.

12 Green Infrastructure was a desirable component of the City s management of stormwater. Green roofs, infiltration swales and planters, flow through swales and planters, and all of the other soil conditions supporting plants and trees contributed to the detention and retention of stormwater. The City assigned runoff coefficients in their stormwater manual to be used in calculating the potential reduction of runoff through planted management systems. The SW Ecodistrict attempted to catch as much water as possible in order to maximize credit generation. Flow Through Swale Flow Through Planter Roof Intensive Roof Extensive 20% Reduction 20% Reduction 40% Reduction 20% Reduction Tree Impervious Compacted Natural Reduction 15 cf/year 0% Reduction 20% Reduction 40% Reduction Flow Through Planter 20% Reduction Infiltration Planter 40% Reduction Flow Through Swale 20% Reduction Infiltration Swale 40% Reduction

13 The primary strategies that were most impactful included reusing stormwater as a source for non-potable uses. The other was to use green infrastructure to slow stormwater runoff and allow it to infiltrate or evapotranspire. However, due to the large amount of rain fall during those times spring, summer, and fall, irrigation demand is low. Moreover, condensate water is generated when airconditioning systems cool humid air for occupants in buildings, particularly in the summer humid months of Washington, DC. Consequently, there is an overabundance of rainwater and condensate due to the high rainfall and humidity in Washington, DC. During the winter months there isa lack of rainfall, as a consequence recycled water wuold be required to meet non-potable demand Winter / Shoulder Season / Summer 60, ,000 Precipitation Inches/Day ,000 30,000 20,000 Condensate Gallons/Day ,000 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Captured Precipitation Condensate Resource Water Balance - All Sources Water Balance - No Black Reuse Water Balance - No Black, No Condensate Reuse Water Balance - No Black, No Grey Water Reuse Water Balance - No Black, No Grey Water, No Condensate Reuse 25,000,000 15,000,000 Gallons / Month 5,000,000 (5,000,000) (15,000,000) (25,000,000) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Building Demand Stormwater Condensate Grey Water Black Water There was an excess of water resources in the summer and a lack of water in the winter. The water system had to be adaptable to changes in seasonal rainfall.

14 4. Cost Sharing Partners could be formed around the potable water system, the district stormwater storage and conveyance system, and how it supported the transformation of the District. The key motivators for cost sharing included project performance, project beauty, and cost. Performance The project demonstrated that it was more efficient for individual building sites to be connected to each other on blocks and between blocks across the district because the stormwater runoff is a sizeable resource in the district. Meaningful partnerships could be formed to reuse stormwater cost effectively based on the following factors: The project takes advantage of the subsurface aquifer that supplies drinking water to the adjacent states of Virginia and Maryland. Partnerships could be institutionalized to capture future avoided costs to finance public space and system infrastructure capital costs. Shared interest for the increase in real estate value through a transformation of the district s setting from an existing office precinct to a vibrant mixed-use area. New community members benefit from and will subscribe to the district systems and community programs in the district. Beauty The SW Ecodistrict s open space plan, as a collection of connected high-performance landscapes, provides needed amenities for occupants across their new homes, workplaces, and gathering spaces. Through the district water and energy systems that use outdoor spaces, a nexus with biophilic solutions emerged. The gentle flow of water or triumphant fountains are coupled with naturalized landscapes that respond to breezes, cast shadows and provide places for nesting and pathways for pollinators. Opportunities to connect with nature are provided in areas that were previously brutal and discordant with natural settings. Occupants are able to enjoy the sense of beauty in the experience of day-to-day life and a neighborhood supports collective community activities in the following ways: Contribution of green infrastructure along 10th Street which would be upgraded as a more walkable environment. Expansion of settings that are tuned to community activities for outdoor programmed events. Making outdoor spaces that complement the interior activities and events across the district. Cost The larger goal to finance and achieve the desired carbon reductions was within acceptable budgetary plan parameters. The cost for heating and cooling, ordinarily fell within the capital development of each building, which in this case could be pooled in a district system shared among building owners in the district. The financing concept here was that the tenants and residents would finance the system through ongoing subscriber fees and assessments.

15 The potential to capture real-estate value due, in part, because of an integration of green infrastructure with open space system is traditionally not counted in investment proformas. The modeling of stormwater collection and reuse, demonstrated the potential to avoid municipal fees to bring potable water to the site by meeting non-potable water demand, to avoid the payment of the impervious area charge and stormwater fees, to avoid the treatment of wastewater at the Blue Plains Treatment facility and to demonstrate that the capital cost for green infrastructure could be paid back very quickly and pay down the capital cost of infrastructure upgrades. As long as the SRC (stormwater retention credit) was worth more than $2.00/gallon, the payback (due to avoided City Potable Water and Wastewater Treatment) would be approximately 5 years. This continues to be a feasible venture because the value of the stormwater credits has ranged from $1.9 per SRC to $2.27 per SRC since September SITE NO ACTION 70% REDUCTION IN MUNICIPAL WATER 100% REDUCTION IN MUNICIPAL WATER $1/SRC 5 Years 11 Years 16 Years $2/SRC 3 Years 4 Years 5 Years $3/SRC 2 Years 3 Years 3 Years $3.50/SRC 1 Year 2 Years 3 Years The modeling of water flow through the site, the capital cost, and the avoided fees for municipal services added to compare the relative payback for different scenarios. No Action Scenario: Assumed that buildings in the district invested nothing in green infrastructure and paid necessary fees and each was responsible for meeting its obligation to meeting the Stormwater regulations. The 70 Percent Reduction in Municipal Water Scenario: Assumed that buildings in the district were connected by a collection, storage and distribution water system achieving a 70% reduction in potable water supply from the City. The 100 Reduction in Municipal Water Scenario: Assumed that buildings in the district were connected by a collection, storage and distribution water system achieving a 100% reduction in potable water supply from the City The modeling of the resource flows recognized that the larger the number of subscribers of the stormwater system, the more potential there was to increase its capacity to manage stormwater and create other water sources from wastewater flows. There is comparatively faster return of capital when a group of buildings uses the open space between them to collect, treat, and reuse stormwater as opposed to managing stormwater building-by-building. When that same group of buildings uses an advanced open loop water system, the return of capital is equal to the current cost each building would need to pay individually. In this case, the same cost the owner was going to pay just to manage stormwater, could be used to pay for municipal water utilities. This aggregates a new model that re-uses stormwater and also reduces demand for potable water and downstream waste treatment from the municipal system.

16 SITE NO ACTION 70% REDUCTION IN MUNICIPAL WATER 100% REDUCTION IN MUNICIPAL WATER Potable Treatment No Yes Yes Flush Treatment Yes Yes Yes Site Area 65 acres (28)* 65 acres 65 acres Population 26,000 26,000 26,000 COST FACTORS The Net Positive water system has a 5 year payback, as compared to a 3 year payback if each building were responsible for compliance with the Stormwater Management Guidebook. Return of Capital 3 years 4 years 5 years Capital Cost Efficiency $5.77/treated area $7.88/treated area $9.46/treated area Operational Avoided Cost Efficiency $1.70/sf treated area per year $1.55/sf treated area per year $1.79/sf treated area per year Credit Efficiency $.65/sf treated area per year $1.54/sf treated area per year $1.54/sf treated area per year Presuming $2/SRC (Stormwater Retention Credit) In the real estate market, there has not been consistent evidence that green infrastructure contributes to faster leasing of space or higher lease rates to offset green infrastructure improvements at a building-by-building scale. Because of the SW Ecodistrict s comprehensive district scale green infrastructure integration with utility infrastructure there was a large avoided operational cost which was unusual and quantifiable. Analysis of the Ecodistrict demonstrated that cost of the facilities to treat, store, and reuse rainwater was Net Positive against lease rates. There was a $.15 to $.46 per square foot increase in net operating income.

17 STORMWATER INFRASTRUCTURE SCENARIO BASELINE 70% REDUC- TION 100% REDUCTION GROSS POTENTIAL RENT $52.80 $52.80 $52.80 Less 7.50% $ (3.96) $ (3.96) $ (3.96) EFFECTIVE RENT $ $ $ Less Op Ex ($/SF/Year) $ (6.00) $ (6.00) $ (6.00) Less RE Tax ($/SF/Year) $ (4.85) $ (4.85) $ (4.85) UNADJUSTED NET OPERATING INCOME STORMWATER INFRASTRUCTURE ADJUSTMENTS Annual Sale of Off-Site Stormwater Credits Incremental Annual Avoided Cost Less Annual Stormwater District Operating Cost Less Stormwater District Assessment Charge $ $ $ $ 0.15 $ 0.80 $ 0.80 $ $ 0.24 $ 0.32 $ $ (.037) $ (0.47) $ $ (0.21) $ (0.25) TOTAL ADJUSTMENTS $ 0.15 $ 0.46 $ 0.39 ADJUSTED NET OPERATING INCOME $ $ $ Source: ZGF Architects; HR&A Advisors

18 Conclusion The SW Ecodistrict could be a precedent to help Washington, DC meet its obligation to achieve the Consent Decree with the EPA. To achieve its goals, the stormwater infrastructure plan demonstrates the feasibility of a water system that is not only Net Positive, but interactive, and beautiful. The water system contributed to regenerate a new open space system that transformed the SW Ecodistrict creating a habitat and softening the landscape. The reenvisioned district was powerful and poetic, holding the interest of not only the policy makers but the developers who had a vested interest in elevating the outdoor experience for future tenants and residents. The water system not only paid for infrastructure improvements but catalyzed district change, resulting in a uniquely lush urban landscape. 10th Street Design integrating real estate, sustainability, and human comfort sets a new context for optimizing natural and financial resources in highperformance districts.

19 Aggressive Goals Opens the door to integrative thinking The Net Positive for energy as measured by carbon goal crystalized stakeholder interest in considering new urban redevelopment technologies. When this project encompassed stormwater, the project pivoted to the role of water in the district to make meaningful and healthful improvements. Functional and Beautiful Configuration Unifies Interests and Commitments While the infrastructure to meet the zero net for energy as measured by carbon goal is significant, the water system made the largest contribution to the transformation of the district to supplement the new activities. The water system leveraged a new high-performance landscape to make settings for new activities. Governance Structure that creates cost neutral benefits and regenerating value When stakeholders share common interests, they can form agreements to split investment costs and share returned benefits. In this case, a tailored governance structure can use the proceeds from future avoided operational costs to help create an innovative neighborhood configuration, by paying for advance water management systems using green infrastructure. In this regard, green infrastructure demonstrates its connection to performance, from water management to human well-being and delight that holds partnerships and agreements together in an enduring and regenerating neighborhood. The vision of the neighborhood, in how the parts would come together is the glue that stakeholders agree too, sharing a common interest and purpose in a functional and beautiful configuration that sets the charge for a governance structure allowing the accrual of cost neutral benefits. The SW Ecodistrict demonstrates how common place technology can be used to organize stakeholder investments and set a pathway to remove regulatory barriers to implementation to achieve measurable water outcomes that leverage economic, social, and resource benefits through human centric strategic open space improvements. References SW Ecodistrict Overview, SW Ecodistrict Plan, 10th Street Stormwater Infrastructure Study, Project Team National Capital Planning Commission District of Columbia ZGF Architects LLP Arup USA HR&A Advisors

20 Project Urban Designer: Charles Kelley AIA, Associate Partner, Charles Kelley is a senior architect and urban designer with more than 30 years of experience. As ZGF Architect s Ecodistrict and urban design initiative lead in the US and international markets, he applies the firm s research and experience through his design leadership. Charles brings the value of integrated design to leverage multiple objectives across mobility, watershed, energy, water, land use, and open space systems that create vital and enduring community oriented projects. He is currently leading the Kashiwanoha Smart City Innovation Campus Plan in Chiba Prefecture Japan, The Beaverton Ecodistrict in Beaverton Oregon, and the SW Ecodistrict in Washington, DC. Project Design Analyst Ed Clark, Associate ed.clark@zgf.com Ed Clark is a design analyst focused on the design and implementation of high-performance building and district strategies. Edward revels in building science and seeks to apply the most applicable solution for every project, pushing for innovation without reinventing the wheel, leaning heavily upon guidance from natural systems. He has a Bachelor of Science degree in Environmental and Resource Sciences from UC Davis, accompanied by a minor in Plant Biology. Edward received a Masters of Architecture and certificate in Ecological Design from the University of Oregon and was a graduate research fellow in the Energy Studies in Building Laboratory.