V. PLANNING PRINCIPLES And

Transcription

1 V. PLANNING PRINCIPLES And Urban Design Framewo rk

2

3 V. PLANNING PRINCIPLES AND URBAN DESIGN FRAMEWORK Gate 1 Gate 2 Overview The St. Elizabeths West Campus Master Plan responds to the planning parameters, the St. Elizabeths Hospital West Campus Cultural Landscape Report (CLR, 2007) and the development potential framework established in the existing conditions. The principles that follow are the first steps toward a physical plan. They represent the broad physical design objectives which can be applied to subsequent concepts developed for the site, with an overall purpose of integrating new construction with existing historic buildings and landscapes and the natural environment. The aim is to realize the protection, enhancement and continuous improvements of historic building and landscape features that are distinctive elements of the site. Moreover the principles aid the master plan in establishing urban design goals that will guide subsequent redevelopment. The description of the site continues to use the five parcels as reference points. Site Parcels Principle: Respect the individual and unique character and history of each site parcel in making redevelopment decisions. Site Parcel 1 contains the most significant views towards Washington, D.C. and Virginia, housing the majority of buildings in the historic core including the Center Building, which acts as a focal point for the campus. It also contains the primary gateway to the campus along Martin Luther King Jr. Avenue. Site Parcel 2 includes the southern formal open space surrounded by buildings 64, 67, 68, 69, 72, 73, 74 and 75 which are some of the most important historic structures on the site. Site Parcel 3 contains the Greenhouses on the upper plateau and a few residences along its steeply-sloped forested areas. Site Parcel 4 includes the Warehouse and Power House buildings. The Power House stacks can be seen from various regional points beyond the campus. Site Parcel 5 is heavily forested in steep slopes and contains the Cemetery. Figure 5.0 Planning Site Parcels The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 73

4 Campus Structure and Organization Principle: Retain, preserve and enhance site elements and spaces that define the existing site character. The major character giving elements of the existing campus are combinations of existing buildings, landscape elements, landscape types, circulation paths, and views. Considering that the character of the site is perceived primarily from only those locations entirely on or immediately adjacent to the site, the principle of retaining and enhancing that character must address the campus as experienced from those vantage points. Plateau Area - The major character-defining element of the campus is its core area, the combination of relatively small red brick buildings arranged around an informal landscape of open lawns with individual and small groupings of trees, fountains and summer houses. This character is continuous from the Site Parcel 3 and the Point, through Site Parcel 1. It connects through to the Site Parcel 2 and the great lawn with its strong building assembly on its east edge and also to the more open meandering plateau-edge buildings on the west and south. The Point Center Building tower Related to this major character-giving element, the individual open spaces each provide a key element to the respective parcels. Site Parcel 1 buildings enclose smaller outdoor spaces that relate back to the major core areas by way of passages between and among buildings providing a change in scale and activity away from the central areas. Similarly there are areas along the plateau edge that are somewhat removed from the central core and are more passive areas that transition from the core to the wooded slopes that make up the western edge of the campus. Sloped Area - The wooded western slopes, particularly on Site Parcel 5 and the majority of Site Parcel 3, are strong character-giving elements. These slopes and the roadways and pathways through them provide an enclosed, shaded environment, isolated from the other areas and activities of the campus. The restoration and maintenance of these wooded areas can offer that distinct experience to campus employees. A similar environment surrounding the Cemetery is a unique character-giving element, providing that setting with its own quiet, respectful character. Gates - The wall and gates on Martin Luther King Avenue are the most externally visible character-giving element for the campus. This assemblage is to be preserved to the greatest extent practicable. In particular, the Gate 1 portion, together with the gate house and landscape between the gate and the Center Building, form the essential formal entry sequence to the campus. The sense of the historic landscape setting should be preserved as part of that entry experience. Reinforce Upper Plateau Proposed Building Frontage Expansion Proposed Grid Expansion Steep Slopes (Topographic Bowl) Areas of Intervention Figure 5.1 Campus Structure and Organization Cemetery 74 Planning Principles NOVEMBER 10, 2008 NCPC SUBMISSION The DHS Headquarters Consolidation at

5 Development Density Principle: Locate new development density on site to respect the character of and relationships among the historic resources. The Master Plan establishes three density zones in order to maximize development of the campus while respecting the character of the existing site and the basic relationship of the existing historic resources to the maximum extent practicable. The existing conditions analysis, and the consultation process for the St.ElizabethsWestCampusNHL suggested an arrangement of densities of new development on the site that would respect the character of and relationships among the historic buildings, landscapes and views. Though urban areas can be dense without tall buildings, height does have an impact on density. The 2006 Comprehensive Plan for the National Capital-District Elements contains recommendations for densities within the St. Elizabeths Campus. Policy FSS recommends that new construction should provide development densities and intensities on the site that are compatible with adjacent residential neighborhoods with moderate to medium density residential and commercial on most of the site, with higher densities clustered in the area closest to the Metrorail station. The Land Use section of the 2006 D.C. Comprehensive Plan, defines four levels of density for various types of uses. Using the Comprehensive Plan definitions as a guide, the Master Plan establishes density zones in order to maximize development of the campus while respecting the character of the existing site and the basic relationship of the existing historic resources to the maximum extent practicable. Site Parcels Key Map Gate 1 Gate 2 Zone I Medium Density Major development including taller structures with larger footprints should be located in this zone up to 8 floors. Zone II Moderate Density This zone includes the Historic Core of the campus. Any additional development in this zone should be placed such as to respect the character of the historic buildings, landscapes and views. up to 5 floors. Zone III Low Density This zone is appropriate for low scale development or no development. In some locations, this zone will act as a buffer area between the campus and adjacent residential communities. In other cases, this zone will reinforce the regional character of the site as a part of the topographic bowl. up to 3 floors. I Medium Density II Moderate Density III Low Density Figure 5.2 Density Diagram The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 75

6 Planning Relationships Principle: Organize programmatic elements on site to maximize operational efficiency and effectiveness. A critical element of the site organization will be the creation of the appropriate links and adjacencies of program elements to each other. All program elements on site will be related to the campus center and the core shared uses, but the operational relationships among the major components is the critical planning principle for the Department s effectiveness in carrying out its mission. Gate 1 Gate 2 The campus center will act as the center of activities common to all the program elements located on the campus. This center will be the point at which personnel from all elements are provided the opportunity to meet, mix and form a common identity among the operational centers. This opportunity is key to transforming the culture of the many agencies into a single culture that is the Department of Homeland Security. Potential Administrative Reuse Proposed New Development Potential Campus Amenities Campus Center Service/Support Figure 5.3 Planning Relationships 76 Planning Principles NOVEMBER 10, 2008 NCPC SUBMISSION The DHS Headquarters Consolidation at

7 Historic and Visual Resources Building Reuse Principle: Protect, preserve and reuse the historic resources of the National Historic Landmark. Gate 1 Gate 2 A major planning principle and planning concept for the Master Plan is the preservation and reuse of the historic resources of this National Historic Landmark. Those resources consist of the historic contributing buildings, the historic landscape and landscape site features, and the ensemble of buildings and landscape that create the unique character of this site. The character of the site is intimately related to the historic evolution of mental health care that occurred here and the social context in which that evolution took place. To protect and preserve that character, the Master Plan strives to retain and rehabilitate the historic structures to the maximum extent practicable and to preserve the various historic resources, including open space, landscape structures and groupings of buildings within that landscape. The Master Plan seeks to maintain and reinforce the historic character, organization and sense of hierarchy of the central campus core and major building anchors and groupings. This includes recognizing, preserving and reinforcing the major place-making site features, such as the Center Building, The Point, the curvilinear road network, the central lawn of the south cottage area, and the surrounding green buffer on the north, west and south edges of the site. The Center Building is the oldest and most prominent building on site, its views out to the city and its central location are critical. The function of the main building should, if possible, be central to the function of the campus or the main tenant. In order to maintain the historic character of the site the best use must be identified for each of the contributing buildings. To reuse and restore the historic structures to the greatest degree possible, an effort has been made to match new programmatic uses that are the same or similar to the originally designed use for each structure (e.g. auditorium conference; firehouse emergency vehicle storage; Power House central plant and cogeneration equipment). In most instances this is not possible and the original buildings will be converted to the new program of administrative and support spaces suitable to a federal government departmental headquarters. Buildings to be reused Buildings not being reused Figure 5.4 Historic Resources - Building Reuse The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 77

8 Historic and Visual Resources Landscape Principle: Integrate historic landscape and natural features into the master plan. Gate 1 Gate 2 The master plan considers the therapeutic, ornamental, agricultural, and service aspects of the hospital s historic landscape, as well as the individual features that constitute that landscape. The historic landscape and natural features in the campus will be integrated into the Master Plan to the maximum extent practicable. Historic landscape patterns will link the various areas of the campus, enhancing views within the site. The St. Elizabeths West Campus Cultural Landscape Report (CLR, 2007) divided these campus features into functional landscape units that correspond to the Site Parcels described below: Site Parcel 1: Therapeutic, Ornamental Landscape Center Building and Main Gate Site Parcel 2: Therapeutic, Ornamental Landscape Lettered Buildings and Secondary Entrances Site Parcel 3: Agricultural Landscape Fields and Greenhouses Site Parcel 4: Service Landscape Powerhouse Ravine and Service Buildings Site Parcel 5: Cemetery and Woodland Slopes Throughout these landscape units/site parcels are significant open spaces, such as the greenspace of The Point and that of the Site Parcel 2; clusters of buildings constructed to implement evolving therapeutic philosophies; circulation patterns developed over the hospital s history and the processional experiences these patterns influence; vegetative features, such as the oak allée adjacent to the Center Building; and man made features, including the summer houses in the Site Parcel 1, that embody the hospital s history. Boundary Line Existing Buildings Historic Woodland Successional Woodland Arboretum Setting Upper Plateau Cemetery Parcel Major Open Space Therapeutic Ornamental Landscape & Overlook Therapeutic Ornamental Landscape around Pavilions & Secondary Entrances Agricultural Landscape of Fields & Greenhouses Services Landscape & Ravine around Powerhouse and Service Buildings Cemetery & Woodland Slopes Figure 5.5 Historic Resources - Landscape Source: St. Elizabeths Hospital Historic Resources Management Plan by Devrouax Purnell Architects, (1993); St. Elizabeths Hospital West Campus Landscape Assessment Plan by 78 Planning Principles NOVEMBER 10, 2008 NCPC SUBMISSION The DHS Headquarters Consolidation at

9 Historic and Visual Resources Views Principle: Maintain and enhance historic views from and within the site, as well as valuable non-historic views from outside the site. Nonhistoric Views Views of the site from prominent locations of D.C. and Virginia, due to its privileged location on the Anacostia Hills (Topographic Bowl). NCPC and CFA have identified these views as valuable to the character of the city. Regional Views (views from surrounding areas towards the campus). All views are zoomed in and real distance is shown in the picture caption. Neighborhood Views (views from immediate neighborhood towards the site) Historic Views These visual resources are those envisioned by the designers of the hospital and consist of views outward from the site and views from within the site itself. Views from St. Elizabeths toward the Anacostia and Potomac rivers, Washington, D.C., and the Virginia shoreline Views of the campus buildings and landscapes available when walking or riding through the grounds Regional and Neighborhood Views The Master Plan will maintain and enhance views toward the campus. The West Campus sits on a plateau in the Anacostia Hills portion of the Topographic Bowl, southeast of the Monumental Core of Washington, D.C. The site is visible from numerous locations around surrounding neighborhood and from the region, as it sits along the green ridge and slopes of the Anacostia Hills. Figure 5.6 Viewshed Context Washington Monument Figures 5.7 and 5.8 emphasize the views from the site to three important landmarks in Washington, D.C.: National Cathedral, Washington Monument, and the U.S. Capitol Building. National Cathedral Old Post Office U.S. Capitol Building Topographic Bowl Slopes and Rims Views Out of the Site Plateau Steep Slope Image relationship to original photograph Figure 5.7 Zoomed in view from the site towards Monumental Core of D.C. (2.85 miles from the Point to Washington Monument) The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 79

10 Views From and Within the Site The Master Plan will maintain and enhance views from and within the west campus. To respect the presence and predominant character of the Center Building on the campus, all proposed buildings will be no taller than its tower at 251 above sea level (msl). Within the campus, numerous multidirectional significant views are found across and around the campus. These include views across the Site Parcel 2 open space surrounded by the historic buildings, views along the allée of trees toward the Center Building from Gate 1, views of the Center Building from the plateau to the north, views of the plateau to the north from the Center Building, and views within the central core area of the campus. SITE PARCEL 2 A Primary Visual Zones Secondary Visual Zones Lost Areas of Visual Zones Additions to Visual Zones Primary Vista/Viewshed Secondary Episodic Vista/Viewshed Tertiary Slot Vista/Viewshed Views Looking Towards the Site Local Views Looking Towards the Site A Section Cut Center Building tower Figure 5.8 Views Diagram Figure 5.9 Existing Conditions Section through Center Building Tower. 80 Planning Principles NOVEMBER 10, 2008 NCPC SUBMISSION The DHS Headquarters Consolidation at

11 Site Access and Circulation Access Principle: Respect and reinforce the historic address for the site on Martin Luther King Jr. Avenue. The main public frontage to the St. Elizabeths West Campus remains along Martin Luther King Jr. Avenue which will be the primary regional public address for the campus. The existing main campus entries, Gates 1 and 2, along the Avenue will be upgraded to serve the new demand while maintaining their historic character to the maximum extent possible Gate 3 will be modified and become an at-grade access point to the west campus. Additional ingress/egress access to the campus will be provided via a new road along the western portion of the site, between Firth Sterling Avenue and the Malcolm X ramp from. Adequate and efficient access for public transit to the campus should be provided. Public transportation vehicles, bicycles and pedestrians will have access to the campus from the same entry gates used by automobiles. Circulation Principle: Use historic roadways and paths to reinforce spatial continuity. The plan should maintain the historic character of the pedestrian circulation within the campus. Employees and visitors accessing the campus by automobile will be immediately directed to parking garages. Within the campus, vehicular circulation will be limited to fully screened vehicles only, including VIP s and internal shuttle buses. The plan encourages primarily pedestrian movement across the campus and the use of the existing campus roadways and campus loops. These will provide clear access to all areas of the campus and will act as an orienting device for employees and visitors. Major Vehicular Entry (Employee/Visitor) Proposed additional Vehicular Entry/Access Primary Public Access Current Campus Circulation Proposed Additional Campus Circulation Figure 5.10 Site Access and Circulation The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 81

12 Parking Principle: Locate parking at the site perimeter to preserve a pedestrian-oriented site, consistent with historic precedent. The strategy for distributing parking at the St. Elizabeths West Campus is to provide structured garages at the eastern and western perimeters of the campus or in the southwest ravine. This allows the garages to be conveniently accessed from major existing and proposed roadways and entry points. Parking spaces will be allocated and distributed in relationship to the access roads employees will be using. Parking garages are permitted to be located within the 100 ft. setback from adjacent roadways. They will be located away from sensitive historic resources in the core of the campus. Parking garages should be below grade where possible. Any above-ground parking structures will be landscaped, screened and buffered from views from the exterior of the site including nearby residential neighborhoods. By locating the parking at the perimeter of the site, the dominant modes of circulation around the site will be on foot or via shuttle buses. Major Vehicular Entry Proposed Additional Vehicular Entry/Access Parking Access Road P Parking Figure 5.11 Parking Distribution 82 Planning Principles NOVEMBER 10, 2008 NCPC SUBMISSION The DHS Headquarters Consolidation at

13 Site Environment Principle: Develop landscape responses that respect the inherent distinctions between different zones of the site while preserving the historic context and restoring ecological functions. Gate 1 Gate 2 The site environmental framework must balance the demands of historic and cultural resource protection, environmental and sustainability goals, and the functional requirements of new construction and tenant specific needs. To do so, the environmental framework depicts 8 different zones, each of which will require a different landscape response. Landscape and cultural resource protection are of primary importance on the plateau, while resource management and restoration of habitat are key objectives for the western slopes. However, because the landscape on the plateau affects the environmental quality of the western slopes, practices on the plateau must address resource management for the wooded slopes. This is particularly relevant for management of rainwater. Varying approaches to stormwater treatment, landscape preservation, and habitat restoration will be emphasized depending on the landscape zone. The zones and their principles include: 1 Arboretum Setting, Views, and Open Space Maintain and preserve the historic and cultural landscape of the plateau. Provide for infiltration of stormwater and reduction of rainwater runoff in order to reduce erosion of stream channels, improve water quality, and to provide a steadier flow to down-slope streams. Respect the view corridors from the plateau, particularly the views from the northwest overlook, The Point. Maintenance of this landscape should mimic historical practices. 2 Development on Plateau A portion of the plateau west of the central building and a larger area south of the power house ravine have been identified for development. Construction and earthwork in these areas pose opportunities for recreating a landscape zone around proposed buildings which can act as a transition between the historic campus plateau and the surrounding slopes. 1 Arboretum Setting, Views, and Open Space 2 Development on Plateau 3 Development on Western Slopes 4 Meadow 5 Woodland 6 Mature Woodland 7 Cemetery Woodland 8 Sensitive Woodland Habitat Figure 5.12 Environmental Framework The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 83

14 Site Environment The landscape typology of these areas should reflect the general landscape characteristics of the plateau - open lawn and shade trees in an arboretum setting, but can depart from the Arboretum Setting as necessary to address functions, aesthetics, and environmental considerations for the adjacent new buildings. These areas pose opportunities for larger stormwater management facilities such as bioretention cells and small ponds to improve site hydrology. 3 Development on Western Slopes The wooded western slope of the campus contributes to the larger regional landscape pattern of the river basin. The bluffs overlooking the river form a wooded, green backdrop around the Capital region, and form part of the topographic bowl surrounding the city. The demolition of large-scale non-contributing buildings makes the western slope area one of high potential for new development. This area may require major earthwork and re-grading to accommodate development. Though the majority of the western slope is vegetated with invasive species and lower quality, successive growth from the past 30 years, it is critical to re-establish a wooded tree canopy on the slopes after construction. Slopes impacted from construction should be reforested with native species to restore habitat, slope stability, and the visual character of the region. As much as possible, this zone should fit into a woodland typology. In addition to reforestation, every effort should be made to recreate a tree canopy. This includes planting trees on the roofs of buildings and large shade trees on any available open space. Bioretention cells or underground retention areas should be used wherever feasible to reduce runoff, increase infiltration, and improve overall site hydrology. 4 Meadow The slope just west of the point and the northeast corner of the site where the greenhouses are located were historically used for agriculture. 5 Woodland The slope north of the cemetery, the lower slopes along, the edge of the property adjacent to, and a small slope north of the power house are all areas appropriate for either maintenance or reestablishment of open woodland. Woodland in these areas provides multiple benefits, including visual screening, increased ecological benefit, and promoting continuity of the wooded slopes of the regional topographic bowl. The intent for these areas is an open woodland character with an eventual mature canopy, but a relatively open understory. Preserve, plant, and maintain native canopy trees. Remove invasive species and cluttered understory. 6 Mature Woodland These areas are remnant woodland, which for the most part have not been heavily impacted since the development of St. Elizabeth s. Some trees in these woods may be older than St. Elizabeth s Hospital. This is particularly the case for the ravine south of the point (6A). The steep slope south of the Power House (6B) has been at least partially impacted, however it does not appear that it was completely cleared of trees at any point in St. Elizabeth s history. The unique quality of these woodlands dictates that these areas must be completely preserved intact and not disturbed during construction. Remove and manage invasive species and improve ecological conditions within mature woodlots, particularly conditions of the small stream in the ravine (6A). 7 Cemetery Woodland Similar to the mature woodlands of the northern ravine (6A) and Power House slope (6B), the Cemetery Woodland includes mature trees that may precede St. Elizabeth s Hospital, or at the least have received little disturbance throughout its history. Unlike the other mature woodlands, this area is regularly maintained. The ground plane is lawn mixed with other low plants and native wildflowers. This condition should be preserved with continued minimal maintenance. 8 Sensitive Woodland Unstable fill, potential soil contamination, and a bald eagle nesting site create a zone of no construction and no disturbance on the southwest side of the campus. Preserve and maintain this area free of any construction or intrusion. Site Habitat Principle: Restore the ecosystem potential of the West Campus environs allowing organisms within their biological communities to live and reproduce. Although the West Campus property has seen a long history of past use, some portions of the campus are relatively pristine compared to the rest of Washington, D.C. Preservation and enhancement of the wooded slopes and ravines present an opportunity for habitat restoration near the banks of a major wildlife corridor, the Anacostia River and the adjacent green corridor of. Taking into account the proposed program requirements, there still remains a great potential to improve the biotic characteristics of the site. These activities should focus Case Studies: Examples of utilizing surface conveyance Maintaining these areas as meadow is a more manageable interpretation of the historic agricultural use. Meadow will preserve views from the point, provide greater ecological benefits, and require less maintenance than the lawn of the adjacent plateau. Case Studies: Examples of pervious surfaces. Case Studies: Examples of managing close to the source. Case Studies: Examples of utilizing surface conveyance 84 Planning Principles NOVEMBER 10, 2008 NCPC SUBMISSION The DHS Headquarters Consolidation at

15 Site Environment Case Studies: Examples of looking for campus wide opportunities primarily on establishment of native vegetation and ravine restoration. Establishment of Native Vegetation Invasive and non-native plant species dominate the west slopes of the West Campus property. Such species provide little benefit for wildflife, displace native species, and detract from the natural history of the St. Elizabeths campus. Removing these species is a key step in promoting a diversity of protective ground-layer vegetation and encouraging regeneration of native trees and shrubs. Reforestation of these slopes should be emphasized within the context of the proposed building program. This presents an opportunity to eliminate unwanted species, Case Studies: Examples of building water Case Studies: Examples of building water reintroduce native vegetation, increase slope stability through restoration of a root mat and restore soil structure and the biological properties associated with soil nutrient cycling. Optimize the Historic Functional Landscape Re-use the historic functional landscape and former agricultural fields for a new interpretation of these uses as meadow, to provide open views, wildlife habitat, and stormwater infiltration. Ravine Restoration The existing ravines are bounded by steep slopes fed by surface water runoff and direct stormwater discharge. Surficial erosion, channel scour and slope failures have created an unstable and eroded condition. Application of appropriate stabilization measures may help mitigate this condition. Techniques such as small stepped pools, boulder cascades and stone weirs should be implemented to dissipate energy, lower channel velocities, increase channel roughness, trap sediment and provide a stable channel environment. However, the primary goal for restoration of these ravines should be to limit the quantity of surface runoff by providing areas for rainwater infiltration on the plateau. By providing groundwater recharge, and limiting flash flow events, the ravine channels can be restored to a more natural condition. Site Hydrology Principle: Accommodate new development while restoring site hydrology by maximizing pervious surfaces, managing rainfall where it falls, using surface water conveyance and seeking campus-wide opportunities. Maximize Pervious Surfaces/ Surfaces Minimize Impervious Impervious surfaces due to new construction can be mitigated through the use of green roofs and pervious pavements. Both of these strategies are viewed as 100% pervious by city standards. Historic roofs are not suitable for green roofs; however modern flat roofs would be ideal for green roof applications. A goal of 50% green roofs on all new buildings should be considered as a minimum. Pervious pavements are ideal for roads and walks on relatively flat surfaces that do not need to accommodate heavy traffic and should be considered wherever these conditions exist. Wherever the historical context allows and heavy traffic is not an issue, pervious pavement should be utilized. Manage as Close to the Source as Possible Runoff from impervious surfaces should be managed for water quality as close to where rain falls as possible in bio-retention cells. Infiltration should be encouraged. A minimum of the first half inch of rainfall should be managed for all events; however a more aggressive goal of 1.5 would allow buildings on the site to meet LEED credit 6.1 by managing over 90% of the average annual rainfall. An analysis of the historic rainfall for Washington D.C. illustrates that managing water quality for the 0.5 event will treat 66.7% of the average annual rainfall. However, managing the 1.5 event will treat 94.6% of the average annual rainfall and allow building projects to receive LEED credit SS 6.1, which requires 90% of the average annual rainfall to be managed (See table below). Utilize Surface Conveyance By moving water in shallow swales, water is slowed and cleaned, more closely mimicking pre-development times of concentration. This should be considered in varying strategies to fit within the historic character of the site. Some swales could be used to retain water for short periods of time, allowing for greater infiltration. This is particularly appropriate for some portions of the historic lawn setting where larger dedicated stormwater facilities may not be as appropriate. Look for Campus Wide Opportunities While steep slopes and uncharacterized fills may make management of large events impractical, there may be opportunities to manage some water quantity events along the western edge of the plateau or along the western slopes of the site, particularly the northwest corner of the site. These facilities may take the form of grass infiltration swales or stepped constructed wetlands to manage water quality and quantity for the site. Building Water Principle: Optimize the use of potable water primarily for uses related to human health. Potable water has become an increasingly valuable resource. Therefore the campus should strive to maximize its efforts to collect and reuse available water supplies on site. There are three main strategies that can be implemented to help achieve this goal. First, the implementation of low-flow or waterless fixtures in lavatories and water closets can have a significant impact on potable water demands. This can be achieved at a minimal initial cost over the cost of standard fixtures. Second, graywater collected from lavatories can be stored and made available for flushing toilets, potentially offsetting all potable water requirements. This strategy requires a dual plumbing infrastructure to allow graywater collection in a separate system. Additionally, a cistern, filtration and pump system are required to store and make graywater available for reuse. Third, stormwater can be collected from rooftops to be used in flushing toilets, potentially offsetting all potable water requirements. This strategy requires a rooftop collection system, filter, pump and cistern for storage and distribution to toilets. The cistern required for this strategy would be substantially larger than a graywater system would require due to the inconsistent nature of rain events. Green Buildings Principle: Orient and collect buildings into clusters to maximize their environmental effectiveness Orient buildings with their long axis in an east-to-west orientation to maximize their capacity to either collect solar benefit or shade unwelcome solar gain. Locate buildings so that spaces between them are of sufficient dimension to allow full solar access to all floors. Create compact collections of buildings to preserve large areas of contiguous habitat and a coherent network of public outdoor spaces. Use building locations and site elements to create micro-climates of sun, shade, breezes and shelter that extend the period of comfortable human occupation of exterior spaces. The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 85

16 Site Infrastructure Infrastructure and Utilities Concept Principle: Centralized site utilities for security, redundancy and operational efficiency. As a consolidated West and East campus the utility and support/service infrastructure is planned around the concept of central facilities for operational, security and maintenance functions. Efficiency of centralized functions will benefit all tenants and enhance energy efficiency and redundancy requirements. As a principle of design GSA promotes energy efficiency and sustainable environmental design approaches. The Master Plan includes those concepts and applies them to the overall campus infrastructure for both the energy demands of operating buildings and for the conservation of water, and the maintenance of water and air quality as it is affected by the development of the site. Gate 1 Gate 2 Principle: Consolidate site utilities and below grade distribution to minimize impact to the historic landscape. As a unified campus the infrastructure for all utilities is planned to provide all services to match the requirements for each facility and to tie all facilities together. Utility support includes water (domestic water, storm and sewer), heating, cooling, electric power, communications and data systems. To the greatest extent practicable all systems will be circulated through the campus along common utility corridors. Common paths will limit the impact on the landscape and will create a limited number of access points required for service and maintenance of systems. Portions of the utility infrastructure will be distributed in tunnel structures and in some cases the tunnels will also be used for personnel movement. Communications infrastructure will also include a set of satellite dishes and other antennas. These are located to insure correct function and to be screened from views both within and from without the campus. The basic heating, cooling and electric power portions of the utility system will be distributed between a central utility plant (CUP) location and the individual structures on site. The CUP location will also include a cogeneration facility that will serve to offset electrical demand on the public utility grid, provide power redundancy, and enhance the overall efficiency of power usage on campus. Major Underground Utility Corridor Primary Public Access Proposed CUP/Cogen Location Figure 5.13 Underground Utility Corridor 86 Planning Principles NOVEMBER 10, 2008 NCPC SUBMISSION The DHS Headquarters Consolidation at

17 Security Principle: Assure the safety and security of the site s occupants and activities while maintaining an appearance of an open, accessible site that is compatible with the and a good neighbor to the surrounding community The St.Elizabeths West Campus will be a single, closed campus surrounded by a security enclosure that will prevent unauthorized entry at the perimeter. This translates into a secure perimeter that provides the necessary security envelope for all the tenants while allowing the site to operate with a minimum of internal controls and security personnel. The security system and perimeter is planned to allow for the campus to operate normally under all but the most severe threat conditions. Normal operations accommodate the normal complement of employees and visitors to the site employing the same security operations and procedures as used during periods of low threat. To accomplish this, the secure perimeter is planned to include all necessary screening for both personnel and vehicles accessing the site. The security concept places vehicle parking at the perimeter of the site so that parking areas are separated from all occupied facilities by required distances and that all personnel entering the site pass through check points that verify authorization for entry. The number of entries to site is kept to the minimum required to accommodate the number of vehicles and personnel arriving and departing the site. While the Department of Homeland Security requires a secure campus it must also strive to retain to the greatest degree possible, the appearance of an open, accessible place, part of the public realm. As part of the total secure perimeter a single point for screening of deliveries is provided. This screening facility will eliminate the need for direct delivery to individual buildings and will provide an efficient and secure method for screening all deliveries to the campus. Principle: Accommodate limited controlled public access to the historic and culturally important aspects of the site. Two particular areas of the campus are of interest to the neighborhood community and wider general public. The Point, the edge of the plateau at the northern edge of the site that overlooks the monumental core of the Capital, is known for its spectacular views of the city. A program will be developed by DHS to accommodate periodic scheduled visitation to this locale for community groups and holiday events. The historic Cemetery is planned to remain outside the secure perimeter of the campus. Public access to the cemetery will be controlled but will be generally open to the public. GSA will provide access control and care for this site. Major Vehicular Entry & Exit Proposed Additional Vehicular Entry/Access Security Perimeter & 100 Stand-off Zone Employee/Visitor Screening D/S Employee Screening/Delivery Figure 5.14 Security Diagram The DHS Headquarters Consolidation at NOVEMBER 10, 2008 NCPC SUBMISSION Planning Principles 87