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Swarthmore College Environmental Sustainability Framework
Analysis and Recommendations for Capital Projects and Facilities...
Framework Contents
PAGE 3
PAGE 6
PAGE 7
PAGE 18
PAGE 27
PAGE 39
PAGE 41
PAGE 42
EXECUTIVE SUMMARY
INTRODUCTION
STORMWATER
...
3
1 Executive Summary
1.1 Introduction
Swarthmore College has made a commitment to
prioritize sustainable practices. The p...
4
1 Executive Summary
1.4 Carbon and Energy Analysis
The Carbon and Energy Analysis provides both
high-level and detailed ...
5
TABLE 1.2: BUILDING ENERGY PERFORMANCE TARGETS
-- Install a minimum of 45% native/adaptive
vegetation and replace turf w...
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2 Introduction
This report is divided into four main sections:
Stormwater Management Analysis, Carbon and
Energy Analysi...
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3.1 Sustainable Site Development
As native land (a greenfield site) is developed, its
ecosystems can be compromised [Fig...
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3.3 Site History
The College was founded on a tract of regenerated
forest and cultivated farmland, traversed by natural
...
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FIGURE 3.6: PRECOLUMBIAN SUBWATERSHEDS
3.4.2 PRE-COLUMBIAN CONDITION
Both LEED and SITES present a similar basis
for un...
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FIGURE 3.7: PROPOSED MASTER PLAN DEVELOPMENT
TABLE 3.4: PROPOSED LAND COVER TABULATION
TABLE 3.3: COMPARISON OF EXISTIN...
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3.6 Sustainable Stormwater Management
In order to understand the impact of development
on the College campus, the desig...
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3.8 Regulatory Requirements
The legislative basis for statewide stormwater
management is the Pennsylvania Stormwater
Ma...
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3.9 Stormwater Mitigation
To minimize the effect of master plan development,
stormwater mitigation will be required to ...
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similar to a municipal stormwater ordinance but for
internal use by the College, and - acknowledging
the College’s desi...
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4 Carbon and Energy Analysis
The College is committed to achieving carbon
neutrality by 2035, approximately 20 years fr...
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4.4 Existing Buildings
The College has made considerable progress
towards its goal of achieving net zero by 2035.
Annua...
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4 Carbon and Energy Analysis
The first step in reducing campus carbon
emissions is to improve individual existing build...
21
4 Carbon and Energy Analysis
4.5 Central Plant Configurations
Efficiently generating heating and cooling is critical
in...
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
Swarthmore College Environmental Sustainability Framework
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Swarthmore College Environmental Sustainability Framework

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Analysis and Recommendations for Capital Projects and Facilities Operations

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Swarthmore College Environmental Sustainability Framework

  1. 1. Swarthmore College Environmental Sustainability Framework Analysis and Recommendations for Capital Projects and Facilities Operations June 1, 2015
  2. 2. Framework Contents PAGE 3 PAGE 6 PAGE 7 PAGE 18 PAGE 27 PAGE 39 PAGE 41 PAGE 42 EXECUTIVE SUMMARY INTRODUCTION STORMWATER MANAGEMENT ANALYSIS CARBON & ENERGY ANALYSIS IMPLEMENTATION RECOMMENDATIONS ENERGY LANDSCAPE & STORMWATER WATER CONSERVATION IEQ & MATERIALS OPERATIONS & MAINTENANCE SUSTAINABLE BUILDING GUIDELINES CONCLUSION APPENDICES STORMWATER CARBON & ENERGY PROJECT CHECKLIST
  3. 3. 3 1 Executive Summary 1.1 Introduction Swarthmore College has made a commitment to prioritize sustainable practices. The primary purpose of this Environmental Sustainability Framework is to organize and codify the College’s sustainability targets in a comprehensive document that will serve as a guide in establishing requirements for sustainable landscape and building development, internal staffing, and funding to achieve specific sustainability goals for the landscape, buildings, and operations. This document will help distinguish the institution as a leader in environmental sustainability. The framework comprises a stormwater management analysis, carbon and energy analysis, sustainable building guidelines, and implementation recommendations. As an arboretum campus, embracing the natural environment has deep roots at Swarthmore College, further supported by the College’s Quaker ideology regarding social responsibility: simple living and conservation of resources. Sustainability at the College has historically focused on a variety of efforts including the preservation of the Crum Woods, environmentally preferable methods of landscape and stormwater management, energy efficiency, and student-led initiatives. This Environmental Framework is intended to build upon these existing practices and provide the structure for developing a comprehensive approach to sustainability that is tailored to the College’s vision and priorities. In 2010, President Rebecca Chopp signed the American College & University Presidents’ Climate Commitment, which commits participating colleges to reduce greenhouse gas emissions (GHG) and implement a climate action plan. The College set the aggressive goal of achieving a net-zero carbon campus, eliminating or offsetting scopes one, two, and three emissions, by 2035. The first action in this initiative was the development of the 2013 Swarthmore College Climate Action Plan, which summarizes the campus emissions as well as the College’s initial plan to meet its goals. As defined in the Climate Action Plan, up to 70 percent of the GHG emissions are related to the operation of buildings and provide the largest potential for reduction. 1.2 Methodology This framework recognizes the College’s history of environmental stewardship and embraces the existing practices of sustainability on campus. Goals, targets, and strategies were developed through an examination of current policy; brainstorming sessions with the campus community; feedback from the College’s staff, faculty, and students; research of peer institutions; engineering analysis; the design team’s previous project experience; and a literature review. 1.3 Stormwater Management Analysis The anticipated growth of the campus building portfolio will affect the landscape character and hydrology of the campus. The Stormwater Management Analysis is a series of studies and recommendations for managing stormwater for the new buildings and additions identified in the 2013 Campus Master Plan. Additionally, a framework for sustainable stormwater performance has been created. This framework requires that the College significantly reduce the environmental impact of new development projects and benchmark progress based on the requirements of the LEED and Sites rating systems. By achieving this high level of stormwater management, additions to the campus will not only minimize degradation of the Crum Woods and Crum Creek but will also offset some of the environmental impacts of previous development. The Stormwater Management Analysis describes specific issues in each sub-watershed on campus and proposes best management practices (BMPs) to address these impacts (Figure 1.1). The extent to which these BMPs are adopted for specific projects can be described in three tiers: Tier 1 (98th percentile storm event), Tier 2 (95th percentile storm event) and Tier 3 (Borough requirements). This framework also proposes that, as part of new development initiatives, project boundaries should be increased to incorporate areas of poor stormwater management, and that the BMPs for new development should incorporate efforts to rectify existing degraded conditions. WS-6 WS-4 WS-7 WS-3A WS-2 WS-1A WS-10 WS-8B WS-9 WS-3B WS-8C WS-8A WS-5 WS-1B WS-11 1A 1B 3B 4 3A 8A 8B 8C 6 7 5A 5B 10 11 9 2 LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED SD OL OL SI BR PP SI BR HS VR BR RH HS SI SD SA OL BR SI OLBR OLVR BR RH PP SIIB RH SI OLBR IB OLVR BR RH PP SIIB VR BR RH HS SI RH VR BR RH HSPP SI VR OL OL HS SD DI SI OL FIGURE 1.1: RECOMMENDED STORMWATER BEST MANAGEMENT PRACTICES KEY FINDINGS -- Swarthmore is already using green infrastructure techniques (green roofs, infiltration beds, bioswales, etc.) to manage stormwater from development projects to the required level of regulatory compliance. -- By increasing stormwater management requirements beyond regulatory levels to the 98th percentile storm event (2.25”), approximately 61,000 gallons of stormwater will be managed per developed acre. -- Increased stormwater management to the 98th percentile event level will help protect Crum Creek and more closely mimic ideal Pre-Columbian land conditions on campus. -- Standalone watershed mitigation projects undertaken separately from development projects can help to further counteract the impacts of past development and improve the health of the Crum Creek watershed. Potential mitigation projects include channel and outfall stabilization, installation of additional or upgraded stormwater infrastructure, and expansion of existing stormwater management facilities. WS-7 WS-3A WS-8B WS-3B WS-8C WS-8A WS-1B 3B 3A 8A 8B 8C 6 7 ITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED SI SA VR OL BR RH IB HS PP SD DI SD SA OL BR SI OLBR SI OLBR IB OLVR BR RH PP SIIB X SOIL AMENDMENT VEGETATED ROOF ORGANIC LAWN BIORETENTION RAINWATER HARVESTING INFILTRATION BASIN HYDRODYNAMIC SEPARATOR PERVIOUS PAVEMENT SUBSURFACE INFILTRATION SUBSURFACE DETENTION DRAIN INLET WATER QUALITY INSERTS PROPOSED PARKING/PAVING WATERSHED BOUNDARY EXISTING BUILDING PROPOSED BUILDING CONSTRUCTED / APPROVED FOR CONSTRUCTION POINT OF INTEREST*/ STORMWATER FEATURE * Point of Interest (POI) refers to the point at which water within a subwatershed is assumed to flow. It is used to allow a single analysis point for stormwater modeling. POI’s have been selected to correspond with drainage features on campus EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  4. 4. 4 1 Executive Summary 1.4 Carbon and Energy Analysis The Carbon and Energy Analysis provides both high-level and detailed information about building generated carbon emissions (Scope 1 and 2 emissions) and energy use on campus. The analysis builds on the College’s energy management practices dating back to 2005. The objective of the Carbon and Energy Analysis is to identify efficiency measures that can be implemented incrementally by the College to meet the 2035 net-zero carbon goal expressed in the 2013 Climate Action Plan [Figure 1.2]. Three development scenarios illustrate the different approaches to meeting this goal, depending on the degree to which on- and off- campus carbon reduction measures are adopted. These scenarios are labeled: Good, Better, and Best [Table 1.1]. All scenarios include building improvements, renewable energy systems and purchased carbon offsets. The analysis begins with historical and current campus energy consumption and carbon emissions data. The effect of recent central plant renovations in reducing emissions associated with switching to gas from oil fuel for heating is apparent, as is the effect of operational policies which greatly reduce energy use in non-occupied spaces. To develop the future scenarios, energy modeling was applied to measured campus energy data. The data was then developed into profiles of current emissions on a building-by-building basis for six campus building typologies: academic, athletics, library, residence, science, and student life. Understanding how energy is used by the different building typologies and the by central systems is the critical first step to developing recommendations for improvement. Energy use targets for the campus were developed by evaluating design strategies which can be used for new and existing campus buildings, the central plant, and renewable energy technologies. For the new construction described in the Campus Master Plan, the most recently published energy performance standard, ASHRAE 90.1-2010, was used as a baseline to which planned new buildings were compared. Newly constructed buildings are expected to be designed to exceed this standard by at least 50 percent. To assess how energy use can be reduced for existing buildings, 17 of the College’s existing buildings were identified as the largest energy consumers and representative of the six major building typologies at the College. Strategies to reduce energy use were analyzed and the recommended strategies vary by building type. Following the analysis of energy efficiency measures for new and existing buildings, recommendations for configuration of the central utility plant and for on-site renewables were developed. Further recommendations include system-wide replacement of hot-water heating systems and extensive use of ground source heat pumps. A photovoltaic (PV) array study illustrates potential locations for adding this type of renewable infrastructure on campus. As much as 1,930 kW of PV could potentially be installed on the campus, which would generate 2,910 MWh annually and offset 1,200 Metric Tons (MT) of carbon dioxide emissions (CO2 ). KEY FINDINGS -- With anticipated building projects, the campus building CO2 emissions are anticipated to increase by 28%. -- Taking into account new built area, up to 40% CO2 savings can be achieved over the Business as Usual 2035 CO2 levels. -- Reducing energy usage in existing buildings by 32% and carbon by 40% will require a significant investment in Energy Conservation Measures (ECMs) such as LED lighting/control enhancements, building envelope improvements and replacement of older inefficient HVAC systems. -- A 60% reduction in fossil fuel CO2 emissions can be achieved with the Best Case Scenario. Good Scenario Better Scenario Best Scenario NEW BUILDINGS and MAJOR RENOVATIONS & ADDITIONS Energy Performance Targets 50% better than ASHRAE 90.1 -2010 + Ground Source Heat Pumps Same as Better Scenario EXISTING BUILDINGS ECM CO2 Reduction 21% 27% 32% CENTRAL PLANT Phase out Steam Plant, Existing Buildings install condensing boilers Same as Scenario A +25% existing buildings use ground source heat pumps ON-SITE RENEWABLES PVs on Roofs, SHW at Residence Halls +PV on Parking and SHW for Dining Same as Better Scenario TOTAL REDUCTION Building ECMs + Central Plant + Renewables 23% 32% 40% CARBON CREDITS AND RENEWABLE ELECTRICITY PURCHASE CO2 Produced from Grid Electricity (MT) 7,729 7,219 6,614 CO2 Produced from Natural Gas (MT) 4,043 3,195 2,554 Offsets Required (MT) 4,043 3,195 2,554 TABLE 1.1: CARBON EMISSION REDUCTION SCENARIOS 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 CURRENT 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 CO2EMISSIONS(MT) CO2 EMISSIONS REDUCTION TIMELINE ELECTRICITY CO2 NATURAL GAS CO2 BUSINESS AS USUAL Good Scenario Better Scenario Best Scenario 40% (Best Scenario) Purchased Renewable Electricity Purchased Carbon Offsets (Natural Gas) FIGURE 1.2: CO2 EMISSIONS REDUCTION TIMELINE EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  5. 5. 5 TABLE 1.2: BUILDING ENERGY PERFORMANCE TARGETS -- Install a minimum of 45% native/adaptive vegetation and replace turf where possible with native/adaptive plantings. -- Manage stormwater runoff for the 98th percentile of rainfall events (Tier 1). -- Install LED, full cutoff exterior lighting fixtures. -- Embrace practices of material conservation and reduce waste associated with landscape and hardscape projects. WATER CONSERVATION Water conservation and reuse is an important design strategy in developing a resilient and sustainable campus. Water reduction targets are diagramed in Figure 1.3 and listed below: -- Reduce potable water use on campus by 35% compared to current use rates. -- Select efficient flush and flow fixtures for new construction and major renovation projects to reduce water use by 40-50%. -- Target a 30-40% reduction in water use for flush and flow fixtures for building retrofits. -- Offset 50% of irrigation with captured stormwater; use irrigation for new projects only after exhausting options for non-irrigated landscapes. -- Utilize captured stormwater for cooling towers and other non-potable uses (e.g. toilets). INDOOR ENVIRONMENTAL QUALITY & MATERIALS To ensure a high environmental quality for the faculty, staff, and students, it is imperative that strategies to improve occupant comfort be employed to create comfortable and dynamic indoor environments. -- Meet thermal comfort standards outlined in ASHRAE Standard 55-2010. -- Provide access to exterior views (90%) and useful daylight (75%) for regularly occupied spaces, where occupants spend at least 1 hour. 1.4 Sustainable Building Guidelines Building on the findings in the Stormwater Management Analysis and the Carbon and Energy Analysis, the Sustainability Building Guidelines provide a comprehensive approach to sustainability in the built environment. These guidelines will aid design teams in understanding the key sustainability issues and associated targets for new construction, renovation, and interior fit-out projects. The guidelines address energy, landscape & stormwater management, water conservation, indoor environmental quality & materials, and operations & maintenance. Key principles, targets, and strategies for each topic are outlined below. ENERGY The recommended measures for reducing carbon emissions and improving energy efficiency are: -- Target net-zero carbon in all new building construction through the use of ground coupled systems and renewable energy. -- Design all new construction to 50% better than ASHRAE 90.1-2010 (before renewables). -- Achieve Energy Use Intensity (EUI) targets for new construction, major renovation and addition projects [Table 1.2]. -- Incorporate Energy Conservation Measures (ECMs) for existing buildings outlined in the Carbon and Energy Analysis Section. LANDSCAPE AND STORMWATER MANAGEMENT Currently, the Swarthmore College campus landscape consists of large lawn areas, circulation paths and roads, specialized gardens and the Crum Woods. New development should create physical and visual connections to the landscape and incorporate the following targets: 1 Executive Summary -- Develop high quality lighting environments and utilize efficient, long-life fixtures. -- Source 50% of materials from sustainable sources to reduce environmental impact. -- Specify low-emitting materials, and zero volatile organic compound materials where possible, to reduce the amount of indoor air contaminants. OPERATIONS & MAINTENANCE The existing preventative maintenance program, integrated pest management, green cleaning, recycling, and educational programs all contribute to sustainable operations and maintenance of the College’s buildings and grounds. Recommendations to expand these efforts in new buildings include: -- Install energy and water meters in buildings; track utility use on a building-by-building basis. -- Install educational dashboards to further educate building users. 1.5 Implementation Recommendations Achieving the College’s environmental performance goals requires a significant commitment of effort and financial resources to support, fund, and prioritize campus sustainability initiatives. Most importantly, success requires the ability to measure improvement and validate project performance, enabling the College to make informed decisions about these sustainability initiatives. STORMWATER BIOFILTRATION/GROUND WATER RECHARGE OVERFLOW POTABLE WATER OVERFLOW TO SEWER SINKS/SHOWERS LOW-FLOW FIXTURES BUILDING RETROFITS 30-40% NEW CONSTRUCTION AND MAJOR RENOVATIONS LOW-FLOW FIXTURES WITH STORMWATER/GREYWATER REUSE 40-50% STORAGE POTABLE WATER TOP-OFF STORAGE GREYWATER FLUSH SEWER COOLING TOWERS TOILETS / IRRIGATION POTABLE WATER SINKS / SHOWERS / TOILETS / IRRIGATION / COOLING TOWERS LOW-FLOW FIXTURES WITH BLACKWATER REUSE CONDENSATE REUSE FROM AHU GSHP REDUCE COOLING DEMAND CAMPUS TARGETS STORMWATER REUSE- IRRIGATION STORMWATER REUSE- COOLING TOWER 50% 20% BUILDING ENERGY TARGETS NEW CONSTRUCTION MAJOR RENOVATIONS Achieveb50% energy consumption reduction over ASHRAE 90.1- 2010 Target Energy Use Intensity: Achieve Energy Reduction over ASHRAE 90.1- 2010: Athletics 80 kBTU/sf-yr Athletics 35% Classroom / Office 65 kBTU/sf-yr Classroom / Office 40% Library 70 kBTU/sf-yr Library 30% Residence Hall 50 kBTU/sf-yr Residence Hall 30% Science 90 kBTU/sf-yr Science 35% Student Center 70 kBTU/sf-yr Student Center 35% The following implementation strategies will help the College achieve the environmental performance goals established in this framework and will guide sustainable campus growth into the future: -- Identify, recognize, and support sustainability leaders within the College. -- Include sustainability goals and criteria in the development of all facilities capital projects which affect buildings and grounds, and foster a holistic problem-solving approach in order to address existing detrimental conditions and past environmental damage in the definition of each project’s scope of work. -- Explore innovative and creative funding opportunities to support sustainability initiatives. -- Enhance tracking and reporting of energy use, site impacts, and post-occupancy evaluation in order to foster continuous improvement in the process of planning, designing and constructing an environmentally sustainable campus. An implementation checklist is included in this Framework to support tracking and reporting of the building guidelines. It includes recommended targets for new construction, renovation, and interior fit-out projects. It is intended to be used along with the framework, not as a stand-alone document. FIGURE 1.3: RECOMMENDED WATER REUSE STRATEGY - RESIDENCE HALLS 1.6 Next Steps The following are proposed next steps for the College in reviewing and integrated the proposed recommendations from the framework: -- Identify standalone watershed mitigation projects to further counteract the impacts of past development and improve the health of the Crum Creek watershed. -- Determine how carbon offsets will be acquired and create a purchase plan accordingly; develop a tracking system to document and account for these offsets. -- From the Carbon Emissions Reduction Scenarios Good, Better or Best describing CO2 reduction strategies (Table 1.1), develop an implementation plan in accordance with the capital plans for campus growth. -- Develop a life cycle analysis protocol for use when evaluating additional project costs including, at a minimum, the College’s policy on rates including escalation, inflation, discount rate and criteria for net present value, internal rate of return, maintenance costs and payback. -- Determine to what extent building metering and sub-system metering is needed to track performance of individual buildings against the larger carbon emissions and energy use goals. -- Develop a timeline for phasing out campus steam, installing new heating systems in buildings and reconfiguring the campus central plant. -- Conduct a campus Transportation emissions audit to determine emissions associated with campus vehicular use and develop a baseline for future improvements to be compared to. -- Develop a plan to implement and collect data from water use meters on a building level. -- Revise Campus Standards documents to include the following performance targets: envelope, lighting, retro-commissioning, HVAC system, plug- in equipment, site lighting, and on-site renewable technologies. -- Perform an assessment of the campus housekeeping protocols and materials. -- Continue to encourage staff to participate in green building conventions. -- Continue to consider using external benchmarking systems to verify landscape and building performance. -- Continue to connect with sustainability groups at other peer institutions. -- Develop an integrated design protocol for project request for qualifications and request for proposal processes. -- Establish funding for the added costs associated with the environmental improvements set forth in this framework. EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  6. 6. 6 2 Introduction This report is divided into four main sections: Stormwater Management Analysis, Carbon and Energy Analysis, Sustainable Building Guidelines and Implementation Recommendations. These sections are related, with complementary goals and strategies that together form a comprehensive framework for sustainability at Swarthmore College. An overview of each section is presented below. 2.1 Stormwater Management Analysis The Sustainable Stormwater Management Analysis employs hydrological modeling to assess campus- wide impacts from recently permitted projects and projects presented in the Swarthmore College 2013 Campus Master Plan. The physiography of the campus was analyzed and watersheds and sub- watersheds were delineated. Stormwater modeling was used to identify existing campus conditions and projected changes associated with campus development projects as shown in the Campus Master Plan. Stormwater impacts were projected for peak rate, volume, and water quality within each sub-watershed. The analysis assessed existing conditions and noted deficiencies in each sub watershed area. Based on the projected Master Plan build-out, the analysis estimates the effects of an unmitigated condition, representing the possible environmental impacts due to development if stormwater is not addressed with best practice management techniques. Recommendations in this analysis assume that the College will approach stormwater management in ways that exceed regulatory requirements. It builds on a tradition of environmental stormwater stewardship that the College embraces; as a result of careful landscape design, curation of the campus arboretum and planned civil engineering exercises. The approach taken is that upcoming projects will have greatly reduced stormwater discharges in order to offset immediate impact as well to offset degradation to protect and restore the environmental conditions of the Crum Woods and Crum Creek. 2.2 Carbon and Energy Analysis Swarthmore College is working toward achieving carbon neutrality by 2035. To achieve carbon neutrality, the College will need to eliminate or offset three categories, or scopes, of carbon emissions: • Scope 1: Direct GHG emissions that are under the complete control of the College. These are predominantly the result of utilizing fossil fuels to heat and cool buildings and to fuel College- owned vehicles. • Scope 2: Indirect GHG emissions that are the result of purchased electricity. • Scope 3: Indirect GHG emissions not covered by Scope 1 and Scope 2. These are primarily non-college-owned transport-related emissions and air travel. The Carbon and Energy Analysis evaluates scenarios for achieving carbon neutrality by reducing all non-transport related Scope 1 and Scope 2 GHG emissions, termed “campus emissions” in this report. The 61 existing buildings (approximately 1.6 million square feet) covered by this plan are primarily on campus but also include non-residential off-campus buildings. Off-campus, college-owned faculty housing and College-owned vehicular use are excluded in this analysis for Scopes 1 and 2. The Energy and Carbon Master Plan takes into account new buildings and additions (totaling approximately 400,000 sf) that will be added to the campus by 2035, and their effect on campus emissions. A complete list of the buildings included in the study is included as an appendix to this report. The Carbon and Energy Analysis shows the effect of building and central plant efficiency measures on campus carbon emissions, allowing Swarthmore College to forecast future emissions and determine the most appropriate mitigation strategies. 2.3 Sustainable Building Guidelines The Sustainable Building Guidelines utilize the Stormwater Management Analysis and Carbon and Energy Analysis to provide additional goals and strategies for the overall campus and individual buildings. These Guidelines provide a comprehensive approach to sustainability tailored to the College. The Guidelines establish a set of targets and outlines strategies for achieving those targets. This document is intended to serve as a resource for project teams during the design, construction and renovation of the campus. Existing practices that promote sustainable building design and operation are incorporated as well. The targets and strategies outlined within the Framework will serve as a guide for the design team in developing efficient and sustainable buildings that improve performance and minimize the campus’s environmental footprint. Many of the goals developed for the campus consist of specific, quantifiable targets for achievement and metrics for these targets. While some are new practices and based mostly on LEED credit goals, others build upon existing processes that are successful on campus today. Aggregation and evaluation of these metrics every three to five years is recommended to allow adjustments as the campus evolves and as codes and standards are updated, or sooner as the achievement of initial goals and targets are met. The Building Guidelines outline five themes in sustainability: Energy, Landscape & Stormwater Management, Water Conservation, Indoor Environmental Quality (IEQ) & Materials, and Operations & Maintenance. Each theme includes campus targets, building targets, and design strategies, as outlined below: • Campus Targets: Campus targets refer to campus-scale goals for all buildings and landscapes. • Building Targets: Building Targets refer to performance goals for individual buildings on campus. Some of the themes, such as energy, have specific goals for new construction, major renovations, and retrofits. • Design Strategies: These are specific strategies that may be considered to meet campus and building targets. Typically, design strategies rely on specific technologies that may change in the future. Therefore, the strategies portion of each section should be updated every 3 to 5 years to reflect technological advancements in the building industry. FIGURE 2.1: SUSTAINABILITY BUILDING GUIDELINES PAGE FORMAT A diagram of this organizational structure appears above. Each section includes campus and building sustainability targets and design strategies for achieving those goals. The text of each section describes key concepts and provides suggestions about how to integrate sustainable design features into current and future projects. 2.4 Implementation Recommendations The implementation section outlines administrative strategies that support the College’s efforts to improve campus environmental performance, including recommendations for developing internal sustainability leadership protocols and establishing funding opportunities, as well as ways to evaluate the performance of new and existing building projects. Building and landscape projects are often highly interdisciplinary, requiring close coordination and collaboration among experts in fields such as architecture, engineering, ecology, and finance. The implementation strategies in this document will help the College develop a clear protocol for project initiation, implementation, evaluation and maintenance. A checklist is provided to track projects and summarize criteria. CAMPUS TARGETS = CO2 DESIGN STRATEGIES Landscape BUILDING TARGETS 1 2 1 2 3 1 2 EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  7. 7. 7 3.1 Sustainable Site Development As native land (a greenfield site) is developed, its ecosystems can be compromised [Figures 3.1 and 3.2]. Land clearing strips native vegetation, disturbing soil and upsetting the natural water cycle, preventing rainwater from being taken up by plants and infiltrated into the ground [Figure 3.3]. Further urbanization, and its related increase in imperviousness due to construction of roads, parking lots and buildings negatively impacts habitats and aquifers. Sustainable site development seeks to repair the damage caused by development with regard to ecosystem services such as water balances, habitats and soil health. Providing for human comfort, health and well-being are also integral design objectives for sustainable site developments. Several sustainable site-related rating systems are available. LEED ® is a building-centric rating system that rates sustainability in buildings as well as their associated site elements. Whereas LEED ® is a system that is used primarily for green building projects, the Sustainable Sites Initiative (SITES™) is a rating system intended to be used for sites with or without buildings. The SITES™ rating system was developed by the LadyBird Johnson Wildflower Center, the US Botanic Garden, and the American Society of Landscape Architects. The SITES rating system is centered on the principles of ecosystem services and human health and well-being. Both the LEED system and SITES address similar issues with respect to the social and environmental ecologies of place. The current versions of the rating systems (LEED v4 and SITES v2) both address site- related development impacts in order to minimize the influence of man-made disruption on the ecological setting. Further, these rating systems also address restoration of previously-impacted sites. Sites that have been damaged by previous construction can be viewed through the lens of environmental or ecological restoration effort. Projects following these rating systems will help minimize or even repair ecological damage through sustainable design practices. The LEED and the SITES rating systems address several common resource and impact categories, including: • Water • Habitat (soils and vegetation) • Energy and greenhouse gas • Materials • Transit alternatives and • Human health and well-being. Each of these topics is the focus of credit categories within the systems. Due to its in-depth nature with respect to site-related impact, the SITES rating system addresses these categories in greater depth and focus compared to their treatment in LEED. 3.2 Green Infrastructure Approach A green infrastructure approach can be used to accommodate the building program proposed in the Campus Master Plan while minimizing impact to the campus itself. An ecosystem service approach, prioritizing restoration of services such as water balances, habitat and soil ecology, is a unique opportunity to improve site ecosystem functions through new building construction. Using the principles of biomimicry and biophilia-- using natural systems to promote the built environment and connect humans to nature-- projects can be designed to perform responsibly and provide human health and well-being in a manner that also repairs the environment. This report focuses on the stormwater impacts of proposed development as outlined in the 2013 Campus Master Plan. Without thoughtful and ecologically sensitive design, the proposed projects would create more impervious land cover across the campus and would upset the campus water balance. Specifically, their impact would be to lower the amount of groundwater recharge due to the increased runoff caused by increased impervious cover and lower amounts of plant evapotranspiration from loss of vegetation. The result would be increased quantities and lower quality of stormwater runoff directed to Crum Creek. This report recommends that the incremental increase in impervious land cover should be managed to meet current regulations and should also compensate for prior campus development. FIGURES 3.1 & 3.2: EVAPOTRANSPIRATION IN VEGETATION AND IMPERVIOUS CONDITIONS. SOURCE: US EPA FIGURE 3.3: THE WATER CYCLE. SOURCE: USGA.GOV 3 Stormwater Management Analysis EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  8. 8. 8 3.3 Site History The College was founded on a tract of regenerated forest and cultivated farmland, traversed by natural springs and Crum Creek. The development of buildings on campus has been incremental, with the majority of the structures having been built between 1940-2010. Building development has extended radially from the original Parrish Hall, bounded to the west by Crum Woods, 220 acres of restored native forest. Although the College did not have its first campus plan until 1984, development has been deliberate and has strived to respond sensitively to the campus setting. This mission extended to building placement along with the removal of roads in the 1990s to improve pedestrian circulation and provide traffic free circulation in the heart of the College. Infrastructure improvements, however, have not always kept up with the incremental nature of this expansion, especially with respect to stormwater management. In 2003, the first of several green roofs was installed to mitigate stormwater that would otherwise be discharged directly into storm drains. A thoughtful and visible design approach to new stormwater elements has allowed Swarthmore College to educate students and visitors on new technologies. On the grounds of the College, the students, faculty, staff and visitors daily experience the collection of the Scott Arboretum. Seamlessly integrated into the campus, the Arboretum is operated as a public garden and learning tool intended to appeal to students and the general public. Made possible by an endowment given in 1929 by Edith Wilder Scott in honor of Arthur Hoyt Scott, former president of Scott Paper Company, the collection today now contains over 4,000 ornamental plants. The College has grown from the original Parrish Hall and 85 acres to over 60 buildings and 425 acres. Its development is in keeping with the goals of the Quaker legacy of social responsibility, simple living, and conservation of resources. The College honors its heritage by purchasing renewable energy credits to compensate for the carbon emissions associated with 100% of its energy consumption. 3.4 Physiography The College campus straddles two physiographic provinces, the Atlantic Coastal Plain and the Piedmont. The southeast portion of campus lies in the Lowland and Intermediate Upland section of the Atlantic Coastal Plain. The dominant topographic form is flat upper terrace surfaces cut by shallow valleys with unconsolidated to poorly consolidated sand and gravel. The underlying rock is schist, gneiss and other metamorphic rocks. The geologic structure is unconsolidated deposits underlain by complexly folded and faulted rocks. The geologic origin is fluvial erosion and some periglacial mass wasting. The northwest section of campus lies in the Piedmont Upland physiographic section, which is characterized by broad rounded to flat top hills and shallow valleys underlain with schist, gneiss, quartzite and some saprolite. The geologic structure is extremely complexly folded and faulted rocks. The geologic origin is fluvial erosion and deposition. The drainage pattern through both of these physiographic sections is dendritic. 3.4.1 SOILS NRCS Soil Survey data are used to classify soil permeability. NRCS classifies soil into one of four hydrologic soil groups, from A to D, where A is the most permeable and D is the least permeable. Soils found on campus (See Figure 3.4) have weathered from the underlying bedrock geology (schist, gneiss, other metamorphic rocks and saprolite) and most are classified in Hydrologic Soil Group B (HSG B). Soils are classified according to their rate of infiltration after prolonged wetting. Group A has the highest rate of water transmission, greater than 0.30 inches per hour (in/hr), while Group D has the highest runoff potential with very low rate of water transmission, (from no water movement to 0.05 in/hr). Some HSG D soils are found in areas with a high water table, which can be the cause of poor drainage. HSG B soils have moderate infiltration rates when wet and consist chiefly of moderately deep to deep, moderately well to well drained soils with moderately fine to moderately course texture. HSG C soils have low infiltration rates when wet and consist chiefly of soils with a layer that impedes downward movement of water and soils with moderately fine to fine texture. FIGURE 3.4: SOIL MAP SURVEY. SOURCE: NRCS WEB SOIL SURVEY MgD2 MgD2 GnB MgC MgC MgC BeA MgC MhE MhE MhE MgD Ch Ch MkF MkF Me Mn Mn GeC2 GeB2 GeE GeB3 MhE MhE We GeE Ch Me Me Mc According to the NRCS Web Soil Survey for the Swarthmore locale, the campus is underlain by a variety of soils from silty loam to loam. The central portion of the campus is classified as “Made Land” (Me, Mc). Me is comprised of constituents from schist/gneiss parent formations and Mc from parent formations of silt and clay. Other soils include the Manor Loam series (MgC, MgD, MgE, MgF) and Beltsville Silt Loam (BeA). The soil found in the lower elevations of Campus (Atlantic Coastal Plain) has been disturbed by various activities including construction of roads and railroads. This has resulted in fairly substantial fill (5 to 10 feet in depth) covering the original ground surface in some areas. Commonly found beneath this fill is granular textured soil that is useful for storm water infiltration. In-situ soil investigations will be needed to confirm soil surveys and to determine actual soil design parameters prior to design of specific building projects. Figure 3.4 above shows the locations of the soil formations. Figure 3.5 on the following page depicts the hydrologic soil group (HSG) of each soil type. HSG’s and soil characteristics need to be confirmed with test pits and infiltration measurements. 3 Stormwater Management Analysis SOIL SOIL NAME HYDROLOGIC GROUP Be(X) Beltsville silt loam C Ch Chewacla silt loam B/D Ge(XX) Glenelg Channery silt loam B Gn(X) Glenville silt loam C/D M(X) Made Land C Mg(XX) Manor loam B Mh(XX) Manor loam and Channery loam B Mk(XX) Manor loils B We Wehadkee silt loam B/D KEY EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  9. 9. 9 WS-6 WS-4 WS-7 WS-3A WS-2 WS-1A WS-10 WS-8B WS-9 WS-3B WS-8C WS-8A WS-5 WS-1B WS-11 1A 1B 3B 4 3A 8A 8B 8C 6 7 5A 5B 10 11 9 2 LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED X WS-7 WS-3A WS-8B WS-3B WS-8C WS-8A 3B 3A 8A 8B 8C LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED X FIGURE 3.5: EXISTING SUBWATERSHEDS AND HYDROLOGIC SOIL GROUPS TABLE 3.1: EXISTING IMPERVIOUS AREAS TABLE 3.2: EXISTING LAWN AREAS WATERSHED BOUNDARY TC FLOW PATH STORM UTILITY CONNECTION HYDROLOGIC SOIL GROUP B HYDROLOGIC SOIL GROUP C HYDROLOGIC SOIL GROUP D POINT OF INTEREST*/ STORMWATER FEATURE 3 Stormwater Management Analysis Stormwater modeling involves understanding and mapping the extent of watersheds, including what is known as subcatchments or subwatersheds. These subcatchments are defined by local grading conditions and stormwater piping infrastructure. Understanding where surface water flows allows for the mapping of the discharge points, called analysis points or points of interest. These points are located around the perimeter of campus and are shown on Figures 3.5 and 3.7. * Point of Interest (POI) refers to the point at which water within a subwatershed is assumed to flow. It is used to allow a single analysis point for stormwater modeling. POI’s have been selected to correspond with drainage features on campus Figure 3.5 also shows the current level of development on campus, and the breakdown of land cover types in each subwaterhsed. These data (see Tables 3.1 and 3.2) are relevant to the stormwater management analyses presented later in this report. EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  10. 10. 10 FIGURE 3.6: PRECOLUMBIAN SUBWATERSHEDS 3.4.2 PRE-COLUMBIAN CONDITION Both LEED and SITES present a similar basis for understanding the stormwater impact of development. The “ideal” condition from an ecosystems services perspective is defined in the rating systems as the Pre-Columbian condition. The Pre-Columbian land cover is assumed to be woods in good condition for this area in Pennsylvania, estimated to be the land cover conditions present on the land at the time of first settlement by non- native settlers. (See Figure 3.6) The Pre-Columbian land cover condition is intended to provide an ideal target that, when achieved, would provide a complete replication of the runoff volume conditions of a completely undeveloped site. Although not required by the State and Borough regulators, this ideal represents an aspirational goal for stormwater and ecosystems impact. 3 Stormwater Management Analysis EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  11. 11. 11 FIGURE 3.7: PROPOSED MASTER PLAN DEVELOPMENT TABLE 3.4: PROPOSED LAND COVER TABULATION TABLE 3.3: COMPARISON OF EXISTING AND PROPOSED IMPERVIOUS COVERAGE 3.5 Rainwater Management Analysis In the Campus Master Plan, some sub-watersheds have more proposed development than others. These affected sub-watersheds will be the focus of mitigation strategies designed to help manage stormwater. Stormwater impact is a function of land cover change. The more the land is changing, adding impervious cover, the greater potential for increased stormwater runoff. Figure 3.7 shows the development as noted in the Campus Master Plan along with currently approved projects for Town Center West (WS-9) and the Cunningham Fields parking lot (WS-8A). Tables 3.3 and 3.4 indicate the degree of change in impervious coverage for each sub-watershed. Land cover changes, such as the addition of pavement and buildings, will increase stormwater runoff. When evaluating potential stormwater impacts, the degree of a watershed’s land cover change from pervious to impervious is an important metric. Please refer to the appendices for a discussion of other metrics including peak rate, volume, and water quality. 3 Stormwater Management Analysis Total  Impervious  (Ac.) Percent  Impervious Total  Impervious  (Ac.)* Percent  Impervious WS‐1A 2.09 48.2% 3.23 74.4% 26.3% WS‐1B 1.13 22.9% 1.39 28.2% 5.3% WS‐2 11.07 65.2% 11.88 70.0% 4.8% WS‐3A 7.83 30.2% 9.44 36.4% 6.2% WS‐3B 0.94 14.1% 0.94 14.1% 0.0% WS‐4 1.50 61.2% 1.50 61.2% 0.0% WS‐5 0.61 38.6% 0.72 45.6% 6.9% WS‐6 4.94 32.8% 5.58 37.0% 4.2% WS‐7 0.40 7.6% 0.54 10.3% 2.7% WS‐8A 0.01 0.2% 0.14 2.2% 2.0% WS‐8B 0.06 0.8% 0.11 1.8% 1.0% WS‐8C 1.26 21.5% 1.26 21.5% 0.0% WS‐9 7.78 32.9% 10.62 44.8% 12.0% WS‐10 2.17 36.1% 2.17 36.1% 0.0% WS‐11 1.31 44.5% 1.40 47.6% 3.1% Total 43.10 31.5% 50.92 37.9% 1.8% TABLE 3:  COMPARISON OF EXISTING AND PROPOSED IMPERVIOUS COVERAGE *   Does not include permeable pavement ** Compared to Existing Conditions Existing Proposed Increase in  Impervious  Coverage  Rate** Watershed Total  Impervious  (Ac.) Percent  Impervious Total  Impervious  (Ac.)* Percent  Impervious WS‐1A 2.09 48.2% 3.23 74.4% 26.3% WS‐1B 1.13 22.9% 1.39 28.2% 5.3% WS‐2 11.07 65.2% 11.88 70.0% 4.8% WS‐3A 7.83 30.2% 9.44 36.4% 6.2% WS‐3B 0.94 14.1% 0.94 14.1% 0.0% WS‐4 1.50 61.2% 1.50 61.2% 0.0% WS‐5 0.61 38.6% 0.72 45.6% 6.9% WS‐6 4.94 32.8% 5.58 37.0% 4.2% WS‐7 0.40 7.6% 0.54 10.3% 2.7% WS‐8A 0.01 0.2% 0.14 2.2% 2.0% WS‐8B 0.06 0.8% 0.11 1.8% 1.0% WS‐8C 1.26 21.5% 1.26 21.5% 0.0% WS‐9 7.78 32.9% 10.62 44.8% 12.0% WS‐10 2.17 36.1% 2.17 36.1% 0.0% WS‐11 1.31 44.5% 1.40 47.6% 3.1% Total 43.10 31.5% 50.92 37.9% 1.8% TABLE 3:  COMPARISON OF EXISTING AND PROPOSED IMPERVIOUS COVERAGE *   Does not include permeable pavement ** Compared to Existing Conditions Existing Proposed Increase in  Impervious  Coverage  Rate** Watershed Master Plan Coverage Summary Swarthmore College Sustainabilities Study Watershed Delineation Watershed Total Area  (Ac.) Lawn (B Soils)  (Ac.) Lawn (C Soils)  (Ac.) Lawn (D Soils)  (Ac.) Permeable  Pavement  (Ac.) Roof (Ac.) Roads (Ac.) Walkways  (Ac.) 4.332622 WS‐1A 4.34 0.92 0.00 0.19 0.00 0.52 2.50 0.21 4.933196 WS‐1B 4.93 3.38 0.00 0.16 0.00 0.44 0.67 0.28 16.9707 WS‐2 16.97 4.47 0.00 0.62 0.00 6.58 0.48 4.82 25.92686 WS‐3A 25.93 13.52 2.96 0.00 0.00 3.28 2.06 4.10 6.672679 WS‐3B 6.67 5.73 0.00 0.00 0.00 0.38 0.27 0.29 2.450345 WS‐4 2.45 0.95 0.00 0.00 0.00 0.58 0.69 0.23 1.578385 WS‐5 1.58 0.86 0.00 0.00 0.00 0.34 0.24 0.14 15.07813 WS‐6 15.08 9.50 0.00 0.00 0.00 1.59 0.75 3.24 5.251722 WS‐7 5.25 4.67 0.04 0.00 0.00 0.00 0.00 0.54 5.685134 WS‐8A 6.37 1.12 3.81 0.00 1.30 0.00 0.00 0.14 6.231995 WS‐8B 6.22 0.00 6.11 0.00 0.00 0.01 0.00 0.10 5.864141 WS‐8C 5.87 0.95 3.66 0.00 0.00 0.05 0.31 0.90 23.67556 WS‐9 23.68 4.04 8.55 0.00 0.47 4.95 4.08 1.59 6.015423 WS‐10 6.01 1.49 2.25 0.10 0.00 0.01 0.46 1.70 2.944849 WS‐11 2.94 0.00 1.54 0.00 0.00 0.67 0.60 0.13 Total 134.29 51.60 28.92 1.08 1.77 19.40 13.11 18.41 TABLE 4:  PROPOSED LAND COVER TABULATION Total Imperv WS-6 WS-4 WS-7 WS-3A WS-2 WS-1A WS-10 WS-8B WS-9 WS-3B WS-8C WS-8A WS-5 WS-1B WS-11 1A 1B 3B 4 3A 8A 8B 8C 6 7 5A 5B 10 11 9 2 LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED X WS-7 S-3A WS-8B S-3B WS-8C WS-8A 3B 3A 8A 8B 8C LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED X PROPOSED PARKING/PAVING WATERSHED BOUNDARY EXISTING BUILDING PROPOSED BUILDING CONSTRUCTED / APPROVED FOR CONSTRUCTION POINT OF INTEREST*/ STORMWATER FEATURE * Point of Interest (POI) refers to the point at which water within a subwatershed is assumed to flow. It is used to allow a single analysis point for stormwater modeling. POI’s have been selected to correspond with drainage features on campus EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  12. 12. 12 3.6 Sustainable Stormwater Management In order to understand the impact of development on the College campus, the design team modeled the hydrology of the campus using stormwater modeling tools, specifically WINSLAMM and HydroCAD. This modeling allowed the team to understand the potential impact of development if left unchecked. The three primary stormwater impacts are: -- Degraded water quality -- Increased rate of discharge -- Increased runoff volume The stormwater modeling effort addresses each of these impacts for each subwatershed area. Once watershed boundaries and subcatchment boundaries are defined, the next step is to look at topography of the campus, specifically the steepness of the slope of the land and its soil conditions. The existing land cover conditions were noted and quantified. Area takeoffs were performed to determine the acreage of various land covers in each subcatchment. A total of land area covered by parking lots and roads and buildings and landscape type is entered into the models, as each of these land covers will have different stormwater generation characteristics. For this study, two hydrology models were used (for detailed descriptions of each model see the appendices). The first model used, HydroCAD, is based on SCS TR-20 methodology, which is a land- cover based model for assessing peak rate of flow and runoff volumes from individual “design storms”. The design storms modeled for this study are the 2-year (50% probability, 3.25”, 24-hour rainfall depth) event and the 100-year (1% probability, 7.71” 24-hour rainfall depth) event. The second model, WinSLAMM, models the stormwater response from urban watersheds over a time period of observed rainfall record. The team chose the rainfall record from March 1992 through February 1993. This range for rainfall data was found by the Philadelphia Water Department to be closest to a “typical” year of record of the past 17 years. WinSLAMM model output represents a continuum of events over the “typical” year. In this climate, precipitation occurs most frequently in small amounts. Small storms represent the majority of both number of rainfall events and cumulative rainfall volume. Simply stated, most of the time when it rains at Swarthmore College, it rains only a small amount. Large, intense rainfall events are infrequent. Figure 3.10 was created by plotting over 30 years of daily rainfall totals as observed at nearby Philadelphia International Airport. Sustainability metrics acknowledge the relationship between rainfall depth and frequency. SITES and LEED reference these graph points of 90 (1.25”), 95 (1.66”), and the 98 (2.25”) percentile as the most beneficial to manage when considering ecosystem services. 3.6.1 BASELINE CONDITION Once the subcatchments are defined and the land characteristics are noted, a baseline conditions model was created. The baseline determines how much stormwater flow is generated from each surface within each subwatershed for the existing conditions. Stormwater information is obtained from the baseline conditions model, including the peak rate of discharge, water quality data, and volume of runoff. The baseline condition describes stormwater impact from current conditions on the campus. Master Plan development conditions can then be simulated by entering the land cover assumptions from the Master Plan. (The watershed boundaries, soil types, and topography are assumed to not change.) Understanding the degree of impact presented in The Master Plan allows the assessment of what strategies may be appropriate to accommodate development. 3.6.2 UNMITIGATED CONDITION By comparing the output of the stormwater models to the baseline conditions, an understanding of the change that would occur was developed, called the unmitigated condition. Evaluating the unmitigated condition yields a sense of how much stormwater management mitigation is warranted to control peak rate, maintain water quality and reduce runoff volume compared to the baseline condition. This approach conforms to the stormwater management analysis required for land development approval in Swarthmore Borough. 3.7 Beyond LEED and SITES Previous development on campus has already compromised ecosystem services and the upcoming master plan development represents a unique opportunity to repair this damage. By going “above and beyond” regulatory and rating system requirements, The College can continue to demonstrate a high degree of environmental stewardship by planning, funding and implementing projects to mitigate and repair long-standing environmental damage (See Figures 3.8 and 3.9 as examples of stormwater stewardship). FIGURE 3.10: PERCENTILE OF DAILY RAIN EVENTS IN PHILADELPHIA (1940-2014) FIGURE 3.9: EXISTING STORMWATER LANDSCAPE AT SWARTHMORE COLLEGE ‘BIOSTREAM’ FIGURE 3.8: EXISTING BIOSWALE AT SWARTHMORE COLLEGE 3 Stormwater Management Analysis Philadelphia Precipitation (@PHL 1940 2014) 8 9 (@PHL 1940‐2014) 6 7 in) 4 5 Precip.( (99%) 2.79 (98%) 2.25 (97%) 1.96 (96%) 1 78 2 3 (96%) 1.78(95%) 1.66 (90%) 1.25 (80%) 0.86 0.65 0.500.400.30 0 1 1009080706050403020100 Percentile of Daily Events Philadelphia Precipitation (@PHL 1940 2014) 8 9 (@PHL 1940‐2014) 6 7 in) 4 5 Precip.( (99%) 2.79 (98%) 2.25 (97%) 1.96 (96%) 1 78 2 3 (96%) 1.78(95%) 1.66 (90%) 1.25 (80%) 0.86 0.65 0.500.400.30 0 1 1009080706050403020100 Percentile of Daily Events EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  13. 13. 13 3.8 Regulatory Requirements The legislative basis for statewide stormwater management is the Pennsylvania Stormwater Management Act of 1978, which is also known as “Act 167”. The Act 167 program requires that each county in a given watershed regulate land use activities that affect runoff and surface and groundwater quality and quantity. In general, development projects that increase impervious coverage also cause an increase in the peak rate and volume of stormwater runoff, which is detrimental to natural waterways due to erosion and flooding. Also, suspended and dissolved pollutants that are present in stormwater runoff can harm water quality and aquatic habitats. The Delaware County Planning Department has developed an Act 167 Plan for Crum Creek that establishes stormwater management regulations to maintain or improve the condition of Crum Creek. The Crum Creek watershed is divided into two Management Districts (A and B). The Swarthmore College campus is located within Management District B. Swarthmore Borough enacted a stormwater ordinance in 2012, titled “Swarthmore Borough Watershed Stormwater Management Ordinance”. This ordinance is based on and is consistent with the Act 167 Plan developed for Crum Creek. Federal regulations require all land development projects that propose to disturb one acre or more to obtain a National Pollutant Discharge Elimination System (NPDES) permit. NPDES permits authorize discharge from erosion and sediment control facilities during construction and approve Post- Construction Stormwater Management (PCSWM) measures. The NPDES program is based on EPA’s Clean Water Act and includes requirements that municipalities and many institutions throughout Pennsylvania obtain permits for their stormwater discharges. Municipal Separate Storm Sewer Systems (MS4) are man-made drainage systems such as gutters, pipes, and ditches, which convey only stormwater. Municipalities subject to MS4 requirements must develop, implement, and maintain comprehensive stormwater management programs with the goal of reducing the discharge of pollutants to receiving waters. Swarthmore Borough does not currently have any MS4 regulations that affect land disturbance projects on the College campus. However, additional regulations could be enacted in the future. The Act 167, the Borough stormwater ordinance, and NPDES regulations work in conjunction to reduce or prevent the water resource and stream impairment issues that arise from inadequate stormwater management in at-risk watersheds. 3.8.1 VOLUME CONTROL The Borough stormwater ordinance and NPDES directives require the net two-year volume increase from pre-development land cover to post- development land cover to be infiltrated. To partially counteract the effects of previous development, the regulations require modifications to the way pre- development land cover conditions are modeled. Rather than defining land covers as they actually exist (typically grass/lawn and impervious surface), all grass areas and 20% of impervious areas must be defined as meadow. This has the effect of reducing the “baseline” runoff rate and volume. Since the post-development rates and volumes may not exceed those of the pre-development condition, the post-development condition is forced to result in lower rates and volumes than would be required if compared to the actual existing land covers. Infiltration of the two-year volume increase replicates the pre-development conditions by providing ground water recharge, which feeds stream base flow. Throughout the state, over 95% of the annual rainfall volume occurs in storm events that are less than the two-year storm event (approximately 3.2 inches of rain in a 24-hour period). With the large majority of storms being smaller than the two-year storm, designing Best Management Practices (BMPs) for the two-year storm can have a significant positive impact on the watershed. 3.8.2 PEAK RATE CONTROL The Borough’s location in Management District B of the Crum Creek Act 167 Plan requires that post development peak rates shall not exceed the following parameters: The pre-development land cover assumptions for the peak rate analysis vary depending on the classification of the project as new development or redevelopment. If considered new development, the pre-development land cover must be considered any combination of woods, meadow or impervious cover. If considered re-development, the ground cover used in determining the existing conditions flow rates for the developed portion of the site shall be based on actual land cover conditions (i.e. lawn area may be considered as lawn, rather than meadow). The Borough’s stormwater ordinance defines redevelopment as “any development that requires demolition or removal of existing structures or impervious surfaces at a site and replacement with new impervious surfaces. Maintenance activities such as top-layer grinding and re-paving are not considered redevelopment. Interior remodeling and tenant improvements are also not considered redevelopment.” Based on this definition, some of the improvements associated with implementation of the campus master plan could potentially be considered redevelopment. The Borough determines applicability of this ordinance section on a case-by- case-basis. 3.8.3 WATER QUALITY The Borough’s stormwater ordinance and NPDES permit do not require quantitative calculations demonstrating removal of pollutant concentrations. Rather, water quality requirements are assumed to be met if the net two-year volume increase is infiltrated. This approach is based on the prototypical performance of BMPs as set forth in the PA Stormwater BMP Manual (2006). In the infrequent cases where the net two-year volume increase cannot be infiltrated due to site soil conditions, additional water quality BMPs and calculations may be required. The goal of the Borough is to demonstrate 85% reduction of Total Suspended Solids and Phosphorus, and 50% reduction of nitrates. The BMP manual does not, however, establish pollutant removal goals for metals such as copper, lead, and zinc. However, these potential pollutants have been modeled in this report. 3 Stormwater Management Analysis Post Development Peak Rate Shall Not Exceed Pre Development Peak Rate 2-Year ≤ 1-Year 5-Year ≤ 2-Year 10-Year ≤ 5-Year 25-Year ≤ 10-Year 50-Year ≤ 25-Year 100-Year ≤ 100-Year TABLE 3.5: POST DEVELOPMENT PEAK RATES EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  14. 14. 14 3.9 Stormwater Mitigation To minimize the effect of master plan development, stormwater mitigation will be required to manage potential detrimental effects from increases in peak rate/volume, and/or degraded water quality. Stormwater impacts are managed by constructing systems known as BMPs. BMPs are measures that have been proven elsewhere to be effective at managing stormwater peak rate, volume, and/ or water quality. Different practices have different effects on peak rate control, volume management or water quality improvement. Figure 3.11 shows the relative stormwater management benefit gained by each BMP. To the extent possible, incorporating landscape- based BMPs into the campus not only accommodates growth by managing stormwater, but also adds to the quality of the Swarthmore College campus. A green infrastructure approach leverages the working landscape while improving ecosystem services such as biodiversity, groundwater recharge and evapotranspiration. 3.10 Sustainability Targets LEED and SITES provide guidance for managing stormwater in a sustainable manner. The current versions of each rating system promote a water balance-based approach. These rating systems require that a site’s stormwater be managed by green infrastructure for a given percentile storm event. As mentioned previously, various “percentile events” have been determined (using LEED/SITES methodology) based on a historic period of daily rainfall observations at Philadelphia International Airport. The results for this climate show the following rainfall depths that would need to be managed according to the rating systems: As seen in LEED v4 Credit “Rainwater Management”, the credit intent is “To reduce runoff volume and improve water quality by replicating the natural hydrology and water balance of the site, based on historical conditions and undeveloped ecosystems in the region.”There are several options for LEED Rainwater Management credit compliance. These options include the most relevant requirements for new building projects at the College. The credit states, “In a manner best replicating natural site hydrology processes, manage on site the runoff from the developed site for the 95th percentile [Option 1 Path 1] of regional or local rainfall events using low-impact development (LID) and green infrastructure.” An alternative approach is to perform the same type of mitigation at the 98th percentile event [Option 1 Path 2]. This credit attempts to restore water balances to an ideal state that presumably existed prior to any current development on a site. Under natural, pre-Columbian conditions, there would not likely be runoff until a point near to the rainfall accumulation from the 95th percentile event. Therefore the LEED credit acts as a proxy for restoring stormwater conditions to an undeveloped state. Achieving the 98th percentile LEED credit would improve the protection of Crum Woods and Crum Creek. SITES credits require similar treatment. The intent of SITES Rainwater Management Credit 3.3 is “Maintain site water balance, protect water quality, and reduce negative impacts to aquatic ecosystems, channel morphology, and dry weather base flow by replicating natural hydrologic conditions and providing retention and treatment for precipitation on site.” A sliding credit scale is provided and maximum points can be achieved through the following: “Retain or treat the maximum precipitation volume on site for the percentile precipitation event associated with the desired point total...” The credit scale ranges from 4 points for managing the 80th percentile event and 6 points for managing the 95th percentile event. Compared to compliance with Borough requirements, achieving LEED /SITES credits have significant benefits. The following table compares the benefits of Borough compliance and LEED/ SITES credit achievement. Percentile Storm Event (%) Rainfall Depth (in) 90 1.25 95 1.66 98 2.25 FIGURE 3.11: BMP BENEFITS Aspect Borough Compliance LEED/SITES Remark Land Area Change in impervious cover only Entire project boundary LEED/SITES increases scope to include previously-disturbed areas Effect Mitigates change from current condition Restores water balance to emulate natural, Pre-Columbian state Borough requirements regulate current land cover change only Ecosystem Services Protects from downstream erosion and flooding, due to proposed changes Restores groundwater recharge, evapotranspiration, and reduces runoff from entire site to Pre-Columbian levels Ecosystem services restoration is a main focus of LEED/SITES credit. Applying LEED/Sites Criteria would enable on- campus development to mitigate past damage on the Crum Woods slopes and to Crum Creek Effects of Previous Development Does not address Restores incremental stormwater effects of historically uncontrolled development. Including previous development in stormwater management design would help compensate for past deleterious effects. 3 Stormwater Management Analysis WATER QUALITY VOLUME CONTROL (UP TO 95%) PEAK RATE TABLE 3.6: RAINFALL DEPTHS TABLE 3.7: BOROUGH VS LEED VS SITES COMPARISON filter units porous pavementgreenroof water receiving landscapes detention water harvesting EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  15. 15. 15 WS-6 WS-4 WS-7 WS-3A WS-2 WS-1A WS-10 WS-8B WS-9 WS-3B WS-8C WS-8A WS-5 WS-1B WS-11 1A 1B 3B 4 3A 8A 8B 8C 6 7 5A 5B 10 11 9 2 LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED Expand Stormwater Management with Wetland Expansion Install Permanent Stormwater Basin to Manage Flow Under Railroad Install Permanent Stormwater Basin to Manage Flow Under Railroad Stabilize and Restore Outfall Swales Install Permanent Stormwater Management Basin to DuPont Lot Improve Permanent Outfall at DuPont Lot Cleaning of Chester Road Drain campus discharge point 3.11 Goals for Development Projects and Campus-Wide Mitigation The stormwater impact of development projects can be mitigated through compliance with the rigorous and restorative LEED Rainwater Credits. It is recommended that the College pursue the 98th percentile event credit level, an analysis of BMP sizing and costs. Depending on budgetary constraints, the College may waive compliance with the 98th percentile requirement and allow for a smaller storm event. A three-tiered approach would allow the College to determine the value of stormwater improvements based on a variety of criteria, including budget, restoration of ecosystem services, and reduction of downstream impacts. The following table lists the goals for development projects in order of preference by the College. In all cases, projects will have to also comply with the Borough’s stormwater criteria. Tier 1 (Preferred) 98th Percentile event Tier 2 95th Percentile event Tier 3 Borough requirements 3 Stormwater Management Analysis FIGURE 3.12: RECOMMENDED CAMPUS-WIDE STORMWATER IMPROVEMENTS PROPOSED PARKING/PAVING WATERSHED BOUNDARY EXISTING BUILDING PROPOSED BUILDING CONSTRUCTED / APPROVED FOR CONSTRUCTION POINT OF INTEREST*/ STORMWATER FEATURE WS-7 WS-3A WS-8B WS-3B WS-8C WS-8A 3B 3A 8A 8B 8C REEK D EK D X SUBWATERSHED PROJECT WS-1 Install permanent outfall from DuPont parking lot Install permanent stormwater management basin to control peak rate, volume and water quality WS-2 Stabilize and restore outfall WS-3A Install permanent stormwater management basin to control peak rate, volume and water quality to discharge point under the railroad Work with Swarthmore Borough and PennDOT to ensure that storm sewer inlets in Chester Road north of the railroad are cleaned and maintained regularly, because a significant portion of the campus relies on this downstream storm sewer system for conveyance WS-4 Stabilize and restore outfall WS-6 Install permanent stormwater management basin to control peak rate, volume and water quality to discharge point under the railroad WS-8 Expand storage volume adjacent to wetland area to manage stormwater discharge at railroad TABLE 3.8: EVENT PERCENTILE LEVELS TABLE 3.9: POTENTIAL CAMPUS-WIDE STORMWATER MANAGEMENT PROJECTS (SEE FIGURE 3.12) In addition to development projects arising out of the Master Plan buildout, the College should assess current stormwater conditions and evaluate the need for standalone watershed mitigation projects. These projects include outfall stabilization and repairs, and/or increasing stormwater conveyance piping on campus. Potential project costs should be estimated subsequent to this report and adequate funds should be set aside as part of the College’s commitment to sustainability projects campus-wide, independent of specific building projects. * Point of Interest (POI) refers to the point at which water within a subwatershed is assumed to flow. It is used to allow a single analysis point for stormwater modeling. POI’s have been selected to correspond with drainage features on campus EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  16. 16. 16 WS-6 WS-4 WS-7 WS-3A WS-2 WS-1A WS-10 WS-8B WS-9 WS-3B WS-8C WS-8A WS-5 WS-1B WS-11 1A 1B 3B 4 3A 8A 8B 8C 6 7 5A 5B 10 11 9 2 LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED SD SI SA VR OL OL BR RH IB HS PP SD DI OL SI BR PP SI BR HS VR BR RH HS SI SD SA OL BR SI OLBR OLVR BR RH PP SIIB RH SI OLBR IB OLVR BR RH PP SIIB VR BR RH HS SI RH VR BR RH HSPP SI VR X OL OL HS SD DI SI OL FIGURE 3.13: RECOMMENDED BMPS BY SUB-WATERSHED 3 Stormwater Management Analysis 3.12 Project-Specific Best Management Practices Given the following selection criteria, Figure 3.13 shows recommendations for selection of Best Management Practices within each sub-watershed area. Specific design criteria such as sizing of systems and suitability of soils must be assessed at the time of the design for each project, so the following should be considered preliminary guidance only. 3.13 Guide to BMP Selection Soil Amendment: This BMP is proposed where existing soil conditions are anticipated to be compacted and/or poorly drained (such as WS- 8). Soil amendment through tilling can alleviate compaction, and addition of compost material can improve organic content and support enhanced vegetative growth. In conjunction with a bioretention basin BMP, soil amendment can increase the volume of stormwater and nutrients/pollutants retained by the stormwater facility. Vegetated Roof: This BMP is recommended for watersheds that are anticipated to have flat-roof buildings or building expansions constructed in the future. Retrofits to convert existing standard roofs to vegetated roofs may be possible as determined on a case-by-case basis, and should be considered for watersheds that have existing flat roof buildings. The feasibility of vegetated roof retrofitting should include a structural analysis to verify that the intended buildings have adequate structural strength. The most common type is the extensive vegetated roof, which has a soil mantle of 2-4” thereby minimizing additional structural loading for the roof. Organic Lawn Management: This BMP is recommended for watersheds with significant areas of maintained grass turf. Maintenance of grass areas without the use of fertilizer can greatly reduce runoff pollutant/nutrient loads without the use of a structural BMP. Rainwater Harvesting: This BMP is recommended for watersheds that are to have new or significant building expansions constructed in the future. The rainwater harvesting systems are anticipated to utilize roof runoff due to the reduced level of filtration that is required and the ease of collection since cisterns could easily be connected to downspouts. This technique should have the collection point in close proximity to the point of use of the harvested water. Bioretention: This BMP is recommended for watersheds with relatively significant areas of impervious coverage and where adequate land area is available for surface stormwater BMPs. Bioretention basins, which provide significant water quality benefits, are also useful where soil conditions are not anticipated to be capable of supporting infiltration BMPs because plant evapotranspiration can provide volume reduction in lieu of infiltration. The “rain garden” version of bioretention is a smaller basin that is suitable for small drainage areas of approximately 0.25 acres. Infiltration Basin: This BMP is recommended for watersheds that have notable areas of grass turf that also have adequate land area available to support a surface infiltration basin. An infiltration basin is typically larger than a bioretention basin, but is planted with turf grass rather than wetland- type seed mixes. Infiltration basins can likely blend into existing maintained turf areas on campus more easily than bioretention basins. Hydrodynamic Separator: This BMP is recommended for watersheds that have a pipe outfall because the hydrodynamic separator can be inserted into the pipeline to remove pollutants prior to discharge to streams/surface waters. When located downstream of other BMPs, the hydrodynamic separator becomes a part of a “treatment train” that enhances water quality treatment. Hydrodynamic separators can also effectively deal with grease and oil, so they are especially useful downstream of vehicular parking and loading areas. Due to the cost of these BMPs, they are not recommended for watersheds that do not have a significant amount of paving and vehicle movement/parking, since those watersheds can be managed adequately and more cost effectively with other BMPs described above. WS-6 -4 WS-7 WS-3A S-1A WS-10 WS-8B WS-9 WS-3B WS-8C WS-8A WS-1B 3B 3A 8A 8B 8C 6 7 LITTLECRUMCREEK WATERSHED CRUMCREEK WATERSHED SI SA VR OL BR RH IB HS PP SD DI SD SA OL BR SI OLBR SI OLBR IB OLVR BR RH PP SIIB X SOIL ADMENDMENT VEGETATED ROOF ORGANIC LAWN BIORETENTION RAINWATER HARVESTING INFILTRATION BASIN HYDRODYNAMIC SEPARATOR PERVIOUS PAVEMENT SUBSURFACE INFILTRATION SUBSURFACE DETENTION DRAIN INLET WATER QUALITY INSERTS * Point of Interest (POI) refers to the point at which water within a subwatershed is assumed to flow. It is used to allow a single analysis point for stormwater modeling. POI’s have been selected to correspond with drainage features on campus PROPOSED PARKING/PAVING WATERSHED BOUNDARY EXISTING BUILDING PROPOSED BUILDING CONSTRUCTED / APPROVED FOR CONSTRUCTION POINT OF INTEREST*/ STORMWATER FEATURE EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  17. 17. 17 similar to a municipal stormwater ordinance but for internal use by the College, and - acknowledging the College’s desire to provide additional control of runoff peak rate, volume, and water quality - should establish a level of stormwater management that exceeds regulatory requirements. Any engineering consultant designing stormwater management features for the College would need to design BMPs that meet the requirements of the College’s policy. For the College’s Stormwater Management Policy, the following are suggested criteria that could be applied for new construction and major renovation projects: 1. Reduce runoff peak rates by an additional 5% beyond that required by Swarthmore Borough’s “Watershed Stormwater Management Ordinance.” 2. Reduce runoff volume by an additional amount by managing the 98th percentile event using low- impact development and green infrastructure. (per the LEED v4 Rainwater Management Credit). Each project shall prepare an analysis of cost/ benefit for the project, addressing the three tiered system presented above. For comparison, the cost of achieving Borough requirements alone shall also be presented. Costs shall be budget- level assessments, and values such as ecosystem services (recharge, volume reduction, water quality increase) shall be estimated. 3. Reduce areas that bypass stormwater management facilities (typically around the periphery of a project) to the maximum extent practical. The consultant should coordinate with the College to determine the maximum extent practical, since geographic and budget constraints will play a major role in determining this extent. 4. When designing stormwater BMPs, consultants should coordinate with College faculty and other stakeholders to determine whether the proposed stormwater BMPs could be utilized as teaching/ learning projects that enhance the College’s goal of academic excellence. 3 Stormwater Management Analysis Pervious Pavement: This BMP is recommended for watersheds that are to have relatively large expanses of paved surfaces at relatively flat grades. Additionally, some existing paved surfaces (such as the Benjamin West parking lot in WS-3A) could be suitable for conversion to pervious pavement from standard pavement. Subsurface Infiltration Bed: This BMP is recommended for watersheds where soil conditions are expected to yield usable infiltration rates, and where competing interests make underground location of a BMP desirable so that land area can be used for multiple purposes. Subsurface infiltration beds can be combined with pervious pavement BMPs to reduce the storm sewer infrastructure required to deliver stormwater to the infiltration bed. Subsurface Detention: This BMP is recommended for watersheds where soils are not anticipated to be conducive to infiltration, where buildings with basements are clustered closely together, and where competing interests make underground location of a BMP desirable so that land area can be used for multiple purposes. Subsurface detention beds can be combined with pervious pavement BMPs to reduce the storm sewer infrastructure required to deliver stormwater to the detention bed. Drainage Inlet Water Quality Inserts: This BMP is recommended for watersheds with existing storm sewer conveyance systems but that do not have adequate space for installation of basin or infiltration bed type BMPs. Water quality inserts can capture a great deal of sediment and debris without the need for earth disturbance that is associated with a larger BMP such as a subsurface infiltration bed. In watersheds where other BMPs are proposed, water quality inserts are less relevant since the other BMPs will provide sediment and debris removal. 3.14 Swarthmore College Stormwater Management Policy In order to further the College’s goals of environmental stewardship and improving stormwater conditions on campus so that they are closer to the Pre-Columbian condition, the College should establish a Swarthmore College Stormwater Management Policy. This document would be EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  18. 18. 18 4 Carbon and Energy Analysis The College is committed to achieving carbon neutrality by 2035, approximately 20 years from the date of this report. As defined by the Greenhouse Gas (GHG) Protocol, this involves the reduction of GHG emissions in three categories: -- Scope 1: Direct GHG emissions that are under control of The College. These are the result of consuming fossil fuels for heating and cooling, and Swarthmore owned vehicles. -- Scope 2: Indirect GHG emissions that are the result of purchased electricity. -- Scope 3: Indirect GHG emissions not covered by Scope 1 and Scope 2 – primarily non-college- owned transport related emissions. The purpose of this plan is to evaluate scenarios for achieving the reduction of Scope 1 and 2 GHG emissions for the 61 existing buildings and future planned buildings; for the purposes of this report these are termed “campus emissions.” This analysis takes into account the Campus Master Plan which includes approximately 400,000 sf of new buildings and additions by 2035. The focus is on emissions associated with building energy use which includes on- and off-campus buildings owned by the College. It excludes faculty housing and emissions associated with college owned vehicles. The appendices has a complete listing of all buildings included in this study and their associated building type designation. 4.1 Definition of Net Zero Carbon Emissions As shown in Figure 4.1, the refined definition of net-zero carbon is the elimination of all direct on-site and indirect off-site (source) emissions in the production of heat or electricity for campus buildings. Achieving this goal will require the eventual elimination of the central steam plant which burns fossil fuels (natural gas and #2 fuel oil) and the elimination of all other fossil-fuel burning heating equipment in individual campus buildings. Where fossil fuel use cannot be eliminated, carbon offsets from a third party will need to be purchased. Meeting the College’s goal will further require that all electricity either be derived from on-site renewable sources, regional renewable sources, or renewable sources from outside the region. 4.2 Methodology The first step in understanding the energy and carbon emissions on campus includes an in-depth review of the central plant, utility data and building metering information. The existing metered data consists of the following: -- Electrical usage metered by campus and by building. -- Electrical usage and natural gas usage at central chiller plant -- Natural gas usage at steam plant and at some buildings with metered gas service -- Oil usage at steam plant To understand the total campus energy usage, 17 existing buildings were identified as the largest energy consumers and representative of 6 major building typologies at The College. Each of the 17 building’s key characteristics were assessed, including exterior envelope, mechanical systems, patterns of use, age/condition of all components. Combining this assessment with the metered data, energy use was apportioned to each of the 61 buildings by utility source – electricity, steam, natural gas, chilled water based on their associated program type. The individual building assessments for the 17 buildings can be found in the appendices. The assessment outlines the current energy use and the energy conservation measures (ECMs) which can be applied to each building to reduce total energy and carbon. The findings from the ECM analysis of the 17 major buildings were extrapolated to all 61 buildings in the study. Future construction projects included in the 2013 Master Plan are targeted to be highly energy efficient and have net zero carbon emissions. The study uses six program types to categorize the buildings on campus: 1. Academic – includes classroom and other non- science academic space 2. Athletics 3. Library 4. Residence – primarily residence halls 5. Science 6. Student Life The six program types were chosen for this study because they represent six distinct patterns of energy utilization. For instance, science buildings are considered separate from classrooms and offices because of their relatively high energy use intensities and unique programmatic requirements. Similarly, athletic facilities are considered different from student center buildings because of differences in energy use intensity and occupancy schedules. While the existing buildings at the College all differ architecturally and in age, each can be classified as one of these six program types. This system of classification enables the use of a representative model of campus energy use to assess the effectiveness of various ECMs in terms of campus carbon emissions. While upgrading existing buildings is the first step in reducing campus GHG emissions, achieving net-zero carbon and eliminating fossil fuel use will require modifications to how heating and cooling is provided from the central plant. Three central plant scenarios were assessed: trigeneration, decentralized heating with condensing boilers, and ground source heat pumps. The potential of renewable energy, primarily with on-site photovoltaic power, was also assessed. It is a challenge to grow the campus while reducing carbon emissions. The building ECMs, central plant scenarios and future campus growth are evaluated in combination over the next twenty years to understand the incremental and total carbon emission reduction achievable by 2035. With the addition of 400,000 square feet, a combination of ECMs, central plant upgrades and renewable energy will be needed to significantly reduce carbon emissions below current levels. 4.3 New Construction & Additions The College plans to build roughly 400,000 square feet of additional space to the campus by 2035, representing a 24% increase over the amount of space existing in 2014. A list of anticipated projects can be found in the appendices. To minimize anticipated increases in overall campus carbon emissions, all new facilities should be designed according to the following aggressive performance standards: -- Achieve 50% reduction in energy use over ASHRAE Standard 90.1-2010 -- Target net-zero carbon, all electric buildings to eliminate burning fossil fuel -- Prioritize ground source heat pumps, when feasible -- Incorporate on-site renewable energy where possible The Sustainable Building Guidelines section of this report outlines these goals in more detail. FIGURE 4.1: NET-ZERO CARBON DIAGRAM Key Findings -- With anticipated building projects, the campus building CO2 emissions are anticipated to increase by 28% -- Taking into account new built area, up to 40% CO2 savings can be achieved over the Business as Usual 2035 CO2 levels -- Reducing energy usage in existing buildings by 32%, carbon by 40% will require a significant investment in Energy Conservation Measures (ECMs) such as LED lighting/control enhancements, building envelope improvements and replacement of older inefficient HVAC systems. -- A 60% reduction in fossil fuel CO2 emissions can be achieved with the Best Case Scenario C. EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  19. 19. 19 4.4 Existing Buildings The College has made considerable progress towards its goal of achieving net zero by 2035. Annual campus GHG emissions have been reduced from a peak in 2005 of approximately 16,000 metric tons of carbon to approximately 12,000 metric tons based on 2013/2014 data (Figure 4.2). This has been accomplished by the following key steps: -- Installation of electric meters at all campus buildings. -- Conversion of the central steam plant from natural gas/#6 fuel oil to natural gas /#2 fuel oil -- Energy use reductions at all buildings through numerous measures including installation of more efficient lighting, reduction in steam plant distribution losses, especially in summer, and aggressive scheduling of heating, cooling and ventilating systems for all campus spaces so systems are turned off or turned down when spaces are not in use. -- Buying renewable energy credits – at minimal or no cost premium. For 2013/2014 this represented a reduction of approximately 6,500 metric tons of annual GHG emissions. LIBRARYATHLETICSSCIENCESTUDENT LIFEACADEMICRESIDENCE ELECTRICAL STEAM CHILLED WATER NATURAL GAS 100,000 BTU/GSF/YR 150,000 BTU/GSF/YR 0 500 1000 1500 2000 2500 3000 LIBRARYATHLETICSSCIENCESTUDENT LIFEACADEMICRESIDENCE 1,500 MT 1,000 MT 2,000 MT 2,500 MT 4 Carbon and Energy Analysis While total campus energy consumption has been tracked and analyzed for some time, a comprehensive breakdown of energy use at the building level was required for this study. A building level analysis is crucial in determining how energy is currently used and which energy efficiency measures can be applied to specific building types to achieve carbon savings. This report analyzed data from 61 buildings and classified each building into one of six categories. Building energy consumption tables were based on data from: -- Electric sub-meters -- Gas meters -- Plant steam output based on boiler efficiency and gas consumption -- Building peak chilled water and steam loads -- Chilled water plant electric consumption and equipment efficiencies -- Building HVAC equipment, occupancy, and programs Sub-meters for chilled water and steam are not in place, so energy use profiles were built based on HVAC equipment, occupancy, program, and peak load information, and then normalized for consistency with overall campus energy consumption. The existing energy and carbon performance for the six major program types is shown in the graphs below. Figure 4.3 shows the average Energy Use Index (EUI) for each building type, which is a measure of energy use per square foot of building floor area, ranging from a high of 156,000 btu/ sf/yr for science buildings to a low of 69,000 btu/ sf/yr for residence halls with an average over all buildings of 89,000 btu/sf/yr. Annual carbon emissions are shown for each building type in Figure 4.4. Emissions are highest for academic buildings with science buildings a close second even though science buildings represent one half the floor area on campus. As seen in the graph of individual building carbon emissions in the appendices, the intensity of emissions for the existing Science Center stands out. The building produces more carbon per square foot than any other building on campus. One strategy to minimize energy consumption and associated carbon emissions is to greatly reduce the requirements for power, heating and cooling at campus buildings by converting to heating and cooling without burning fossil fuels, and to generate some portion of the electric power on-site or regionally. The following section of the report looks at existing building Energy Conservation Measures (ECMs) to identify the most effective building measures to pursue in reducing the campus carbon emissions. FIGURE 4.2: SWARTHMORE CLIMATE ACTION PLAN SCOPE 1&2 EMISSIONS FIGURE 4.3: ENERGY USE INDEX (EUI) BY BUILDING TYPE FIGURE 4.4: ANNUAL CARBON PRODUCTION (METRIC TONS CO2) EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  20. 20. 20 4 Carbon and Energy Analysis The first step in reducing campus carbon emissions is to improve individual existing building operation and efficiencies. Based on the 17 building assessments, six energy conservation measures were identified: envelope upgrades, lighting improvements, retro-commissioning, HVAC modifications, HVAC retrofits, and equipment improvements. A summary of the potential carbon reduction for each of these measures can be found in Figure 4.5. 4.4.1 ENVELOPE UPGRADES Increasing the assembly R-value of opaque walls, replacing windows with insulated glazing units (IGUs) with low-e coatings, and improving air-tightness will improve energy performance. Improved thermal resistance and air-tightness will prevent heat loss during the winter, reducing the building’s heating demand. This Framework includes a detailed analysis of building envelope upgrades along with recommended performance values for existing buildings. See the Energy section of the Sustainable Building Guidelines for specific technical values, such as insulation and glazing performance values. Full envelope upgrades are challenging as isolated energy conservation measures, but should be a part of major renovations and deep energy retrofits. Coupled with steam heating plant efficiency, envelope improvements have the potential to reduce the College’s annual carbon equivalent emissions by roughly 4%. However, envelope upgrades may not be feasible for all buildings and are typically more expensive than other efficiency measures. Before considering envelope upgrades, the College should perform a cost-benefit analysis to weigh the potential energy and carbon savings against the cost of implementation. Certain types of envelope upgrades may be cost prohibitive – especially for program types where conductive heat loss is a relatively small fraction of total energy consumption, such as laboratories. 4.4.2 LIGHTING IMPROVEMENTS The College has already performed a number of lighting retrofits on campus – replacing incandescent lighting with more efficient fixtures and advanced lighting controls. This type of upgrade is appropriate for all program types, but will make the most impact on building types with high electric lighting loads, such as residence halls. The college should seek to replace incandescent lighting with LEDs and incorporate occupancy and vacancy sensors as part of the lighting control strategy. Daylight dimming control for perimeter spaces is also a valuable energy efficiency strategy, along with separate controls for audio visual lighting in classrooms and auditoriums. If all buildings at the College in need of lighting upgrades were updated, the campus carbon campus carbon emissions would be reduced by almost 4%, assuming the current central plant configuration. Although lighting retrofits are commonly assumed to be cost effective, the College should perform a cost benefit analysis to determine the payback period for these types of upgrades. Furthermore, the savings to investment ratio is likely to be greater in the future, as the price of solid state lighting (LEDs) continues to fall. 4.4.3 RETRO-COMMISSIONING Retro-commissioning is typically one of the most cost-effective energy conservation measures. The savings derived from improving existing system performance often offsets the cost of the retro- commissioning process. By identifying opportunities for efficiency improvements and making adjustments to building operations, the College can reduce campus carbon emissions by roughly 5%. The recommendations for retro-commissioning include strategies such as changing fan speeds and reprogramming air handling schedules. For this study, larger HVAC modifications, such as boiler replacements, are included in the HVAC Modifications ECM. The College already has an incredibly hands-on and proactive facilities staff. In this spirit, retro-commissionig can further support these best practices by systematically reviewing and adjusting mechanical, electrical, and operational performance. 4.4.4 HVAC MODIFICATIONS HVAC modifications are component replacement opportunities, not system-wide replacements. Modifications explored in the energy studies in this report for existing HVAC systems on campus include chiller and boiler replacements, solar thermal systems for domestic hot water, and improved system controls, among others. These efficiency measures are more modest in scope than full HVAC retrofits, but have significant associated energy and carbon savings. The carbon abatement potential for HVAC retrofits is roughly 8%, given the current central plant configuration. Many of these efficiency measures, such as chiller and boiler replacements, have relatively quick payback periods (less than 10 years) and should be implemented immediately. Furthermore, the costs of such improvements are often partially covered by incentives from the state or from the utility provider, PECO Energy. 4.4.5 HVAC RETROFITS HVAC Retrofits are wholesale renovations of a given building’s heating, ventilation, and cooling system. Examples of such upgrades include replacing all-air systems with hydronic systems connected to ground source heat pumps, or replacing constant volume units with variable air volume systems connected to energy recovery units. HVAC Retrofits have the potential to reduce the College’s annual carbon emissions by roughly 18%. However, these energy efficiency measures may require significant changes to a building’s internal layout. Changes to the heating and cooling distribution systems, in particular, may require some degree of interior demolition. Therefore, full HVAC retrofits are rarely implemented in isolation, and should be considered part of major renovations alongside envelope upgrades, lighting improvements, and equipment upgrades. Supplementary funding may also be available to support the hard and soft costs associated with replacing HVAC systems as described in the Implementation section of this report. 4.4.6 EQUIPMENT IMPROVEMENTS Carbon savings attributed to equipment improvements are difficult to estimate, but amount to roughly 2% of total campus carbon emissions. Equipment improvements include measures such as receptacle switching and Energy Star appliances. Although the energy and carbon savings are relatively modest, equipment upgrades are typically inexpensive and considered best practice. Purchasing Energy Star equipment can ensure the ability to incorporate energy meters and connect to building management systems. 0 2000 4000 6000 8000 10000 12000 14000 CURRENT ENVELOPE UPGRADES LIGHTING IMPROVEMENTS RETRO COMMISSIONING HVAC MODIFICATIONS HVAC RETROFITS EQUIPMENT IMPROVEMENTS CO2EMISSIONS(MT) BUILDING LEVEL ENERGY EFFICIENCY MEASURES CO2 EMISSIONS REDUCTIONS 7318 SWARTHMORE MASTERPLAN SAVINGS CURRENT 1.7%4.2% 3.5% 4.7% 8.2% 18.7% 35.8% CUMULATIVE REDUCTIONS FIGURE 4.5: CO2 EMISSIONS REDUCTIONS EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION
  21. 21. 21 4 Carbon and Energy Analysis 4.5 Central Plant Configurations Efficiently generating heating and cooling is critical in reducing campus carbon emissions. Three central plant scenarios were compared to the performance of the current plant configuration. The current central plant includes a chilled water plant and steam boilers that provide chilled water and steam heat to most buildings on campus. While the current equipment has relatively good efficiencies, alternative strategies could be implemented to further reduce carbon emissions. But critically, the steam distribution system has significant leakage contributing to energy losses. The three scenarios analyzed are: a trigeneration system, replacing the central steam plant and steam use on campus with decentralized condensing boilers and ground source heat pumps. While a trigeneration system or decentralized heating can provide reduced carbon emissions, ground source heat pumps are the only option that could completely eliminate natural gas use and achieve net-zero carbon with an all electric system using renewable energy generated on-site and/or purchased from the grid. 4.5.1 CURRENT CENTRAL PLANT The current campus central plant consists of an electric chiller (4.4 COP), a gas chiller (1.6 COP) and a steam boiler (75% thermal efficiency). The electric chiller provides about 80% of the overall chilled water and the gas chiller provides the remainder. In addition to this equipment, building-level direct exchange (DX) units (2.5 COP) for cooling have also been accounted for in this study. The steam distribution network losses are assumed to be at 18%. For the 61 buildings assessed, the overall campus CO2 emissions stand at 12,000 metric tons (MT CO2 ). Implementing building level energy efficiency measures without upgrading the central plant will reduce the overall carbon emissions to 7,700 MT CO2 which translates to a 35.8% savings [Figure 4.8]. 4.5.2 TRIGENERATION SYSTEM A trigeneration system uses steam turbines to produce electricity and steam. The electricity is supplied directly to the campus and electric chillers. Electricity will still need to be imported from the grid to meet the campus electrical demands throughout the year. Steam is used for heating and steam chiller power. The trigeneration system configuration appropriate for the College is based on the assumption that the system will track thermal loads during the summer and electrical loads in the winter. Based on this assumption and the electrical peak loads during summers and winters, a 2 MW trigeneration system consisting of two micro-gas turbines at 1MW capacity each is sized to meet the entire wintertime electricity consumption and half of summertime electrical consumption; this avoids steam waste. Averaged over the entire year, this translates to the trigeneration system meeting 70% of the overall electrical requirement. Additionally, an absorption chiller (1.6 COP) is used in the summer to created chilled water. The analysis shows that by decommissioning the existing central plant and building DX units, this new central plant configuration, without implementing any building-level energy efficiency measures, will help reduce the CO2 emissions to 10,625 MT (11.4% savings). After implementing the building level efficiency measures, this central plant configuration will reduce the overall CO2 emissions to 7,425 MT CO2 or 38.1% savings over the current emissions level. STEAM BOILERS POWER TO SITE NATURAL GAS TO SITE GRID SUPPLY ELECTRIC CHILLERS NATURAL GAS STEAM CHILLED WATER ELECTRICITY NATURAL GAS ABSORPTION CHILLERS TRIGEN SYSTEM STEAM BOILERS POWER TO SITE NATURAL GAS TO SITE GRID SUPPLY ELECTRIC CHILLERS NATURAL GAS STEAM NATURAL GAS CHILLED WATER ELECTRICITY GAS CHILLERS POWER TO SITE GRID SUPPLY ELECTRIC CHILLERS HEATING HOT WATER CHILLED WATER ELECTRICITY CONDENSING BOILERS POWER TO SITE NATURAL GAS TO SITE GRID SUPPLY ELECTRIC CHILLERS NATURAL GAS CHILLED WATER ELECTRICITY GAS CHILLERS CENTRAL PLANT CENTRAL PLANT CENTRAL PLANT CENTRAL PLANT CURRENT CENTRAL PLANT TRIGENERATION DECENTRALIZED HEATING WITH CONDENSING BOILERS GROUND SOURCE HEAT PUMPS FIGURE 4.6: CENTRAL PLANT SCHEMATIC DIAGRAMS EXECUTIVE SUMMARY INTRODUCTION IMPLEMENTATION RECOMMENDATIONS STORMWATER MANAGEMENT SUSTAINABLE BLDG GUIDELINES CARBON & ENERGY APPENDICESCONCLUSION

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