Designing for Resilient Ecosystems

Designing for Resilient Ecosystems DESIGN INVESTIGATIONS

every piece of the built environment is situated within an existing ecosystem

No building exists within a vacuum. Every piece of the built environment is situated within an existing ecosystem – a complex, interconnected web of flora and fauna accompanied by all the geological, hydrological, and atmospheric resources that support it. The building acts upon the site, and the site acts upon the building; a truly successful design achieves a harmony between the two in which the combined result is better than either component alone. In the words of Bill Reed, founder of Regenesis, “Your project is not the project.

The project is the system of life.“i Our ecosystems are under constant pressure from both natural processes and human activities. Natural forces have always played a part in shaping and reshaping our environment. These forces may be climatic (related to atmospheric changes), biotic (related to flora and fauna), and edaphic (related to soil composition). Severe weather, seasonal changes, droughts, or wildfires can all impact soil, air, and water systems and the living things that depend on them. Human factors include development, population growth, industrial agriculture, pollution, deforestation, overharvesting, and climate change.

Nature has a remarkable ability to adapt; however, we are testing the limits of the ecosystems around us and their ability to survive and thrive.

This survival capacity is bolstered by resilience – the ability to withstand, adapt to, and recover from the shocks or stressors driving change. Resilient ecosystems embody the concept of autopoiesis, or the tendency of an organism or system to self-generate or self-perpetuate. Examples include cells created within the human body to maintain health, barrier islands which shift and replenish after a hurricane, and even diseases which can selfpropagate. Autopoiesis is the mechanism through which nature finds a way to continuously adapt to the conditions around it. This tendency is strong, but can be overcome by external forces.

Resilient Ecosystems & the Role of the Architect When we understand the interconnected elements that contribute to resilient ecosystems, we are better able to design in harmony with nature and allow for future adaptations. Architects and planners must first strive to work with all stakeholders and design entities to understand the complex ecosystems surrounding our sites, and then to keep ecosystem resilience front of mind as we reimagine the relationship of structures and ecosystems. A deep understanding of “place” is critical; we can analyze the natural processes, past historical events, and future potential acting on a site, and then investigate optimal strategies to allow these processes to flourish. We can actively integrate elements that encourage biodiversity, and we can choose to prevent activities that will cause harm.

Architects and planners can work simultaneously from two directions – designing to reduce the impacts of the built environment on a site, and designing to restore and rehabilitate a site through beneficial interventions. In the context of resilient ecosystems, both approaches are critical.

We can actively integrate elements that encourage biodiversity, and we can choose to prevent activities that will cause harm.

Designing to Minimize Harm & Provide Maximum Benefits Decisions made during the earliest stages of design can have profound impacts on the site and surrounding ecosystems. From initial project conversations through building occupancy, holistic strategies to reduce site impacts and support ecosystem health will yield intensive resilient strategies.

Site Design Site selection is a critical first step in minimizing harm. Before committing to a site, teams should conduct a thorough analysis of current and potential future conditions, being mindful of future climate projections. Sites which are well above flood zones today may be prone to high waters in a decade due to the impacts of climate change. Where possible, clients may wish to reclaim and rehabilitate an existing site in order to avoid greenfield construction; adaptive reuse or urban infill both provide opportunities to make use of existing construction footprints. Where a greenfield site is the best alternative, buildings should be sited to avoid sensitive areas such as wetlands and wildlife corridors and minimize site disturbance.

At the city or campus scales, smart growth involves planning for strategic development and targeted density. Planning around multimodal transit and connecting with bike and pedestrian greenways will promote walkability and reduce vehicle miles traveled (VMT) to the site. The idea of a “15 minute city” offers widespread popular appeal, and locating growth within easy reach of existing amenities will boost access and engagement.

Owner’s Project Requirements A discussion of the Owner’s Project Requirements (OPR) helps teams to establish project priorities early, and guides discussions of the values and vision for the project. Topics may include goals for energy and water conservation, ecological diversity, and operations plans as well as logistics such as communications and meeting cadence. Goals enshrined in the OPR serve as touchstones through the life of the project, and will inform all design decisions moving forward.

A resilient design begins with a thorough site analysis. A deep understanding of geology, topography, hydrology, wind patterns, microclimates, and biomes is foundational to working in concert with the land. Ideally these elements will inform not only the structure and systems in the design for durability and safety, but also the aesthetics and function.

A well-designed site will support healthy soil, cleaner air, and thriving habitats as well. Landscaping with native, droughttolerant plants; considering diverse microclimates, providing wildlife corridors, pollinator gardens, beehives, or edible landscapes; and eliminating pesticides in maintenance plans will all contribute to biodiversity and ecosystem health.

A site layout designed for walkability offers a host of benefits including better health and wellness for building users, less air pollution, and less noise. The design of the vehicular circulation should also be efficient for safety and access. Pervious pavement will reduce stormwater runoff and better accommodate existing site hydrology, and tree wells will help to shade parking lots and reduce heat islands.

A small, efficient building footprint which is located to minimize cut and fill will limit site disturbance and maximize green space.

Building on piers is another way to minimize site work (and is a common strategy in coastal areas to elevate structures above high water zones). The building location should also maintain green buffers and wildlife corridors through the site as appropriate.

Case Study Organizing Around a Vibrant Green Spine This neighborhood development plan protects and showcases the site’s natural amenities by wrapping the Main Street around the existing creek and riparian buffer.

The landscape becomes a central “green spine” that anchors the district, and natural amenities are woven into the plan throughout the site in the form of programmed play areas, natural landscapes, and multimodal pathways.

The vision for this reimagined district is to bring new uses, new opportunities, and new investment to a historic neighborhood that has traditionally been marginalized and under resourced. As it is implemented in phases, the district will become a mixed use anchor and destination for the entire city. The flood plain and creek offer unique challenges that are to be showcased rather than overlooked; pairing key program elements with unique nodes allows the design to harness the best aspects of the natural landscape.

Working with Water The interconnected network of terrestrial aquatic systems extends well beyond the boundaries of any site, and understanding and preserving a site’s natural hydrology is important to the health of the ecosystem as a whole. Freshwater ecology includes rivers, blueline streams, lakes, seasonal ponds, and groundwater/aquifers. Even if a body of water isn’t visible on the site, water that falls on it impacts the entire watershed.

Coastal hydrology, likewise, includes an array of salt water and brackish environments from wetlands to salt marshes which are vulnerable to disruption.

Any site development must respect these water systems and manage the impacts of construction and development, from the site selection process through building occupancy. Damage to waterways during the construction process, such as from site erosion or uncontrolled runoff, can be devastating to aquatic life downstream and can take years to remediate. Prevention is a more effective strategy for safeguarding waterway health.

Beyond the construction process, it is important for all involved to understand the water needs of a building or development before breaking ground. Do existing municipal or regional water systems have sufficient water capacity to support the requirements of the project? Will this capacity be sufficient in ten years, or twenty?

We must acknowledge the full impact of a project over time in order to make informed decisions about feasibility, as regions struggling with historic droughts are learning.

The site’s hydrology includes any stormwater that falls upon it, and that stormwater must be managed in terms of both quality and quantity. Low Impact Development (LID) strategies help to filter and retain stormwater on site, and green infrastructure that contributes to stormwater management can become an attractive amenity. The Whole Building Design Guideii details a variety of techniques, including: • Rain gardens (bioretention cells) • Bioswales • Permeable pavement • Tree box filters • Disconnected downspouts • Rain barrels/cisterns • Native landscaping • Soil amendments/aeration • Green Roofs • Pollution-preventive lawn care

Larger stormwater retention ponds are often integrated into the landscape design as well, but implementing the right balance of LID strategies may reduce or eliminate the need for a separate retention pond.

Coastal environments come with a unique set of stormwater management challenges such as flatter terrain and higher water tables. These conditions require additional insight and expertise from qualified site/civil engineers and landscape designers for optimal effectiveness. It is important to note, however, that successful stormwater management in coastal areas relies upon successful stormwater management across the watershed, as water falling inland impacts the quality and quantity of water far downstream.

In planning for best practices for stormwater management, designers and clients will need to be mindful of increasing storm impacts due to climate change. Warmer air holds more water, and rainfall totals in a given storm may far exceed historic averages. The full design team including site/civil engineers will need to plan accordingly for stormwater capacity, including accommodating stormwater from an unexpected “rain bomb” event. Designing for additional freeboard – the height above base flood level which acts as a safety factor – can provide leeway during a high water event.iii

Building-Level Strategies At the building level, strategies to minimize harm and support healthy ecosystems include designing with forms, scales, and materials that harmonize with the natural environment. Green space is critical to ecosystem health, so development should be limited to the most efficient footprint possible. Deliberately softening the boundaries between the indoors and outdoors with layers of landscaping and integrated spaces like patios, outdoor workspaces or classrooms, and vegetated roofs adds benefits for building occupants and ecosystems alike.

Healthy sites and ecosystems also support biophilic design strategies which strengthen connections between the built and natural environments. Many studies have quantified the positive impacts of these connections on stress reduction, cognitive performance, and mood for building users.iv Designing for views to nature and providing options for enticing and enjoyable outdoor experiences yields benefits for both ecosystems and people.

Low-Impact Lighting helps human and wildlife site occupants maintain a healthy circadian rhythm. Designers should work closely with lighting engineers to provide safe lighting at ground level while preserving dark sky areas to the greatest extent possible. Many animals (such as hatching sea turtles) rely on celestial navigation to move at night, and harsh artificial lighting can be disorienting.

Mechanical systems should be designed to minimize noise.

Engineers can recommend appropriately sized, high performance equipment and strategies to provide sound barriers and buffers

around mechanical systems to reduce disturbance to humans and wildlife. Additionally, engaging with a commissioning agent to test that the building systems meet project requirements will optimize project success. Early onset energy modeling strategies may also yield mechanical systems more appropriately sized to reduce disturbances.

Reducing heat islandsv on the site is an increasingly important strategy for a healthy ecosystem. Planting trees not only increases shade, but also produces evaporative cooling and adds to the beauty of the site. Strategic tree wells are particularly important in shading parking areas, where pavement can become dangerously hot. Pervious paving can also lower surface temperatures. Cool pavements to reflect solar energy, cool roofs, and biosolar/green roofs also assist in reducing heat gain on sites.

Bird-safe design is another important consideration. The National Audubon Society reports that up to one billion birds per year are killed by collisions with glass, most often during migration seasons.vi To help birds distinguish reflective surfaces from open flyways, the organization recommends installing patterns 2-4” apart on glass surfaces (such as through adhesive vinyl dots), external window screens, closing internal blinds or curtains, and placing bird feeders directly on windows. Internal plants near windows, glass corners, and landscaping close to reflective surfaces are all visually confusing to birds and therefore dangerous.

Case Study Designing to Celebrate Nature For this technology client, a steeply sloped and heavily forested 80-acre site offered an unparalleled opportunity to design with the land, not just on top of it. The campus is rooted in its natural environment with buildings that nestle in and cascade down the hillside.

The design of the vast site drew from the existing natural elements: three intermittent creeks, vegetation, trees, and rocks. Preserving trees was a key priority, but the site also provided plenty of opportunities to interact with the environment. A campus greenway with three “mobility hubs” encourages activity and provides a place for employees to recharge. Water elements throughout the site provide visual interest and calming interludes in the site circulation.

The campus design inverts the traditional corporate office paradigm, too often notable for a sense of “placeless space,” into a campus that grows from its environment.

Buildings and landscape work in harmony: the campus is inseparable from its site, and the site is woven through every design.

The campus includes outdoor workspaces with wireless access and charging stations on three large outdoor terraces, encouraging employees to connect with the environment and work outside as much as desired

Case Study Sitting Lightly on the Land This client challenged the design team to create a building which disturbed the forested site as little as possible. The site design preserves as many trees and natural features of the site as possible, maintaining shade to create welcoming outdoor paces and reduce the building’s heat load. The materials palette includes heavy timber and cypress siding to further integrate the building and site. Layered spaces such as shaded terraces, balconies, walkways, and decks further soften the boundaries between the interior and the landscape. Even the landscaping materials such as mulch pathways integrate with the natural site. The retention pond, a key component of the stormwater management strategy, has become a popular amenity with running trails and wildlife.

Carefully selected river rock at the base of the building catches rainwater from the roof, preventing erosion and serving as a primary filtration surface.

Designing for Efficient Use of Resources Within and beyond the site boundaries, preserving and supporting every ecosystem begins with low carbon, low energy designs. Getting to zero carbon as quickly as possible is essential for mitigating the most harmful effects of climate change. A recent McKinsey & Company study found that over 50% of a building’s lifetime carbon emissions occur during the construction stage.vii Strategies to reduce both embodied and operational carbon as well as energy use can yield substantial impacts over the life of the building. Note that achieving zero carbon energy use through a massive influx of solar panels and carbon intensive materials use strategies is counterproductive to environmental stewardship. A more integrated approach involves passive design strategies, a bio-climatic mindset, and a minimal overall square footage through efficient programming and a compact footprint. These strategies will greatly reduce energy needs from the onset of the project and allow for targeted use of right-sized onsite renewables to meet project energy needs.

Choosing adaptive reuse over new construction can significantly reduce the amount of carbon needed for a project by capturing the embodied carbon in the original structure. Adaptive reuse also reduces the need for new materials and reduces landfill waste. For all types of construction, designers can be thoughtful about minimizing waste through design, such as through careful attention to standard materials dimensions to reduce cut-offs. Prefabricated and modular construction also offer opportunities to minimize waste through offsite fabrication for construction optimization.

The ”cradle to gate” mindset for materials selection means considering the impacts of every step of the process, from extraction of raw materials to transport to demolition. Designers have a responsibility to understand and mitigate the carbon and energy impacts of every materials choice. Lower carbon options include recycled/recyclable materials, salvaged/refurbished elements, and building components which can be disassembled, adapted, or reinstalled at the end of a building’s useful lifespan.

Strategies for designing for deconstruction include detailing with mechanical fasteners instead of adhesives to avoid glued-together or welded components which can’t be separated ending up in a landfill, and defining interior spaces with flexible demountable partitions or furniture groupings instead of hard construction.

Structural systems designed for eventual disassembly may be reusable for other purposes at the end of a building’s lifespan, whereas cast in place concrete systems are not.

Sourcing materials with healthy ecosystems in mind also means minimizing harmful materials in the environment. Beyond impacts on air quality or human wellness when installed in their final location, materials impact the ecosystem across their lifecycle. Selecting the most appropriate materials requires research, transparency, and continuous discussions about project values. Many architecture firms (including LS3P) have signed the AIA Materials Pledge to specify building materials which support human health, equity, ecosystem and climate health, and a circular economy.viii

Case Study Adaptive Reuse Preserves Both Green Space & Embodied Carbon This adaptive reuse project in downtown Wilmington, NC repurposed a historic building for use as a modern office. Along with reclaiming an existing site and avoiding greenfield construction, the project preserved the building’s embodied carbon to minimize demolition and the need for new materials. Retaining the building’s original raw exposed brick and hardwood floors also added to the building’s design aesthetic, which celebrates the imperfections that gives character to the materials over time while blending with contemporary elements for contrast.

Compounding Benefits The benefits of designing for ecosystem resilience are manifold.

Healthier ecosystems are part of a thriving environment, but they are also important to human health and wellness. When we design with ecosystems in mind, we also reduce air, water, and noise pollution; mitigate the impacts of climate change; and create more beautiful places that contribute to tourism, engagement, local economies, and a stronger social fabric.

Investments in resilience also make economic sense: the National Institute of Building Sciences reports that, on average, every $1 spent on increasing resilience saves an average of $13 in disaster costs.ix Third-party rating systems may provide valuable guidance in designing for resilient ecosystems. The LEED building certification checklist for building design and construction includes detailed requirements for location, sustainable site development, and water efficiency, among others; the SITES certification process also focuses on site elements such as water, biodiversity, habitat, and connections to nature, GBI Guiding Principles addresses Climate Resilience, and both Green Globes and LEED support credits for design for disassembly. The AIA Framework for Design Excellence is another valuable resource for exploring opportunities to design for site and ecosystem resilience.

The imperative to design for ecosystem and site resilience may be viewed through many lenses. The human benefits include creating an environment for beauty, enjoyment, and wonder as

well as wellness and public safety. The environmental benefits include biodiversity, habitats, and a more stable climate, and the economic benefits include the potential for reduced operational and damage repair costs as well as higher property values and lease rates.

The return on investment for designing for resilient ecosystems – people, planet, and profits – has become increasingly clear. The Fifth National Climate Assessment in 2023 details the risks and opportunities the US faces in a rapidly changing climate.x Any viable path forward for navigating climate change will involve some combination of mitigation (reducing the emissions that cause climate change), adaptation (evolving to manage climate change) and resilience (the ability to recover from disruptive events). Widespread adoption of best practices for site design will yield compounding benefits, resulting in healthier environments for all.

Works Cited Reid, Bill, AIA, LEED AP. “Climate Adaptive Design Symposium Keynote: State of Architecture.” Lecture, Asheville, NC, November 3, 2023.

i.

Guillette, Anne. Updated November 3, 2016. “Low Impact Development Technologies.” https://www.wbdg.org/resources/low-impact-development-technologies.

ii.

iii.

FEMA. Updated July 8, 2020. “Freeboard.” https://www.fema.gov/glossary/freeboard .

iv.

Browning, William; Ryan, Catherine; and Clancy, Joseph. 2014. “14 Patterns of Biophilic Design: Improving Health and Well-Being in the Build Environment.” https://www. terrapinbrightgreen.com/reports/14-patterns/ .

v.

EPA. Updated July 10, 2023. “What You Can Do to Reduce Heat Islands.” https://www.epa. gov/heatislands/what-you-can-do-reduce-heat-islands.

Audubon. N.d. “Bird-Friendly Buildings.” Accessed August 7, 2023. https://www. audubon.org/bird-friendly-buildings .

vi.

Cutler, Zack; Dayton, Taylor; Grant, Matthew; Mahomed, Shu‘aim; and Ojetayo, Jemilat.

October 17, 2022. “Reducing Embodied Carbon in New Construction.“ https://www. mckinsey.com/capabilities/operations/our-insights/global-infrastructure-initiative/ voices/reducing-embodied-carbon-in-new-construction .

vii.

AIA. November 30, 2023. “Materials Pledge Starter Guide.” https://www.aia.org/ resource-center/materials-pledge-starter-guideMaterials-Pledge-Starter-Guide-2021.pdf (aia.org) .

viii.

ix.

National Institute of Building Sciences. 2020. “Mitigation Saves.” https://www.nibs.org/ files/pdfs/ms_v4_overview.pdf .

x.

US Global Climate Change Research Program. Revised December 2023. “The Fifth National Climate Assessment.” Fifth National Climate Assessment (globalchange.gov).