Our magnificent planet, with its expansive oceans, lush forests, and breathtaking natural wonders, faces monumental environmental challenges unlike anything in history. As civil engineers, we have an obligation and opportunity to help safeguard the health of our irreplaceable home. The infrastructure shaping our built environment profoundly impacts ecosystems, communities, and the climate. Through thoughtful design, we can construct a sustainable world.

How Our Infrastructure Choices Shape the Environment

The imprint of infrastructure spreads far beyond the project site. Transportation networks fragment habitat. Dams disrupt rivers. Buildings consume resources. Yet infrastructure also provides essential services like clean water that protect the public and environment. We must thoughtfully weigh tradeoffs to maximize benefits and minimize harm.

Poorly planned projects have led to unintended ecological consequences. Highways carved up landscapes, leaving wildlife disconnected and imperiled. Dams blocked ancient fish migrations, starving creatures downstream of life-giving nutrients. Inefficient buildings swallowed energy and spewed emissions.

But with care and creativity, infrastructure can improve environments rather than degrade them. Thoughtful design enhances rather than diminishes. Permeable pavements allow cleansing rainwater to soak into soil. Green roofs sprout oases amid concrete while controlling runoff. Bridges designed specifically for wildlife safeguard creatures crossing dangerously dense corridors. Solutions exist if we seek them.

Consider wetlands constructed to filter wastewater naturally before it rejoins rivers. Treatment plants have started generating their own clean power using methane digesters fueled by waste. Sensors monitor infrastructure performance, catching small issues before they become big disasters. Digital tools map sensitive habitats and model resilient designs.

With conscientious planning centered on long-term sustainability, infrastructure and environment can thrive together through symbiosis instead of struggle.

Examples of Harmful Practices

Urban sprawl enabled by highway expansions and new road infrastructure carves up open space and critical habitat. As cities keep spreading out further into surrounding countryside, forests and wetlands are fragmented or completely destroyed. Species that can’t adapt often decline or disappear from developed areas. For example, road mortality from traffic is a major threat for wildlife like deer, birds, turtles and amphibians.

Dams that block or severely reduce natural river flows have contributed to the decline of salmon and other migratory fish species in the western United States. Altered temperature and chemistry below dams can make waters unsuitable for native fish adapted to natural cycles. Interrupting the transport of tree logs and sediment disrupts habitats downstream that support spawning and other aquatic life. 

Buildings that aren’t energy efficient or conserve water end up consuming way more electricity, natural gas and water than they need to. Older structures built under less stringent building codes tend to be the biggest offenders. New buildings also add to resource demand, especially larger homes with low occupancy rates. Energy production and excessive water use takes a toll on the environment in many ways. 

When we design infrastructure without accounting for future climate change impacts, it ends up being vulnerable to rising sea levels, floods, storms and wildfires. For example, coastal roads that get repeatedly washed out by storms or buildings damaged by flooding from bigger rainstorms. Aging drainage and levee systems also lack the capacity to handle increased rainfall intensity. Proactively planning for climate adaptation would minimize these issues.

Examples of Sustainable Practices

Many cities are now using permeable pavements for roads, sidewalks and parking lots. These materials allow rainwater to soak through into the ground below instead of running off into storm drains. This recharges groundwater aquifers and reduces flooding and pollution in nearby streams. Fewer puddles also means less disruption from repairs. It does require more frequent maintenance like vacuum sweeping but overall it’s been very effective.

Green roofs have sprouted up on buildings around the world as an innovative solution that provides wildlife habitat and also helps absorb and filter rainfall. The layers of soil and vegetation act like a sponge, reducing runoff volume from heavy rains. Green roofs also insulate buildings, reducing energy use, and filter out air pollution. New York City has over a million square feet of green roofs including the famous roof garden at Rockefeller Center.

LEED certification has become the benchmark for sustainable construction practices. LEED (Leadership in Energy and Environmental Design) provides certification for buildings that meet stringent criteria for energy use, water conservation, toxics reduction and waste management. LEED certified buildings can use 25-50% less energy and water compared to conventional buildings. The number of certified projects grows each year though it’s still a small fraction of new construction. 

Civil engineers are finding ways to design bridges and other infrastructure to allow wildlife movement. Crossings under highways or overpasses at key locations provide safe transit paths for animals when habitat is fragmented. Specially designed culverts and tunnels maintain creek connectivity across barriers. Thoughtful design really makes a difference for protecting wildlife populations fragmented by roads and other barriers.

When planning major new infrastructure corridors like highways, proactively preserving habitat connectivity helps mitigate environmental damage. Identifying key wildlife crossings and narrowing right-of-way widths in sensitive areas lets more nature remain intact. Retrofitting existing corridors with crossings is also worthwhile but new construction provides the most flexibility for creative solutions.

These are just a few examples of forward-thinking solutions civil engineers have employed to reduce the environmental footprint of infrastructure. As you can see, small design changes can make a big difference. Now let’s dive deeper into how we can expand the implementation of sustainable practices.

How Civil Engineers Can Design Sustainably

Clearly, civil engineering profoundly shapes the built environment and impacts the natural environment all around us. So where should we be focusing our efforts to incorporate sustainability into infrastructure design? Here are some key areas where sustainable design practices can have a very positive influence.

Sustainable Transportation Infrastructure

Making roads, bridges, rail lines, ports and airports more sustainable represents a major opportunity for improving how infrastructure interacts with the environment. As we’ve touched on already, transportation enables urban sprawl and fragments habitat. But relatively simple design changes can mitigate these effects.

For roads and parking lots, using pervious paving materials is one of the most effective strategies as it allows rainwater to infiltrate the soil rather than running off as polluted stormwater. Concrete and asphalt can be designed to be pervious, as well as alternate materials like porous pavers, gravel, and reinforced grass. Permeable pavement also reduces flood risk in heavy rains and recharges groundwater.

Urban design that promotes livable density with compact, walkable neighborhoods minimizes sprawl into natural areas. Building robust public transit networks and safe infrastructure for biking and walking also reduces automobile dependence. Less need to keep expanding highways and the space dedicated to automobiles equals smaller transportation footprints.

Installing infrastructure for alternative transportation modes like bike lanes, sidewalks and trails promotes active lifestyles while reducing vehicle emissions. Prioritizing pedestrians and cyclists in how we design streets and communities makes these healthy, sustainable choices easy and accessible for more people.

Recycled materials like rubberized asphalt made from old tires can be used in place of standard paving mixes in many applications. This reduces landfill waste while creating a durable, long-lasting pavement. Steel with recycled content is now commonly used for guardrails, signs and other fixtures.

Wildlife crossings built at key locations along highways, railways and other corridors provide safe transit for animals over or under the infrastructure. This could look like an underpass tunnel, culvert or bridge span designed specifically for animal movement. Fencing helps guide animals into crossing areas that bridge habitat gaps created by infrastructure.

Sustainable Water Infrastructure

Next let’s explore how water systems could be designed and managed more sustainably. Stormwater, drinking water, and wastewater systems all have room for improvement in terms of environmental protection.

Integrating natural drainageways, wetlands and vegetation into community stormwater management provides low-cost filtration and cleaning of runoff. Bioswales, drainage channels with native plants that retain and filter runoff, are a great green infrastructure element that can be woven throughout sites. Rain gardens can also help absorb runoff from roofs and pavement into the ground.

Minimizing impervious surfaces across a development site keeps more area available for rainfall infiltration into the soil and groundwater. Using alternative permeable paving materials helps achieve this as does designing compact communities with less driveway and street pavement overall. 

Aging drinking water and wastewater pipes lose incredible volumes of treated water through leakage, wasting the energy required to pump and process this water. Prioritizing repair, maintenance and replacement of aging infrastructure reduces these losses over time. 

Treatment plants can utilize renewable energy systems like solar panels or methane generators using waste biosolids to reduce grid energy consumption. Many plants in California have installed large solar arrays to power operations during the day. This saves money while reducing greenhouse gas emissions.

Constructed wetlands use natural biological processes in shallow wetland “cells” to filter and clean wastewater before it’s released back into surface waters. This provides a low-energy, low-cost natural treatment alternative to mechanical filtration and chemical processes. Wetlands also create wildlife habitat.

Sustainable Buildings and Housing

Green building design and sustainable housing development provide many opportunities to reduce infrastructure’s environmental footprint. Especially with buildings, small design tweaks can really add up when applied across numerous structures.

Energy efficiency is a prime focus area. Insulating properly, sealing air leaks, specifying energy efficient systems like lights and HVAC and using Passive House design principles can dramatically reduce energy consumption. Solar panels and other on-site renewable energy generation helps buildings produce what they use.  

Specifying low-flow plumbing fixtures like faucets, toilets and showerheads reduces indoor and outdoor water use. Drought tolerant native landscaping and efficient irrigation cut back on outdoor water demand. Greywater reuse systems pump used household water into gardens instead of wasting it down the drain.

Sustainable building materials like recycled metal siding, plastic lumber made from milk jugs, low-VOC paints and finishes improve indoor air quality while reducing extraction of virgin resources. Reusing materials salvaged from demolition in new construction is another great way to minimize waste and resource consumption.

Construction waste management via recycling and reuse helps divert huge amounts of materials from landfills. Everything from concrete rubble to scrap metal and wood can be reclaimed rather than discarded. Deconstruction practices can salvage usable fixtures and other elements from old structures set for demolition.

Including features like green roofs, living walls, courtyard gardens, and other useful outdoor space creates habitat while also helping to absorb and filter rainfall close to where it falls. This reduces stormwater runoff and heat island effects in urban areas.

Adapting Infrastructure for Climate Resilience

As we touched on earlier, designing infrastructure today that fails to account for climate change leaves it highly vulnerable to sea level rise, flooding, fires and extreme weather down the road. We have to plan ahead to build resilience.

Conducting vulnerability assessments illuminates which infrastructure systems most urgently need adaptation to handle changing conditions. What roads, bridges or rail lines are prone to repetitive flooding in storms? What drainage canals no longer have capacity to prevent flooding from more intense rain events? 

Upgrading stormwater infrastructure by expanding pipe diameters, adding detention basins and improving road drainage provides increased capacity to adapt to heavier rainstorms. Maintaining protective natural areas like wetlands and floodplains instead of developing in high risk zones improves community resilience.

In fire prone areas, establishing defensible space buffers between vegetation and structures, constructing fire resistant buildings, and burying power lines underground help protect infrastructure assets from increasing wildfire frequency.

For critical infrastructure like electricity poles, bridges, roads, rail lines and pipelines, proactive retrofits and replacements can harden them to withstand exposure to harsher conditions brought on by climate change. Elevating bridges, armoring shorelines and riverbeds with erosion protection, and bracing drainage culverts can prevent failure.

In coastal areas facing sea level rise, relocating or abandoning infrastructure may emerge as the most pragmatic option in some cases. Retreating inland rather than fighting a losing battle against the tides allows new infrastructure to be built where it has a chance of surviving long term. 

Adapting infrastructure to cope with our changing climate is crucial for avoiding catastrophic failures that leave communities vulnerable. With foresight and preparation, we can maintain functioning systems capable of weathering coming environmental shifts.

Implementing Sustainable Practices

Clearly there are quite a few ways civil engineers can design infrastructure sustainably to lessen environmental impacts. But what needs to happen to transition these practices from occasional use as demonstration projects into broad mainstream adoption? Here are some of the most important elements needed to drive large scale implementation.

Policy Changes

Updating infrastructure codes, specifications and regulations at the federal, state and local level provides a structures framework to facilitate sustainable design. For example, requiring green stormwater infrastructure elements on new development sites or minimum energy standards for publicly funded buildings. Performance benchmarks for sustainability set mandatory expectations for new infrastructure.

Tax incentives can provide financial motivation to implement projects that exceed minimum requirements for sustainability metrics like energy efficiency, water conservation and greenhouse gas reduction. Rebates, grants and investment partnerships also help offset any incremental costs of enhanced design.

Requiring thorough environmental impact assessments for new infrastructure proposals helps fully evaluate potential harms and alternatives capable of preventing damage. This allows truly sustainable options to be identified rather than greenwashing after design is complete. Regulations with teeth are needed to reject unsustainable proposals.

Industry Collaboration

Partnering with ecologists, biologists, natural resource managers and other environmental science professionals brings essential ecosystem expertise to infrastructure planning. Asking “How would nature handle this?” is the perfect question when designing anything from a stormwater pond to a wildlife crossing.

Learning from related engineering fields with sustainability knowledge to share is also beneficial. For example, environmental engineers deal with water and wastewater treatment, air quality management and remediation of hazardous waste sites. Biomimicry studies natural design to spark sustainable solutions.

Attending sustainability focused engineering conferences, training seminars and continuing education keeps civil engineers at the forefront of rapidly evolving technology and design practices. Meeting colleagues and collaborators in person strengthens the community supporting this important work.  

New Technology

New digital tools provide detailed mapping and predictive analytics to enhance understanding of environmental constraints and guide design refinements. For example, LiDAR and drone data can map sensitive habitats, erosion prone slopes and other useful details across project sites. Climate modeling projects future impacts.

Stormwater modeling software helps design the right ponds, wetlands and drainage capacity into projects based on peak rainfall data. Hydraulic modeling ensures culverts, stream crossings and drainage channels won’t be overwhelmed by larger storm events. Software takes much of the guesswork out of designing for resilience.

New sustainable construction materials are constantly under development, like photovoltaic coatings that help buildings generate renewable energy through windows and siding. Self-healing concrete uses embedded fungi to automatically seal cracks and improve durability. Pavements engineered specifically for flood resilience resist washouts.

Sensor networks and digital monitoring systems give civil engineers enhanced ability to track infrastructure performance and catch issues immediately. For example, pressure gauges that detect leaks in water pipes or vibration sensors on bridges that identify developing cracks or scour damage before failure occurs. Having problems show up on screens instead of after disaster strikes allows rapid repairs that limit costs and environmental damage. Smart infrastructure is safer, more resilient and more efficient.

Conclusion 

I hope this gives you a good sense of the major ways civil engineering practices impact the natural environment around us, both for better and for worse. But it’s clear there are so many options for designing infrastructure sustainably that benefits ecosystems rather than degrading them. The technology and knowledge exists – we just need the initiative and creativity to put solutions into practice.

With transportation, buildings and water systems representing massive segments of the built environment civil engineers shape, seemingly small design decisions scale up tremendously. The choices we make ripple outward to touch forests, wetlands, rivers, air and communities far beyond project sites. An industry shift toward prioritizing sustainability and climate resilience in infrastructure design is absolutely critical for environmental protection.

Failing to account for natural systems when developing projects has led to enormous harm through unintended consequences – dams that collapse salmon runs, road networks that fragment habitat, buildings that waste energy and water. We can do so much better. Sustainable design considers environmental needs right from the start.

Updating policies, collaborating across disciplines and taking advantage of technology will speed adoption of sustainable practices and materials. But a passion for protecting the natural systems that sustain all life is the real key. With care, creativity and proactive planning, civil engineers have an immense opportunity to lead the way toward a healthier environment. Our infrastructure decisions shape the world future generations will inherit. Let’s build them a bright green future.