When It Comes to Green Infrastructure, Consider the Benefits
The World Economic Forum advises that greening global economic growth is the only way to satisfy the needs of today’s population and up to nine billion people by 2050. Jacobs Water Resources Engineer Jesse Williams shares his take on how a benefits-driven approach to implementing green infrastructure can achieve lasting outcomes for the future.
Picture it: a huge, vegetated roof on the Seattle waterfront aiming to reduce stormwater runoff and promote a thriving pollinator habitat. Recently, while reviewing project proposals from students of a local university, I questioned the students about why this would make a prime location for pollinator habitat. Where would the pollinators come from? What plants would be pollinated and what stormwater benefit would be realized?
As you might guess, they didn’t know. And that’s OK – it inspired a valuable conversation about when to implement green infrastructure, what benefits they wanted to achieve and how to ensure the particular best management practice (BMP) would achieve their goals.
The green movement
I’m a proponent of green infrastructure. I’m on the green side. Green infrastructure – or an approach to water management that protects, restores or mimics the natural water cycle – is gaining traction across the nation, with many young and impassioned practitioners joining the design community. Green solutions, for example, could mean planting trees and restoring wetlands to recreate natural processes, rather than building a costly new wastewater treatment plant or hardening the shoreline. Green infrastructure frequently has multiple advantages over traditional or gray infrastructure, sometimes even offering more benefit for less cost.
Public agencies across the country are adopting green infrastructure as their standard of practice, and I’m thankful to work on leading projects. And there have been many times during the last dozen or so years when I’ve had to challenge green infrastructure proposals that didn’t make sense, were not sensitive to the context, would not achieve the intended outcome, were not maintainable, or simply wouldn’t work as proposed. Most project proponents, particularly public agencies, have a low tolerance for failure, and we need to work together as a design community to avoid projects that don’t consider the surrounding community, don’t make good use of public funds, create a safety hazard or undue maintenance burden, don’t achieve the desired goal, or simply look bad.
We don’t have many chances to get it right. We need to reduce or eliminate the failures that may prevent the future consideration of legitimate green solutions.
Let the benefits drive the solution
After designing green stormwater infrastructure (GSI) – we used to call it low impact development or “LID” – for multiple LEED buildings and other redevelopment building projects in my earlier career, I joined CH2M (now Jacobs) in 2012 with the hope to improve Puget Sound water quality and salmon habitat by designing green stormwater retrofits, culvert replacements for improved fish passage and other cutting-edge water quality improvement projects. Six years and many satisfying projects later, I’ve appreciated lessons learned, as well as opportunities to reflect on the differences between LID, GSI and green infrastructure.
When we think about the future of such efforts, I suggest that, instead of advocating for use of a solution or class of solutions, we describe the benefits or outcomes we desire from infrastructure. Then, allow a transparent process to determine if green infrastructure is the right solution or suite of solutions, which particular BMPs would best fit the context, or even if a combination of different solutions (green+grey) may be most appropriate and effective.
For example, if the goal of a project is to build bike lanes, the most efficient way to achieve that goal may be finding the route or location where installation is least expensive, least difficult, or least opposed. If the goal, however, is to increase bicycle ridership, improve community health and lower energy use all at the same time, bike lanes may need to be constructed in locations that are inherently more difficult, but are more helpful to the bicycle network – or a different solution such as a bikeshare network or improved bicycle access to mass transit may be more effective. Instead of setting out to implement a solution (bike lanes), let’s take time to define project goals and confirm our solution meets these goals.
Similarly, if the goal is to build green stormwater infrastructure, finding the least expensive or least challenging location may be most efficient. But, if the goal is water quality improvement, traffic calming, urban greening, or something else, focusing on that goal may result in selecting different green infrastructure practices or implementation in more challenging locations, but may ultimately improve the performance of the infrastructure.
For instance, building green infrastructure such as cisterns or bioswales on large residential lots in landscaped areas may be the lowest-cost, but may offer less pollutant removal and peak flow mitigation than building green infrastructure in the right-of-way in more dense areas. These dense areas might likely have significantly higher cost, but may also have significantly higher pollutant removal and ultimately better cost efficiency.
Before setting out to build an infrastructure solution (bike lane, cistern, bioretention swale, tree, trail, etc.), let’s take the time to establish our ultimate goals and confirm that our proposed solution will best meet those goals.
We should ask ourselves why we want to design or build green infrastructure. If we do honest math and green infrastructure is found to best meet our project goals, we are more able to answer our critics and to address legitimate questions regarding efficiency and best use of space and funds. And we are more likely to create beautiful high-functioning projects that benefit the community and the environment.