Stormwater Management + Stream Restoration
Streams in cities often suffer significant erosion as they are overwhelmed by the huge amount of water running off pavement, buildings, and other impervious area. Excess erosion can damage infrastructure (e.g., roads and bridges), harm water quality, and impact fish and other biota. These eroding streams can be "restored" to help make them more resistant to erosion, but this addresses the symptoms, rather than the cause of the problem. Stormwater management can help capture this excess runoff, preventing it from reaching streams in the first place. Still, it is unclear how to best design stormwater controls to minimize stream erosion and what additional benefits stream restoration can provide when coordinated with these practices. I'm exploring the links between stormwater management and stream restoration to help provide design-relevant guidance to practicing engineers and city stormwater managers.
Natural Infrastructure for Flood Management
Most people think of infrastructure as bridges, roads, dams, and power lines. However, natural systems also serve as infrastructure and provide valuable services to society. For example, functioning river floodplains can store and slow flood water, reducing the extent and severity of flooding downstream. This natural infrastructure can also provide additional benefits, such as improving water quality and enhancing biodiversity. The potential of natural infrastructure is being increasingly recognized, but there is not clear guidance on how to plan and design these features. As an example, flood control levees may protect some properties from flooding, but can actually increase flood risk elsewhere. Strategically removing or setting back these levees can restore natural river-floodplain connections, creating a natural infrastructure system to reduce flood impacts. I am interested in these types of riverine natural infrastructure solutions and improving our understanding of when and where these types of projects are most effective.
Reducing Nutrient Pollution
Nutrient pollution - excess nitrogen and phosphorus - cause algal blooms which damage aquatic ecosystems and contaminate drinking water supplies. Common sources of nutrient pollution are urban wastewater and stormwater and agricultural runoff. Strategies to reduce nutrient pollution at the source is critical, but we may also be able to enhance the natural filtering capabilities of the streams and rivers that carry this pollution downstream. Targeted stream restoration can help remove nitrogen and phosphorus from streams either through biogeochemical processes (e.g., denitrification) or through deposition and storage of contaminated sediment (e.g., on floodplains). Still, stream restoration may not be effective in all cases and, even if it is, quantifying these benefits is extraordinarily difficult. I am working on improving these methods and improving our understanding of the potential for stream systems to trap and remove nutrient pollution.