By taking it a step further and implementing a resilient urban design approach, our critical systems and infrastructure can adapt and stand up to changing environmental conditions.

Rising sea levels and evolving rainfall patterns are changing our environment, shifting traditional approaches to sustainability efforts, particularly as they relate to resilient infrastructure design.   

As a direct response to climate change, industry professionals are taking sustainability to the next level, analyzing environmental impacts on communities and identifying how to address those changes through system designs that can adapt and endure. These impacts might include an increase in higher intensity rainfall events and in rising sea levels along the coast. Design approaches need to plan for these long-term changes as part of new and upgraded infrastructure projects. Green infrastructure approaches also can be part of the solution in restoring natural hydrology and systems in urbanized areas subject to flooding, water quality issues and erosion from urban runoff and coastal processes.

Realizing the potential, some coastal U.S. cities have already taken steps to implement such designs within their communities.

The Big Canyon Watershed in Newport Beach, California, consists of more than 1,000 acres that drain to the Upper Newport Bay Ecological Reserve. In 2007, Big Canyon Creek, which rests at the base of this urbanized watershed, was identified as having elevated levels of selenium, potentially affecting wildlife. The creek also was a source of localized flooding due to increased watershed runoff, and higher peak storm flows caused erosion of stream banks. Impacts also include loss of historical salt marsh habitat from previous dredging activities. This multifaceted problem required a multiphased approach.

During Phase 1, the project team addressed such urbanization impacts in the watershed through a multibenefit approach that included restoring the natural systems and providing more stable hydrology. These solutions also considered long-term effects of climate change that included variations in rainfall patterns and, in future phases, the effect of sea level rise.

The team first addressed water quality impacts from selenium with a diversion around high concentration groundwater seeps that effected the creek water. Also, the construction of a natural wetland treatment system removed pollutants from stormwater runoff from local roadways. Using a natural system approach provided a more resilient and sustainable design that can adapt to the changing environment. Capturing and slowly filtering stormwater runoff through the natural treatment system also tackled flooding and stream bank erosion by restoring natural hydrology. With the water quality concerns addressed, the project team could then restore the creek habitat through bioengineering vegetated bank stabilization techniques. New trails were added as well, connecting to existing trails that lead throughout the restored coastal creek habitat.

The Big Canyon nature preserve now provides an opportunity for local and regional students, including those from vulnerable communities, to explore the natural environment and discuss the effects of urbanization and long-term climate change.

Phase 2, which concentrates on the lower portion of the Big Canyon Park adjacent to the Upper Newport Bay, is currently under study and includes an assessment of alternatives to restore historical salt marsh and address the impacts of sea level rise on the restoration and existing infrastructure. A roadway used by the community for hiking, biking and vehicle access to the park needs to be considered with existing drainage structures. This phase provides additional educational opportunities to further support the growing interest of STEM in young adults, especially future scientists and engineers.

In San Diego County, the Los Peñasquitos Lagoon restoration design project also is underway, using the same approach to restore natural hydrology and systems in urbanized areas subject to flooding, water quality issues and erosion from urban runoff and coastal processes. The design addresses impacts to historical salt marsh habitat from urban runoff that has increased sediment accumulation in the upper lagoon as well as increased freshwater from greater storm flows from the urbanized watershed.

Flooding also has been an issue in the upper lagoon, which has been commercially developed. Upgrades to the existing flood management infrastructure will incorporate resiliency in the design by addressing long-term changes in rainfall patterns and the impact from sea level rise that can influence drainage after larger storms. Additionally, sediment management that could affect planned restoration efforts will be considered as part of the infrastructure upgrades using the approaches outlined.

From restoration projects to constructed wetlands, rising sea levels and evolving rainfall patterns need to be addressed as part of the overall project design. By taking it a step further and implementing a resilient urban design approach, our critical systems and infrastructure can adapt and stand up to changing environmental conditions. But that’s only one of many benefits. Making this type of investment also results in economic growth and greater community support for infrastructure projects designed to also enhance the safety, welfare and quality of life for all.

 

In response to the growing threat of natural disasters, a global initiative is underway to design critical infrastructure that is more sustainable and resilient, incorporating solutions that not only address immediate needs but also enhance quality of life far into the future. When it comes to developing new resilient and sustainable design standards, find out where to begin and how to overcome significant challenges.  

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by
David Pohl, a project manager at Burns & McDonnell, leads design-build and environmental projects, delivering multibenefit water resources, water quality compliance and habitat restoration solutions for municipal and industrial clients.