In the global movement of sustainability, one of the biggest questions is: In a time of continued rapid city growth and industrialization, how can we incorporate sustainable infrastructure and increase resilience? Community resilience can refer to a variety of community characteristics, but for the sake of this article I am referring specifically to resilience against environmental challenges. There is definitely a lot to unpack, but simply put, nature has the answers!
Historically, rapid growth of cities and industries has led to overconsumption of resources which has a negative impact on the environment. The locations of our cities, the materials we use to build infrastructure and the solutions we propose to natural problems (like storms, erosion, etc.) are all factors of development that have the potential to affect the resilience of our communities. One of the most important ways cities can increase structural resilience against environmental challenges is to implement blue-green infrastructure. Blue-green infrastructure (BGI) is the use of natural elements in urban planning and design to build more sustainable cities and protect communities from climate related-issues. BGI is often discussed in contrast to gray infrastructure, which refers to human-made structures often made of cement or metal (SCAG). Instead, BGI emphasizes the reintroduction and protection of natural spaces to protect, mimic, and/or enhance their function to create more sustainable solutions.
Traditional gray infrastructure includes storm drains, seawalls, roads, and more. The intended purpose of the infrastructure is to protect from environmental challenges like flooding, coastal erosion, and general stormwater management. Yet, they have created new problems for communities and the environment. The impervious surfaces of urban neighborhoods like asphalt roads and concrete sidewalks cause water to flow quickly towards the ocean as it picks up a plethora of pollutants along the way. Similarly, the storm drains on our sidewalks help to protect from flooding on our roads, but again direct unfiltered runoff into the ocean (GHD). Seawalls meant to protect our shores from coastal erosion due to wave impact actually aid in quicker degradation of our shores because rather than absorbing the force of waves, they deflect the force onto the sediment in front of it causing it to wash away more quickly. With traditional gray infrastructure we are left with poor water quality and weakened resilience to natural forces.
Fortunately, nature comes in with plenty of solutions! Green spaces, like parks, with soil and diverse vegetation can protect communities from flooding and slow runoff because it is a permeable surface. Permeability means that water can soak into the land rather than flowing right over. When water absorbs into natural landscaping pollution can be filtered out. Bioswales are shallow, vegetated depressions in the ground, similar to rain gardens. They are often filled with native plants and gravelly soil to increase permeability. Bioswales and rain gardens can be seen along the sides of city streets, in local parks or can even be made in your front lawn to slow runoff, filter water, and contribute to groundwater recharge (NACTO). Nature also has a better solution to shore protection than the use of cement seawalls. Native eelgrass and oysters help to protect shores from wave impact by absorbing wave shock and locking sediment into place with their roots and a cement-like adhesive secreted by oysters. By restoring and protecting these natural areas we can ensure they continue serving these functions for generations to come.
Rain gardens in a front lawn (left) and along city streets (right) collecting and filtering water (PC: Cal Recycle, DOEE).
Blue-green infrastructure comes with many co-benefits. Tree canopy cover in parks and along neighborhood streets help to reduce the urban heat island effect. The urban heat island effect refers to the phenomenon where urban areas experience warmer temperatures than surrounding rural areas due to the lack of vegetation. Urban areas built with concrete and metal absorb heat and store it, contributing to warmer surfaces and temperatures. Trees and other green spaces – like bioswales and rain gardens – also absorb heat but instead use it to produce energy, so it is not stored and actually helps to cool the surrounding areas.
One example of blue-green infrastructure in Orange County is Heisler Park on the coastal bluffs in Laguna Beach. At first glance, Heisler park looks just like any other park. There are green grass lawns, seating to take in the view, native plants and a walkway for people to enjoy a nice stroll. But each piece was intentionally built with the goal of filtering the surrounding communities runoff before it flows into the lush marine ecosystem below which is a designated Area of Special Biological Significance (ASBS). Storm drains and irrigation in the park are strategically placed to redirect runoff to treatment sites and take advantage of natural infiltration (City of Laguna Beach). Storm water and other runoff must pass through the bioswale and vegetation of the landscape which gives it time to filter and prevent excess runoff from entering the ocean. Even the concrete used in the park is used to enhance the BGI with the tilt of the walkways and edges of planters aiding in redirecting water through the vegetation and slowing the flow. The use of BGI is not only helping to protect the Heisler Park ASBS, but it is also reducing the rate of erosion occurring along the bluffs. The landscape provides benefits to the natural environment and for our recreational and educational uses, demonstrating the multifunctionality of blue-green infrastructure.
You can participate in the implementation of BGI in your neighborhoods and cities in a lot of different ways. In our homes we can start by using native plants in our landscaping or implementing greywater filter systems to reduce the amount of water we use. You can also participate in community tree planting efforts or advocating for increased green spaces in local government. With OC Habitats’ restoration projects, you can participate in picking up trash, planting native species, gaining further education, and much more all across the ecosystems of Orange County. Helping to restore what we have left of our local habitats helps to enhance the ecosystem services they provide and increases the resilience of our local communities. By investing in blue-green infrastructure today, we can give future generations the benefits from all that nature has to offer!
Sources: GHD, SCAG, NACTO, National Park Service, City of Laguna Beach
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