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California ramping up flood mitigation efforts with green infrastructure

In the last several years, California has taken steps to “greenovate” their state by implementing green infrastructure programs to prepare for extreme weather events, like floods and wildfires. Among the most impressive is rehabilitating floodplains by moving levees back from rivers and planting greenery in the land between. This method controls flooding, rehabilitates the local flora and fauna, and recharges depleted aquifers. To start this process, farmlands that bordered the rivers were sold to state and federal agencies and were then converted into woodlands that sit below the levees. According to a New York Times article, the state of California is currently working on 20-30 different projects for watershed management in addition to the levee project. In 2016, California also allotted $80 million to the Urban Greening Program, which funds the building of non-motorized trails to encourage biking and walking and to discourage car usage.

This California stormwater curb extention combines flood control with green space (wikimedia commons/PSA1966)
This California storm water curb extension combines flood control with green space (Wikimedia commons/PSA1966)

While these methods are a step in the right direction, the state has a long way to go in meeting the goals laid out by Governor Jerry Brown. The California legislature recently approved Governor Brown’s 2017 proposal that $387 million should be put towards providing new flood protection along the Central Valley and the Sacramento-San Joaquin River Delta over a two-year period, rather than the previously proposed five years. “We have our aging infrastructure and it’s maxed out,” said Gov. Brown, referring to dams that had spilled over after a winter flood. The governor admitted that this proposal is just scraping the surface of an estimated $187 billion that needs to be spent long-term to protect from flooding.

“There’s always an opportunity to use vegetation and this green infrastructure to lower flood risk — move the water where it will do the most good and redirect it from places that will do the most harm,” says Julie Rentner, executive vice president of River Partners, the conservation group that restores the farmlands.  “And you can do that in a way that is durable and sustainable over time.”

The concept of using green infrastructure to cope with risk is something the Dutch, historically through the use of dykes, have been implementing for over a thousand years. Since the Netherlands are below sea level and flooding is a regular occurrence, the Dutch have learned to live with the water rather than attempt to stop every flood. With climate change exacerbating storm surges and flooding, the country has implemented innovative solutions to prevent damage. “This starts with little things, like getting people to remove the concrete pavement from their gardens so the soil underneath absorbs rainwater, said Arnoud Molenaar, the Chief Resilience Officer of Rotterdam.

The most well-known and comprehensive plan the country has laid out is “Room for the River,” which has the goal of restoring rivers’ natural floodplains for protection, similar to the programs California is implementing. The difference is in the scale of the projects—the Dutch have a $2.3 billion budget and started in 2007, whereas California has a $900 million budget and began in 2016. The scale of green infrastructure and resilience in totality is also much different. The Netherlands incorporates sustainability and flood preparation into several aspects of their development, such as housing and infrastructure planning, while the early stages of California’s programs have focused on large scale flood-prevention measures.

The Room for the River program illustrates that preparing for climate change can be an opportunity for resilience building and economic growth. Many, if not all, of the projects in the Netherlands have dual purposes of handling flooding and helping the community on “blue sky” days. One drug-ridden neighborhood was transformed, using community-initiated projects, into a massive dike with a rooftop park and buzzing shopping center which funds the park upkeep. On a larger scale, entire “water plazas” have been built in underserved neighborhoods with basketball courts, gardens, and more that serve as retention ponds.  “It’s an example of what you can do if you connect storm-water management with social welfare and neighborhood improvements,” Molenaar said. “It’s what we mean here in Rotterdam by ‘resilience planning.’”