Green Infrastructure Key to Solving 21st Century Water Crises

Cities and communities all over the world are facing severe water crises. Sub-Saharan Africa is experiencing its worst drought in decades; and while California is finally seeing its parched reservoirs being refilled, the intensity and fierceness of the storms bringing this relief also harbor new dangers, triggering mudslides, flooding, blizzards, and avalanches - thereby putting lives at risk. Intense and erratic weather patterns such as these endanger much of our natural infrastructure, and, among other things, make access to clean water uncertain and costly.

Unfortunately, most cities and nations are trying to fix 21st century problems with 20th century technology. They turn to “gray solutions” - massive public works made of steel and concrete, such as dams, treatment plants, and storm drain networks - with results that can be inadequate at best, harmful at worst. Traditional gray solutions have themselves contributed to environmental degradation and are often vulnerable to environmental impacts like climate change. This gray infrastructure also comes with a high price tag: some $10 trillion will be required to repair and expand the world’s existing water infrastructure by 2030. With only $500 billion being spent annually on traditional infrastructure, we are far from meeting that.

To deal with soaring costs and deteriorating infrastructure, leaders gathered in Davos, Switzerland for the 47th World Economic Forum this week are driving the agenda to restore not just roads and bridges, but also our forests and rivers.

Delivering water and sanitation for all in the 21st century will require a new approach - one that does not solely rely on gray solutions, but gray in combination with “green” systems such as forests, grasslands, and wetlands, which protect our access to clean water and are more resilient to environmental change. Such “green infrastructure” can both reduce costs and manage the risks to water systems very effectively. Measures such as protecting watersheds to provide water regulation and filtering services can avoid the need for new capital expenses and reduce operational costs. In Lima, Peru, we have seen that a green-gray combination of water management options could save 18% on costs compared to a strategy that relied on gray infrastructure alone.

In addition, investing in watershed health can significantly reduce the level of risk to water systems. Healthy watersheds control erosion and reduce operational risks to water treatment plants from excessive sedimentation, but also mitigate flooding risks to downstream property. Cities as different as Santa Fe, New Mexico; Quito, Ecuador; and Melbourne, Australia are making investments in improved forest management practices to reduce wildfire risks and resulting erosion that can threaten downstream water supplies.

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