Clean Water Supplies Through Green Infrastructure
And this is true for many of us – the majority of Americans get their drinking water from surface water, including streams and rivers, and so keeping our rivers clean and flowing is critical for reliable supplies.
To do this, it’s important to keep rainfall soaking into the ground where it can recharge local streams, providing in many places the basic level of water (referred to as baseflow) and filtering and cleaning that water.
Better protecting the small streams and wetlands that provide drinking water for millions of Americans is one way, and better managing water in our developed and developing areas, by using green infrastructure approaches (like rain gardens and green roofs) is another.
When we pave over natural areas as part of the typical development process, the rainfall that would usually soak into the ground and replenish our streams and rivers is instead routed quickly downstream as polluted stormwater runoff. And this can have a big impact.
In our report Paving Our Way to Water Shortages, we evaluated the effects of poorly planned development on drinking water supplies, and estimated the water “losses” from developed areas’ failure to absorb rainfall.
For instance, in Atlanta, the estimated water losses in 1997 from developed areas caused by the failure to infiltrate rainfall amounted to enough water to supply the average daily household needs of 1.5 million to 3.6 million people per year. Similarly, in North Carolina’s fastest growing cities it amounted to the household needs of 780,000 to 1.8 million people per year.
That’s why we’re working on projects and policies to advance more green infrastructure for clean and healthy rivers. In Georgia’s Flint River, for example, we’re working to retrofit some of the currently paved area with rain gardens and other practices to replenish the river. In the policy area, current rules under the Clean Water Act haven’t achieved clean water and so we’re advocating for stronger stormwater rules that will require objective-performance-based standards that will drive the use of green infrastructure.
With water supplies now even more vulnerable to increased droughts, smart strategies for clean and reliable water, like green infrastructure should be top priorities.