TL;DR
When rainfall lands on impermeable surfaces like asphalt, concrete or lawn, it cannot replenish our groundwater. Plants, especially native species, pull rain into the soil. This filters the water, refills wells, and extends the life of sewer systems.
How much thought do you give to groundwater?
As drought engulfs more and more of the United States, it’s time to think differently about groundwater. It’s not just about how much rainfall you get, it’s about where that water goes. Here’s what you need to know.
Rainfall needs to go somewhere.
Before we covered the world in asphalt, concrete, and lawn, very little rainwater became runoff. Roughly half of it used to return right back to the atmosphere via evapotranspiration. A quarter would sink into the soil and become groundwater. Another quarter sank even deeper and became baseflow. But only 10% or less became runoff.
Nowadays, that’s changed. In developed areas, 55% or more of rainwater now becomes runoff. That means, instead of refilling our groundwater and our wells, it is shunted into sewer systems that dump it into rivers and streams.
Plants absorb rainfall.
Changing your landscaping is the easiest way to ensure more rainfall is entering the groundwater. Fashions favoring lawn or hardscaping need to be countered with visions of plantings and rain gardens. Replacing lawn with native plants is one of the best ways to reduce runoff and also improves biodiversity.
Beautify public works.
Roadways and driveways do not need to be lined with grass. By designing bioswales and gardens as part of public infrastructure projects, you get beauty while replenishing the groundwater.
Porous pavers are a new option.
Gardens are’t the answer if you need a driveway or a patio – but porous pavers are. These alternatives to traditonal concrete or asphalt allow rain to penetrate the material and sink into the groundwater.
There are health benefits to reducing runoff.
When water is absorbed into the earth, it does not have the chance to run along the surface and pick up pollutants. The result is better water quality. Increased absorption also protects our streambanks, which are at risk of erosion when runoff rushes into them.
Improving groundwater also has cost benefits.
When rainfall can enter directly into the soil, you extend the life of your sewer systems. You also need to invest less in piped infrastructure.
Think Differently about Groundwater
As temperatures increase and rainfall patterns change, the ability to replenish groundwater will only become more important. Open your mind to new approaches to landscaping and infrastructure that take into account the need to replenish our groundwater.
Photo by Christian Lue on Unsplash.