How Rainwater Harvesting Replenishes Groundwater

California Governor, Jerry Brown, has recently taken action to address the dire groundwater situation in that state. What’s the issue? Namely that groundwater is being pumped out faster than it’s being replenished—think of it like overdrawing a bank account.

 

The issue:

Historically, the state of California has not monitored groundwater with enough detail to determine exactly where the limit is in terms of how much water is truly available. Wells are not typically metered, so in most cases farms, businesses, and residents are drawing from the same shared sources without any control on how much is too much.

 

What does rainwater harvesting have to do with it?

While the state takes regulatory action, we can’t forget the power we have as individual Citizens of the Planet to manage the water that falls upon us (literally). In fact, with proper management of rainfall, we even have the power to recharge groundwater under our own feet.

 

Here’s how:

HeirloomFestivalDemo

When you collect rainwater on your site, either in tanks or barrels for later use, or in landscaped infiltration basins and swales, you harness that valuable and increasingly scarce gift of free and fresh water by holding it on your site and allowing it to infiltrate at a rate that assimilates nature. While you nourish your garden with the cheapest and highest quality water available, you also allow the excess to infiltrate, recharging the very groundwater resources that supply most of our community needs.

 

 

 

What happens otherwise?

Humans have drastically altered the global hydrologic cycle by covering much of our earth’s living, breathing surface with hardscape—think buildings, roads, parking lots, driveways, and even the roof over your own head. In a natural landscape, over 50% of the rainfall that hits the earth infiltrates to recharge groundwater. In our urbanized/suburbanized world, that figure drops below 15%. This leads to the twin issues of stormwater pollution and groundwater overdraw.

So do your part! Dig out some infiltration features in your landscape, and install some rainwater tanks (or barrels!) to harness this precious resource. It’s in your power to have a positive impact on the drought!

This diagram shows infiltration rates in natural versus developed environments.

This diagram shows infiltration rates in natural versus developed environments.