Families Protecting the Valley makes excellent points about how recharging aquifers is not easy and dams aid in the percolation rate. They are partisan advocates for California Central Valley agriculture in the relentless battle for water in California. The drought is currently slamming the Central Valley and things will get worse. They advocate well for their positions. I don’t necessarily agree with them. However, they are definitely worth listening to.
Dams, they say, are needed to recharge aquifers.
A lot of enviros are pushing the idea that we can just recharge our underground aquifers instead of building dams. We have to admit that to the untrained average citizen this probably seems like a good idea. We have all this underground capacity, why not use it instead of building new expensive dams and reservoirs?
Here’s the deal: when it rains, water that can’t be stored flows down the rivers and out to the ocean. It takes time for water to percolate into the underground. You actually need dams for this to happen. The water can be released at a rate that meets the percolation rate. We think environmentalists understand this, but it messes up their argument against dams.
There isn’t a big hole where you can dump all kinds of water as fast as you desire. It seeps into the ground slowly. We have seen this over and over again as excess water that can’t be stored in dams flows to the sea because it can’t percolate into the ground fast enough.
We do not have enough above ground water storage at this time to recharge the underground. They go hand in hand.