Everybody knows that California is experiencing a drought and that agriculture is having a major impact on groundwater. But these are not just issues just affecting our state.
If you’ve ever flown across the Great Plains and looked out the window, you’ve seen giant circles of green inside squares of yellow or brown. These farms irrigated using “center pivot” systems using a single giant well in the middle of a 160 acre block that supplies a line of wheeled sprinklers that slowly rotates around the field. The corners of the field receive no irrigation.
Unlike in California, most of the irrigated farmland in Nebraska, Oklahoma, Colorado and other plains states grow commodity crops like corn and soybeans that are primarily fed to livestock or used to make ethanol. Farmers began irrigating as a way to augment the rain that fell in the area during the growing season. But over the last twenty years, it has rained less and less in the summer and they’ve had to pump more and more. Lately the area has been in a semi-permanent drought that appears related to long-term climate change.
The underground supply that farmers in the Plains are tapping into is called the Oglalla Aquifer. When pumping began forty years ago, everyone thought the water would last forever. But much like in California’s Central Valley, there are places where it the groundwater recharges and others where it does not. Some of the latter areas have already exhausted the supply, like parts of West Texas.
Even some of the wettest parts of the U.S. having been experiencing severe droughts in the last few years. Last year the Pacific Northwest and parts of the Southeast had a serious drought, and this year it’s New England’s turn. Throughout Maine, New Hampshire and Massachusetts this summer, rivers and reservoirs have shrunken to mud puddles and wells have dried up. Farmers have had to abandon their fields. Water systems in these normally wet climates are not built to store water for months or years but rather for a few weeks between rains.
The flip side of drought is flooding, and more and more, when it does rain in temperate parts of the U.S., it rains too much. Small, local reservoirs cannot hold the water and catastrophic flooding occurs. Towns and cities are inundated, and farmers’ crops are washed away. Events like this used to be called “one hundred year floods”, but have been happening much more frequently.
In other words, climate change is making the weather in the rest of the country more and more like California’s weather. Our water system is built to capture rain and snow from a handful of (hopefully) intense storms each year and pipe it to where it most needed — cities and farms both. It was built for a much smaller population, and it needs to be updated and upgraded. But it has proven remarkably resilient, even when subjected to ever-increased demands and stresses.