By Mike Ekberg, manager of water resources monitoring and analysis
The drought headlines coming out of the western US are sobering.
“The West is in the midst of a very serious megadrought,” said USDA Chief Meteorologist Mark Brusberg in an interview posted to Twitter by @pattrn June 23. “We refer to it as a ‘megadrought’ because it’s lasted for decades.”
According to Brusberg, 87 percent of US western states are in a drought, with 26 percent in the most serious category of drought. And although severe drought is thousands of miles from our region, it could have a local impact.
“If we are in a situation where the drought is severe enough to where it impacts agricultural production, that will rattle the markets,” Brusberg said. “We will see a rise in food costs…It might be localized to the West initially, but those could have a ripple effect.”
The local situation
As of June 22, Ohio was not reporting drought conditions anywhere in the state. Only a few counties in the northwest and a few counties in the eastern part of the state were seeing “abnormally dry” conditions.
How stable is our aquifer?
The buried valley aquifer in our region stores an estimated 1.5 trillion gallons of good quality water. What are the chances that our aquifer could run dry? Are the water levels in the Great Miami River Watershed and its buried valley aquifer increasing, declining or staying the same? (The watershed is all of the land that drains to the Great Miami River.)
According to the measurements taken by MCD over the last 35 years, the water supplies in the Great Miami River Watershed are in what’s called a “steady state.” That means the amount of water that flows into the watershed is roughly equal to the amount of water that flows out. In other words, the amount of water stored in the 4,000 square miles of land that drains into the Great Miami River is relatively constant over the last 35 years. Most of the water stored in the Great Miami River Watershed is in aquifers and lakes.
2020 Great Miami River Watershed precipitation totals
In 2020, the Great Miami River Watershed received 42.56 inches of rain and snowmelt (inflows) which is 2.26 inches above the 30-year average. That amount of water equals 2.9 trillion gallons of water.
Water leaving the region through evaporation and plant uptake (outflows) averages about 26 inches or nearly 1.8 trillion gallons. Runoff leaving the Great Miami River in 2020 totaled 1.1 trillion gallons of water. All runoff in the Great Miami River Watershed eventually ends up in the Ohio River. Runoff is water that flows over the land (overland flows), runs through soils (interflow) and into the aquifers (groundwater flow).
That’s 2.9 trillion gallons into the watershed and another 2.9 trillion gallons out of the watershed.
Groundwater levels in the aquifer
Groundwater levels are a good indicator of groundwater storage. There are fluctuations in water levels year to year. But over the long term, precipitation and runoff balance each other out, leaving the total amount of water stored in the Great Miami River Watershed essentially the same.
MCD is keeping an eye on the future
While our water levels are steady today, that’s no guarantee for the future. Changing climate could impact water levels as could water use. That’s why it’s critical to track water over time and why MCD monitors groundwater and measures precipitation and river flows throughout the watershed. Modern, high-tech gages transmit data real-time, which MCD verifies by regular manual readings and analyzes with its valuable long-term water records.
We’ll continue to monitor water levels because that information is essential to detecting changes in groundwater levels. And we’ll continue to share the information with decision-makers so they can develop policies and programs that can safeguard our water supplies.
Visit our website for more information about water stewardship.
Links to articles referenced at the beginning of this post
Western U.S. may be entering its most severe drought in modern history
Potentially the worst drought in 1,200 years
The shocking numbers behind the Lake Mead drought crisis