Recent Heavy Rainfall No Quick Fix

Don’t be fooled by the recently heavy rainfall that occurred this week in some parts of the state.

Alabama still has a long way to go before it makes up for the steep shortfalls in rainfall that have plagued much of the state since the first of the year.

“We can’t replenish 14 months of drought with one heavy rainfall,” says Dr. James Hairston, the Alabama Cooperative Extension System’s water coordinator and professor of agronomy and soils, who has been closely monitoring rainfall patterns throughout the state.

Meanwhile, Ken Bonner of The Daily Sentinel in Scottsboro describes the drought as one of “historic proportions.”

He’s right, Hairston says, citing stream levels in the region as tangible proof. Some North Alabama streams are at the lowest level they have been in some 114 years of record keeping, he says.

And it’s not likely to get better any time soon. It may even get worse, despite the recent letup in dryness, according to Alabama Regional Extension Agent Charles Pinkston, who was quoted today in the Cullman Times.

The rains not only are too little and too late, Pinkston says, but also are likely to be short-lived. Indeed, despite the heavy rainfall in some regions of the state, sustained dryness is the usual pattern this time of year — the reason he predicts that surface water levels likely will start dropping again.

Pinkston describes this summer’s drought as “the most serious in [his] lifetime.”

Even so, many people believe that any heavy rainfall following prolonged dryness marks the end of drought. But that’s simply not the case, Hairston says.

“People see these streams and reservoirs temporarily filling up, and they think everything has been recharged and is ready to go,” he says, “but they’re not — far from it.”

While surface waters may rise slightly following heavy rainfall, the one thing that is especially needed following prolonged drought isn’t happening — water table recharging. While much of this rainfall may end up in rivers and streams, it falls too fast to be absorbed into the ground to replenish the water table.

Also, much of what ends up in lakes and streams eventually washes down into the Gulf of Mexico, Hairston says.

What especially concerns Hairston and other water experts is the steady pressure exerted on the state’s groundwater supplies.

“People think there is a never-ending supply of groundwater,” Hairston says. “But you’ve got to consider the long-term effects when you’re drilling more wells to provide water to municipal drinking water systems and irrigation systems, especially if the groundwater isn’t being recharged fast enough to replace what’s taken out.”

While the drought cycle ultimately will end at some point, there’s still the question of when. In the Southeast, drought cycles typically occur every 12 years, though they may last as long as 7 years.

A long-lasting drought is another scenario that concerns Hairston and his other experts, especially considering the current stress on groundwater supplies.

“The twenty-five or so inches of rainfall we get this year may sound like a lot to people in other parts of the country, but that’s historically low when you consider that we typically get about 50 inches of rainfall every year,” he says.

Posted by Jim Langcuster at June 20, 2007 04:22 PM | TrackBack