Little more than a decade ago, the notion would have been laughable: divvying up water from the state’s abundant supply. This is a place replete with rivers and lakes, a place so wet that artisan wells don’t quit flowing.

Then came the drought in the late 1990s that never really ended until 2015. Then came the drought-spurred “water wars” dispute with North Carolina — the sort of legal fight more associated with arid Western states. Just like that, water in this region became a supply-and-demand commodity, like fuel.

Now state agencies are working with Clemson University and a private contractor to develop a computer model to judge how much water is in a given river basin at any given point and time, and what might happen to that supply as various amounts of water are taken out. It could provide solid data for everything from drought management to deciding water-use permits

It’s a first of its kind in the state, and maybe the most significant thing to come out of the North Carolina dispute. It could help decide future water disputes, such as the recent Walther potato farm controversy on the upper Edisto River.

Right now nobody really knows how much water is out there — even though the S.C. Department of Health and Environmental Control regularly issues permits for large-scale withdrawals of surface water.

More than 966 billion of gallons were withdrawn in the state in 2014, according to DHEC, although the total includes a massive amount pulled for cooling power plants, that is rapidly returned to the same river.

“We have very limited scientific information as to how much water we have,” said Ken Rentiers, S.C. Department of Natural Resources deputy director of land, water and conservation. The model “will give us sound science to provide reliable information to decision makers.”

The project, in fact, is being paid for with $1.5 million allocated by the state Legislature. It stemmed from that dispute with North Carolina, when a water utility proposed pulling water from the Catawba River and using it in a place that would drain to another river basin.

That’s not too unusual. In the Lowcountry, water from the Santee River basin flows into the Marion-Moultrie lakes, where part of it is diverted to the Cooper River basin. A not-so-widely known marl tunnel runs water from the Edisto River to the Cooper River, to supply nearby manufacturing plants and serve as a back-up for the Charleston water supply.

But the utility proposed its “interbasin transfer” in the midst of the drought, denying downstream Catawba users some of the river flow. Those users include most people who drink water in the Charleston area.

South Carolina had to fight the case against a legal precedence of rulings that favor the upstream river user and against a state, North Carolina, that showed up in court with data from its own river basin computer modeling. The case was settled with few concessions to South Carolina.

No sooner than the Legislature allocated the project money, the Walther farm controversy erupted, a 2013 legal and legislative fight over an 800 million gallon-per-month withdrawal from the upper Edisto, sought by a Michigan-based company for an industrial-sized potato farm south of Columbia.

It was supported by business groups such as the S.C. Farm Bureau, opposed by a collection of downstream water users, including small farm and recreational interests. It ended in a compromise that satisfied neither side.

Having the modeling in hand, “certainly would have been a benefit,” Rentiers said. When it comes to withdrawal permitting, “that’s where the rubber meets the road.”

But the modeling is no real solution unless it leads to more rigorous permitting, said Tim Rogers of Friends of the Edisto, one of the groups that opposed the Walther permit.

“You can have all the information and data in the world, but if you have no permitting requirements, it doesn’t do you any good,” he said. “The practical effect (of the modeling project) is it delays facing the difficult and up-until-now politically intractable problem of creating a permitting system.”

The model would work from data from river gauges, as well as historic data dating to the 1930s. It would display in spreadsheets or graphics, similar to lake level tracking now in use on any number of water bodies in the Carolinas, and would be available for public use by people who register and take a training session.

A similar model to assess groundwater supply is being developed by the U.S. Geological Survey, Rentiers said.

Reach Bo Petersen at 843-937-5744, @bopete on twitter or Bo Petersen Reporting on Facebook.