The U.S. Supreme Court will hear arguments this morning on a water dispute over the Catawba River. WFAE's Julie Rose explains: South Carolina is suing North Carolina over the amount of water it draws from the Catawba River before it cross the state line. Two years ago the U.S. Supreme Court agreed to hear the case. Since then, it's been tied up in a dispute over who else can be part of the lawsuit. The City of Charlotte, for one, thinks it needs to be an equal party with North and South Carolina in the lawsuit because it's the largest water user on the river. "We are the party with the most at stake, based by the claims made by South Carolina in the lawsuit," says Charlotte City attorney Mac McCarley. "We think if you call somebody out, you ought to be allowed to answer the charges. That's why we ought to be a full-fledged party in this lawsuit." Duke Energy also wants to be a full-fledged party in the lawsuit because of the dams and reservoirs it operates in both states. "So one reason we feel that it's appropriate for us to intervene in this case is to protect our ability to operate our facilities and to provide electricity to our customers," says Duke Energy spokesman Jason Walls. The lawsuit could also impact Duke Energy's efforts to get another 50-year hydropower license on the river. If the Supreme Court were to rule in South Carolina's favor, Duke Energy and Charlotte may be forced to draw less water from the Catawba River. The same is true for the cross-border counties of Union and Lancaster which operate a shared water treatment plant and are also trying to intervene in the lawsuit. The State of North Carolina has said it welcomes the additional participants. But South Carolina Attorney General Henry McMaster insists the two states should be able to represent all of the interests. "We don't need other people to get involved with their special views, or special interests," says McMaster. "That will slow down the case. It will complicate the case. It will make it much more expensive for everybody involved, and it's unnecessary expense." McMaster says South Carolina is already spending more than a million dollars a year on the lawsuit. The City of Charlotte is spending a similar amount. The U.S. Supreme Court will hear oral arguments about which parties should be part of the lawsuit this morning at 10 a.m.. A decision on the larger question of how to fairly divide the water could take many more years.