Mexican engineers are raising concerns about President Trump's proposed border wall.

They say a new wall could cause flooding along the border.

In an interview with National Public Radio (NPR), Antonio Rascón, the chief Mexican engineer on the International Boundary and Water Commission, said the wall could violate a 47-year-old treaty that governs the shared waters of the Rio Grande.

He's talking about the 1970 Boundary Treaty that lays out the precise border between the two countries, part of which runs through the middle of the river.

It says if structures are built that could impact the flow of the Rio Grande, or its flood waters, then both countries must agree before there is any construction.

"{The treaty says} that both countries agree that if one country, either country, should build structures in a place that would deflect waters and flood waters along the river course - that they would be forbidden from doing that unless the other country agreed. The problem here, specifically, is that this kind of structure or impediment {the proposed wall} would cause, under certain hydrological condition, flooding, etc., would cause the boundary to move. Neither country is permitted to move the boundary without the other countries consent," said Stephen Mumme, a political science professor at Colorado State University.

The Mexican government has already voiced opposition to the wall.

Mumme predicts if the U.S. continues with plans to build the border wall, there will be a showdown between Mexico and the U.S.

"It has a treaty right and it will assert that treaty right if the United States is unwilling to compromise and cooperate with Mexico," Mumme said.

He predicts if it comes to a showdown, Mexico would win.

"I think Mexico is very confident that it has good engineering on its side and that's why I take the position that I do, because I think that it actually has the upper hand right now," he said.

The House Oversight Committee held a hearing Thursday to discuss the economic and security benefits of the proposed border wall.

"It's one thing to talk about barriers and these built structures as border security, it's another thing to actually make them work," Mumme said.  "That is a much more complicated piece of business, and its something that requires Mexico's cooperation and that's been sorely missing in all of this discussion about the wall."