The crisis at the border rolls on:

Not even Trump’s proposed wall could stop the wave of migrants overflowing shelters in the Rio Grande Valley, where the vast majority are turning themselves in to apply for asylum, McAllen Mayor Jim Darling said.

A wall would go up on levees about a mile from the winding Rio Grande, which is the U.S.-Mexico border. Migrants will just have to cross the river to be in U.S. territory and seek asylum, he said.

“That’s not a solution for asylum-seekers,” Darling said.

Once in the U.S., the migrants — mostly families from Central America — are crowding into facilities designed to hold single adult men, said Theresa Brown, director of immigration and cross-border policy at the Washington-based Bipartisan Policy Center and a former CBP policy adviser for Presidents George W. Bush and Barack Obama.

Increasingly, smugglers are bringing larger numbers of families together and delivering them across the Rio Grande, knowing they’ll overrun facilities and be released until their immigration court date, she said. Under U.S. law, Border Patrol is not supposed to hold any migrant for longer than 72 hours.

Usually, Border Patrol hands them over to Immigration and Customs Enforcement, which can detain families for up to 20 days. But all of those facilities are overcrowded, Brown said, leading Border Patrol to skip the transfer to ICE and release migrants to shelters en masse.

“This is a system-wide collapse,” she said.