President Trump’s border wall likely will require the installation of hundreds of storm gates to prevent flash floods from undermining or knocking it over, gates that must be left open for months every summer during “monsoon season” in the desert, according to U.S. border officials, agents and engineers familiar with the plans.

The open, unmanned gates in remote areas already have allowed for the easy entry of smugglers and migrants into the United States.

At locations along the U.S. southern border where such gates already are in operation, Border Patrol agents must manually raise them every year before the arrival of the summer thunderstorms that convert riverbeds into raging torrents that carry massive amounts of water and debris, including sediment, rocks, tree limbs and vegetation. Trump’s wall, which features 30-foot metal bollards spaced four inches apart, effectively acts as a sewer grate that traps the debris; when clogged, the barriers cannot withstand the power of the runoff.