The US Army isn't ready to attack across rivers

Soldiers with the 101st Airborne Division (Air Assault) execute a wet gap crossing with the 502nd Multi-Role Bridge Company, 19th Engineering Battalion on Fort Knox on April 28, 2022. Staff Sgt. Michael Eaddy/US Army

• The US Army lacks the equipment and experience to successfully attack across a river.
• These capabilities have atrophied and need an overhaul, an Army major argued.
• River crossings are dangerous and only getting more difficult.

Assaulting across a river is among the most dangerous military operations. Yet if the US Army went to war tomorrow, it would lack the equipment, doctrine and experience to launch an attack across a defended river, according to one Army engineer.

“The Army has not conducted such an operation since World War II,” wrote Maj. Aditya Iyer, an Army engineer, in an essay for the Association of the United States Army. For example, Army divisions don’t have adequate bridging capabilities of their own to conduct what the Army calls “wet gap” attacks, and would need support from corps-level units that might not be available.

“The current wet-gap crossing doctrine, organization, materiel and leadership are ineffective for division-level wet-gap crossing operations independent from the corps,” Iyer warned. River crossings are especially dangerous because the massed vehicles can be targeted as they funnel across or even become stranded on the far bank against a larger enemy.

As an example of neglecting river assaults, Iyer points to the fiasco of Russia’s May 2022 attempt to cross the Siverskyi Donets River, which the 74th Guards Motorized Rifle Brigade tried to storm using mobile pontoon bridges. The result was an estimated 500 casualties and dozens of tanks lost.

Iyer lists multiple mistakes by Russian commanders, including attacking at only one point on the river, lack of prior reconnaissance, and attacking in daytime instead of night. “In contrast, the Ukrainian forces had accurate intelligence that showed the Russian troops massing along the river,” Iyer said. “The Ukrainian engineer reconnaissance teams had also identified potential river crossings and had pre-coordinated artillery targets on the crossing sites, and they were right; Russian forces did indeed use those sites.”

To be fair, the US Army also has a checkered history with river assaults. At the Battle of Fredericksburg in December 1862, the Union Army made a foolish and bloody attempt to cross the Rappahannock River against entrenched Confederate defenders. In January 1944, the US 36th Infantry Division launched an ill-prepared and disastrous night assault across the Rapido River in Italy that cost almost 2,000 casualties (the furious survivors spurred a congressional investigation after the war).

Indeed, the Army was unprepared for river crossings at the start of World War II. Divisions lacked sufficient bridging equipment — including bridges robust enough to bear the weight of tanks — which made them dependent on corps-level assets. Nor was there a centralized authority to coordinate complex crossing operations. However, by the time of Operation Plunder — the massive assault across the Rhine River in 1945, involving a million men and nearly 6,000 artillery pieces — many of these problems had been rectified. The Rhine crossing even used US Navy landing craft normally used for amphibious assaults on the ocean.

If anything, river crossings are even harder nowadays. The ruses that commanders like Napoleon used — such as surprise descents on a weakly held point, or feints to mask the real crossing point — are much harder when drones are constantly overhead as in Ukraine. If the enemy can spot the crossing, they can blanket the bridgehead with long-range missile and artillery strikes.

This wasn’t such a problem in counterinsurgency operations in the mountains and deserts of Afghanistan and Iraq. Major combat operations against Russia and China would be different, especially in regions like Eastern Europe, where there are plenty of rivers and canals. “The Russo-Ukrainian War has highlighted that military technologies have evolved in recent decades and that the U.S. military must be prepared to conduct wet-gap crossing operations against a well-organized and technologically advanced force,” said Iyer.

A 3rd Infantry Division Armored Multi-Purpose Vehicle drives off of a 497th Multi-Role Bridge Company, 92nd Engineer Battalion barge on Sept. 21, 2023. Kevin Larson/US Army

The Army’s current wet gap deficiencies resemble those of World War II. Divisions, and the engineer battalions in brigade combat teams, don’t have sufficient bridging capabilities of their own. The division is supposed to use at least four Multi-Role Bridge Companies to cross a 400-meter (1,312-foot) river. But those special bridging companies are controlled by corps headquarters.

“Divisions rely on the corps augmentation for wet-gap crossing operations, including other enablers, such as military police and smoke,” Iyer noted. Nor does the Army have enough Multi-Role Bridge Companies to support all its divisions.

What’s more, many of the Army’s bridges, such as the Improved Ribbon Bridge, aren’t strong enough to bear the weight of heavy vehicles such as the 70-ton M1 Abrams tank. “The current bridging equipment has the same capability shortfalls that we had in World War II,” said Iyer.

The Army also needs a centralized doctrine for river crossing operations that goes beyond merely building the bridge itself, and not how to seize and secure a bridgehead. “Publications remain technically focused on engineer considerations and calculations to execute a crossing,” Iyer said.

Simply having the engineering capability to quickly build a bridge across a mile-long river is no minor feat. The question is whether it can be done if the enemy objects.

Michael Peck is a defense writer whose work has appeared in Forbes, Defense News, Foreign Policy magazine, and other publications. He holds an MA in political science from Rutgers Univ. Follow him on Twitter and LinkedIn.

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