Operation Impact Plain (11 April 1945) was the first of two amphibious operations carried out to support the right flank of the British advance into the Argenta Gap, the final battle for the Eighth Army in Italy.
On their right the 56th Division launched their first amphibious attack, Operation Impact Plain. This saw an infantry brigade land near Menate, about half way along the shore of the extended lake, and seven miles to the north-east of the key bridge of Bastia. The attack achieved surprise, and Menate and nearby Longastrino both fell to the amphibious attack. Another brigade advanced west from the ‘wedge’, along the north bank of the Reno, to join up with the amphibious force.
The aim of the operation was to capture the villages of Menata and Longastrino, in the narrow spit of land between the flooded area west of Lake Commachio and the Reno River. In order to take Menata, the Allies needed to capture a bridge over the Menata canal, which ran north-east from near Argenta to the lake. The flooded area had been created by blowing a hole in the Argine Dike, which ran east-west along the edge of the flooded area (and presumably now forms one bank of the canal that surrounds the drained area.
The plan was for 40 RM Commando to attack along the dike and take the bridge and pumping station at Menate, then advance along the ‘Strada del Pioppa’ (probably the modern Via Argine Pioppa, which runs west/ north west from Menate. They would be followed by three battalions from the 169th Brigade, 56th Infantry Division, moving in LVTs (Landing Vehicles, Tracked). The 2nd/5th Queen’s Royal Regiment would cross the canal bridge and take Menate, the 2nd/6th would take Longasrtrino, a short distance to the south-east and the 2nd/. 7th formed the reserve.
40 RM Commando advanced along the Argine Dike. When they reached the breach they crossed it using two rubber boats to form a pontoon bridge, but soon ran int mines on the western side of the breach. Despite the explosions, they remained undetected. They then reached the point where the canal reached the dike, and at that point came under fire. The marines attacked towards the bridge, but the entire assault party was wounded or captured and the Germans occupied the pumping station. However they were unable to blow the bridge, as the wires to the explosive charges had been destroyed in the fire fight.
Soon afterwards the leading LVTs with the 2nd/5th appeared, and the Germans surrendered. The marines were then able to cross the canal and secure the pumping station, taking 19 prisoners and capturing a self propelled gun. The two battalions from the Queens also crossed the canal, and by 2100 hours had secured both villages. This was 40 RM Commando’s last battle of the war, and it cost them 27 dead and 45 wounded, but the attack towards Menate helped open up the Argenta Gap, which led to the Eighth Army breakthrough into the Po and the collapse of German resistance.