The passage of the Alva River of 17-18 March 1811 was a nearly bloodless success for Wellington’s army during the French retreat from Portugal in the spring of 1811. On 16 March the French had abandoned their position on the Ceira River at Foz de Arouce, and retreated towards the Alva. Once there they discovered that the bridge at Ponte de Murcella had been destroyed by the Portuguese and were forced to spend the rest of the day repairing it, all the time expecting Wellington’s advance guards to appear.
In fact Wellington had chosen to spend 16 March resting, partly in order to give a supply convoy time to reach his army. This gave Masséna enough time to get his army across the Alva, and to take up strong defensive positions on the north bank. The 2nd Corps was sent east, to defend the ford at Sarzedo, placing a detachment at Arganil on the south bank of the river. The 6th and 8th Corps remained around Ponte de Murcella, guarding the fords across the river.
The line of the Alva was a strong defensive position. During Masséna’s advance into Portugal in 1810 Wellington had intended to defend, but to his surprise the French had chosen a more northerly road, crossing the ridge at Bussaco.
Now he was faced with the same defensive position, Wellington had no intention of launching a frontal assault against the strong French positions. Instead, the 1st, 3rd and 5th Divisions and the Portuguese brigades were all sent along the mountain road from Furcado to Arganil, while only two divisions were sent towards Ponte de Murcella. These last two divisions remained hidden from Ney, who could only see cavalry on the southern bank of the Alva.
During the afternoon of 17 March the main British column reached Arganil, driving out the detachment from Reynier’s 2nd Corps. At this point no infantry had been seen at Ponte de Murcella, and Masséna was convinced that the British intended to either attack at Sarzedo, or to move even further east, cross the river beyond the French left, and attempt to block their line of retreat. Accordingly he ordered Junot’s 8th Corps to leave its camps on the French right and move to Galiges, to the east of Sarzedo, to extend the French left.
Wellington’s plan was actually rather less ambitious than Masséna believed. On the morning of 18 March the Guard’s Brigade of the 1st Division left the road from Furcado to Arganil, and forced their way across the Alva at Pombeiro, between Ney’s position at Ponte de Murcella and the rest of the French army. Realising that he was in real danger of being trapped between the two wings of Wellington’s army, Ney abandoned his position with great speed, and managed to elude Wellington’s trap. Despite this, the British and Portuguese had forced the French out of a potentially very strong position with very little lose. The French were forced into a lengthy night march which saw the British capture 600 prisoners.