Barrage de Nitray, Needle dam in Athée-sur-Cher, France

Barrage de Nitray is a 19th-century dam that stretches across the Cher river between Athée-sur-Cher and Saint-Martin-le-Beau. The structure has a concrete base supporting wooden needles that can be raised or lowered to adjust the water level, along with a masonry lock chamber for boat passage and a lock keeper's house built in stone.

Built between 1836 and 1841 to improve navigation on the Cher river as part of the Berry Canal project linking Montluçon and Tours, the dam saw heavy boat traffic in the 1800s. The rise of railways in the late 1800s caused commercial shipping to decline sharply, and it nearly stopped by 1957.

The lock keeper's house at Nitray has two separate dwellings, one for the lock keeper and one for the dam operator, plus a shared bread oven. A storage room beside the house held the wooden needles over winter. The lock and its house stand on the left bank, unlike other Cher dams, because the mill and spillway already occupied the right bank.

The dam, lock and lock keeper's house stand on the left bank at Athée-sur-Cher, while the mill and its fixed spillway are on the right bank at Saint-Martin-le-Beau; the site lies just north of the Château de Nitray, at about 53 m altitude. The lock chamber measures 35.00 × 5.20 m and is closed by two double-leaf wooden gates. An animated model in the lock keeper's house explains how the needle dam works.

The dam uses a clever system of wooden needles invented by engineer Poirée in 1833 that allowed operators to adjust water levels without machines by adding or removing them one at a time. Though no longer used for boats, this hands-on method shows how people once engineered solutions with simple materials and manual skill.