工人们在水坝周围建造了围堰，以便在干燥条件下进行基础维修工作。

The workers constructed ___cofferdams around the dam to carry out foundation repairs in dry conditions.

救援队迅速搭建围油栏，防止泄漏的原油污染附近海域。

The rescue team quickly set up ___cofferdams to stop the leaking crude oil from contaminating the nearby waters.