They are better controlling their water by building stone barriers to help the soil keep the rain that does fall.

他们通过建造石质壁垒来帮助土壤存留降水，从而更好地控制湖泊水量。

In the morning, the stranger began to dig the foundations at an astonishing speed, and at nightfall he set off towards the mountains to obtain the building stones.

早晨，这个筑墙者开始以惊人的速度挖地基，在傍晚时分，他去山上去拿建筑要用的石头。