The New Adventures of Lassie (2014)

S1E20 Trapped

Zoe, Lassie, and Harvey venture into the high country alongside Graham as they notice the water levels of Diamond Lake mysteriously dropping, putting the animals that rely on it at risk. Concerned, Graham suspects that something may have obstructed the water's flow. The rangers soon find a logjam that has blocked the creek supplying the lake and begin to dismantle it. However, they remain unaware that Graham is caught in an underground channel, which will be flooded as soon as they break the logjam.