The poem contrasts the deep and rapid motion of the water in the canal with the dry earth to symbolize both the limited resources of his hometown and the rich inner life of the speaker that has yet to be nurtured. The dirt is mentioned twice in the poem, first when the boys are “hurling large rocks at the dusty ground” (Line 9), symbolizing an acting out against their disappointing hometown, and then again later when their own shadows stretch out and “gripped loose dirt” (Line 17). The latter reference symbolizes their own lonely experience and the feeling of being trapped on that earth like shadows. Dry dirt is no place to grow and expand; it is difficult to seed, plow, irrigate, and cultivate. For that reason, it works well as a symbol of their inability to thrive and expand in their hometown and the need to move and grow somewhere with more fertile ground.

In contrast, the water of the canal brings rapid motion to the poem, moving out of town like “migrating birds” (Line 12), like a swaying train (Line 18), and like the teenagers hope to do as well. The water is “white-tipped but dark underneath” (Line 21), symbolizing a roughness on the outside that hides a greater depth underneath.