Why are watersheds important to humans? and, Why are watersheds important to wildlife?

A watershed is the definition of the area drained by a water course (so for example the watershed of a river in a valley would stretch from the peak of the hill range on one ride, to the peak of the ridge on the other. They are usually defined along the largest river eg the river which meets the sea, or lake (since if two streams drain into the same RIVER, then although the streams may have separate watersheds, both within the RIVERS watershed).





Watersheds aren't really important to humans (or wildlife) in and of themselves, its it the amount of precipitation what is caught up within the watershed.





Look at Brazil in an atlas. The Amazon has a vast watershed and it is easy to see, the mountains to the north and west and the hill ranges to the south border and define the amazons watershed.