Example 4: Crane Creek, Oregon
(Schaffer 1941).
Prior to 1924 beavers were present
in Crane Creek and the meadows had
stirrup-high native grasses that were
sub-irrigated by beaver ponds. In 1924
the beavers were trapped out. In 1925
the channel began to incise and by
1935 the channel had deepened 25 feet.
Instead of stirrup-high native grasses,
there were clumps of new sagebrush
and only sparse remnants of the original
grasses, showing how fast channelization
and transformation of an ecosystem
could occur. In 1936 the beavers were
reintroduced, and by 1938 the water table
had risen and the hay meadow production
had improved. 1939 was a drought year,
yet water was abundant on the ranch with
beaver ponds, while absent downstream
on the ranch without beaver ponds.