When we went to check out the cherry blossoms (see here and here) we toured the area with the car, so were relatively free to do anything and stop anywhere we wanted. Driving back I saw that there was an enormous dam and we stopped to check for otter signs (see here for my post on these otters) and were duly rewarded.
The dam in itself was also quite beautiful, and we had fun skipping stones and watching a canadair drop into the water time and time again. Not a bad end to the adventurous day!