From the Hana highway you can see a lot of waterfalls of various sizes, some are tall and just a trickle of water, while others are short and wide.  The flow of water depends mostly on the rain and how much water is being held back upstream by the East Maui Irrigation Company.  They have built water catchment canals and dams across most streams to redirect all that water to central Maui to use for growing sugar cane.  Maui’s watershed is quite small so daily rain is very important to keep the water levels high going over the falls. Get more information from Hana Picnic Co.