Watersheds of the Region

 

A watershed is a defined ‘basin’ area that collects rainfall and drains into a body of water.  The watersheds of the Maunalua Bay region generally, but not exactly, match ahupua`a (Hawaiian land division) boundaries, running from the sea to the mountain top.  From the west to east, they are:  Wai`alae Nui, Wai`alae Iki, Wailupe, Niu, Kuli`ou`ou, Haha`ione, Kamilo Nui and Kamilo Iki.

 

When healthy, these watersheds capture rainfall in this relatively dry Kona district of the island, allowing it to remain on the land and percolate slowly underground.  Plants – from trees to ferns – serve as a filter as water moves downhill, especially during heavy downpours.

 

The most dramatic change has been paving of these valleys and ridges. Human-made drainage systems and the overall hardening of the land have altered the natural system of the watersheds, resulting in excessive outputs of sediments and land-based pollution.  This harms the bay’s reefs and all life that depend on clean water.  If we want a healthy bay, we must address these problems.