West Maui Restoration Model

West Maui watersheds suffer from stressors to the nearshore reefs, including the impact of pollutants from legacy agriculture, increasing urban runoff, and wastewater injection wells that connect to the ocean.

As former agricultural lands begin to re-stabilize after abandonment, one of the major concerns is the eroding legacy sediments. These sediments, found in channels or gulches, appear to be a significant source of sediment to downstream reefs. Sedimentation poses a threat to reefs as it increases turbidity, clouding the water and blocking light from reaching the light-dependent zooxanthellae upon which coral relies.

Fortunately, the headwater areas within the West Maui watershed have been protected and preserved. Extensive efforts have occurred there to remove and keep out invasive and non-native animal species (wild pigs) and to block illegal recreational motor biking. Until recently, the middle watershed areas were intensively cropped for pineapples, seed corn, and sugarcane.

The relatively erodible soils entrained within the streambeds and flanking terraces within the middle portion of the watershed continue to transport legacy sediments.  Preliminary findings suggest that these are mobilized by relatively small rain events.

It is our intention to work within these middle and lower watershed areas to address sediment transport within the gulches. Using bioengineering practices we can act to restabilize these areas for the long-term and help to mitigate the impacts from potential future land use changes. After developing a successful restoration model to deal with these mobile sediments in one watershed we will be able to transfer those methods to other West Maui watersheds, including those held by private landowners and corporations.