We pull up to the edge of the steep red canyon and get our first view of the Maunalei Gulch, looking down at the biggest watershed on the Hawaiian island of Lāna‘i. As I look down, the bare valley walls of the canyon are exposed, devoid of plants that might keep soil from rushing down onto the island’s fringing coral reef below.
From this vantage point in the wintertime, you can see humpback whales in the channel between Lāna‘i and the island of Molokaʻi, which is part of the Hawaiian Islands Humpback Whale National Marine Sanctuary. During the winter, you can also see massive flash floods racing down this canyon when it rains, carving out soil and blanketing the adjacent reef with sediment until the reef takes on the color of a cappuccino.
By contrast, in the summer the Maunalei Gulch is almost bone-dry. As on many Pacific islands, watershed degradation from land-cover change has led to sustained high sediment runoff, which has damaged the nearshore reefs and fisheries that benefit many local people. Deforestation for agriculture, overuse of freshwater resources during the pineapple plantation era and overgrazing by introduced feral deer and mouflon sheep have led to the disappearance of Maunalei Stream — once the only permanent stream on the arid island.
To address these issues, in 2012 the CI Hawaiʻi program started working with Lānaʻi community members to implement a coastal restoration project in the area, combining traditional knowledge and modern science. Continue reading