| The value of Hawai‘i’s watersheds are vastly underestimated in terms of their service and contribution to the state’s economy and quality of life to residents and visitors.
Water Forested watersheds provide several basic and crucial functions related to maintaining a source of high quality water. The first is that of an umbrella. Tree leaves, branches, and understory plants intercept rain before it reaches the ground. The erosive, kinetic energy of falling rain is absorbed by the foliage, which reduces erosion and increases infiltration of rainwater into the ground. Watershed forests also acts as a sponge, soaking up rainfall into its soil, leaf litter, mosses, ferns, and foliage, and slowing evaporation by shading the water-holding soil layers. Not only rainfall is absorbed in this way, but forest vegetation can also pull moisture from passing clouds that are not raining. Cloud and fog condensation on trees and other vegetation is an important source of water. Cloud and fog interception in Hawai‘i can increase total precipitation by as much as 30% above the base annual rainfall. When foliage, litter, and soil are fully saturated, they buffer the release of stored water, delivering a more consistent and dependable source of water for use long after the rain has ceased falling. Thus stream flow, from intact, forested watersheds are cleaner and more consistent during dry periods. In contrast, denuded watersheds are “flashy,” sending floods of muddy water into streams during rain and dry up rapidly when the rain stops. A forest watershed is that of an entry valve into the groundwater cycle. The cool ground-level shade provided by intact forest and dense shrubland greatly suppresses the loss of water through evaporation. This allows much of the rainfall and condensed fog drip to infiltrate into the ground, percolate through the soil, and enter ground water or stream systems as clean water. Another major function of a forested watershed is that of a soil anchor and filter. The roots of trees, shrubs, and associated understory plants grip the steep mountain soils tenaciously, and prevent soil from washing into our streams and ocean. This helps maintain clear surface waters dependent on surface flow and also protects our ocean reefs and other marine life from sedimentation. Native Species and Ecosystems Watershed partnerships and alliances have drawn attention to the important relationship between functioning watersheds and native Hawaiian ecosystems. The watershed vegetation of the KWA is Habitat for thousands of native plants, birds, snails, insects, and other invertebrates. Kaua‘i contains 47% or 383 of 813 endemic species of flowering plants of the archipelago, 55% of Hawai‘i’s endemic bird species, and 42% of the islands’ natural communities. There are species and forms found only in the lands within the KWA area, and scientists estimate the area is home to an untold number of undescribed species. Greatest Value Perhaps the greatest value of the thousands of native species in our upland forests is the function that they perform together, as part of a complex, natural ecosystem. The balance achieved over the millennia has produced forests that can best weather the typical cycles of drought and flood in the region and are uniquely adapted to the climate and soils of the mountain. Native forest ecosystems provide the best chance for a stable watershed. Native species and ecosystems also play a crucial role in Hawaiian cultural practices and in scientific research. Woodworking, weaving, cordage, herbal medicine, feather work, and lei-making remain important. The significance of native forests to Hawaiian culture also includes the intellectual and spiritual foundation of the Hawaiian worldview, based on ancient relationships between the people, gods, and land. The native forests is wao akua (the realm of the gods), and the realm of inspiration for the high arts of chant and hula. Finally, there are few better natural laboratories than Hawai‘i for the study of evolution, the role of individual species in an environment, and the complex relationship between organisms. Other Resource Values In a recent economic study (“Environmental Evaluation and the Hawaiian Economy,” prepared by the University of Hawai‘i), the total value of native forest was estimated to be worth billions of dollars. Clearly our forests are enormous economic assets. Just as clearly, the cost of maintaining them is not reflected in the price we pay for water and other benefits they supply. Tourism, hunting, hiking, fishing, forestry, agriculture, and biotechnology are all industries that directly benefit from our forests. Public Support for the protection of native forests is evidenced in a 2001 Malama Hawai‘i poll that showed 70% of respondents supported funding for increased watershed protection. Equally important, forest protection is merited on economic grounds. Protection of this natural resource facilitates economic development. A healthy watershed means a greater amount of groundwater and surface water for the states residents and businesses. In addition, the world renowned beauty of Hawai‘i’s watershed areas and their recreational opportunities are one of the major draws of Hawai‘i’s number one industry – tourism. |
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The Kaua‘i Watershed Alliance The Watershed The Value of Forested Watersheds |
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| Introduction and Background - The Value of Forested Watersheds Native Ecosystems - Primary Threats - Existing Management |
| Introduction and Background - The Value of Forested Watersheds Native Ecosystems - Primary Threats - Existing Management |