Hanalei Science Today

Hanalei Watershed Fact Sheet
  • The Hanalei Bay Watershed includes the ahupua'a of Waikoko, Waipa, Wai'oli and Hanalei.
  • A watershed is an area of land, extending mauka to makai, with a common outlet to the ocean. Rainfall “sheds” off the land and into rivers and the Bay. Some rainfall is stored as a “shed” stores tools.
  • Native forests are more effective at intercepting and storing rainfall and fog drip than forests comprised of non native plants. Hanalei forests have limited native plants.
  • The reefs and water quality of Hanalei Bay and River have been studied for over twenty years.
  • Debris such as trees and rocks generated from Hurricane Iniki moved down the Hanalei River in the floods of 1995-96, causing the river to jump its bank and form a new channel. The irrigation intake and ‘auwai that deliver water to some Hanalei farmers do not work well after a flood because rocks move, forcing the water down the new channel, which bypasses the intake pipe.


Pollutants of concern include turbidity, nutrients and bacteria:

  • Turbidity is a measure of the amount of sediment and plant material in water. Sediment is generated at both natural (background) and accelerated rates. Increases are caused by human and animal (e.g. pig) disturbances and changes in vegetation from native to non native plants (e.g. Australian Tree Fern).
  • Nutrients such as Nitrogen and Phosphorus occur naturally in waters. Increased concentrations can result from fertilizers, sewage discharges, and green waste from farming and landscaping.
  • Bacteria come from people, pigs, and other warm blooded animals. Disease causing bacteria are referred to as pathogenic.


Things you can do to improve the water quality in Hanalei:

  • Plant native plants; volunteer with efforts to restore mauka forests; use Best Management Practices [KD1] when digging or working on the land; replace cesspools; service your septic tank.
  • Do not over fertilize a garden, lo'i or farm. Read and follow package directions.
  • Compost and mulch all green waste. Do not blow or wash green waste into storm drains.
  • Report any land use practices that do not incorporate Best Management Practices.
  • Support local efforts to monitor our lands and waters. Support enforcement.


Recent events of concern in Hanalei:

  • Late rains in the summer of 2011 delivered valley mud to the bay. There was no summer swell to move this mud out to sea. Some coral die off was observed.
  • Warming oceans cause acidification, which also causes some coral death.
  • Land use practices in Hanalei Valley did not use filters and screens to prevent mud flow


If you see something of concern:

Hawaii Department of Health           Gary Ueunten                    241-3323

Coastal Zone Management             Les Milnes                         241-4064

Hanalei Watershed Hui                   Makaala Kaaumoana           826-1985


For more information about water quality in Hanalei, please come to our community talk story with Andy Hood of Sustainable Resources Group Intn’l, Inc. on May 2012

To learn more about the Hanalei reefs, please join us on June 2 at 6:00 pm at Waipa. Drs. Alan Friedlander and Eric Brown will be here to talk story about the Coral Reef Assessment and Monitoring Program in Hanalei.


The Hanalei Makai Watch Program welcomes your interest and participation in community based resource monitoring and enforcement support.
Watershed Management Plan for HanaleiBay Watershed


The Hanalei Bay Region is currently targeted by planning efforts with the goal of improving the health of watersheds, streams and rivers, nearshore waters, and coral reefs. A Watershed Management Plan (WMP) is being developed for the Hanalei Bay Watershed. The WMP summarizes general watershed conditions with an emphasis on identifying the sources, transmission, and fate of land-based non-point source (NPS) pollutants. Using this information, management strategies are recommended for preventing and treating NPS pollutants. The WMP identifies locations for management practice implementation and prioritizes installation based on potential effectiveness and relative cost. Monitoring protocols help determine how well the solutions are working. Stakeholder involvement is essential in developing and implementing the WMP, and details on activities to engage the local community in efforts to reduce NPS pollution are identified. The plan supports activities designed to achieve Total Maximum Daily Loads (TMDLs) that have been developed for the area.

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