of Waikamoi Preserve in Maui, Hawaii.
Aerial view view of Waikamoi Preserve, Maui. © Ian Shive/Tandemstock.com

2018 Hawai'i Impact Report

Food and Water for Generations to Come

On Maui, we are ensuring a future supply of fresh water and improving ocean health, while on Hawai‘i Island we're reviving traditional Hawaiian aquaculture.

girl in a rain jacket in the jungle
TNC’s Roxie Sylva hiking in Waikamoi Preserve, Maui. © Ian Shive/Tandemstock.com

Ensuring Fresh Water for the Future

A sustainable water supply in Hawai‘i depends heavily on the health of our native forests. Healthy forests act like a sponge, collecting rain and moisture from passing clouds, slowly delivering fresh water into streams and aquifers, and reducing runoff onto our shorelines and reefs.

In 2018, the University of Hawai‘i Economic Research Organization conducted an evaluation of TNC’s 9,000-acre Waikamoi Preserve, which lies within the greater East Maui Watershed, the island’s primary source of water.  The evaluation put the value of the fresh water that Waikamoi produces at $36.2 million and projected that our conservation efforts will save 63.7 billion gallons of fresh water over the next century, including 32.5 billion gallons in groundwater recharge. By 2072, our conservation work will also prevent 4,300 tons of sediment per year from washing into the ocean.

in Maui.
Testing water quality in Maui. © Bruce Forrester

Improving Our Ocean Water Quality

Major storms can leave coastal waters a brown, soupy mess. With that brown water comes diseases, chemicals, pesticides and other contaminants harmful to human health and to coral reefs and the marine life and food they provide.

On Maui, the frequency and severity of these events prompted TNC and its partners to launch Hui O Ka Wai Ola, a citizen science water quality group that trained volunteers to provide much-needed assistance to the State Department of Health (DOH).

Following strict EPA and DOH standards, the group collects critical water quality data that informs management of the island’s nearshore waters. This past year, its 40 volunteers expanded their efforts from 18 to 39 sites on Maui and developed a quality assurance plan that has become the prototype for other groups across the state. The group’s data is already being used to affect local policy and funding decisions, and the program is being shared with international reef managers as a model to improve water quality at local scales.

people building a rock wall around a pond
BUILDING THE KIHOLO ROCK WALL part of a restoration project at Kīholo Fishpond Preserve in West Hawai‘i. © Nancy Erger

Restoring Fishponds for People and Nature

Hawaiian fishponds, or loko i‘a, are an advanced form of aquaculture unique to Hawai‘i. But over the past century, nearly all were destroyed or fell into disrepair. Fortunately, some survived, and today there is statewide interest in reestablishing these important cultural resources and enhancing local food security.

In 2018, TNC and our community partners made tremendous progress in restoring our Kīholo Fishpond Preserve in West Hawai‘i.  More than 1,000 volunteers removed enough weeds to fill 18 dump trucks and working with local kūpuna rebuilt 950 feet of the pond’s traditional rock walls. In addition, we built a 1,950-foot fence around the ponds to keep out feral goats that destroy native vegetation. We are now constructing an on-site nursery and restoring the area’s traditional native plants.  Kīholo is providing a thriving habitat for native shrimp, crabs, snails and limu (algae), and native fish populations are rebounding, with a 10-fold increase in ‘anae (large mullet) since 2012.

in Hawai'i waters.
School of Āholehole in Hawai'i waters. © TNC

Read More from Our 2018 Impact Report

Kō i ka Pono: Carrying Out Our Mission