WATER IS ONE OF THE MOST PRECIOUS RESOURCES that is increasingly threatened by more frequent droughts, wildfires, flooding, and extreme climate events.
In Hawai‘i, freshwater sources are especially limited. Local communities depend on surface and groundwater for residential, agriculture and business needs, while the military’s extensive presence places additional strains on this vital resource.
In order to improve water resiliency in the state, the US Department of Defense (DoD) Naval Facilities Engineering Expeditionary Warfare Center (NAVFAC EXWC) partnered with the University of Hawai‘i System, National Security Innovation Network and One World Water to explore new ways to steward, sustain and reimagine water resources in Hawai‘i through a groundbreaking initiative called the Ho‘olana Water Resilience Prize Challenge.
Through a $300,000 investment from NAVFAC EXWC, this collaborative endeavor seeks to foster the sustainable growth of research and early-stage ventures that address governmental and commercial water challenges and opportunities. Through $75,000 seed funding and mentorship, NAVFAC EXWC aims to empower selected teams in refining their solutions, advancing their research or technologies, expediting contracting pathways, and enhancing cross-service partnerships.
The pilot program launched in fall 2023 and two of 13 proposed water resilience solutions were selected for further development. One project employs analytical and machine learning image analysis to detect cloud immersion in Hawai‘i’s tropical montane cloud forests. The other is exploring the potential of bivalve aquaculture to improve Pearl Harbor’s water quality and ecosystems.
“While both teams presented distinctly different projects and methodologies, they each offer innovative, community-based solutions to significant environmental challenges,” said Cameron Becker, NAVFAC EXWC environmental engineer. “The cloud immersion project excels in its technical simplicity, which will facilitate a smoother transition and widespread adoption of the technology within and beyond the DoD. On the other hand, the restorative aquaculture project excels in its community-informed approach and the integration of restorative measures to address escalating environmental issues.”
Detecting Cloud Immersion
through Machine Learning Analysis
Sitting between than 800-3,500 meters in elevation, tropical montane cloud forests are unique tropical ecosystems characterized by frequent ground-level cloud immersion or fog. Cloud droplets collecting on vegetation is an important source of water in these forests, while persistent cloud immersion cools the air and blocks sunlight, significantly reducing water loss from evaporation. Fog plays a key role in the propagation of plants and biodiversity in these ecosystems, and better understanding fog patterns can aid in conservation, reforestation, and natural resource management.
Unlike rainfall, the phenomenon of fog meteorology and its interaction with vegetation is still misunderstood and understudied, as conventional instrumentation for measuring cloud droplets is expensive and difficult to calibrate and maintain across multiple sites.
However, a team from the University of Hawai‘i at Mānoa (UH Mānoa) Water Resources Research Center is working on using machine learning to detect fog and estimate cloud water content from camera images. This low-cost, image-based solution to capture near real-time cloud immersion data and enhance researchers’ understanding of fog and its impact on montane regions in Hawai‘i.
“By using cameras as a low-cost approach for estimating the availability of cloud water in tropical montane cloud forests, we hope to better monitor spatial and temporal cloud immersion patterns across diverse geographies and ecosystems,” said Dylan Giardina, who is part of the team’s research staff. “This represents an important first step in beginning to understand how much water is intercepted by vegetation, developing wall-to-wall climate maps for cloud immersion, and understanding how cloud water availability might be impacted by climate change.”
In addition to their applications in fog monitoring, cameras can be leveraged to support helicopter and field operations at remote sites.
Restoring Natural Habitats
of Pearl Harbor
Another team from University of Hawai‘i at Hilo (UH Hilo) Pacific Aquaculture and Coastal Resources Center (PACRC) has partnered with Hui o Ho‘ohonua, Waipahu High School and Goose Point Oyster & Hawaiian Shellfish on O‘ahu to identify opportunities for using oyster bivalves to improve water quality and habitats in Pearl Harbor.
Long before Pearl Harbor became a historic naval installation, the estuary was better known as Wai Momi or “Pearl Waters” for its abundance of native pearl oysters. However, continual dredging of the harbor and decades of residual runoff pollution and sedimentation from urbanization, agriculture, flooding and erosion, have drastically changed the landscape and area’s ecosystems.
As suspension feeders, oyster bivalves ingest and filter out excess phytoplankton resulting from run-off from terrestrial sources like nitrogen and phosphorus. They also help settle sediment from erosion, helping to maintain water clarity.
“Wai Momi was once a majestic estuary, rich with biodiversity,” said Rhiannon Tereari‘i Chandler-’Īao, UH Hilo aquaculture policy and extension specialist and former Waiwai Ola Waterkeepers Hawaiian Island executive director. “So much of its natural ecosystems have been transformed or lost; it’s hard to find even one pearl oyster in the harbor now. It’s no surprise that water quality is an issue.”
Before addressing water quality, the team will focus on locating, identifying, and confirming native and other local bivalve species, including the Hawaiian Oyster (Dendostrea sandvichensis), Black-lip Pearl Oyster (Pinctada margaritifera), Rayed Pearl Oyster (P. radiata) and the non-native Eastern Oyster (Crassostrea virginica).
By applying modern genetic sequencing, the team hopes to learn more about these less-studied invertebrate species, including the possibility of discovering new ones. Once identified, the native oyster species will be collected and transported to UH Hilo’s hatchery for a labor-intensive spawning and conditioning process, which will be performed by local college and high school students interested in aquaculture.
“Water restoration is an incremental process,” explained Maria Haws, UH Hilo aquaculture professor and pearl oyster specialist. “We have to take these basic but difficult first steps in finding and propagating these native bivalves before moving on to their potential environmental, commercial and cultural opportunities. But once we do, it will be an explosion of possibilities, including aiding in the restoration of Pearl Harbor’s loko i‘a (fishpond).”
Added Chandler-’Īao, “Being in these marine areas and trying to find these species is like piecing back together the fabric of our history and culture. Restoring our relationships with these marine species is a win-win not only for the Navy and our environment, but also for the community, culture and even our economy. That is why we also need to take kuleana (responsibility), as a community, for the types of fertilizers, detergents and household pollutants we use, that eventually flows down into the watershed of Pearl Harbor.”
Next Steps
Both teams will continue to work with NAVFAC EXWC through the end of the year, when they plan to present research updates to government, industry and venture capital communities to determine further development and possible acquisition opportunities.
“Water resilience is a global problem that will not be solved overnight,” said White. “It will require an ongoing effort and this challenge is allowing us to build long-term partnerships and help us diversify our knowledge, resources and collective efforts.”