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Wetland Water and ‘Ike (WAI): Improving Understanding of Hydrology to Inform Management Decisions

Wetland Water and ‘Ike (WAI): Improving Understanding of Hydrology to Inform Management Decisions

Wai flows through the Heʻeia wetland and feeds the brackish Heʻeia Fishpond.

Using a reciprocal collaboration approach, this project revealed complex patterns of surface and groundwater flow to support Indigenous resource management strategies for biocultural restoration.

Native Hawaiian communities hold wai (fresh water) and its life-giving power as sacred. Wai has been historically managed by Native Hawaiian communities to sustain food security on the most remote islands on Earth. However, in the past century, land use and socio-economic change has transformed many of Hawaiʻi’s coastal landscapes, leading to altered groundwater recharge, storage, and transport, and reduced surface water flows. These changes have contributed to the decline of traditional agroecology and aquaculture systems at Heʻeia National Estuarine Research Reserve (NERR) on Oʻahu, Hawaiʻi. To bring back abundance into the Heʻeia ahupuaʻa (Native Hawaiian social-ecological land and sea division roughly following watershed boundaries), the community expressed the need to understand how much and what kind of wai flows through the wetland and estuary, and its potential influence on the restoration of Indigenous biocultural systems.

This project performed an in-depth characterization of surface and groundwater flow throughout Heʻeia to inform biocultural restoration and future groundwater management. Building on previous conceptual understandings, the project team measured surface and groundwater flow within Heʻeia. This project elucidated main questions characterizing the quantity, quality, and ages of surface and groundwater flowing through the Heʻeia watershed, with downstream implications for food and wildlife, fishpond productivity, and nearshore reef health. Looking forward, this work established collaborations with Indigenous resource managers, interfaced with complimentary work conducted by utility and government agencies, and provided ʻike to inform comprehensive and collaborative management of wai in the Heʻeia ahupuaʻa. The project’s collaborative process was essential to this work and included the convenings of a project advisory group and intended users (named Hui WAI). Iterative Hui WAI meetings shaped the project from its beginning to end, through the codevelopment of the proposal, research methods, workshops, and outputs. This process enhanced communication and relationships among investigators, resource managers, educators and helped build collective knowledge of the ways wai links biocultural restoration projects at partner sites.

Major outputs from this work include: 1) a dataset describing above and belowground hydrology and water quality in Heʻeia, including seasonal and extreme event variability; 2) a consolidated web-based access point to multiple data streams related to water quality and hydrology in Heʻeia; 3) workshops that promoted intergenerational transfer of ʻike (knowledge) of water management, with shared objectives of Indigenous and conventional knowledge on cultural, scientific, policy, and management aspects of water; 4) piloted water science and management education programs at partner sites; and 5) data analysis reports and conference presentations shared with local, national, and international audiences advancing the knowledge of hydrology and nutrients as they relate to biocultural restoration.

The Impact

  • Enhanced communication and relationships among investigators, resource managers, educators, and users which has inspired future reciprocal and collaborative efforts at the watershed-scale.
  • Researchers and partners attained a more nuanced understanding of hydrology and nutrient dynamics in Heʻeia watershed, and will apply this understanding to policy decisions, agro-ecosystem and Indigenous aquaculture restoration planning, and habitat conservation.
  • Improved access to up-to-date data from multiple sources, allowing resource managers to better adjust management practices on daily to monthly scales.
  • Better understanding of cultural values surrounding wai, local hydrology, relevant water policies through the workshops and implementation of education curricula.
  • Tiered mentoring helped develop the skills and confidence of water scholars at stages in their career and education.