Speaker: Dr. Jonathan Scheuer
Abstract:
The Hawai‘i Water Code mandates groundwater management by the determination of Sustainable Yields (SY), a modification of the “safe yield” concept forwarded over a century ago. The Water Commission, trustees of the water resources trust, have not changed their basic approach to setting SY since it was adopted in the 1990 Water Resources Protection Plan. Nearly every aquifer’s SY in Hawai‘i is regulated assuming the area has a single unconfined basal aquifer, and the Robust Analytical Model (RAM) is applied. The Commission is to be commended for regulating groundwater withdrawal and not setting SY equal to recharge. However, the approach has often failed the design goal of preventing rising chlorides in wells, led to decades of litigation, and in many areas failed to protect Public Trust uses of water. Frequent debates across Hawai‘i over the “correct SY” for particular areas distract from the structural shortcomings of the current SY approach. Continued universal application of RAM-driven SY favors resource extraction over Public Trust interests, and climate change driven reductions in recharge will increase disputes. A new approach to fulfilling the Code’s mandates is needed—guided by community identification of what needs to be sustained, with an explicit consideration of justice and grounded in current science. Specific “correct SY” discussions will be reviewed to illustrate these points and suggest pathways forward.