Land-use planning and water resources in Hawaii under climate change.
Giambelluca, T.W., M.A. Ridgley, and M. Nullet
The Pearl Harbor basin on the tropical oceanic island of O’ahu, Hawai’i, is characterized by extreme climatic gradients, a fragile hydrolic system, and rapid land-use change. With all the management problems posed by those attributes, planners must now also consider the effects upon the regional hydrolic system due to possible climatic change. This paper describes an ongoing modeling effort to design and evaluate alternative land-use patterns under present and possible future climates. First, the paper focuses on the hydrogeological effects of climate change by estimating such possible effects through the application of a water-balance simulation model to each of 49 different climate scenarios. Evaporation is estimated to increase if temperature increases. Water-balance model runs demonstrate that for an increase of potential evaporation of 10%, even an increase in rainfall of 10% may still result in a significant decrease in available water. The problem of incorporating such findings into planning models is then addressed, with the discussion centering on the applicability of interactive multiobjective optimization. Reference-based programming techniques, perhaps utilizing some notions from fuzzy and stochastic programming, are considered especially suitable.