SWAGMAN Options: A hierarchical multicriteria framework to identify profitable land uses that minimize water table rise and salinization

摘要

In irrigation areas of southeastern Australia, recharge from rice cultivation is contributing to water table rise. The presence of a shallow water table exacerbates the damage potential of waterlogging and soil salinization, and threatens the long-term productivity of irrigated agriculture. By minimizing farm net recharge, water table rise and the damage potential of waterlogging and salinization can be minimized. A hierarchical multicriteria framework, SWAGMAN Options (Salt Water And Groundwater MANagement), is developed to identify profitable nonriceland uses which complement rice growing and induce discharge from shallow water tables without exceeding critical levels of soil salinity. The framework is multidisciplinary in its approach. Fundamentals of agronomy, irrigation, economics, hydrogeology, and operations research are used to formulate this framework. SWAGMAN Options is applied to the Camarooka Project Area in New South Wales, Australia, to study the sensitivity of maximum rice area per farm, rice field water use limit, rainfall conditions, optimal depth, critical salinity, initial piezometric levels, and weights associated with the objective functions on subsurface drainage and farm net returns. Results indicate that complementing rice production with maize and canola and restricting rice to fields where rice field water use is less than 14 ML ha−1, will minimize the water table rise and improve farm profitability. A description of the framework, SWAGMAN Options, and the results from sensitivity analyses are presented in this paper.