Sustainable management of water-agriculture-ecology nexus system under multiple uncertainties.

ABSTRACT

The shrinkage and ecological degradation of the Aral Sea resulting from the uncontrolled use of water resources and the unregulated expansion of agriculture activities call for sustainable management of water-agriculture-ecology (WAE) nexus from a basin perspective. However, managers face thorny challenges brought by multiple uncertainties in the management and planning processes. In this study, an interval stochastic fuzzy programming (ISF) method is developed for tackling multiple uncertainties presented as probability distributions, flexible variables and interval parameters. Then, an ISF-WAE model is formulated for Aral Sea Basin, which considers 108 planning scenarios that reflect different food-security and ecology-restoration requirements, as well as risk-response attitudes of decision maker over a long-term planning horizon (2021-2050). Results reveal that for Aral Sea Basin (i) managers should set strict acreage benchmarks for cereal crops, in which wheat would account for a range of [29.1, 31.2] % of the total agricultural area; (ii) for promoting ecological restoration, the proportion of agricultural water allocation should decrease by a range of [12.7, 16.1] % during the planning horizon; (iii) due to low water requirement and high ecological value of grassland, it is recommended to expand grassland area to improve the sustainability of the Aral Sea Basin in the case of limited water resources.