Many economic, social and ecological problems can be attributed to the scarcity and mismanagement of water and land resources. In this study, a multi-objective fuzzy–robust programming (MOFRP) method was developed for supporting the optimal use of land and water resources in agriculture. MOFRP improved existing methods through taking ecological services of crop cultivation into account. It was also capable of reflecting fuzziness in preferences, priorities and parameters that were largely neglected in previous agricultural decision making. This method was applied to address a case in arid northwestern China. Optimal plans of crop cultivation reconfiguration were generated for sustaining local development under economic, ecological and social objectives as well as physical restraints in water and land resources. Compared to the status quo, the optimized plan would increase economic and ecological benefits by 12.2% and 18.8%, respectively. The efficiency of irrigation water could also be enhanced with the economic and ecological benefits per unit water being raised and the water consumption per unit land being reduced. The comparisons of the MOFRP model to four alternatives validated that it was capable of achieving satisfactory benefits and reducing system-violation risks without neglecting valuable uncertain information and ecological services of crops. The proposed method was also applicable to other multi-objective management problems under uncertainty without loss of generality.

The presence of elevated total dissolved gas (TDG) downstream of a spillway may result in an increased incidence of gas bubble disease in fish. Supersaturated TDG is transported and dissipated more slowly in reservoirs than in natural rivers because of a higher water depth and lower turbulence and thus endangers fish. This paper presents the operational regulations concerning the mitigation of the TDG supersaturation impact on fish in the Bala Reservoir on the Zumuzu River. The paper includes the joint operations of the upstream and downstream power stations. A laterally averaged two-dimensional model is employed to simulate the TDG transportation and dissipation in the Bala Reservoir in addition to the hydrodynamics and water temperature. According to a comparison of the simulation results of different operational scenarios, this paper suggests a regulation scheme. With respect to the upstream power station, the adoption of an interval-discharge pattern instead of a continuous-discharge pattern is recommended to minimize the negative effect on the reservoir caused by supersaturated TDG. With respect to the downstream power station, the adoption of a surface tunnel rather than a bottom tunnel is recommended as a release structure. This paper is a reference for the eco-environmentally friendly operation of large and deep reservoirs.