This paper proposes an innovative procedure to improve an initial hydropower schedule by minimizing spillages in the short-term operation of multiple reservoir systems. This procedure is named as the field levelling (FL), which tries to eliminate scheduled spillages as much as possible by pushing forward and pulling backward the spillages in turn to explore spaces so as to absorb them, emulating the flied-levelling practice that pushes and pulls the protruding dirt in turn to find valleys to take it in. Even for a large-scale reservoir system, the procedure solves the problem very fast attributable to its stage-by-stage property. The procedure has the ability to handle the water travelling time between reservoirs and the nonlinearity in the optimization, and it is very useful in locally modifying an either feasible or infeasible scheduling solution to a feasible and satisfactory one. The model and procedure are applied to deal with the Yunnan provincial hydropower system that consists of 45 reservoirs. Start with a very good initial solution derived in our previous work, the present FL improves the solution by 0.58% and 134% reduction in water and energy spillages respectively. (C) 2018 Elsevier Ltd. All rights reserved.