The approach of constraint relaxation and adjusting tank level achieving from upper level was proposed to avoid unfeasible solutions of lower - level optimal model . hierarchic genetic algorithm ( hga ) was established to solve direct optimal operation model of system with tanks . hga is appropriate for optimal model including multi - constraints and multi - variants 对含有蓄水池供水系统的直接优化调度模型，本文结合遗传算法的特点，提出分层遗传算法优化的思路，并建立了适合遗传算法求解的第一层、第二层优化模型，可以有效解决变量和约束多的城市供水系统直接优化调度问题。
