The particular challenges of modeling control systems for the middle route of the south-to-north water transfer project are illustrated.Open channel dynamics are approximated by well-known Saint-Venant nonlinear partial differential equations.For better control purpose,the finite difference method is used to discretize the Saint-Venant equations to form the state space model of channel system.To avoid calculation divergence and improve control stability,balanced model reduction together with poles placement procedure is proposed to develop the control scheme.The entire process to obtain this scheme is described in this paper,important application issue is considered as well.Experimental results show the adopted techniques are properly used in the control scheme design,and the system is able to drive the discharge to the demanded set point or maintain it around a reasonable range even if comes across big withdrawals. The particular challenges of modeling control systems for the middle route of the south-to-north water transfer project are illustrated. Open channel dynamics are approximated by well-known Saint-Venant nonlinear partial differential equations. For better control purpose, the finite difference method is used to discretize the Saint-Venant equations to form the state space model of channel system. To avoid calculation divergence and improve control stability, balanced model reduction together with poles placement procedure is proposed to develop the control scheme. scheme is described in this paper, important application issue is considered as well.Experimental results show the adopted techniques are properly used in the control scheme design, and the system is able to drive the discharge to the demanded set point or maintain it around a reasonable range even if comes across big withdrawals