Abstract:The Heihe Watershed is located in the northwest arid region of China. A balanced development option among water, ecology and economy is required for the sustainable development of such watershed. This study employs the system dynamic model, intends to create such an option. Three options were chosen for the model test, i.e., the water-ecology protection option (WEP), the water-rapid economic growth option (WEH), and the water-ecology-economy balanced development option (WEE). After running the system dynami...