THE STUDIES OF WATER RESOURCES UTILIZATION OR WATER RESOURCES AND ECOLOGY-ENVIRONMENTS SAFETY IN MIDDLE REACH OF HEIHE RIVER BASIN

s: As a result of analysis on Heihe River hydrology materials, water resources is relatively stable in the basin due to replenishment of ice glacier, water resources difference between extremely water abundant year and extremely drought year is 2 to 1, which is seldom to seen in north part of China. The multiyear average water resources volume in the basin is 3 231 million m3/a with per capital water resources of 1 689 m3, which is slightly lower than per capital water resources safety warning line of 1 0001 700 m3/a accepted in the world. The characteristic of water resources in the basin is multi transfer and multi utilization, if we leave 750 million m3/a for ecology the water resources situation is still safety with extension of water saving technology and under gong integrated treatment in the basin. Ecoenvironment crisis in the downstream can be resolved through unified water resources allocation. According to nature water resources inflow from ice glacier, water and soil development and utilization scale as well as middle stream ecoenvironment situation, 2 600 million m3/a nature water inflow will be the water resources safety critical line and 2 400 million m3/a nature water inflow will be the water resources safety warning line under the condition of adopting water saving technology and control irrigated land remaining at current level. 