Research On Ecological Water Poverty And Ecological Management Model In Shaanxi-Gansu-Ningxia Old Liberated Regions

Based on the analysis of climate and hydrology data and the investigation on the spot, the new concept and new way were developed by the synthesis of eco-environment studies in Shaanxi-Gansu-Ningxia old liberated regions. The new concept, ecological water poverty, was proposed first; and the way of evaluating ecological water poverty and management measures to improve ecological environment by "Ecological Purchase" were established. The analysis basis is the records by the year of 2000 from more than 40 hydrological and weather stations. Soil water, the poverty in runoff and soil water, climatic warming and drying, water poverty from water and soil conservation, ecological water poverty and economic water poverty are investigated in the 6 field sites in Northern Shaanxi, Guyuan and Qingyang. This research can provide theoretical support for further study of ecological hydrology and the solutions to the bad circulation in ecological change - ecological water poverty -ecological worsening.The study shows that the runoff is reducing year by year in the recent 50 years by about 0.5 108 m3/a in the area. Now the runoff is less than 400m3 per person, which is lower than 500m3/a, the minimum level of water resource lack country defined by the United Nations. Dry-warming trend is showed in climate in Shaanxi-Gansu-Ningxia old liberated regions. The temperature increased by about 0.0194 /a, higher than global trend for recent 100 year (0.005 /a). The precipitation decreased by1.0759mm/a. The 1990's is the period during which soil erodes seriously in Shaanxi-Gansu-Ningxia old liberated regions, although so many soil and water conservation measures are carried out. The maximum soil erosion is 0.784cm/a. The proportion of sheet erosion to gully erosion ranges between 1:20 and 1:30. The relation between the requirement and consumption of ecological water is established: ecological water poverty is the difference between the requirement and the consumption. Analysis in typical region theoretically suggests that eco-environment natural recovery is a "win-win" way between water and soil conservation and surface runoff increase. Recommendations for policy on "Ecological Purchase" are made, and the path to realize it is given. For permanent eco-environment security, the suggestions should be taken that the government should implement market economic system in eco-environment construction and carry out the ecological purchase project in Shaanxi-Gansu-Ningxia old liberated regions, where the environment is extreme sensitive and has overall significance. The appointed organizations to pay the tree's and grass's owners with money every year according to the resumption of the tree and grass and the eco-environment quality, which can realize the "win-win" benefits at last that the land is covered with vegetation and peasants take money. The research shows that, in Shaanxi-Gansu-Ningxia old liberated regions, "Ecological Purchase" could make hills green and river flowing, and rid the ecological water poverty in the region.The main innovative achievements are as follows:1. For the first time, according to the theory of "receptor model", ecological water poverty, space water scarcity respond to global change, is put forward. Integrated definition of ecological water poverty is given. Climate change influences the surface runoff in the region greatly. The expression between annual runoff and annual rainfall as well as averagetemperature is carried out. The decrease in both dynamic and static human body water reservoir is account for 0.35% of 1990's mean annual surface runoff.2. The developing mode of vegetation and soil water reservoir (Fig 3-28) and the relation between ecological water poverty and stage goals of ecological construction (Fig 3-29) are established. The natural recovery is the key to eco-environment reconstruction of Loess Plateau, to convert barren hill and uncultivated land into beautiful landscape.3. The amount of ecological water poverty, calculating method and evaluation model are set up. In t...