Effects of Rainwater Harvesting on the Regional Development and Environmental Conservation in the Semiarid Loess Region of Northwest China

摘要

Water is the major limiting factor for farming, forestry and animal husbandry in the Loess Plateau of northwest China and it is also the key factor for environmental improvement. Precipitation is the major water source for use in this region. However, limited and erratic precipitation often results in crop failure as well as serious soil and water loss. Rainfall harvesting can change the distribution pattern of rainfall runoff in time and space, which would supply humankind with steady water sources to some extent. Characterized by simple operation, high adaptation and low cost, rainwater-harvesting techniques have a great potential to be used in many aspects. Rainwater harvesting would provide the possibilities of setting up new agricultural ecological system and whereby improve ecological environments in the semiarid regions. This paper deals with the major environmental issues in the Loess Plateau and evaluates the influence of rainwater harvesting implemented since 1980s on the regional development and environment conservation. Based on the experiment on rainfall harvesting and field investigation, microcatchment model for ecosystem construction was proposed to improve regional environment. The Microcatchment rainfall-harvesting model with small watershed as a unit is characterized by incorporation of rainfall harvesting with yard economy and environmental construction. ≥ 25° sloping land is protected as water conservancy zone by prevent human and livestock interference; tree (or shrub) and grass can be planted in the gentle slope by means of microcatchment water harvesting techniques. The natural slope can also be treated as catchment for collecting runoff into the cistern for supplemental irrigation for farmland, which is the main part of the system for supply food to farmer by various water-saving agriculture techniques. The village and yard is the center of human activity, which can be regarded as an economic zone by using harvested water to develop greenhouse and animal husbandry.