Ecological water requirement based on ecological protection and restoration targets in the lower reaches of the Heihe River, northern China

Abstract

Owing to the irrational use of water resources in the Heihe River, northern China, the eco-environment has deteriorated seriously in its lower reaches. Some ecological problems exist (i.e., lake shrinkage, the decline of the underground water table, vegetation degradation, land desertification, and sandstorm damage). Subareas of ecological protection and restoration in the lower reaches of the river are proposed, considering the course of the river, its ecosystem characteristics, and the range of impact of water resource allocation. Based on a comprehensive decision-making method and GIS technology, the targets of ecological protection and restoration in the lower reaches of the river were determined quantitatively. Using a phreatic evapotranspiration model and a groundwater balance equation, the ecological water requirements of the riparian forest ecosystem, the desert ecosystem, the water area ecosystem, and the underground ecosystem, given various eco-restoration targets in different level years, were calculated and analyzed. The results show that the total ecological water requirements of the Shaomaying section were 548 million m³ in 2000 to maintain the normal growth of its natural vegetation and a stable groundwater table in the lower reaches of the Heihe River. The total ecological water requirement of the Shaomaying section is expected to be 632 million m³ in 2010, 635 million m³ in 2020, and 635 million m³ in 2030.

Keywords

ecological water requirement / ecological protection and restoration / quantitative method