Eco-hydrological study on restoration threshold of the Lhalu wetland

As the largest wetland with the highest elevation located in urban region, the Lhasa Lhalu wetland is chosen as a typical area in this research. The wetland is regarded as "The Lung of Lhasa City" due to its outstanding ecological benefits. It will become more efficient and reasonable for the protection of wetland eco-environment by applying the principle and method of ecohydrology to set a series of ecological restoration thresholds of the Lhalu wetland. After analysis on ecohydrological changing process and characteristics of the Lhalu wetland in recent twenty years, a new coupled model is developed on the basis of groundwater flow model, soil water movement model, water sucking model of plant roots and plant evapotranspiration model. This coupled model can be applied to describe the ecohydrological process of the Lhalu wetland and focuses on how plant biomasses react to various ground water levels and annual precipitation levels, based on which, we bring forward the restoration threshold value which provides scientific strategic base for ecological construction and management of the Lhalu wetland.