Research on the ecological operation in the lower reaches of Tarim River based on water conveyance

Abstract

This paper analyzed the ecological water conveyance characteristics, process and model, assessed the environment changes after ecological water conveyance, and preliminary discussed the strategy and model of ecological water operation, based on the methods of data collection, field investigation and lab analysis in downstream area of Tarim River Basin. The conclusions stated as follows: the water conveyance model changed from single and double-channel patterns in prophase to branches and faceted patterns in anaphase; from the point of channel dissipation, the rate of recharging groundwater, soil and vegetation consumption, water surface evaporation and flowing into lake were 59.6%, 35.6%, 2.4% and 2.4% separately; with the ecological water conveyance carrying out, the environment condition turned around, such as groundwater table rose, the groundwater quality got better, vegetation area expanded, community species increased and the growth status of Populus euphratica turned around, all which indicated that the ecological degradation trend in lower reaches of the Tarim River was contained, but the vulnerability was still on; in order to show the effects of ecological water conveyance, the reasonable ecological water operation plan was the annual discharge volume from Daxihaizi Reservoir should be 350 Mm3, where no less than 15 Mm3 was used to protect the Taitema Lake, and the period water discharge was from September to November, with multi-ways and flexibility; ecological environment change was a long and slow process, and its response to the water conveyance project also need long-term monitoring from the point of surface water, groundwater, vegetation response, biodiversity, etc.