Research on Improving Water Conveyance Mode in Lower Reaches of Tarim River

Abstract

[Objective] In view of problems such as unbalanced recharge, excessive ineffective evaporation, and limited water supply range in the current intermittent channel water transport exist in the lower reaches of the Tarim River, the spatial and temporal water transport modes during the growth and non-growth periods and the influence of improvements of water transport mode on the groundwater level were analyzed in order to further improve the ecological restoration system of rotary infiltration irrigation and to provide a theoretical basis for ecological restoration in the lower reaches of the Tarim River. [Methods] The study was conducted in Yingsu monitoring section of the lower reaches of the Tarim River. Groundwater depth was monitored during ten ecological water conveyances from 2012 to 2021. The Modflow model was used to numerically simulate two-dimensional flow movement of the groundwater profile in Yingsu section. The response data of ten intermittent ecological water deliveries in Yingsu section was fitted and analyzed. The process of groundwater level evolution and water quantity change during the growth period, the non-growth period, and in the artificial water channels in non-growth period were predicted and analyzed. [Results] ① Under the proposed schemes of water delivery during the growth period, non-growth period, and in the non-growth period with the artificial river channels, the groundwater levels on both sides of the artificial river channels were raised by 2.5, 0.7, and 3.2 m, respectively, compared with the current water delivery system. ② The area of groundwater depth less than 8 m in the study area was increased by 10.89%, 19.33%, and 26.17% under the three improvement schemes compared with the current water delivery system. ③ The groundwater storage capacity was increased by 10.97%, 11.88%, and 14.39% compared with the current water delivery system. [Conclusion] The artificial water channels in the non-growth period combined the advantages of both artificial water channels in the growth period and the non-growth periods, improved the utilization rate of downstream water discharge, solved the problem of difficult recovery of groundwater level under the current water delivery mode in the main river channel, and created conditions for the recovery of the inter-river ecological system and the establishment of a safe zone for downstream biodiversity.

Keywords

• ecological water conveyance
• groundwater level
• modflow model
• lower reaches of tarim river
• artificial channels water conveyance in non-growth period