Research On Ecological Effect In The Lower Reaches Of Tarim River After Water Transport

Research on ecological effect in the lower reachesof Tarim River after water transportCui Wangcheng (Grassland Science)Surpervised by Xu PengEcological water transport in the lower reaches of Tarim River has obvious effect on natural vegetation retrieval, green corridor protection and environment reform. On current conditions, the only approach to save natural vegetation is ecological water transportation.1. The response of groundwater level is obvious. Along the watercourse in the lower reaches, the response of groundwater level is gradually weakened along with the distance of water transport increase. The transverse response scope of groundwater level is gradually enlarged along with time and frequency of water transport increase. The response width of groundwater level is within 800m by the monitored data (at Yingsu section). 2. The response scope of natural vegetation in the lower reaches is obvious. Within 350-750m in width, the rise of groundwater level was 1-3 meters, only Populus euphratica or Tamarix families could accommodate to that environment. Once in a while, sporadic herbage could survive in the billabong. Outside 750m in width, the change of vegetation isn't bigger than before water transport. So, the widest response scope of vegetation in the lower reaches of Tarim River after water transport was the 750m.3. Optimized the project of ecological water transport in the lower reaches of Tarim River. The natural vegetation nearby the watercourse is saved and restored along with water transport. The response scope of Populus euphratica is enlarged from 200~250m in width after the first water transport to 750m after the forth water transport. Therefore it is significant to confirm on the reasonable ecology water level and lowest requiring water quantity to keep ecological safety of the lower reaches of Tarim River 4. Realization sustainability of ecosystem. The linear water transport along watercourse can only recover the original vegetation. It can't realize the renewal of plants; moreover, it can hardly realize sustainability of regional ecosystem. It is appropriate that two watercourses water transport and combination of linear and area water transport should be used. In accordance with maturity time of seeds of Populus euphratica and Tamarix families in the lower reaches of Tarim River, the optimum period of water transportation is from August to September every year, which can provide suitable condition for seeds burgeoning. This way can realize sustainability of ecosystem.