黑河下游河床渗漏试验研究

Lysimetric Experiment on the Riverbed in the Lower Reaches of Heihe River

黑河下游受自然和人类活动的影响 ,植被遭到严重破坏 ,额济纳旗绿洲正在逐步萎缩 ,生态环境的恶化已经引起广泛的关注。脆弱的生态需水主要依靠少量河水和地下水维持着 ,由于地表水资源的短缺 ,提出采取工程措施减少下游河床沿途入渗的建议。对此 ,运用美国SOILMOISTUREEQUIPMENTCORP .制造的Model 2 80 0Guelph入渗仪 ,对黑河下游河床入渗能力进行了定点测量 ,发现黑河下游河床入渗能力 (Kfs)相当强。初步分析河床入渗对下游植被生态的影响 ,以及为减少河床渗漏而采取工程措施的可行性。

Located in the central part of the Hexi Corridor, the Heihe River rises in the Qilian Mountain and flows through Qinghai Province, Gansu Province and Inner Mongolia Autonomous Region, it is one of the large continental rivers in northwest China, and its length and catchment area are 821 km and 1.3×105 km2 respectively. Because of the impacts of natural factors and human activities, the vegetation is degenerated, the Ejina Oasis is shrinking, and the ecological environment is degenerated due to the drawdown of groundwater level caused by the reduction of the stream flow to the lower reaches. All these have been paid a great attention to. Considering from the shortage of the local surface water resources, it is suggested to reduce the seepage along the river channel in the lower reaches of Heihe River by some engineering measures. However, the vulnerable ecology relies on the limited stream water and groundwater for its existence. In this paper, the lysimetric experiment on the riverbed in the lower reaches of Heihe River is carried out. After measuring the seepage along the riverbed in the lower reaches of Heihe River by using the Model 2800 Guelph lysimeters, it is found that the penetration power of the riverbed is very strong, which is necessary for recharging groundwater from stream flow and also the necessary conditions for maintaining the vegetation in the lower reaches and for the existence of Ejina Oasis. Therefore, it is considered that the groundwater recharge will be reduced, the vegetation in the lower reaches will be further degenerated, and the safety of Ejina Oasis will be threatened if the engineering measures are applied for reducing the seepage along the river channel in the lower reaches of Heihe River.