洪水过程对垂向潜流交换作用的影响

选取洪峰和涨洪历时两个参数,利用COMSOL模拟研究了单峰洪水一个周期内河床表面压力分布变化条件下,在河道潜流区地表水与地下水进行潜流交换时,潜流交换量随时间的分布特点、示踪粒子在河床中滞留时间的变化规律以及潜流交换在潜流带深度方向的变化规律。结果表明,在单峰洪水一个周期内,涨洪历时的大小对潜流交换量和交换深度影响并不显著,但随着涨洪历时的增长,粒子滞留时间会随之增大;洪峰大小与潜流交换总量、交换深度均呈线性关系,即洪峰越大,潜流交换量越大,潜流交换深度也越大;随着洪峰的增大,粒子滞留时间也会随之增大。

The Impact of Flood Process on Vertical Aquifer Exchange

Selecting flood peak and flood duration as two parameters, COMSOL software was used to simulate the distribution of aquifer flux over time, variation of the tracer particle residence time in the riverbed and the aquifer exchange variation with depth direction in the aquifer zone. This simulation was completed under a condition that the pressure distribution on bed surface would change in a period of a single peak flood when stream water and subsurface water exchanged in the aquifer zone. The results show that within a period of a single peak flood, the impact of flood duration on the aquifer flux and depth is not obvious. However, the particle residence time increases with the flood duration; flood peak is linear with the total aquifer flux and exchange depth, that is, the greater the flood peak, the greater the aquifer flux and exchange depth; the particle residence time increases with the flood peak.