Interactions Between Suspended Kaolinite Deposition and Hyporheic Exchange Flux Under Losing and Gaining Flow Conditions
Interactions Between Suspended Kaolinite Deposition and Hyporheic Exchange Flux Under Losing and Gaining Flow Conditions
复制标题
DOI：
10.1029/2018gl077951
复制
发表时间：
2018-05-16
影响因子：
5.2
通讯作者：
Arnon, Shai
中科院分区：
文献类型：
--
作者：
Fox, Aryeh;Packman, Aaron I.;Arnon, Shai
细颗粒沉积和河床堵塞影响许多生态和生物地球化学过程，但人们对地下水流入和流出河流对堵塞的影响知之甚少。我们评估了失去和获得流动对沙河床中悬浮高岭石粘土颗粒沉积的影响，以及由此产生的潜流交换通量 (HEF) 速率和模式的变化。对水柱中粘土沉积、河床沉积物中粘土堆积以及与河床的水交换的观察表明，河床中的粘土沉积显着降低了 HEF 和潜流带的大小。粘土沉积和 HEF 强烈耦合，导致水和粘土流入床层的区域快速堵塞。局部堵塞使交换水横向转移，产生粘土沉积层，减少了垂直潜流并有利于水平流动。在增益条件下，HEF在空间上受到上升流水的限制，这使得粘土沉积集中在每个床层上游侧的一个小区域。因为在增益条件下流入床层的面积最小，所以局部堵塞在增益条件下比中性或损耗条件下需要更少的粘土质量。这些结果表明，在评估潜流交换、河流中的细颗粒动力学以及河床堵塞和恢复时，需要考虑失去和获得流动的条件。
Fine particle deposition and streambed clogging affect many ecological and biogeochemical processes, but little is known about the effects of groundwater flow into and out of rivers on clogging. We evaluated the effects of losing and gaining flow on the deposition of suspended kaolinite clay particles in a sand streambed and the resulting changes in rates and patterns of hyporheic exchange flux (HEF). Observations of clay deposition from the water column, clay accumulation in the streambed sediments, and water exchange with the bed demonstrated that clay deposition in the bed substantially reduced both HEF and the size of the hyporheic zone. Clay deposition and HEF were strongly coupled, leading to rapid clogging in areas of water and clay influx into the bed. Local clogging diverted exchanged water laterally, producing clay deposit layers that reduced vertical hyporheic flow and favored horizontal flow. Under gaining conditions, HEF was spatially constrained by upwelling water, which focused clay deposition in a small region on the upstream side of each bed form. Because the area of inflow into the bed was smallest under gaining conditions, local clogging required less clay mass under gaining conditions than neutral or losing conditions. These results indicate that losing and gaining flow conditions need to be considered in assessments of hyporheic exchange, fine particle dynamics in streams, and streambed clogging and restoration.