The groundwater(GW)in the floodplain riparian area frequently interacts intensely with surface water(SW).Heat as a tracer is one of the hot research fields in investigating GW-SW interactions,and analytical approaches...The groundwater(GW)in the floodplain riparian area frequently interacts intensely with surface water(SW).Heat as a tracer is one of the hot research fields in investigating GW-SW interactions,and analytical approaches have been proposed for the calculation of exchange flow velocity.However,few studies have considered the effects of very dynamic flow conditions and monitoring instrumentation on the calculation with field measured data.Herein,taking the middle reaches of the Heihe River as the study area,different types of monitoring wells were constructed under the riverbed and near the river,and multiple methods(Darcy’s law,heat tracing,and isotopic mixing methods)were employed to trace the exchanges between the river and groundwater.The results indicate that different methods demonstrate diverse information with obvious unevenly distributed flux along the vertical direction.And the combination of multiple methods has an important role in studying the interaction between GW and SW.Fully screened wells produce intraborehole flow and disturb the heat transport,which is relevant to flow velocity,and further affects the temperature distribution,impacting the temperature-based flow velocity calculation.Dynamic flow conditions aggravate riverbed sediment disturbances,e.g.,scour and deposition,and additionally affect the interaction and monitoring data.展开更多
The vertical seepage velocity is an important parameter in the groundwater-surface water （GW-SW） exchange process. It is reported that the periodical fluctuated temperature record of the streambed can be used to det...The vertical seepage velocity is an important parameter in the groundwater-surface water （GW-SW） exchange process. It is reported that the periodical fluctuated temperature record of the streambed can be used to determine the seepage velocity. Based on a 1-D flow and heat transport model with a sinusoidal temperature oscillation at the upstream boundary, a new analytical model is built. This analytical model can be used to determine the seepage velocity from the amplitude ratio of the deep and shallow test points. The process of calculation is discussed. The field data are superimposed by multi-periods, so the spectrum analysis and the data filtering are desirable. For the typical seepage medium, the analytical model is effective to compute the seepage velocity between -2 m/d and 6 m/d by using the record of the daily period fluctuation. The temperature time-series analytical model is used to determine the upwards seepage under the condition that the spacing of test points is small （less than 0.2 m）. Lastly, a case study for the Russian River shows that this model is very convenient to determine the temporal changes of the GW-SW exchange.展开更多
基金supported by the National Natural Science Foundations of China(No.42425207)the Key R&D Program of the Xinjiang Uygur Autonomous Region(No.2024B03022).
文摘The groundwater(GW)in the floodplain riparian area frequently interacts intensely with surface water(SW).Heat as a tracer is one of the hot research fields in investigating GW-SW interactions,and analytical approaches have been proposed for the calculation of exchange flow velocity.However,few studies have considered the effects of very dynamic flow conditions and monitoring instrumentation on the calculation with field measured data.Herein,taking the middle reaches of the Heihe River as the study area,different types of monitoring wells were constructed under the riverbed and near the river,and multiple methods(Darcy’s law,heat tracing,and isotopic mixing methods)were employed to trace the exchanges between the river and groundwater.The results indicate that different methods demonstrate diverse information with obvious unevenly distributed flux along the vertical direction.And the combination of multiple methods has an important role in studying the interaction between GW and SW.Fully screened wells produce intraborehole flow and disturb the heat transport,which is relevant to flow velocity,and further affects the temperature distribution,impacting the temperature-based flow velocity calculation.Dynamic flow conditions aggravate riverbed sediment disturbances,e.g.,scour and deposition,and additionally affect the interaction and monitoring data.
基金supported by the National Natural Science Foundation of China (Grant No. 41272265)the Scientific Research and innovate Foundation to support college graduate of Jiangsu Province (Grant No. CX09B_167Z)
文摘The vertical seepage velocity is an important parameter in the groundwater-surface water （GW-SW） exchange process. It is reported that the periodical fluctuated temperature record of the streambed can be used to determine the seepage velocity. Based on a 1-D flow and heat transport model with a sinusoidal temperature oscillation at the upstream boundary, a new analytical model is built. This analytical model can be used to determine the seepage velocity from the amplitude ratio of the deep and shallow test points. The process of calculation is discussed. The field data are superimposed by multi-periods, so the spectrum analysis and the data filtering are desirable. For the typical seepage medium, the analytical model is effective to compute the seepage velocity between -2 m/d and 6 m/d by using the record of the daily period fluctuation. The temperature time-series analytical model is used to determine the upwards seepage under the condition that the spacing of test points is small （less than 0.2 m）. Lastly, a case study for the Russian River shows that this model is very convenient to determine the temporal changes of the GW-SW exchange.
