Assessing surface water–groundwater interactions in a complex river‐floodplain wetland‐isolated lake system

Abstract

Floodplain systems are most often hydrologically complex settings characterized by highly variable surface water–groundwater interactions that are subjected to wide‐ranging wetting and drying over seasonal timeframes. This study used field methods, statistical analysis, and the Darcy's law approach to explore surface water–groundwater dynamics, interactions, and fluxes in a geographically complex river‐floodplain wetland‐isolated lake system (Poyang Lake, China). The floodplain system of Poyang Lake is affected by strongly seasonal shifts between dry and wet processes that cause marked changes in surface water and groundwater flow regimes. Results indicate that wetland groundwater is more sensitive to variations in river levels than the seasonal isolated lakes. In general, groundwater levels are lower than those of the isolated lakes but slightly higher than river levels. Statistical analysis indicates that the river hydrology plays a more significant role than the isolated lakes in controlling floodplain groundwater dynamics. Overall, the river shows gaining conditions and occasionally losing conditions with highly variable Darcy fluxes of up to +0.4 and −0.2 m/day, respectively, whereas the isolated lakes are more likely to show slightly losing conditions (less than −0.1 m/day). Although seasonal flux rates range from 7.5 to 48.2 m/day for surface water–groundwater interactions in the floodplain, the flux rates for river–groundwater interactions were around four to seven times higher than that of the isolated lake–groundwater interactions. The outcomes of this study have important implications for improving the understanding of the water resources, water quality, and ecosystem functioning for both the river and the lake.

Soil Hydrology of Agricultural Landscapes: Quantitative Description, Research Methods, and Availability of Soil Water

“…A practical comprehensive solution to the five problems listed above will create the prerequisites for a new step in the hydrological research of soils: the development of soil-agrolandscape hydrology (in this paper, we will not consider the thermophysical area, however, the principles of consideration for the hydrology and thermal physics of soils of agrolandscapes are identical). Currently, we can have all the components of soil-agrolandscape hydrological research: the scientific theory of agrolandscape zoning using soil-landscape and agrochemical maps, state-of-theart hydrological parameters for assessing moisture reserves in various layers of agricultural soils, digital devices for obtaining dynamic information about soil moisture and temperature, dynamic physically based models of moisture movement in the agrolandscape, statistical models for analyzing and predicting hydrological characteristics in space and time [16,17,28].…”

Assessing Hydrological and Sedimentation Effects from Bottom Topography Change in a Complex River–Lake System of Poyang Lake, China

“…The average depth of the lake is about 8 m and maximum depth can reach 29 m during flood seasons. As an open lake that connects to the Yangtze River, hydrological characteristics of Poyang Lake are affected by both the catchment inflows and the Yangtze water level or discharge [22]. Due to the blocking effect of the Yangtze River, the peak water level of the lake normally lags behind the maximum catchment inflow (Figure 1c,d).…”

Drought responses in floodplain forests obtained by remotely sensed and tree‐ring data

“…However, the nature of drought within floodplains is still not well understood. Specifically, soil moisture in floodplains may be subsidized by groundwater (Li et al, 2019; Miguez‐Macho & Fan, 2012). The importance of groundwater subsidy can be clearly observed in ecosystems that are generally limited by water availability (e.g.…”

“…However, the nature of drought within floodplains is still not well understood. Specifically, soil moisture in floodplains may be subsidized by groundwater (Li et al, 2019;Miguez-Macho & Fan, 2012).…”