Vegetation controls on variably saturated processes between surface water and groundwater and their impact on the state of connection

Abstract

[1] The vadose zone plays an important role in surface water-groundwater interaction and exerts strong influences on biogeochemical, ecological, and hyporheic processes. It is also the presence of an unsaturated zone that controls the state of connection between surface water and groundwater. Despite recent advances on how hydrogeological variables affect surface water-groundwater interactions, there is limited understanding of the hydroclimatic effects of precipitation and evapotranspiration. More specifically, there is a need for a physically based understanding on the changes that may occur in response to changes in vegetation. While it may seem qualitatively obvious that the presence of vegetation can cause an unsaturated zone to develop underneath a riverbed and alter the state of connection, it has so far not been demonstrated quantitatively. Also, the influence of variables such as root extinction depth, topography, and the influence of land clearance has so far not been explored. In this study, fully coupled, physically based 2-D transient homogeneous models were used to simulate the impact of land clearance and revegetation on the state of connection of a perennial river system. The simulations showed that the presence of vegetation can create an unsaturated zone between a river and an aquifer and affect the state of connection and that the removal of deep-rooted vegetation from a catchment may have a significant impact on the state of connection as well as the condition of the water resource.Citation: Banks, E. W., P. Brunner, and C. T. Simmons (2011), Vegetation controls on variably saturated processes between surface water and groundwater and their impact on the state of connection, Water Resour.

Dynamic of Dalinor Lakes in the Inner Mongolian Plateau and Its Driving Factors during 1976–2015

“…Since [26,[30][31][32]. It seems that revegetation on sandy land may be acted as a double-edged sword: it could increase vegetation greenness, but may also consume the groundwater.…”

Heterogeneous or homogeneous? Implications of simplifying heterogeneous streambeds in models of losing streams

“…Fox and Durnford, 2003;Brunner et al, 2009a,b;Banks et al, 2011). Fox and Durnford (2003) investigated the formation of an unsaturated zone beneath a partially penetrating stream caused by nearby groundwater extraction.…”

“…Fox and Durnford (2003) investigated the formation of an unsaturated zone beneath a partially penetrating stream caused by nearby groundwater extraction. Banks et al (2011) analyzed the impact of land clearance and revegetation on the state of connection for perennial streams. Brunner et al (2009a) outlined a criterion which can be used to determine whether a 1D flow system can become disconnected.…”

Long-Term Quantification of Stream-Aquifer Exchange in a Variably-Saturated Heterogeneous Environment

“…Proper quantification of this process helps in decision making about the allocations of water to different users, including environmental water to preserve the natural ecosystem. SW-GW exchange depends on many factors, including topography, subsurface hydraulic properties, climate, and vegetation (Banks et al 2011). The exchange of water has a controlling influence on the stream chemistry, nutrient fluxes, near stream biota, and biogeochemical conditions in the vicinity of the creek and creek flow during dry periods (Frei et al 2009).…”

“…Guzman et al 2015) have been used over different scales which often undermine the impact of near stream water dynamics, temporal and spatial hydrological and geological heterogeneity, and anisotropy on SW-GW exchange. Banks et al (2011) evaluated the importance of vegetation on the nature of the connection between SW-GW and conceptualized the impact of a clogging layer (a low hydraulic permeability layer at the bed), evapotranspiration, and the slope of the catchment using the 2-D HydroGeoSphere model, assuming both homogeneous and isotropic conditions. Batlle-Aguilar et al (2015) calibrated and validated a 2D model for an ephemeral stream assuming isotropic and no flow conditions at the soil surface.…”