Studies of a regulated dryland river: surface–groundwater interactions

Abstract

Unlike rivers in humid regions, dryland rivers typically exhibit reduced flow in the downstream direction as a result of transmission losses, which include seepage of streamflow into the aquifer, evaporation, and transpiration. However, much remains to be learned about the nature of the exchange between surface water and groundwater in these landscapes, especially in terms of spatial and temporal variability. Our study focused on streambank seepage and groundwater flow in the alluvial aquifer, specifically on answering questions such as: Is there seasonal variability in seepage losses? Is seepage permanently lost? Can losses be reduced by killing riparian vegetation? To better understand the magnitude, variability, and fate of streambank seepage, we assessed river stages, groundwater hydraulic gradients, and groundwater flow paths at two sites along a reach of the Pecos River, a dryland perennial river in West Texas. We found that along this reach the river was losing water to the aquifer even under low‐flow conditions; but seepage was controlled by a number of different mechanisms. Seepage increased not only during high‐flow events but also when the groundwater level was declining owing to long periods of no irrigation release. Tamarix (saltcedar) control did not affect hydraulic gradients nor reduce streambank seepage and given that this reach of the Pecos River is a losing one, streamflow will not be enhanced by controlling saltcedar. These findings can be used to improve basic conceptual models of dryland river systems and to predict hydrologic responses to changes in the timing and magnitude of streamflows and to riparian vegetation management. Copyright © 2012 John Wiley & Sons, Ltd.

River network evolution and fluvial process responses to human activity in a hyper-arid environment – Case of the Tarim River in Northwest China

“…With the accelerated expansion of human activities from temperate and humid environments into arid environments, many dryland rivers have already been strongly influenced by, or are under significant threat from, various human interventions such as land reclamation and flow regulation, which often have more significant potential to disturb hydrological (e.g., Jacobson et al, 1995;Schick, 1995;Tooth, 2000a;Mansur and Nurkamil, 2010;McDonald et al, 2013) and fluvial processes (e.g., Graf, 1978Graf, , 1979Ortega et al, 2014). Related research has mainly been carried out in recent decades, for example, the changing channel patterns of the Gila River in Arizona, in the southwestern United States of America, resulting from flow regulation and the introduction of Tamarix, an exotic plant with more suitability than local vegetation (Graf, 1978(Graf, , 1979(Graf, , 1988; the flow regime and hydrologic change of the Murray and the Barwon-Darling Rivers (Maheshwari et al, 1995;Thoms and Sheldon, 2000); the adjusted channel morphology of ephemeral streams due to urbanization in southwest America (Chin and Gregory, 2001;Coleman et al, 2005); and changes in the dynamics and morphology of ephemeral rivers in Mediterranean regions Bledsoe, 2011, 2013).…”

Regional-scale interactions between groundwater and surface water under changing aridity: evidence from the River Awash Basin, Ethiopia

“…Piezometric records: maps of hydraulic heads are widely used to assess surface water-groundwater interactions. Localscale piezometric maps (100 m) are widely used in computing surface water-groundwater interactions using Darcy's law (Mcdonald et al 2013). At regional scales, a lack of data as well as heterogeneity and anisotropy in hydraulic conductivity complicates the interpretation of piezometric evidence.…”

Deriving transmission losses in ephemeral rivers using satellite imagery and machine learning

“…This can provide larger scale estimates of the groundwater recharge by means of hydraulic (e.g. McDonald et al, 2013) or chemical measurements (e.g. Hoehn and Von Gunten, 1989;Massmann et al, 2009;Popp et al, 2021;Schaper et al, 2022).…”