Groundwater surface mapping informs sources of catchment baseflow

Abstract. Groundwater discharge is a major contributor to stream baseflow. Quantifying this flux is difficult, despite its considerable importance to water resource management and evaluation of the effects of groundwater extraction on streamflow. It is important to be able to differentiate between contributions to streamflow from regional groundwater discharge (more susceptible to groundwater extraction) compared to interflow processes (arguably less susceptible to groundwater extraction). Here we explore the use of unconfined groundwater surface mapping as an independent dataset to constrain estimates of groundwater discharge to streamflow using traditional digital filter and tracer techniques. We developed groundwater surfaces from 98 monitoring bores using Kriging with external drift. Baseflow estimates at the catchment outlet were made using the Eckhardt digital filter approach and tracer data mixing analysis using major ion and stable isotope signatures. Our groundwater mapping approach yielded two measures (percentage area intersecting the land surface and monthly change in saturated volume) that indicated that digital filter-derived baseflow significantly exceeded probable groundwater discharge during the high flow period of spring to early summer. Tracer analysis was not able to resolve contributions from ungauged tributary flows (sourced from either shallow flow paths, i.e. interflow and perched aquifer discharge, or regional groundwater discharge) and regional groundwater. Groundwater mapping was able to identify ungauged sub-catchments where regional groundwater discharge was too deep to contribute to tributary flow and thus where shallow flow paths dominated the tributary flow. Our results suggest that kriged unconfined groundwater surfaces provide a useful, empirical and independent dataset for investigating sources of fluxes contributing to baseflow and identifying periods where baseflow analysis may overestimate groundwater discharge to streamflow.

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Groundwater surface mapping informs sources of catchment baseflow

Hydrology and Earth System Sciences ◽

10.5194/hess-19-1599-2015 ◽

2015 ◽

Vol 19 (4) ◽

pp. 1599-1613 ◽

Cited By ~ 13

Author(s):

J. F. Costelloe ◽

T. J. Peterson ◽

K. Halbert ◽

A. W. Western ◽

J. J. McDonnell

Keyword(s):

Digital Filter ◽

Groundwater Discharge ◽

Independent Data ◽

Groundwater Extraction ◽

Shallow Flow ◽

Surface Mapping ◽

Flow Paths ◽

Data Set ◽

Groundwater Mapping ◽

Regional Groundwater

Abstract. Groundwater discharge is a major contributor to stream baseflow. Quantifying this flux is difficult, despite its considerable importance to water resource management and evaluation of the effects of groundwater extraction on streamflow. It is important to be able to differentiate between contributions to streamflow from regional groundwater discharge (more susceptible to groundwater extraction) compared to interflow processes (arguably less susceptible to groundwater extraction). Here we explore the use of groundwater surface mapping as an independent data set to constrain estimates of groundwater discharge to streamflow using traditional digital filter and tracer techniques. We developed groundwater surfaces from 88 monitoring bores using Kriging with external drift and for a subset of 33 bores with shallow screen depths. Baseflow estimates at the catchment outlet were made using the Eckhardt digital filter approach and tracer data mixing analysis using major ion signatures. Our groundwater mapping approach yielded two measures (percentage area intersecting the land surface and monthly change in saturated volume) that indicated that digital filter-derived baseflow significantly exceeded probable groundwater discharge during most months. Tracer analysis was not able to resolve contributions from ungauged tributary flows (sourced from either shallow flow paths, i.e. interflow and perched aquifer discharge, or regional groundwater discharge) and regional groundwater. Groundwater mapping was able to identify ungauged sub-catchments where regional groundwater discharge was too deep to contribute to tributary flow and thus where shallow flow paths dominated the tributary flow. Our results suggest that kriged groundwater surfaces provide a useful, empirical and independent data set for investigating sources of fluxes contributing to baseflow and identifying periods where baseflow analysis may overestimate groundwater discharge to streamflow.

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The influence of hyporheic fluxes on regional groundwater discharge zones

10.5194/hess-2021-148 ◽

2021 ◽

Author(s):

Brian Babak Mojarrad ◽

Anders Wörman ◽

Joakim Riml ◽

Shulan Xu

Keyword(s):

Groundwater Modeling ◽

Groundwater Discharge ◽

Water Fluxes ◽

Flow Paths ◽

Spectral Solution ◽

Scale Modeling ◽

Naturally Occurring ◽

Boreal Landscape ◽

Regional Groundwater

Abstract. The importance of hyporheic water fluxes induced by hydromorphologic processes at the streambed scale and their consequential effects on stream ecohydrology have recently received much attention. However, the role of hyporheic water fluxes in regional groundwater discharge is still not entirely understood. Streambed-induced flows not only affect mass and heat transport in streams but are also important for the retention of solute contamination originating from deep in the subsurface, such as naturally occurring solutes as well as leakage from the future geological disposal of nuclear waste. Here, we applied a multiscale modeling approach to investigate the effect of hyporheic fluxes on regional groundwater discharge in the Krycklan catchment, located in a boreal landscape in Sweden. Regional groundwater modeling was conducted using COMSOL Multiphysics constrained by observed or modeled representations of the catchment infiltration and geological properties, reflecting heterogeneities within the subsurface domain. Furthermore, streambed-scale modeling was performed using an exact spectral solution of the hydraulic head applicable to streaming water over a fluctuating streambed topography. By comparing the flow fields of watershed-scale groundwater discharge with and without consideration of streambed-induced hyporheic flows, we found that the flow trajectories and the distribution of the travel times of groundwater were substantially influenced by the presence of hyporheic fluxes near the streambed surface. One implication of hyporheic flows is that the groundwater flow paths contract near the streambed interface, thus fragmenting the coherent areas of groundwater upwelling and resulting in narrow “pinholes” of groundwater discharge points.

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Regional groundwater flow paths in Trans-Pecos, Texas inferred from oxygen, hydrogen, and strontium isotopes

Journal of Hydrology ◽

10.1016/j.jhydrol.2006.10.015 ◽

2007 ◽

Vol 334 (3-4) ◽

pp. 334-346 ◽

Cited By ~ 35

Author(s):

Matthew M. Uliana ◽

Jay L. Banner ◽

John M. Sharp

Keyword(s):

Groundwater Flow ◽

Strontium Isotopes ◽

Flow Paths ◽

In Trans ◽

Regional Groundwater

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Historical analysis of a karst aquifer: recharge, water extraction, and consumption dynamics on a tourist island (Cozumel, Mexico)

Annales de Limnologie - International Journal of Limnology ◽

10.1051/limn/2021013 ◽

2021 ◽

Vol 57 ◽

pp. 16

Author(s):

Gerardo Hernández-Flores ◽

Martha Angélica Gutiérrez-Aguirre ◽

Adrián Cervantes-Martínez ◽

Ana Elizabeth Marín-Celestino

Keyword(s):

Catchment Area ◽

Water Resource Management ◽

Karst Aquifer ◽

Historical Analysis ◽

Water Extraction ◽

Groundwater Extraction ◽

Aquifer Recharge ◽

Monthly Data ◽

Cozumel Island ◽

Increasing Trends

On Cozumel Island, access to freshwater depends on the extraction of the resource from the aquifer located north of the island (catchment area). Water resource management on the island must be based on updated knowledge of the indicator dynamics related to the recharge of the aquifer, groundwater extraction and the distribution of the resource. In this study, trends, variations and time series of 30 years of monthly data for precipitation, temperature, evapotranspiration, and estimated aquifer recharge were calculated for the catchment area. Additionally, groundwater extraction, water consumption for the main uses over a 13-year period (monthly data), and the 5-year status of wells were considered. The results show decreasing trends in precipitation and estimated recharge volumes in the catchment area, in addition to increasing trends in mean air temperature, evapotranspiration, water extraction volumes and consumption by the commercial sector for the considered time periods. Additionally, an increase in dejected (77%) and reposed (38%) wells within the catchment area was observed. Evidence from this study suggests a dynamic behaviour of the analysed indicators over time that increases pressure on karstic, Caribbean aquifers for which monthly monitoring and data analysis are encouraged as the basis for adequate management.

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