TY - CONF

T1 - A synthetic study on constaining a 2D density-dependent saltwater intrusion model using electrical imaging data

AU - Antonsson, Arni Valur

AU - Nguyen, Frederic

AU - Engesgaard, Peter Knudegaard

AU - Kemna, Andreas

PY - 2007

Y1 - 2007

N2 - In groundwater model development, calibration is one of the critical aspects that determine its reliability and applicability in terms of e.g. system (hydrogeological) understanding, groundwater quality predictions, and general use in water resources context. The result of a groundwater model calibration is determined by different factors, where both data quantity and quality is of crucial importance. Typically the availability of conventional monitoring installations (e.g. depth specific monitoring wells for salinity measurements) and the cost of constructing new ones limit the amount of obtainable data. These factors can seriously hinder a successful monitoring strategy and consequently limit the reliability of the calibrated model. An effective alternative to conventional measurements is the use of geophysical methods to monitor changes in the subsurface e.g. salinity distribution. Compared to conventional methods, which only give (few) point information, electrical images can give data over large spatial distances but that can be of great value for groundwater modeling purposes.The aim of this study is to investigate in a synthetic way, the applicability of using electrical images to calibrate a 2D synthetic seawater intrusion model. A vertical 2D density-dependent flow and transport model was established for a   synthetic coastal aquifer in order to simulate saltwater intrusion. All the relevant hydraulic parameters applied in the model were given realistic values. The result of the synthetic model, basically a salinity distribution in the coastal aquifer, was converted to resistivity distribution by assuming a certain petrophysical relation between water salinity and electrical conductivity. The obtained resistivity distribution was then used when electrical data acquisition was simulated. By applying an advanced inversion approach, electrical images of resistivity were obtained and based on the assumed petrophysical model the salinity distribution was derived. A number of different intrusion simulations were conducted with the aim of assessing the applicability of the method under different hydrological conditions.The results of this synthetic study demonstrated some of the (potential) benefits of applying the electrical imaging data for calibration of seawater intrusion models. Furthermore, it also shows some of the limits this method has as well as the associated uncertainties. This study was conducted as a part of the European project ALERT (GOCE-CT-2004-505329).

AB - In groundwater model development, calibration is one of the critical aspects that determine its reliability and applicability in terms of e.g. system (hydrogeological) understanding, groundwater quality predictions, and general use in water resources context. The result of a groundwater model calibration is determined by different factors, where both data quantity and quality is of crucial importance. Typically the availability of conventional monitoring installations (e.g. depth specific monitoring wells for salinity measurements) and the cost of constructing new ones limit the amount of obtainable data. These factors can seriously hinder a successful monitoring strategy and consequently limit the reliability of the calibrated model. An effective alternative to conventional measurements is the use of geophysical methods to monitor changes in the subsurface e.g. salinity distribution. Compared to conventional methods, which only give (few) point information, electrical images can give data over large spatial distances but that can be of great value for groundwater modeling purposes.The aim of this study is to investigate in a synthetic way, the applicability of using electrical images to calibrate a 2D synthetic seawater intrusion model. A vertical 2D density-dependent flow and transport model was established for a   synthetic coastal aquifer in order to simulate saltwater intrusion. All the relevant hydraulic parameters applied in the model were given realistic values. The result of the synthetic model, basically a salinity distribution in the coastal aquifer, was converted to resistivity distribution by assuming a certain petrophysical relation between water salinity and electrical conductivity. The obtained resistivity distribution was then used when electrical data acquisition was simulated. By applying an advanced inversion approach, electrical images of resistivity were obtained and based on the assumed petrophysical model the salinity distribution was derived. A number of different intrusion simulations were conducted with the aim of assessing the applicability of the method under different hydrological conditions.The results of this synthetic study demonstrated some of the (potential) benefits of applying the electrical imaging data for calibration of seawater intrusion models. Furthermore, it also shows some of the limits this method has as well as the associated uncertainties. This study was conducted as a part of the European project ALERT (GOCE-CT-2004-505329).

KW - Faculty of Science

KW - saltwater intrusion

KW - model calibration

KW - electrical resistivity tomography

KW - density-dependent flow

M3 - Poster

Y2 - 9 September 2007 through 13 September 2007

ER -