Resistivity Monitoring

Resistivity Monitoring

The monitoring and maintenance of earthen structures, including levees, impoundments, dams, and embankments, is an ongoing and critical process to ensure the integrity of these structures, and prevent failure and the potential consequences. Resistivity monitoring provides a uniquely broad, yet detailed, picture of seepage occurring through such earthen structures. We are asking that these structures hold back significant amounts of water or other waste materials and ensuring that they are operating safely is paramount. With a monitoring program that specifically includes resistivity, we can minimize risk to downstream structures by identifying potential points of weakness in these earthen structures or providing an early warning for changing conditions of existing seepage.

 

Resistivity monitoring can minimize risk to earthen structures by providing a greater understanding of seepage through levees, impoundments, dams, and embankments.

 

A geophysical electrode as part of an electrode array. An electrode array is a configuration of electrodes used for measuring either an electric current or voltage. Geophysical electrode arrays are typically installed in a linear bidirectional fashion and called lines,
 

A resistivity monitoring program involves making repeated measurements of resistivity over time. By observing a changing resistivity value, we can more accurately pinpoint issues related to stability, erosion, or assess possible conditions that give rise to inadvertent seepage. In some of our previous investigations, we have found water moving along old stream channels, weaknesses in pre-construction geology, and sand lenses and other buried structures that provided conduits for water to preferentially flow. When these data are then combined with site knowledge, borings, or other hydrological data, a more complete assessment can be made for conceptual model design.

 

 

Monitoring seepage through an earthen dam using time-lapse electrical resistivity. The percentage change profile (bottom image) indicates regions of the dam structure and foundation where the conductivity has increased or decreased. This indicated the seepage was occurring through several preferential flow paths associated with the historic creek channel and a reworked portion of the dam structure.
 

The advantage of the resistivity method, as is the case with most other geophysical methods, is its scalability to meet the desired resolution, coverage, and depth of investigation. By looking at the resistivity parameter over time, we can discern important features that provide detail regarding the movement of water internal to the structure. The advantage to using HGI to acquire these data is that we can design surveys that meet the demand of the project, from the small scale embankment to the large scale levee and everything in between. We also manufacture equipment specifically tailored for resistivity monitoring of the riskiest containment systems <<link to LDM somewhere within our sites>>.

 

hydroGEOPHYSICS is well suited to monitor your earthen structure, as we have applied our geophysical methodology to a large number of earthen structures over the past two decades. We can help assure that risk is minimized through the power of visualized knowledge.

 

Over the past decade, we have applied our geophysical methods on a number of earthen structures and we have gained an unprecedented wealth of knowledge about how each earthen dam may function. With this knowledge, hydroGEOPHYSICS can help you understand a newer level of your structure, help improve safety, and reduce risk.