Zappel is a tool that plots the catchment area and the position of the isochrones of a borehole under the effect of pumping.
Example of simulation of the calculation of a water well catchment area and isochrones

Example of simulation of the calculation of a water well catchment area and isochrones.


Plotting the borehole catchment area 

Developed by BRGM, Zappel software plots the borehole catchment area. 

The catchment area can be defined as the area of an underground water table corresponding to groundwater flows which at some stage will end up at the borehole. This catchment area depends on the flow rate from the well and the water table characteristics. 

Isochrone position calculation 

Zappel also calculates the position of the isochrones. These are lines (contours) that connect points from which the time required for groundwater to reach the borehole is equal. 

For example the 50-day isochrone means that any free molecule of water circulating in the underground water table at a location on this contour will take 50 days to reach the borehole, not taking dispersion phenomena into account. 

Isochrones thus represent the interpolation of a set of points, each corresponding to a transfer time. The result can be exported in a SIG file. 

Practical information 

  • Operating system: Windows (XP, 7), Linux 
  • Programming language: C++ 
  • Language: French 
Drilling at the BRGM geothermal platform, Orléans

Zappel download form

Fill out the form below. You will then receive an email containing a link to download the software.
* Indicates required field

Your need

Your message

Please tick the boxes for the type of information you would like to receive

Your contact details

Validate the form

To validate this form, read our data protection policy and validate the security test to confirm that you are a human user.

About the personal data collected on this form

  • Purpose of the form: enable BRGM to reply to you following a request for information on its software, or to enable you to download software made available by BRGM.
  • Users of the data provided: the departments in charge of communication and user of information systems reception, support and assistance, and software management, who may share the data with persons or departments concerned by your request in-house at BRGM and/or with subcontractors or service providers.

Your rights

Within the limits of the Regulation, in particular Articles 15 to 22 of the GDPR and having provided proof of identity, you have:

  • the right of information and access to your personal data,
  • the right to have your personal data rectified,
  • the right to delete or limit processing of your personal data.

To exercise these rights, please contact our data protection officer at:
Any request that constitutes an abuse of current laws and regulations may be rejected.
More information on the policy for third-party personal data protection