Fluoresceine dye spreading into river waters (Eastern Réunion, 2010). © BRGM - Bertrand Aunay

TRAC: computer-assisted tracer-test interpretation for porous environments

TRAC is an application designed to interpret and represent hydrogeological tracer test results (graph plots).

TRAC is a freeware application to aid interpretation of hydrogeological tracer tests, developed by the BRGM for scientists and engineering consultancies, in particular for the prevention of accidental pollution.

Interpreting hydrogeological tracer tests for pollution prevention

Hydrogeological tracing is frequently used to track groundwater movements. The reappearance of a substance (usually a tracer dye) at one or more outlets of an underground water system, after injection at a given point upstream, is usually interpreted in terms of flow direction and speed of transfer.

However, it is possible to obtain further information in addition to direct tracer results. The tracer signal at the outlet  can be interpreted to provide information on the behaviour of the tracer underground, its exchanges with the environment and its dispersal. These parameters help to assess the properties of the underground environment when it is affected by accidental or diffuse pollution.

Injecting a fluorescent tracer upstream from a leak to track the groundwater flow. © Bruno Leclerc

Injecting a fluorescent tracer upstream from a leak to track the groundwater flow. © Bruno Leclerc

Assistance to groundwater protection agencies

TRAC is designed primarily to help prepare a tracing operation by simulating the underground propagation of a tracer based on existing data and any previous tracing results.

It is intended as a means of assisting water protection agencies, especially in defining the protection perimeter of drinking water abstraction points.

The TRAC home page

The TRAC home page

TRAC in simulation mode

TRAC in simulation mode

TRAC in simulation mode



  • Operating system: Windows (XP, 7)
  • Programming language:VB.NET
  • Languages: French, English (translations may be provided in other languages)

Download the software and user guide


TRAC software


Direction D3E / Unité GDR

3, avenue Claude-Guillemin

45060 Orléans Cedex 02


E-mail: trac@brgm.fr


More information about the TRAC project

BRGM - 3 avenue Claude-Guillemin - BP 36009 45060 Orléans Cedex 2 - France Tel.: +33 (0)2 38 64 34 34