Nérac: geology and natural hazards

Seismic zone

1 of 5 (very low)

Radon potential

Category 1 of 3 (low potential)

Recognised natural disasters

25 since 1982

Underground cavities recorded

8

Ground movements recorded

3

Risk prevention plans

2

Natural and technological hazards to which the commune is exposed, according to the national GASPAR database.

• Inondation: par une crue à débordement lent de cours d’eau
• Mouvement de terrain: affaissements et effondrements d’origine anthropique (anciennes carrières souterraines, hors mines), eboulement ou chutes de pierres et de blocs, glissement de terrain, tassements différentiels
• Transport de marchandises dangereuses

25 events recognised as a natural disaster by ministerial order since 1982.

• Inondations et/ou coulées de boue: 11
• Sécheresse: 10
• Mouvement de terrain: 3
• Tempête: 2
• Inondations remontée nappe: 1

1. Inondations et/ou coulées de boue

   Event from 08/02/2026 to 23/02/2026, order published in the Journal officiel on 24/02/2026.

2. Sécheresse

   Event from 31/12/2024 to 30/12/2025, order published in the Journal officiel on 12/06/2026.

3. Inondations et/ou coulées de boue

   Event from 23/05/2023 to 24/05/2023, order published in the Journal officiel on 28/07/2023.

4. Sécheresse

   Event from 01/07/2022 to 31/12/2022, order published in the Journal officiel on 03/05/2023.

5. Inondations et/ou coulées de boue

   Event from 29/01/2021 to 04/02/2021, order published in the Journal officiel on 28/03/2021.

6. Mouvement de terrain

   Event from 04/01/2021 to 05/01/2021, order published in the Journal officiel on 30/03/2022.

7. Inondations remontée nappe

   Event from 31/12/2020 to 27/02/2021, order published in the Journal officiel on 02/12/2024.

8. Sécheresse

   Event from 01/07/2017 to 31/12/2017, order published in the Journal officiel on 07/12/2018.

9. Inondations et/ou coulées de boue

   Event from 25/01/2014 to 27/01/2014, order published in the Journal officiel on 06/08/2014.

10. Sécheresse

    Event from 01/04/2011 to 30/06/2011, order published in the Journal officiel on 21/10/2012.

11. Mouvement de terrain

    Event on 26/04/2009, order published in the Journal officiel on 21/10/2009.

12. Inondations et/ou coulées de boue

    Event from 24/01/2009 to 27/01/2009, order published in the Journal officiel on 29/01/2009.

13. Sécheresse

    Event from 01/07/2005 to 30/09/2005, order published in the Journal officiel on 23/04/2008.

14. Sécheresse

    Event from 01/07/2003 to 30/09/2003, order published in the Journal officiel on 31/05/2005.

15. Inondations et/ou coulées de boue

    Event on 04/06/2003, order published in the Journal officiel on 27/06/2003.

16. Sécheresse

    Event from 01/01/2002 to 31/12/2002, order published in the Journal officiel on 26/07/2003.

17. Inondations et/ou coulées de boue, Mouvement de terrain

    Event from 25/12/1999 to 29/12/1999, order published in the Journal officiel on 30/12/1999.

18. Inondations et/ou coulées de boue

    Event on 13/09/1999, order published in the Journal officiel on 26/02/2000.

19. Inondations et/ou coulées de boue

    Event on 06/08/1999, order published in the Journal officiel on 04/12/1999.

20. Sécheresse

    Event from 01/01/1997 to 31/08/1998, order published in the Journal officiel on 13/11/1998.

21. Sécheresse

    Event from 01/01/1991 to 31/12/1996, order published in the Journal officiel on 30/12/1997.

22. Inondations et/ou coulées de boue

    Event on 13/08/1990, order published in the Journal officiel on 07/02/1991.

23. Tempête

    Event on 06/07/1989, order published in the Journal officiel on 16/09/1989.

24. Sécheresse

    Event from 01/05/1989 to 31/12/1990, order published in the Journal officiel on 27/12/1991.

25. Inondations et/ou coulées de boue, Tempête

    Event from 06/11/1982 to 10/11/1982, order published in the Journal officiel on 19/11/1982.

Seismic zone

Zone 1 of 5: very low. This regulatory zoning, in force since 2011, sets the rules for earthquake-resistant construction.

Radon potential

Category 1 of 3: low potential. The geological formations have the lowest uranium content. Radon is a naturally occurring radioactive gas that can build up in poorly ventilated rooms.

What BRGM maps say at the town hall. They describe that single point: elsewhere in the commune, the ground may be quite different.

• Shrink-swell clays

• Rising groundwater

• Underground cavities

• Ground movements

• Earthquakes

• Nature of the ground

Recorded across the whole commune by BRGM, in its national databases of underground cavities and ground movements.

8 underground cavities recorded (quarries, cellars, military works, natural cavities…).

3 ground movements recorded (landslides, rockfalls, collapses, mudflows…).

See cavities and ground movements on the map

• PSS - Nérac

  Natural risk prevention plan.

• PPRN-I - NERAC

  Natural risk prevention plan, under revision.

The zoning and regulations of each plan, which may prohibit or restrict building, can be consulted at the town hall and on Géorisques.

• Espiens (47)
• Barbaste (47)
• Lavardac (47)
• Fréchou (47)
• Calignac (47)
• Andiran (47)
• Vianne (47)
• Fieux (47)

Listed hazards, natural disasters, seismic zoning, radon potential, cavities, ground movements and prevention plans: Géorisques, published by the French ministry for the ecological transition, under Licence Ouverte Etalab 2.0, data accessed on 03/11/2026. Summary beneath the town hall: BRGM map services, queried when the page is displayed. List of communes and populations: API Découpage administratif (geo.api.gouv.fr), d’après le code officiel géographique de l’Insee, version of 30/10/2026.

This information reflects the state of knowledge at the scale of the commune or of a single point. It replaces neither a soil survey nor the official risk statement (état des risques) required for a sale or a rental, which is drawn up on the official French government service.