Welcome to the Dauntsey Drainage Board  (DDB) web site. We feel that this is by far the most complete  information on flooding in Dauntsey, its history, causes and what still needs to be done to reduce and/or control flooding.

If you have any additional flooding information the please contact us so we can share it with everyone else.

Only by fully understanding the causes of flooding can the problems be resolved. This is a community problem and can be solved with community help - hiding information from insurers is likely to invalidate insurance while hiding it from buyers could end up in court.

Here you can find information about flooding in and around Dauntsey, what has been  done to reduce the risk and what we are still trying to achieve.

As part of  this work, DDB has also recognised the importance of digital mapping. We now use Open Source (free) software and, under the Public Sector  Mapping Agreement (PSMA) with Ordnance Survey have free access to most of their digital maps.

NOTE This site was originally created by Andrew Chapman when he led the  Dauntsey Parish Council Drainage Board to contain information on  flooding and as a resource for people learning to use free GIS software. As there are no members of the parish council with equivalent knowledge of flooding or GIS, this site now has no connection with Dauntsey Parish Council.



Nationally 2012 was a very bad year for flooding, but Dauntsey didn’t suffer any property damage... so is the problem fixed?

A lot has been done to rectify the lack of maintenance problems of the main rivers (Brinkworth Brook, Dauntsey Brook and The Bourne) plus the ordinary watercourses (ditches etc.) There is still a major disagreement with the Highways Agency about their flooding study (see below) which downplays the amount of overland flow from Brinkworth Brook into Dauntsey Brook when excess flow cannot get under the M4 due to the M4 blocking the flood plain.

The Wilts & Berks Canal was officially abandoned in 1914 by an Act of Parliament but, while the right of navigation officially finished, the canal continued as an ordinary watercourse. The canal was neglected and even filled in at certain points so its historic ability to attenuate floodwater and pass flow from west to east has been largely lost. Work by the Wilts & Berks Canal Trust to restore the canal should, when completed, reduce the flash flooding from Lyneham Banks.

Possibly the biggest reason why Dauntsey didn’t flood in 2012 is that the worst rainfall moved slightly west and “Dauntsey’s” rain fell on Malmesbury - Malmesbury flooded, Dauntsey didn’t.

Highways Agency Flooding Study

The Highways Agency together with Mott MacDonald have produced their latest “final” M4 Dauntsey Flood Risk Assessment and released it in response to a Freedom of Information Request in  December 2012. Repeated requests over a period of approximately 18 months to see this information via members of Wiltshire Council’s  Operational Flood Working Group were ignored by the Highways Agency but a FOI request produced the report in 24 hours... so if you are trying to  get information and hit a wall of bureaucracy, you could try FOI.

This version finally agrees that the construction of the M4 has made flooding worse in Dauntsey, but there are still significant differences between actual and Highways Agency predicted flood levels, especially south of the motorway. Pressure is being exerted via James Gray MP and the Wiltshire Council Flood Working Group to get the different parties together to review this version of the report and, hopefully, eventually get a report and computer model that coincide with reality.


We have run two of our free GIS (computer mapping) training courses. Read all about them.

We would like to do more but, as these have been funded by those presenting the courses, we cannot run further days unless we can find external funding.

As a result of the courses however, there are an increasing number of users starting to come together and share knowledge and experiences. We have a Wiltshire based QGIS Users Group that has started to hold pub evenings - if you would like to come along, contact us.


We are still in the process of building this site. We hope you find what is already here interesting. Visit again and there should be more to see.


There are many differing views on the causes and ways to remove or reduce the likelihood of future floods. As we learn more it is expected that the information on this site will change, but we will always try to provide as complete information as possible.

The Environment Agency Flood Maps for Dauntsey are wrong! The flood extents shown are based on the 1932 flood. Since then, the M4 has been built on an embankment cutting the floodplain. The Church Lane overpass is at right angles to the flow and is a major impediment to the historic flow. Despite clear evidence to the contrary (including the EA’s “Dauntsey Pre-feasibility Study in 2008), the EA still publishes a map with gross errors. The only recent change that they have made is to acknowledge that flooding is unlikely to cover Church Lane where it crosses the motorway!

If you feel that what is presented is incomplete or incorrect, please let us know.

Information on this site is copyright Dauntsey Drainage Board. The maps are based on Ordnance Survey OpenData and additionally covered by that licence.

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