25 July, 2012

Dublin City Council Sandbag Policy

The City Council does not provide or distribute sandbags to individual premises at risk of flooding. The prime responsibility for the protection of such premises rests with the owners of those properties.

The primary role of the City Council during pluvial events is to manage the drainage network in order to minimise the extent of flooding to the general public. The supply and distribution of sandbags would present a considerable impediment to this task. In addition the inevitable increase in telephone requests for sandbags to emergency call centres would seriously interfere with the ability of those centres to cope with major flooding events.
The use of sandbags has become established in the public’s mind as an effective flood protection measure. This is reflected in demands for the City Council to make sandbags available to householders and businesses at risk of flooding.

The Council maintains strategic stocks of sandbags at a small number of locations. These amount to around 9,000 at various locations including Clontarf, Sandymount, Glendhu Park, and the drainage depots at Marrowbone Lane and Bannow Road. The stocks at these sites are maintained for strategic purposes and play a useful role in areas when dealing with flood events which have sufficient advance warning.

General advice to property owners on dealing with floods is provided by the OPW in booklet format and on the website www.flooding.ie. The OPW advice recommends property owners at risk of flooding to have a supply of sandbags close at hand. The advice notes also acknowledge that sandbags can be difficult to deploy during flood events and can also pose health risks if contaminated with sewage.

A major report on of the serious pluvial flooding that occurred in the UK in 2007, known as The Pitt Review, concluded the following with regard to the role of sandbags as a means of protecting individual properties during flood events:

• While it is clear that sandbags have a useful role in certain types of floods when used strategically, their benefits are less clear when they are used by householders to protect individual properties. This weakness is further heightened by their relative inefficiency when compared with alternative dedicated flood defence products that have been developed in recent years, such as floodgates and airbrick covers.
• Extensive evidence of public over-reliance on sandbags which often proved of little value in protecting against flooding.
• Many householders and business owners put time and energy into obtaining and installing sandbags which would have been better spent on other activity such as moving possessions to safety and deploying door boards.
• Sandbags can be effective when it is marginal, as to whether water enters a house or not, but in relation to large volumes of water they are largely ineffective, contrary to public perception.

 To supply sandbags to all properties at risk of flood during sudden rainfall events would require a level of resources that is much greater than is currently available to the City Council. Even if such resources were provided the deployment of sandbags in sufficient time to prevent significant flooding of properties, particularly during monster rainfall events, would be logistically impossible. During a flood event, invariably the transport network is very busy, which means that DCC crews have great difficulty in reaching certain areas to deploy pumps, close flood gates, or deliver sandbags. If there is little notification that an event will occur, delivering sandbags would not be possible.

The provision of sandbag stores at specific locations around the City that could be accessed locally by residents on foot of flood warnings would require considerable investment by the City Council to manage and maintain. The unpredictable nature of flood warnings which can average 4-5 a year would result in sandbags being deployed more often than required, leading to the unnecessary expense of maintaining the required stock of bags at each location. The transportation and placement of sandbags from local containers would still require a considerable effort by local residents and they would be unlikely to be in position in time to prevent flooding to most properties subject to sudden rainfall events.  Furthermore, if sandbags were deployed at certain locations, there is no guarantee that the people who need them will get them. During a flood, panic generally sets in, and those who are not in risk of flood could easily exhaust the supply of bags at the expense of those in need.
Owners of properties that are at risk of flooding are encouraged to keep where possible, their own stock of empty sandbags together with sufficient stocks of sand to fill bags at times of potential flooding. Preferably owners should invest in the provision of suitable proprietary flood gates and covers to protect openings such as doors, windows and vents.

There is a general expectation by the public that during periods of flooding the City Council will make sandbags available to properties at risk of flooding. Other than for exceptional circumstances this is not the case. The prime responsibility for protecting premises lies with the property owner.