Flooding on Site: How to protect your plant from the worst


Surface water producing channels on a construction site can result in flooding. Flooding provides a high risk within construction for numerous reasons. The construction site itself as well as equipment or materials can be extremely damaged by floods, increasing the incurred costs of this natural disaster. Equipment may experience overhauls, or need parts replacing, leading to expensive fees. Construction can also be severely delayed by floods. For this reason, construction experts will benefit from understanding the risk of this destructive force.

The need for careful flood risk management within the construction industry is becoming more prevalent as the industry progresses. In turn, the development of flood resilient construction methods is becoming more widely studied. However, the broad range of construction styles, as well as fluctuating levels of flood risks means there are still many areas to be considered. Despite this, it is evident that the construction field will likely experience an uptake of flood resilient materials. Until flood resilient technologies are progressed, there are various methods that can be employed to minimise disastrous results from flooding.

Flood prevention methods – an overview

A safe scheme of work must be planned before using any construction plant equipment. The health and safety on a construction site is the responsibility of the construction firm. Construction sites that are near to rivers or coasts are not the only sites at risk of flooding. All construction professionals can profit from assessing the flood risk on the site and developing a water management plan. Lack of water management plan in case of a flood, may result in expensive machinery being written off. Additionally, plans where sediment/silt run off could be a problem would benefit from creating an erosion and sediment control plan. This plan could comprise data including property boundaries and contour descriptions.

In order to assess the flood risks of a construction site, numerous factors must be considered. Watercourses near to the site and the flood history in the area must be researched. Routes to water must be identified, as well as areas of potential erosion. These issues can be researched using flood maps. It is important to note, however, that even if there are no water sources nearby and the area has never flooded, it is to possible for a flood to occur.

Designers and planners will account for the risk of flooding on the building itself. However, the task that many construction firms face is finding the best way to prevent the flooding of the site. Buildings under construction may lack the standard measures that would typically protect them from disaster, meaning they are at risk of extensive damage. The first easy step to take would be to check there are no restrictions on the site that would cause the water to build up into large puddles. This can be done through keeping paths and exits clear and open. Additionally, steps should be taken to avoid pipes bursting from frozen water causing them to burst. Running water through the pipes can prevent water from freezing and expanding.


The company responsible for the construction site should have emergency evacuation procedures in place. These procedures should include methods for workers to be able to leave quickly and easy. Plans to avoid the impacts of erosion should also be considered. For example, sustainable drainage systems can be a very effective approach to avoiding flooding on construction sites if they are planned and designed correctly. It is the responsibility of the site manager to ensure that these drainage systems are not threatened by construction activity. Moreover, if a flood is suspected to occur, it may be wise to have a water drainage pump on site.

Machinery, where possible, should be moved to higher elevations. This is where it would be useful to be aware of past flooding history, as safe areas could be designated. For heavy machinery that can’t be transported to higher locations, exposed metal surfaces should be coated with grease. It’s possible that flooding may lead to sediment run off, which in turn effects the contour of the land. This may lead to overturning, so it is important to ensure all heavy machinery is as stable as possible at all times.

Whilst materials such as concrete are water resilient, and steel construction material may not be damaged by water, other materials may be damaged. For example, plasterboard or composite wood will be damaged by water. Electrical and mechanical equipment will also need to be moved to safe locations if a flooding is expected. Flooding is one of the few natural disasters that may come with a warning. If a flood is suspected, evaluate the materials that need to be kept dry. Portable barriers can also be erected in order to prevent damage from floods, such as sandbags or flood walls.

After flooding

If a construction site has been affected by flooding, there are various things to remember:

  • Flood water may contain sewage and diseases. Do not wade in the water.
  • Water must be pumped out and drained before the construction site can be entered.
  • Pressure washing is an efficient way of thoroughly cleaning plant equipment.
  • Electrical problems may not be evident straight away.
  • The steps you should follow after a flood varies on the machines and level of flooding.
  • An insurer and authorised machinery dealer should be consulted before attempting repairs.
  • Do not start any equipment until it is checked by a qualified mechanic.
  • Starting a flood-affected engine may lead to serious impairment to the internal engine mechanisms.
  • Consider using a water drainage pump.

Additional Information

For further information on how to avoid your construction site being flooded, as well as what to do if a flood has occurred, look at the Health and Safety Executive (HSE) website. Additionally, the environment agency has useful tips on flooding and related issues.

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