Flood Resistant Building Design Strategies

Floods are natural calamities that bring significant problems to buildings and structures around the world. Specifically, one-third of the entire continental United States are at the risk of flooding this spring mainly in the areas: Northern Plains, Upper Midwest, and Deep South. 

The deadly floods in the year 2019, resulted in thousands of deaths in several parts of Mozambique, Malawi, Zimbabwe, and Iran.

No construction or architecture can completely protect from most deadly floods. But there are several techniques that can be followed to mitigate the damage and consequently save the occupant's life.

Planning Policy and Building Standards for Flood Resistant Building Construction

Some of the key planning objectives followed as per Planning Policy Statement 25 (PPSE5) Development and Flood Risk, England, United Kingdom, are:

1. The flood risk must be taken into account at all stages of the planning process.
2. Provide a more strategic approach to managing flood risk, considering it as early as possible in the planning stage.
3. Guidance on the need to include Flood Risk Assessments (FRA) at all the levels of the planning process has to be strengthened.
4. Provide the opportunity to reduce the flood risk to communities by re-creating and safeguarding the flood plain.
5. Promoting green space and sustainable drainage systems within urban areas.
6. New development is taken as per the climatic change.

Flood Resistant Building Design Considerations

Important factors that need to be considered that will influence the design of new building:

1. Potential Sources of Flooding
2. The predicted flood level
3. The duration of the flood
4. Frequency of flood - shallow or deep
5. Flood depth

Among all the above factors, flood depth is considered as the main factor required in the design strategy.  The design flood depth at a building from knowledge of the predicted flood level and the ground level and to set a practical design floor level. This is an iterative process, as the level of access and cost factors are taken into consideration.

Design Approached and Flood Resilient Design and Construction

Based on the flood parameters; depth, frequency, and duration are taken from the flood risk assessment at the planning stage. Depending on these factors, different ranges of construction measures are considered. They are:

1. Flood Avoidance Construction

Constructing a building and its surroundings (at site level) in such a way to avoid it being flooded (e.g. by raising it above flood level, re-siting outside flood risk area, etc).

2. Flood Resistance

Constructing a building in such a way to prevent floodwater from entering the building and damaging its fabric.

3. Flood Resilience

Constructing a building in such a way that although flood water may enter the building its impact is reduced (i.e. no permanent damage is caused, structural integrity is maintained and drying and cleaning are facilitated).

4. Flood Repairable

Constructing a building in such a way that although flood water enters a building, elements that are damaged by flood water can be easily repaired or replaced. This is also a form of flood resilience.

Also Read: How To Cleanup Your Flooded Basement?  Flooded Basement Restoration