2.8 million properties susceptible to surface water flooding in 2023

Whether you're a developer or investor, being aware of potential hidden risks can be the difference between making a profit or a loss on a project.

Many people associate flooding with rivers overtopping their banks, but don’t consider the risk of flooding from other sources located miles away from rivers or streams. Compared to river or coastal flooding, surface water flooding (or flash flooding as it's sometimes referred to) is difficult to predict and pinpoint as it happens simply because there is nowhere else for the rainwater to go.

Nimbus Maps demonstration of Surface Water Flooding feature within Location Analysis tool. 

What causes Surface Water Flooding? 🌊⚠

Surface water flooding occurs for many reasons but the most common cause is when heavy rainfall overwhelms the drainage capacity of the local area, which according to the Environment Agency, leaves over 2.8 million people at risk of flooding in England alone. 

• Ground conditions - When ground conditions are dry and hardened they become less receptive to the absorption of water, likewise with saturated and water-logged areas. The reduced ability of soil to absorb further rainwater causes water to flow overland and can cause surface water flooding.
• Infrastructure & Development - Buildings, roads, car parks, driveways and other watertight/ water-resistant surfaces can add to the build-up of surface water. 

💡Side note: Planning permission will be needed for laying traditional, impermeable driveways that are more than five square meters that do not allow for the water to run to a permeable area. 

• Topography - Steep valleys, hills and gradients in land can channel large amounts of rainwater to properties below. 

How Nimbus helps to identify risk

Whilst surface water flooding is something that can be monitored and reduced, it’s essential to bear in mind that one-in-six properties across the UK are still at significant risk of flooding. According to a report prepared for Defra, repairing a property after a flood can cost anywhere between £10,000 and £50,000, depending on the flood depth.

Knowing the degree of risk to flooding before acquiring a property can ensure the proper infrastructure is put in place to slow down the flow of water whilst factoring it into the overall development costs.

This might include:

• Increasing the soft landscape nearby
• Installing bigger drains or/and large tanks to hold the excess water and then slowly releasing it into the system
• Increasing heights of buildings

How to use it in Nimbus

Simply select the Location Analysis tool in the top right of the Nimbus Maps platform, then select Surface Water Flooding from the Planning Policy dropdown menu. The affected areas will be identified in various shades of blue.

Want to learn more about how Nimbus Maps will help you assess potential land and property opportunities?  Request a free trial today, which includes a 1-to-1  demo of the platform. 

💡Side note: Did you know you can now also request a full Local Search through our Client Solutions service, which covers a number of hazards such as radon, contaminated land, ground stability, air quality, etc? Find out more.