Westland, Ellesmere Port

Overview

Westland Horticulture Ltd. planned to expand their existing site in Ellesmere Port by building a larger warehouse, extending their yard, and adding a new substation.

To support their planning application, they needed a Flood Risk Assessment (FRA) to show that the development wouldn’t pose an increased risk of flooding to the development site or surrounding areas.

The site is located in the Westlands area of Ellesmere Port, within the administrative boundary of Cheshire West and Chester Council. The area is characterised by industrial and commercial land uses, with existing infrastructure and drainage networks in place.

Challenges and Solutions

The scope of our flood risk assessment included:

• Assessing flood zoning and subsequent flood levels: We reviewed flood maps and data from the Environment Agency. The site is partly in Flood Zones 2 and 3, which indicates a medium to high chance of flooding during extreme events. However, flood defences are already established nearby, meaning the risk is considered low if those defences are maintained.
• Assessed levels and identified areas of safe refuge: We supported the wider design team by determining safe refuge locations in case flood defences are breached by evaluating the modelled flood levels, topography, and proposal plans.
• Reviewed existing drainage and sources of surface flooding: The current drainage system comprises a pumping station and interceptor tank. The extent of impermeable surfaces (such as concrete and roofs) was not increasing as part of the development, so the catchment of water runoff from the site remained unchanged. The system was therefore considered acceptable and will continue to be utilised.
• Reviewing the local geology and groundwater conditions: The ground mainly consisted of clay and peat, which have poor infiltration properties. Groundwater levels were also considered to be high.
• We ensured the plans followed national and local flood risk policies whilst ensuring we met the clients needs.

MCA's Contribution

Mason Clark Associate’s Civil engineering team provided a comprehensive flood risk assessment which detailed several recommendations:

• A safe refuge area was incorporated on a mezzanine level within the warehouse, positioned above predicted flood levels.
• The substation was elevated outside of the flood zone, and constructed so that water flows away from it.
• An emergency flood evacuation plan and flood warning systems were implemented to ensure people's safety.
• The existing drainage system was confirmed to have sufficient capacity, with no additional loading introduced by the development.
• It was deduced that the existing drainage system will handle surface water, and no extra pressure will be put on it.

Results

The FRA demonstrated that the proposed development could proceed without increasing flood risk on-site or elsewhere.

The assessment satisfied national and local planning policy requirements and incorporated robust mitigation strategies, including resilient design, drainage integration, and emergency planning.