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Drainage Strategy Neston, Cheshire

Drainage Strategy Neston, Cheshire

4 Housing Development

Location

Chester High Road, Neston, Cheshire

Service

Drainage Strategy, 4 Plot Housing Development

Completion Date

May 2026

Status
  • Completed

Project Overview

Maple Oak Kennels proposed a residential development of four new dwellings with associated parking and access off Chester High Road, Neston. A detailed drainage strategy was required to support two outline planning applications and demonstrate compliance with national and local flood risk policies.

Challenges & Approaches

Challenge

Although the site is located within Flood Zone 1, several constraints influenced the drainage design. The site is brownfield with existing structures to be demolished, limited space for drainage infrastructure, and proximity to a railway line restricting soakaway locations. Additionally, there are no nearby surface water or combined sewer connections, requiring a fully self-contained drainage solution for both surface and foul water.

Approach

Courous Ltd. developed a comprehensive drainage strategy which included

  • Application of the SuDS hierarchy to prioritise sustainable drainage solutions

  • BRE365 infiltration testing confirming viable infiltration rates (0.028 m/hr)

  • Utilisation of an existing on-site pond as an infiltration basin with 256m³ storage capacity

  • Integration of permeable paving to provide additional attenuation and source control

  • Climate change modelling (+45% for 1 in 100-year storm events) and 10% urban creep allowance

  • Design of a separate foul drainage system using a packaged treatment plant

  • Sizing of a cellular soakaway for treated effluent in accordance with BRE 365

  • Hydraulic modelling using InfoDrainage to verify system performance

Outcome

The strategy confirmed:

  • Surface water managed entirely on-site via infiltration to the existing pond
  • No requirement for off-site discharge, aligning with SuDS hierarchy best practice
  • No flooding on-site during a 1 in 100-year storm event plus climate change allowance
  • Effective runoff reduction through permeable paving and landscaped SuDS features
  • A compliant foul drainage solution using a package treatment plant and soakaway system
  • Full compliance with NPPF, SuDS standards, and Building Regulations

Conclusion

The drainage strategy delivered a fully sustainable, self-contained solution tailored to the site’s constraints. By utilising on-site infiltration and integrating both surface and foul water strategies, the design minimises environmental impact while ensuring long-term resilience. The report successfully supported planning submissions and provides a robust foundation for detailed design and construction.