Environmental Assessment for Corporation Street Hotel, Rochester

Lustre Consulting was appointed by Corporation Street Hotel Ltd to provide a comprehensive contaminated land and geotechnical assessment for the redevelopment and regeneration of a site along Corporation Street in Rochester, Kent. Formerly a petrol station and currently operating as a car wash, the site had several unique environmental challenges and constraints. Leftover infrastructure from the petrol station, including a forecourt canopy, office building, and foam-filled underground storage tanks (USTs), along with the site’s use as a commercial car wash, required a specialist approach to ensure safe and compliant redevelopment.

Our assessment aimed to address these challenges and provide Medway Council with the necessary assurances to support the proposed redevelopment of the site into a six-storey hotel with basement level. The hotel will include bedrooms, a plant room, restaurant, and retail outlets, with landscaped external areas.

Phase 2 Site Investigation and Remediation Strategy

Our work began with a Phase 2 Site Investigation to determine the extent of contamination risks associated with the site’s former use as a petrol station. The scope of this work included:

• Drilling of boreholes and excavation of trial pits: Located across the site to target potential sources of contamination (such as USTs) and recover soil samples for inspection and testing. At the same time, monitoring wells were installed to check for ground gases, vapours and water.
• Soil Sampling and testing: Selected soil samples were sent to a UKAS accredited laboratory for analysis. Testing included a wide range of contaminants commonly associated with site’s use as a petrol station and garage, to see if the ground had been effected.
• Gas and groundwater monitoring: Weekly monitoring to measure for the presence of ground gas (such as methane and carbon dioxide), hydrocarbon vapours (petroleum, oils and solvents) and groundwater.

This established a comprehensive understanding of these risks, guiding the formation of a bespoke Remediation Strategy to mitigate the identified contamination. Key actions included:

• Removal of Legacy Infrastructure: The decommissioned USTs and other remnants of the petrol station was carefully removed to eliminate contamination sources. This process also involved removing and disposing of any associated contaminated soils in line with environmental guidelines.
• Soil Treatment and Excavation: We targeted areas found to have elevated petroleum, oils and solvents. Contaminated soil was excavated and treated on-site to reduce pollutant levels and prevent potential exposure.
• Ground Gas Mitigation: Due to elevated carbon dioxide levels, we recommended a ground gas protection system be installed in the building. This system acts as a barrier to prevent gas ingress, protecting the future users of the hotel from potential exposure.

As the development involves a multi-storey building with a basement situated over a sensitive Chalk aquifer, the Environment Agency required a Piling Risk Assessment to evaluate potential contamination migration risks during foundation piling. This assessment ensured that the selected piling techniques would not disturb contaminated soils and allow pollutants to spread into the groundwater. By understanding the risks and selecting the most appropriate piling methods, we demonstrated that the risk associated with building foundations could be sufficiently mitigated, protecting the Chalk aquifer.

To verify the success of our remediation measures, we routinely carried out validation site visits to oversee the removal of USTs and inspect surrounding soil conditions. During these visits, we monitored the excavation process, confirmed that all decommissioned infrastructure was properly managed, and tested the soil to ensure that any remaining contaminants were within acceptable thresholds. These validation checks provided crucial documentation for Medway Council, demonstrating that the site was ready for safe development.

Geotechnical Investigation

In addition to ground contamination assessments, we conducted a Geotechnical Investigation to evaluate the engineering capability of the ground and ensure it could support the proposed six-storey hotel structure.

This included soil strength testing, load-bearing analysis, and a review of subsurface composition, which informed foundation design and ensured that the building’s structural integrity would be maintained over time. This assessment was essential for allowing a structural engineer design a suitable foundation, especially given the basement-level construction.

The environmental and geotechnical assessments played a pivotal role in securing planning approval from Medway Council for the redevelopment of the site. By addressing contamination risks, developing a targeted remediation strategy, and conducting validation visits, we ensured that the site met all required building and technical standards and was fit for redevelopment.

Our work provides Corporation Street Hotel with the foundation for a safe and compliant development project, contributing to the successful regeneration of Rochester.

For more information on how Lustre Consulting can support your project with environmental and geotechnical solutions, please contact us today.