Site Investigations and Remediation Strategy.

Last week Adam Czarnecki, Managing Director at Earth Environmental & Geotechnical, was back visiting Victoria Meadows.  This is our third project in Ripponden, West Yorkshire,  following Site Investigations and Remediation Strategy services.

“It’s always enjoyable to see projects that we were involved with progressing, and great to see a former area of tipping on a derelict site transformed to provide quality new housing. Very proud to see the development progressing so well despite the problem with trade supplies. Great to see the Remediation Strategy being implemented”

Earth Environmental & Geotechnical Ltd. conducted site investigations and developed the remediation strategy to address the challenges of developing on this former derelict site. The site investigations, risk assessments, and resultant remediation strategy, supported the successful planning application to develop 24, three, and four bedroom properties, some with stunning views over the River Ryburn.

The project included a Construction Environmental Management Plan (CEMP) which provided a site-specific statement on how the effects of construction on the surrounding environment and community will be mitigated or minimised. The plan also provided specific detail on the control of noise, dust, and odour based on the relevant guidance documents.

Earth Environmental & Geotechnical Ltd was also commissioned to provide a Remediation Method Statement (RMS) for the site at Halifax Road, Ripponden.

The Background

The development site lies northeast of Ripponden, a conservation village in the beautiful Ryburn Valley. Nearby is Rishworth Moor, an area of outstanding natural beauty, home to a wealth of wildlife and a series of ancient round barrow burial sites, known as the ‘Cat Stones. With great connections to both Leeds and Manchester via the M62, and Sowerby Bridge train station less than 2 miles, the site’s in a great location.

The proposed residential development of twenty-four plots, consisting of a mixture of two and three storey dwellings, combined with a split-level design for the residential units, in sympathy with the site’s topography.

The initial phase 1 desk study in 2016 had identified several areas requiring further site investigations and risk assessments including:

• Geotechnical hazards
• Differential settlement issues for foundation and pavement design.
• Potentially deep piled foundations.
• Potential for localised landslips along slope, which may require ground improvement

• Clay heave affecting foundations
• Excavations affecting local structures’ stability.
• Extent of wall foundations affecting foundations

• FRA- The site was within an Environmental Agency flood plain, and a Flood Risk Assessment was required.
• Gas monitoring visits and targeted investigation and survey of potential contamination
• Japanese knotweed and Himalayan balsam required an ecology survey

An appropriate ground investigation strategy was required including Window Sampler Boreholes & Trial Pits to retrieve geotechnical data of the ground conditions.

Earth Environmental & Geotechnical Ltd were requested to provide a summary of land stability on the proposed development area having previously completing a Phase 2 Site Investigation Report for the site in 2018.

Geological records suggest that the majority of the site is underlain by Head deposits consisting of clay, silt and sand. Previously a cable and percussive drilling rig had been used to drill a number of boreholes on the site, which revealed variable ground conditions with a shallow rockhead, the East Carlton Grit of the Millstone Grit Group.

The previous phase 1 desk study with site walkovers suggested that to maintain the stability of the existing retaining wall, strict controls over excavations and earthworks would be required during construction, with the relevant risk assessment and method statements set in place during the detailed earthworks, pavement and structural design.

Furthermore, some form of monitoring regime of the retaining wall would be required during construction works to ensure stability of the highway.

The greenfield site being developed for the residential development was situated on a poorly drained sloping site that lies adjacent to the River Ryburn. The site investigations and land stability assessment recommended that due to the sloping nature of the site, plots should be constructed at different finished levels and incorporate retaining walls and comprehensive surface water drainage system. Land gradients were therefore designed to be reduced with an overall improvement in land stability.