HS2 C2-C3

HS2 is one of the largest and most complex civil engineering projects to be undertaken in the UK for many years, and it is these large scale complex infrastructure projects which WJ specialise in.

Whilst WJ are renowned for our groundwater control and drilling these are not the only services we offer, and the 80km C2-C3 section of the HS2 alignment gave us an opportunity to showcase our groundwater and surface water monitoring capabilities.

Due to the length of the section the groundwater and surface water monitoring requirements were extensive, comprising over 270 groundwater monitoring locations, over 120 surface water monitoring locations, and over 160 discharge locations (usually attenuation ponds or discharge points), which had a requirement to be visited on regular (usually weekly or monthly) basis to undertake a range of testing including:

• Water Level Monitoring
• Multiparameter Field Readings
• Water Quality Sampling

In addition to the regular in-person visits, WJ also installed a series of automatic sondes which were deployed within borehole and stilling wells to provide “real-time” monitoring data which we, our client and all relevant stakeholders could access via our bespoke online monitoring dashboards.

In addition to this more conventional monitoring, WJ also partnered with Five Rivers to undertake aquatic ecology monitoring which included:

• Macroinvertebrate surveys
• Macrophyte surveys
• Phytobenthos surveys
• Fish community surveys
• Spot flow gauging

This was a significant undertaking for WJ, with four teams (comprising an environmental monitoring technician and supervisory environmental monitoring technician) working full time on the project, periodically supplemented by a fifth and sixth teams when required to ensure project delivery requirements were met.

Due to the nature of the testing and sampling requirements WJ staff were often taken to isolated locations therefore the project required a significant investment from WJ to ensure we had absolute confidence in our staff’s ability to properly assess hazards and risks (especially around water) and work in a safe manner to obtain the data required. This investment included:

• SSSTS training
• FAW training
• British off-road driving 4×4 training
• Rescue 3 (DEFRA Level 2) swiftwater and Flood first responder training

Due to the quantity of data being collected a streamlined approach to data collation and presentation was required. A Smartsheet and Webforms platform was utilised to collect site data electronically, enabling the field data to be seen as soon as it was collected. Key stakeholders were provided with access to the platform to ensure they had “real-time” access, as well as to enable a notification system to be utilised should any pre-assigned trigger values be breached.

In addition to this our bespoke in-house monitoring dashboard was utilised to provide a cloud based ‘real-time’ portal for our clients to access data obtained from the water level sondes that were installed across the C2 and C3 alignment.

The works are still ongoing (and not anticipated to complete until 2027), however so far the project has demonstrated that WJ are the ideal partner whether groundwater control or environmental monitoring is required on your project.

• LOCATION: Chilterns

• CLIENT: EKFB / HS2