HMP Glasgow

The project is being built on a post-industrial brownfield site, formerly the Provan Gas Works, which operated until the mid-1970s, when the site was decommissioned, cleared, and demolished. Due to its previous industrial use, the site carries significant environmental challenges including contaminated ground with hydrocarbons, asbestos, and cyanide present, along with remains of partially demolished structures such as retaining walls, floor slabs, basements, and foundations.

Careys has delivered the advance works phases to prepare the site for the main construction works. Phase 1 focused on site clearance and contamination management, while the ongoing Phase 2 (AW2 Lite) includes the main earthworks and infrastructure installation. The purpose of the enabling/ advance works is to create the working platform to allow the main works to commence while managing the known ground contaminants.

• Advance Works Phase 1 completed successfully, Q4 2024
• 7,500m³ of material moved to the SuDS pond for reshaping using 22.5t Hitachi with GPS
• 5,600m³ of material sent to stockpiles for upcoming phases
• Over 3,250m³ of concrete broken from retaining walls using 49t Hitachi excavator
• 5,700m³ of concrete from slabs and foundations processed for crushing and reuse (completed in week 12)
• 1,500m of haul roads installed
• Siltbuster dewatering system processed over 500,000 litres of water daily
  
• Phase 2 (AW2 Lite) duration is 42 weeks (ongoing)
  
• Drone GPS survey used for site monitoring
  
• Early formation of dewatering filter trenches allowed progress during rainy days
  
• Over 300,000m2 of earthworks cut & fill

HMP Glasgow is being built on a brownfield site which previously housed the Provan Gas Works. Since decommissioning in the 1970’s, the land has been used for storage and distribution and remains heavily contaminated ground due to its industrial legacy.

Geotechnical testing has shown extensive pollutants across the site, including hydrocarbons, asbestos, and cyanide from the former gas works operations. To mitigate this we have developed a bespoke environmental management plan, EMP, which includes a material management plan that ensures contaminated materials are properly handled and treated. This proactive approach has included instructing experts to assist in implementing mitigation strategies including using filter trenches and a SuDS pond on site to received all the water runoff from the site including potentially contaminated storm water. This pond was connected to a Siltbuster treatment system which processed and treated over 500,000 litres of water daily, before it was released into the nearby Molendinar burn.

The decommissioning of the site has left a number of legacy structures and hidden services / infrastructure. The remains of partially demolished structures include retaining walls, floor slabs, basements, and foundations required careful demolition and processing.

Ecology and environmental management have been significant challenges at HMP Glasgow as multiple invasive non-native species including cotoneaster, giant hogweed, buddleia, Canadian pondweed, and Nuttall’s pondweed are all present on site. To minimise the negative effects we implemented our established processes which include targeted control methods which were adapted to the site conditions both terrestrial and aquatic including using a wheel wash and manual pressure washer to clear the basin which is intended to be enlarged and enhanced with native wetland species.

Nearby residential areas Germiston and Blackhill border the site and were noted as areas of potential risk regarding both noise and dust. Prior to the commencement of works we installed noise and dust monitors were installed in the community. During summer months, dust levels have significantly increased as the ground dried significantly, creating potential for dust clouds and noise associated with the construction works has affected nearby residential neighbourhoods of Germiston and Blackhill. To mitigate these challenges to the community we have implemented control measures including acoustic shielding, dust suppression and capture. In addition, internal haul roads have been regularly damped down in summer months to control dust levels.

Construction activities have been carefully planned from pre-construction to co-ordinate with other stakeholders and service providers on-site. Site logistic have been planned to ensure planned to suit construction sequencing. Site split into zones and grid square to enabling better planned construction sequencing. Logistical movements and processing of large volumes of materials on-site while maintaining productivity and environmental compliance have proved challenging at HMP Glasgow due in part to the close proximity of the residential areas surrounding the site and other stakeholders working on site.

We developed a site specific traffic management plan, TMP, for construction phase in collaboration with Kier. As the project continues there will be additional phasing for Highway Works which will be planned and agreed with Glasgow City Council and Kier to ensure minimal disruption is caused to the local road network.

To combat this we have implemented stringent collaboration and communication tools which mean everyone is clear on their roles, responsibilities and duties. The daily activity briefing, DAB, which take place each morning, communicates to all operatives the activities to be undertaken that day and provides clear direction for any deliveries, vehicle movements, offloading arrangements or unusual activities scheduled that may impact or require knowledge and consideration in order to reduce risk.

In line with our sustainability strategy we have adopted sustainable working at HMP Glasgow. One of the most stand out aspects of sustainable practice was the recycling of concrete and soil across the site. A cut and fill process was used to level the ground. The extracted topsoil from the higher levels on site was placed in alternative lower areas. This process has significantly reduced the carbon footprint and the costs associated with soil transportation. Similarly, during demolition and obstruction removal, concrete was stored, and the steel rebar extracted. The old concrete subsequently went through a crusher to be used for aggregate. This entire process was done on site, significantly mitigating some of the carbon impact of concrete and cement production, one of the biggest emitters of greenhouse gases.