Client: Northumbrian Water Limited
Location: Chester-le-Street, County Durham
Contract Value: £2.3 million
Contract Period: August 2009 until May 2010
The scheme is being undertaken as part of sewerage improvement works for Northumbrian Water Limited as part of their Sewer Flooding Sub-Programme, during the Asset Management Plan (AMP) 4 Period. The works will alleviate flooding of residential properties throughout the Broadwood View and Garden Farm Estates and will require continual community interaction as rolling road closures are in place leading to restricted access to properties and various vehicular diversions.
Before commencing the works a public open forum was held at Chester-le-Street Cricket Ground attended by Client, Consultant and Contractor highlighting the works and allowing any potential questions or issues from residents to be raised and answered. This was followed up throughout the scheme with letter drops to affected residents outlining scope of works and timescales including site staff contact details for any queries. Due to the complexity of the scheme and the number of estate roads which required temporary closures the Site Manager remained in continual contact with Durham County Council to ensure they were up-to-date with works with ‘live’ status. This then allowed the Local Authority to relay information to the local Emergency Services.
The works were coordinated concurrently with an average of five gangs working across four areas ranging from estate roads to open fields. A main compound was sited within the Broadwood View area of Beverley Gardens with a further two satellite compounds located at Coniston Close and Park Road.
Broadwood View
Works within this area predominantly consisted of upsizing the existing pipework through the main and estate roads under rolling road closures which were undertaken to minimise the impact to residents within the affected areas of work. This section of works also included the construction of a cast insitu combined sewerage overflow chamber (CSO) which was fitted with a 6mm wedge wire static peak screen in order to screen flows in times of flood. From the CSO an overflow pipe was installed leading to a new outfall, which was constructed on the banks of the River Wear. This overflow line will be used as an outlet in times of floods. A section of the overflow drainage was installed under the A167 dual carriageway using trenchless guided auger bore methodology. This technique was also used for a section of the inlet pipework leading to the CSO and alongside the gable end and through the garden of two residential properties.
Coniston Close
This area comprised the construction of a new storm water storage detention tank using 2.4m diameter plastic weohlite pipework with a holding capacity of 1,200m3. Flows were diverted into the tank using a combination of new drainage infrastructure and upsizing to the existing pipework. This was undertaken via estate roads with rolling road closures used. A ventilation column was installed to the tank with a large concrete grass crete access track leading to the tank which was constructed to allow future maintenance and supervision to be undertaken by NWL operatives.
Park Road
This section of works comprised of a new CSO chamber and associated drainage, which comprised of 1,350mm diameter weohlite plastic pipework. Again these works were carried out using rolling road closures throughout residential estates. During the duration of the works regular progress meetings were held between the Client, Consultant and Contractor detailing general progress, additional works and programme revisions.
