Flood Management - Attenuation Basin, Earthworks and Drainage

Earthworks

Preliminary topsoil stripping and storage was undertaken prior to profiling the subsoil. The removal of an existing redundant culvert was carried out. Subsequently a 60m bund running parallel with Paternoster Drain was formed with further profiling to form the attenuation basin sides. Grading and laser levelling was also undertaken in the basin bottom.

Carrier drains (900mm, 750mm, 450mm and 225mm) were installed together with associated manholes of varying depths and sizes enabling later connection from the residential development.

Five concrete headwall outfalls with handrails were also installed together with 128m of filter drain forming the drainage design along the length of the basin design along with a 3.5m wide maintenance access track from the residential road.

A pedestrian footpath running alongside Paternoster Drain was diverted for the duration of the works to facilitate the installation of a large 2.4m diameter penstock manhole discharging into the live Paternoster Drain.

On completion of the works, reinstatement works comprised topsoil replacement with amenity type grass seed incorporated to protect the bund, slopes and basin bottom.

Footpath Diversion

Works often entail footpath restrictions and/or road closures or diversions to protect or segregate the public. It was necessary to obtain all licensing and permissions from the relevant authorities, whilst maintaining good relationships with residents already living in the development. Communication of any anticipated inconvenience was undertaken at the earliest opportunity as part of the project programming.

Health & Safety

All workings were carried out compliantly under CDM 2015 protocols requiring Construction Phase Plans together with comprehensive assessment of all risks and method statements to minimise risks for all work elements.

Sweeting Bros Ltd are unique in that we have invested in mountain rescue sleds and equipment to facilitate patient evacuation in the event of an accident. Our work is often in secluded, inaccessible areas with very poor ground conditions.

Biosecurity

Moving machinery from one property to another often requires biosecurity and environmental protocols to minimise transfer of contaminants or invasive species such as black grass.

Working with Water

Working in or around water poses hazards for employees arising from the natural environment. The presence of vermin and exposure to leptospirosis, together with the possibility of drowning, add to the normal risks involving accidents concerning machinery and moving parts. Works taking place in live watercourses also pose problems arising from adverse weather and increased rainfall. It was necessary to monitor and adjust programmes to accommodate and minimise risks. Pumping out of accumulating or rising ground water is often necessary to ensure safe working conditions.

Cooperation

As with any large project where multiple contractors or works are taking place, co-operation is key for success. Sweeting Bros Ltd are adept at managing multi-agency stakeholders.