Dunnottar Park, Carron Den, Stonehaven
Dunnottar Park is a housing development close to the A90 dual carriageway in the south of Stonehaven.
The site is bound on two sides by waterways – Carron Water and the smaller Burn of Glaslaw – and had been on the radar of housing developers for several years, but the challenging access and environmental complications had frightened them off in the past. The first challenge was to provide construction access to the site. The existing bridge on to the site was solely for agricultural use and was deemed unsuitable for construction activities. A temporary bridge with a 70t load capacity was constructed in conjunction with a temporary haul road.
Permanent vehicular access to the site required the construction of an inclined access road over Carron Water. The key feature of this element of the project was the construction of a 32m long BEBO bridge. BEBO – a contraction of the German word ‘BEtonBOgen’ meaning concrete arch – is a modular bridge building system consisting of pre-cast reinforced concrete arch, spandrel and wing wall elements. The system is well suited to large-span, low-rise, high-overfill applications such as that at Carron Den. The bridge required the construction of substantial foundations and 1.5t sand bags were used to provide a natural reinforcement for the embankment.
The site has a clay subsoil and surface water management was critical to ensure water quality in the river and the burn were not compromised alongside the need to create stable ground conditions for building works to proceed. W M Donald developed a natural alternative to flocculation to prevent ‘dirty’ water from entering the waterways (see ‘Learning Point’ below) and obtained approval from SEPA to implement this approach. Other surface water management activities included the construction of lagoons.
Other activities on site included the use of directional drilling to allow the diversion of an 11kV overhead cable, and the construction of a pumping station and rising main to exit into a public sewer.
W M Donald is working collaboratively with Clancy Docwra, the utility contractor on site, to ensure the effective implementation of gas, electricity and water connections to properties on site.