National Building and Construction Project of the Year Award winner
Project Principals and Objectives
Part of the Open Lea project, Hat Gardens saw the transformation of a disused car park into an asset of community value by opening up the concealed river culvert. The project was secured by competitive tender at RIBA stage 3. Ryebridge was to undertake a full design and build including responsibility for three significant risks:
o Design completion.
o Contaminated ground (site investigations had identified this).
o Environmental Agency approval/sign off. All works delivered on budget with all funding milestones achieved.
The car park had been forced to close after a structural defect was identified in the culvert, and although there was a repair budget available, the costs were prohibitively high so it was kept shut and the area became a wasteland. The site was known to have issues with flooding, with risks to nearby housing and businesses if the culvert collapsed, but there was also a sheer lack of green space in the town centre for local residents and workers, so council officers discussed rejuvenating the area by opening up the river and turning it into a park, helping to restore the rare chalk stream which makes up the Lea and tying into a town centre masterplan for the next 20 years. The council identified that the £1.6m scheme could be part-financed using European Regional Development funding, and so it worked up the concept, secured planning permission and opened it up for tender, with Ryebridge Construction winning the bid.
PROJECT WORKS AND KEY QUANTITIES
• Bulk Excavation 1,930m3 • Retaining Walls/Head walls 2no. 30m3 East Headwall and 35m3 West • Gabion Baskets 140m3 • Landscaping 642m2 • Large Trees 7no. • Block Paving 332m2 • Resin Bound Paving 123m2 • Bespoke Stone copings along renewed River Walls 70m • Roads and Taxi Rank 355m2
Innovation and best practice
The works involved removing the existing lid to the river, building new head walls and retaining walls, and constructing new stepped seating and a planted terrace populated with carefully selected vegetation designed to boost wildlife. It was not a standard building project, and part of the work involved diverting the river using piping to access the culvert itself, which was then removed and replaced, forming a new bank and terrace for the river. The scheme involved having to consider adjoining highways and clearing areas of contamination left behind on the site, with Sustainable Urban Drainage Systems incorporated into the design alongside soft and hard landscaping. The project involved close liaison with the Environment Agency to ensure compliance working alongside and over an extremely rare chalk stream. An archaeologist was also present to follow the progress of the excavation works and see if any historical elements were found, adding an extra element to the works.
Moving forward
The site was designed to offer opportunities for various community uses including as a outdoor classroom, a place for mini-concerts, or with a cinema screen on the far bank. The success of the initial project triggered plans for further pocket parks along the river, not only to help with flooding, social impact and wellbeing, but to re-introduce some of the biodiversity and ecological infrastructure back into the town centre. In November 2023 the Hat Gardens was awarded National Building and Construction Project of the Year Award winner. Ryebridge is well placed to deliver these schemes.
