On the Road to Minimise Flood Risk

A major new sustainable road drainage scheme is providing stormwater control and reducing flooding risk following the £9.5 million improvement of the A340 Aldermaston Road in Basingstoke.

Hydro International’s Stormbloc® infiltration blocks and Downstream Defender® silt protection units were installed to help resolve flooding of a pedestrian underpass whilst also addressing the need to improve and prevent pollution of groundwater.

The existing A340 Aldermaston Road layout was constructed in the late 1960s with drainage ditches and soakaways to distribute surface water from the road and new ring road around the centre of Basingstoke. Subsequent developments in the surrounding area resulted in a number of modifications to the original drainage scheme; some of these have resulted in regular flooding of the pedestrian underpass.

The replacement and supplementary drainage on the A340 and the Aldermaston roundabout will comprise in-kerb surface water drainage systems which collect and direct water to carrier drains.  The drains channel the stormwater through Hydro’s Downstream Defender® hydrodynamic vortex silt and oil separators to Hydro’s Stormbloc® modular blocks which provide a storage and infiltration blanket over the underlying chalk formation.

In total, four Downstream Defender® Separators and over 5,000 cu.m. of Stormbloc® modular infiltration blocks were installed.  The Hydro products are located under soft landscaped areas within the perimeter of the Aldermaston roundabout (at the North, South East and South West points) and to the West of the A340.  In all, the infiltration blankets provide storm drainage for around 500 m of carriageway, and 700 m of roundabout circulatory carriageway.

Read the full A340 Aldermaston case study

Learn more about Hydro Stormbloc®