AstraZeneca have a continuing development programme at the Alderley Park site, among the projects are a lecture theatre and several new laboratories. There is justified concern that the capacity of the existing Foul drainage network will be unable to cope with the increase in flows when the planned buildings become operational.
It was suspected that problem of high effluent flows was being exacerbated by ground water infiltration after periods of rainfall, possibly at cracks in pipes and manholes. Several areas of hardstanding were also thought to be directly connected into the foul system.
Wilde Consulting Engineers undertook a year long programme of monitoring rainfall, groundwater levels and foul flows to evaluate the extent of this ground and surface water infiltration.
Rainfall events were found to significantly increase the foul water flows by an average of 47%.
With this knowledge Wilde Consulting Engineers were able to target and recommend remedial measures including computer modelling of the drainage system.
