Cambridge water commissioned ESI, now part of Stantec, (supported by APEM) to help deliver its AMP6 Restoring Sustainable Abstraction Programme
For AMP6, the Environment Agency had identified a number of sites in the Cambridge area at which it required South Staffs/Cambridge Water to deliver schemes or investigations related to impacts of abstraction on stream flows and hydro-ecology. This included: development of an augmentation scheme for the springs at Nine Wells and investigation of potential impacts of groundwater abstraction on flows/ecology of the Cherry Hinton Brook.
South Staffs Waterhad previously appointed ESI, supported by aquatic ecology specialists APEM, to deliver similar services in the Midlands. With the purchase of Cambridge Water by South Staffs Water, ESI/APEM were commissioned to deliver Cambridge Waters AMP6 RSA programme as well.
For Cherry Hinton Brook this involved a desk study and site visit to identify the key issues for a potential options appraisal.
At Nine Wells, ESI developed a specification for the contractors to drill and test four injection boreholes in the immediate vicinity of the springs. A geophysical survey was commissioned to investigate the likely thickness and character of the Chalk near the springs. Due to the environmental sensitivity of the site, reverse circulation drilling was applied.
The Cherry Hinton desk study suggested that, at current rates of abstraction Cambridge Water’s abstractions were not having a significant impact on the brook and that he observed problems in the ecology in the lower reaches were related to extensive modification of the channel and urban impacts. APEM monitored stream flow, water quality and ecology and this data set now forms a baseline against future conditions can be assessed so that which any concerns the Environment Agency has about the risk of deterioration should abstraction rates increase (within licensed rates) can be allayed.
At Nine Wells, the boreholes were successfully drilled and tested and have now been passed to Cambridge Water’s implementation team to link up with the planned pipeline which is to deliver the augmentation water to the site. Meanwhile, ESI continues to provide support on developing the stream flow baseline for the site.