Surface water and foul water from the development are to be drained separately.

 

SURFACE WATER

 

Surface water from the development will be collected and stored in a landscaped attenuation basin, located in the northern part of the site behind the new building, and also in cellular attenuation tanks located underneath the car parking areas for both units.  The on-site surface water storage has been designed to provide sufficient sufficient storage for events up to the 1 in 100-year storm event, including a 40% allowance for climate change.  In the unlikely event that the capacity of the storage is exceeded, flood water will be directed away from neighbouring buildings and pool within the service yard and car parking areas in front of the new building.

 

The surface water attenuation basin to be located behind the building, adjacent to the High Street boundary

 

From the attenuation basin, the collected surface water will be pumped off-site via a new rising main, to connect with the existing surface water sewer to the north of the site at the junction of Woodfield Way and Rotherfield Close.  The rate at which the water will be pumped off-site has been approved by Thames Water and they have confirmed that the existing surface water sewer has capacity to take the additional flow from the development.

 

The nearest point of the existing surface water sewer, at the junction of Woodfield Way and Rotherfield Close (highlighted in blue) – a new rising main will pump the collected surface water from the site up to the sewer

 

FOUL WATER

 

There is an existing foul water sewer that runs within the site along the northern boundary, parallel with the High Street. The development’s foul water pipes will connect directly into this sewer on-site via a rising main.

 

The approximate location within the site where foul water from the development will connect into the existing foul water sewer (highlighted in white) – the sewer runs within the site along the boundary with the High Street