Shoebury Garrison is a mixed use development site located in Shoeburyness on the northern bank of the Thames Estuary in Southend-on-Sea, Essex.
Ardent was originally commissioned by Garrison Developments LLP to prepare a Flood Risk Assessment (FRA) and SuDS compliant drainage strategy for the final phase of the development. The proposed development comprises 172 residential units and 15,000m2 of offices (Class B1). However, the site is subject to fluvial, tidal, pluvial and groundwater flood risk. Ardent undertook 1D-2D fluvial, tidal and pluvial modelling to assess and mitigate the overall flood risk to the development and design a scheme to maximise the area of developable land within the site.
Initially Ardent met with the Environment Agency and Southend-on-Sea Borough Council to understand the current flood risk. Following initial hydraulic analysis, it was established that fluvial, pluvial and groundwater flooding could be mitigated; however tidal flooding could not in terms of a viable residential scheme. Hydraulic analysis identified that following a breach and over topping of the defences, flood depths in excess of 2m to 3m were observed on site. The only viable option was to raise the existing tidal defences, in line with the aim of the Thames Estuary 2100 programme.
Ardent triggered discussions with the council and developer on the viability of a “Partnership Funding” scheme in line with government proposals. A figure put forward by the developer secured the relevant cost benefit score to attract the relevant funding to deliver the tidal defence scheme.
A compliant SuDS strategy for the site ensured that the development proposals did not increase flood risk on or off site in addition to preserving the ecologically sensitive areas within the estuary.
The flood defence scheme put forward not only ensures a viable development but also provides wider benefits in terms of reducing the risk of flooding to the wider community. Shoebury Garrison is an example of where Ardent has provided added value and shown innovation in terms of delivering a sustainable development.