Deep Well Dewatering - Unity Square

Project Overview

Testing, design and installation of a temporary dewatering and aquifer recharge system

Part of the development of the HMRC building included construction of a basement with lift pits to 5.2m below ground level.

The groundwater level was around 2m below ground level, so a deep well dewatering system was designed to ensure dry and stable conditions for excavation. The system included 7no x 10m deep wells installed around the basement area.

Ground conditions consisted of highly permeable River Terrace Deposits (Loose silty, sandy f-c GRAVEL c/w cobbles) overlaying the Nottingham Castle Formation.

Objective

The client needed to reduce the groundwater level to allow the excavation of a lift pit. However, there was no suitable discharge point for the abstracted groundwater.

Solution

Stuart Wells proposed a dewatering system with all abstracted water being recharged back to ground to comply with EA conditions to abstract and discharge groundwater.

All abstraction water was discharged through14no x 10m deep recharge wells, located 200m away and downstream of the natural groundwater flow.

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