Events & Courses

Course overview

Excavations, shafts and tunnels which extend to below the standing groundwater level in water bearing soil or rock require a strategy to control water ingress and maintain stability during construction. This is typically achieved either by pumping, referred to as dewatering, or exclusion techniques which may be used separately or in combination. The most used dewatering systems include sump pumps, wellpoints, deepwells, ejector systems and passive relief drains. Exclusion techniques, for example secant piles, frequently combine structural support with restrictions to groundwater flow and may subsequently be incorporated as part of the permanent finished structure.

Other exclusion systems, such as steel sheet piles, provide excavation support but may then be removed thereby avoiding long term restrictions on groundwater flow. In all situations any failure to adequately control groundwater will result in delay, cost overruns and occasionally catastrophic failure. While the fundamental principles have not changed the methodology has evolved over the last 100 years due to; improvements in materials, plant and technology; improved design methods and monitoring data; the demand for bigger, deeper and more complex underground spaces particularly for infrastructure in urban settings; a tightening regulatory regime; and the ever present need to reduce cost, construction time and risk. 

Over the last 30 years, the need to protect water resources and groundwater dependent environmental features, together with the potential for adverse off-site impacts and flood risk concerns has led to increased oversite and regulation of well installation, groundwater pumping and off-site discharges. This has in turn led to an increased need for hydrogeological investigations, including pumping tests, to more accurately assess flow rates, potential off-site impacts and the effectiveness of any mitigation measures required.

The regulatory regime varies nationally and sometimes locally, subject to the scale of the works and the perceived risks in the particular hydro-geological, environmental and socio-economic setting. Treatment of the abstracted groundwater may be required prior to discharge. Groundwater pumping systems have low greenhouse gas (GHG) emissions particularly compared to physical exclusion techniques which incorporate cement or steel, and which may permanently impede groundwater flow if not removed in the course of construction. As a result, there can be tension between minimising GHG emissions on the one hand and short-term environmental protection and construction risk on the other. 

This course is aimed at construction professionals, engineering geologists, hydrogeologists and regulators who require an understanding of temporary works groundwater control techniques or who need to refresh and improve their knowledge. The course will be delivered in six modules covering:

• Basic concepts of groundwater flow, pore water pressures, effective stress, settlement and stability.
• Dewatering techniques including their range of application and advantages and disadvantages.
• Pumping test design and analysis, water treatment systems and regulatory regimes.
• Dewatering strategies for excavations, shafts and tunnels.
• Design procedures for groundwater control systems and monitoring arrangements.
• Risks, potential offsite impacts and mitigation strategies.

Each module will make extensive use of the practical experience of the presenters together with case studies from around the world.

Who is this course aimed at?

The course is aimed at Hydrogeologists, Engineering Geologists and Construction Professionals and should be of interest to both graduates and Chartered Fellows looking to enhance their knowledge. The course would be relevant to contractors, consultants and regulators who require knowledge of groundwater control techniques.

Learning objectives

1. Understand the relationship between groundwater level, pore water pressure, effective stress, settlement and excavation stability.
2. Understand the techniques available for controlling groundwater for construction projects, their range of application and their advantages and disadvantages.
3. Understand the purpose of undertaking a pumping test, methods of analysis and the factors which control pumping test design. Recognise the need for environmental protection and regulatory compliance as drivers for the development of a groundwater control strategy.
4. Appreciate the need for an effective groundwater control strategy for excavations and tunnels which may combine a partial or full physical cut-off with active pumping and which may need to target multiple aquifers.
5. Gain insight into design procedures for groundwater control systems and the specification of instruments for performance and compliance monitoring. 
6. Appreciate the risks associated with groundwater lowering, the potential for impact on neighbouring structures or environmental assets and mitigation strategies. 

Programme

Module 1: 15 April 2025

Module 2: 23 April 2025

Module 3: 30 April 2025

Module 4: 7 May 2025

Module 5: 14 May 2025

Module 6: 20 May 2025

Speaker Bio

Dr Toby Roberts, CGeol
Toby Roberts is an expert in the design and implementation of groundwater control systems for large excavations, foundations and tunnels with 40 years contract experience in Europe, the Middle East and Canada. Toby is a founder member and current Chairman of the international dewatering contractor WJ Groundwater. He has authored/co-authored more than 40 publications on construction dewatering including CIRIA C750 (2016), the current best practice guide for construction dewatering. Dr Toby Roberts is a Fellow of the Royal Academy of Engineers, a Chartered Geologist and Charted Civil Engineer.

Prof William Powrie  
William Powrie is Professor of Geotechnical Engineering at the University of Southampton and former Dean of the Faculty of Engineering and the Environment. Williams main areas of interest are in geotechnical aspects of transport infrastructure, and sustainable waste and resource management with particular expertise in groundwater control, in-ground construction to reduce environmental impacts in urban and other sensitive areas, understanding and mitigating vegetation and climate change effects, and fundamental soil behaviour. William has authored or co-authored 150 papers in international journals, CIRIA report C750 Groundwater control – design and practice, 2nd edition (2016) and C760 Guidance on embedded retaining wall design (2017) and the widely respected textbook, Soil mechanics: concepts and applications. Prof William Powrie is a Fellow of the Royal Academy of Engineers and a Chartered Civil Engineer.

Dr Gary Holmes, FGS
Gary Holmes interests are in contracting and consultancy in geotechnical engineering & hydrogeology specialising in construction dewatering, ground source energy systems, groundwater remediation, pumping test interpretation and numerical modelling. Gary is Chief Technical Officer for the international dewatering contractor WJ Groundwater Ltd with responsibility for the management and development of WJ’s engineering and technical operations. This includes remediation, instrumentation and monitoring, ground source energy systems, thermal response testing, pumping tests and dewatering system design in Europe, Canada, the Middle East and the Philippines. Gary is a Fellow of the Geological Society.

Location

This course will be delivered virtually via Zoom. Joining details will be sent out the day prior, alongside any course materials that may be needed.

Fees (including early-bird rate)

* Early-bird discount applicable for all registrations until 15 February 2025. Simply select your delegate type on the registration form and the discount will be applied and reflected in the payment section at the bottom of the registration form.*

Group Discounts

We offer competitive group discounts on all Training Courses:
5 – 9 delegates: 20% off
10 – 14 delegates: 25% off
15 delegates or more: 30% off

For more information on how to access the Group Discount, please email [email protected]

Concessions

We offer students a generous discount. Please verify your student status by either registering with your student email address, or uploading a photograph of your student identification/acceptance letter.

The Society offers a limited number of concessionary rates for those in financial hardship. Contact [email protected] (Please note you may be required to provide details/evidence to support your application for this.)

If you require an invoice to register for this course, please email [email protected]

Registration will close 24 hours before the event takes place.

GSL reserves the right to postpone or cancel a Training Course in the event of low interest. In this instance, a full refund will be offered for registration fees.