THe young professionel of the year 2023

THE

GEM

EDITION

#2 DECEMBER 2023

THE GROUNDWATER ENGINEER MAGAZINE

YOUR GUIDE TO THE LATEST NEWS AND INSIGHTS INTO THE GLOBAL DEWATERING INDUSTRY

A Monster Job

van Tongeren Watertechniek

Young professionals in dewatering

Groundwater A matter of scale

Learn from the TDI Award winners

International Association of Hydrogeologists

Unlocking Excellence in Health and Safety Keller

CONSTRUCTION DEWATERING

MINE DEWATERING

GROUNDWATER CONTROL The Groundwater Engineer Magazine Edition#2

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The Groundwater Engineer Magazine Edition#2

FOREWORD

Responsible Water Management Foreword by Julian Conrad - Managing Director at GEOSS South Africa

THE

GEM THE GROUNDWATER ENGINEER MAGAZINE

Your guide to the latest news and insights into the global dewatering industry

TEAM Publisher The Dewatering Institute Designer Ian Mackie Content Writer Nicole Steyn Business Associate Director Riëtte Laas Marketing, Sales & Content Riëtte Laas Contributer Vivian Botha-Veldstra Disclaimer The views expressed in this publication are not necessarily those of the publishers.

Whilst every effort was made to ensure accuracy the publisher and editors cannot be held responsible for any inaccurate information supplied and/or published.

Copyright The copywrite for all material published in this magazine is strictly reserved.

Tel: +27 +711 773 779 Email: riette@dewateringinst.com www.dewateringinst.com

in

I

magine a world without groundwater – a barren landscape devoid of life.

The hidden resource beneath our feet that affects the entire planet, sustaining life and shaping landscapes.

While the groundwater community continues to grow, there is still a great need to expand into new countries and scientific developments to ensure this vital resource is cherished and not squandered.

The Dewatering Institute has become a resourceful place for the dewatering and groundwater industry to come together as a community, to learn and share knowledge. With the addition of The Groundwater Engineering Magazine (The GEM), this community can easily share groundbreaking projects, case studies, and techniques related to managing this precious resource.

In September 2023, we were able to come together as a global community from 55 countries at the Congress of the International Association of Hydrogeologists (IAH), in Cape Town, South Africa. The congress theme "Groundwater: A Matter of Scale" resonated deeply amongst the community.

We saw presentations tackling challenges from micro-scale local aquifers to vast transboundary systems. Through it all, one resounding message emerged: responsible management is key, no matter the scale. We learned to embrace the delicate connection between water supply and dewatering, understanding them as two sides of the same coin. And perhaps most exciting, Managed Aquifer Recharge (MAR) emerged as a gamechanger, offering hope for replenishing resources and mitigating environmental impact.

With the rapid rate of progress in groundwater research, such events like IAH and publications like The GEM are paramount to ensure that we not only keep moving forward as an industry but also protect the precious resource that is our groundwater.

There has to be a responsible approach to groundwater abstraction and we have the knowledge, tools and models to do this. In many instances groundwater is seen as a “nuisance” that needs to be

eliminated, however, groundwater abstraction for water supply for primary beneficial use is possible. A great example of this is the City of Cape Town’s multi-pronged approach to “droughtresilience”, which includes preparing well fields now for responsible groundwater use in times of need.

Within this edition of the GEM, you'll find the voices of those who are shaping the future of groundwater. Discover revolutionary projects, explore innovative case studies, and groundbreaking techniques that will inspire and equip you. Witness how Griffin Dewatering tackles uranium removal, marvel at Hölscher Jensen's SCADA monitoring methods, and celebrate the achievements of esteemed companies like Project Dewatering Ltd, Hölscher Ferrer North America, and O2DIT, recognized at the 2023 TDI Awards.

We are aware of the continual pressure on our water resources, and we must embrace responsible management ensuring that our actions today secure a legacy of water abundance not only for generations to come but for the sake of our ecosystems too. Together, let's turn the tide and protect this lifeblood of our planet, one drop at a time.

Julian Conrad (jconrad@geoss.co.za) GEOSS South Africa (Pty) Ltd Managing Director and Hydrogeologist IAH-SA – Committee Member and Co-chair of the 2023 IAH Congress, Cape Town, South Africa.

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CONTENTS

Contents Front cover image: New Metro station Ny Ellebjerg part of the extension of the South Harbor Metro, Hölscher Jensen.

FOREWORD 3

Responsible Water Management by Julian Conrad INTERVIEWS

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TDI’s Young Professional of the Year Experienced Leader appointed as TDI Advisory Council Member

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COMPANY PROFILES 22 30 52 54

Unlocking Excellence in Health and Safety Keller North America Leading the Way. NCS Fluid Handling Systems How do you dewater? East Coast Dewatering TDI Mission Statement ARTICLES

5 16 25

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Groundwater: A Matter of Scale

By Dr Kevin Pietersen and Julian Conrad Functionality is consistenty

By Timothy Lynch at Roscoe Moss Company Prioritizing Mental Health in the Construction Industry CASE STUDIES

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A monster job on the N631. Van Tongeren Watertechniek Carnotite Groundwater Treatment. Griffin Dewatering Sydhavens Metro Project. Hölscher Jensen SLC Airport Central Tunnel. Griffin Dewatering TDI AWARDS

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The 2023 Award Winners TDI 2024 Awards. Enter Now Drilling for Decarbonisation. Project Dewatering Limited Livable Urban Waterways Project – Hydrogeological Characterisation of the Sand River Catchment.

GEOSS South Africa Analysis and Solution Orillia Sanitary Sewage Pumping Station. Hölscher Ferrer North America Committed to the most sustainable technology in rainwater infiltration and return drainage. O2DIT Foundation North East Scarborough Community & Child Care Centre.

Aquatech Dewatering Project Prinses Amaliahaven.

Van Tongeren Watertechniek TDI Events - Virtual Webinar Training Courses

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47 See how we put water to work at www.henkvantongeren.nl

TDI ARTICLES 54 56 57 58 4

Mission Statement Events Testimonials Fun Facts The Groundwater Engineer Magazine Edition#2

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ARTICLE: IAH 50TH CONGRESS

Groundwater:

A Matter of Scale

Authors: Dr Kevin Pietersen and Julian Conrad - Managing Director and Hydrogeologist GEOSS South Africa. Julian Conrad - Technical Advisor Groundwater Research Fellow, Institute for Water Studies, University of the Western Cape, South Africa Research Fellow, INTI International University, Malaysia.

T

he International Association of Hydrogeologists (IAH) recently held their 50th Worldwide Congress in Cape Town, South Africa. The IAH is a scientific and educational charitable organisation that aims to further the understanding, wise use and protection of groundwater resources worldwide.

From small beginnings, IAH has grown into a truly global organisation with over 4,000 members in more than 130 countries. Congresses have taken place

worldwide, upholding IAH's commitment to reach as broad a geographical spread as possible. The IAH South Africa National Chapter and Ground Water Division of South Africa (GWD-SA) arranged the 50th congress. The Congress theme for IAH 50 was Groundwater: A Matter of Scale, exploring the connectedness of groundwater to the earth and human system. The participants discussed groundwater issues, techniques and solutions to improve access to safe and sufficient water and sustainably manage groundwater.

In addition to plenary and invited speaker presentations, there were poster presentations, exhibition booths, special sessions including a session for young professionals, and scientific presentations covering every aspect of hydrogeological sciences.

We had various Commission and Networking meetings taking place.

The participants benefitted from interacting with colleagues from around the world. There were 500 delegates from 53 counties.

Below: Julian Conrad (Co-chair of the IAH2023 Congress) and Candice Lasher-Scheepers (City of Cape Town) collecting water from the outlet of the Orjanezicht Spring to be passed onto the organisers of the IAH2024 Congress in Davos, Switzerland.

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ARTICLE: IAH 50TH CONGRESS IAH 50 was an incredible event, and we were proud as South Africans hosting the 50th IAH Worldwide Congress.

The congress started with field excursions to sites contributing to Cape Town's water resilience. The excursions included a trip to Steenbras Wellfield, which targets the surface Nardouw Aquifer and deep Peninsula Aquifer of the Table Mountain Group. The Atlantis Water Resource Management Scheme (AWRMS) excursion showcased managed aquifer recharge (MAR) using treated domestic wastewater and stormwater as the source.

The MAR source then infiltrates the aquifer and is abstracted ~750 metres downgradient at the Witzands Wellfield.

The Cape Flats Aquifer (CFA) is under investigation as the City of Cape Town aims to abstract up to 76 megaliters per day (Ml/day) from the CFA while adding 64 Ml/day back into the aquifer via an active (i.e. injection-based) MAR scheme. The delegates were shown features of the proposed Cape Flats Aquifer Management Scheme. The fitter delegates went on the Table Mountain Dams Hike to visit the reservoirs that initially supplied water to the city and environs. The Wetlands,

Winelands, and Isotopes field excursion entailed a visit to the Eerste River Catchment, where hydrochemistry and different complementary isotopic tracers and dissolved gases were used in determining the reason and extent of the wetlands' water balance deficiency and lack of recovery.

We were grateful to have our political decision-makers at the opening session of the congress. The Deputy Minister of Sanitation, David Mahlobo, challenged the congress to reflect on "What differences are you making for a better world?". He stated, "Any country that does not value science and expertise will perish". Zahid Badroodien, the Mayoral Committee Member: Water and Sanitation for the City of Cape Town, welcomed congress participants to Cape Town. He noted, "Preserving our groundwater is not just about securing water for our present needs but also about ensuring the well-being of future generations".

A highlight of the congress were the keynote presentations. Wendy Timms emphasised the principles for data prioritisation, whilst Seifu Kebede Gurmessa highlighted Pan-African Hydrogeology characteristics. Five parallel

Below: Aerial view of the Cape Flats Wastewater Treatment Works showing the construction of the advanced water reclamation plant for Managed Aquifer Recharge.

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sessions followed the opening, grouped into the conference's subthemes. The closing session focused on a young professional providing a keynote address on "Research and implementation of MAR in a changing climate".

Awodwa Magingi presented case studies on MAR and future research activities. Harrison Pienaar followed her presentation on Circular Economy and Water - A South African Outlook: Implications and Opportunities for Groundwater". He noted that to achieve meaningful impact; the public and private sectors require investing in replicating current successful groundwater initiatives, localising international best practice examples to local settings, and the identification of new opportunities for groundwater through ongoing RDI. "The participants found the congress inspiring as a young professional reflected, "Meeting delegates from 53 countries broadened my professional and cultural horizons. Winning first prize for my poster presentation was a moment I'll always cherish, fueling my passion for pushing the boundaries of knowledge in my field. The insightful talks have left a lasting impact on my early career approach," Dr Kevin Pietersen.

“

ARTICLE: IAH 50TH CONGRESS

I am grateful for these opportunities as I move forward, carrying the lessons and memories from Cape Town, ready to make a meaningful impact.

”

Another delegate stated, "A truly enlightening experience in Cape Town for the International Association of Hydrogeologists 50th Conference.

New ideas for responsibly utilising groundwater to build our city's water resilience. The scientific programme was excellent, with exciting and relevant research and plenary sessions.

It is noticeable and apparent that groundwater continues to play a critical role in supplying water to the global community; therefore, we all need to be custodians to safeguard this valuable resource. IAH and GWD have truly exceeded expectations with their panels, presentations, and posters".

The predictions are that climate change significantly impacts water resources globally, especially in Africa, with more frequent surface-water droughts and extreme rainfall events. Understanding how climate change affects groundwater resources, identifying potential risk areas, determining the implications for these vulnerable areas, and developing mitigation and adaptation strategies are complex. The IAH congress presented an opportunity to showcase capacities and skills to address our profound global challenges as we accelerate towards crossing critical environmental thresholds.

Riëtte Laas, Business Associate Director of TDI attending the IAH Congress in Cape Town.

The International Symposium on Managed Aquifer Recharge (ISMAR) is the premier international event on MAR research and practice, held every three years under the auspices of the International Association of Hydrogeologists (IAH), the American Society of Civil Engineers (ASCE), and the United Nations Educational, Scientific and Cultural Organization (UNESCO). This series of conferences advances the goals of IAH’s Commission on MAR “to expand water resources and improve water quality in ways that are appropriate, environmentally sustainable, technically viable, economical and socially desirable”.

It’s a great privilege for Cape Town, South Af rica, to host the next ISMAR Conference from 28th April to 2nd May 2025. Planning for the event has commenced, and more information will soon be available about ISMAR12.

Umvoto Africa booth at the IAH Congress in Cape Town.

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AWARD: WELLS & DRILLING

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Drilling for Decarbonisation Project Dewatering Limited Summary

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ecarbonisation is the process of reducing or eliminating carbon dioxide (CO2) emissions from various sources to mitigate the impact of climate change. This entails moving away from fossil fuels and other high-carbon energy sources and embracing cleaner and more sustainable alternatives. One such alternative is the use of geothermal energy, a renewable and environmentally-friendly energy source that taps into the Earth's natural heat reservoirs to supply heating, cooling, and electricity.

This case study details Project Dewatering Limited's involvement in drilling geothermal wells deep beneath the City of London to contribute to the City’s vision of a carbon-neutral future.

The wider project involves the installation of a ground source heat pump system which takes groundwater sent from the boreholes, which work in conjunction with existing Combined Heat and Power (CHP) boilers and chillers. It is anticipated that this system will reduce carbon dioxide emissions by up to 50%, meeting the requirements of the City of London

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Company: Country: Location: Duration:

and the Greater London Authority.

Furthermore, this system will expand capacity, lower operational costs, and enhance air quality by reducing NOx emissions

Introduction Project Dewatering Limited was responsible for the supply, installation, testing, furnishing and commissioning of the three boreholes This included all necessary plant, equipment, traffic management and temporary works.

The full scope comprised the drilling of three boreholes to 200 m below ground level at a nominal 450 mm finished diameter. The boreholes, drilled at 670 mm diameter to the top of the chalk formation (assumed to be approximately 50 mbgl) were installed with 12 mm wall thickness steel casing to this depth. The boreholes were then drilled open hole to full depth, at a nominal 450mm diameter.

Once drilled the boreholes were developed using airlift techniques both before and after acidisation. Permanent pumps and pipework installed are capable of pumping at up to 30 L per

Project Dewatering Limited UK London 6 Months second with 150 mm abstraction and recharge pipework.The pumping tests undertaken on all three wells following installation of the permanent pump infrastructure were then completed.

The works can be broadly divided into the following activities (the list is shown for one well only to show the sequence of events); • Off site organiasation & setup of traffic diversion signs and implementation of the one-way system • Fencing off of the compound area to segregate the works from live traffic and public areas.

• Temporary civil works to break through the pavement, brick arch structure and basement slab.

Works includes the following: • Provision of temporary surface support for drilling works.

• Setup of the drilling equipment.

• Installation of steel casing from ground level to below basement slab.

• Commence drilling to top of chalk at

AWARD: WELLS & DRILLING minimum 600 mm diameter.

• Install and grout permanent casing to top of chalk.

• Continue drilling to 200 m below ground level at minimum 450 mm diameter.

• Develop well using airlift techniques.

• Treat the well with acid.

• Redevelop well using airlift techniques.

• Install permanent pump riser pipe and recharge pipe together with wellhead.

• Undertake pump tests and submit pump test report.

Methodology Project Dewatering Ltd proposed to drill the wells at the Decarbonisation Project using Reverse Circulation drilling methods. In Reverse Circulation water flush drilling, the fines free water from the settlement tanks was allowed to circulate down the annulus of the borehole to the drill bit. As such, the water in contact with the borehole wall did not have significant entrained soil particles (fines). At the base of the borehole, the water collected the drill cuttings and then using airlift or suction, depending on the depth, the water with associated cuttings was lifted to surface inside the drill rods.

Using this methodology, the drill cuttings were not exposed to the borehole wall, and therefore the likelihood of blinding the permeability of the borehole was reduced in comparison to traditional direct mode flush (where the clean water was pressure injected down the inside of the rods and then carried the cuttings up the annulus in contact with the borehole face). This method was also attributed to provide improved borehole stability during drilling operations. In addition, this Reverse Circulation methodology typically generated cuttings that more easily settled in the above-ground settlement tanks, allowing for more cost-effective disposal of waste (this was discussed later in this proposal). The Reverse Circulation methodology was particularly suited to the specification on this project due to the diameter and depth of the boreholes (where traditional direct flush drilling required very high injection flow rates to successfully lift cuttings to surface).

Drilling rig Project Dewatering Ltd proposed using a Nordmeyer DSB 3 Drilling Rig, supplied

by PDL’s parent company, Holscher International GmbH (Europe’s largest groundwater engineering contractor).

The rig was available for work in the UK but needed some modifications to improve the exhaust emissions and meet the strict government requirements.

PDL proposed the use of this rig because it is very powerful and had been proven undertaking projects at greater diameters and to greater depths, yet it was also very compact and was suited to

this space-constrained site both due to its relatively small footprint and due to the fact that the flushing pumps required for reverse circulation drilling were located on the rig itself. This reduced the need for additional plant in the works area, optimising the available space.

Installation of basement casing PDL proposed an engineering solution that allowed drilling of the boreholes from the street level through the vaults beneath the road surface. It was initially proposed by the clients’ advising engineers that the road structure would need to be substantially modified using steel beams to build a platform to support the rig before opening of the arch vaults was allowed.

to the base plate located at surface, and on which the rig feet seat.

All three plates and basement steel casings were installed at the beginning of the project. The 700 mm casing was installed sufficiently into the made ground, beneath the basement slab, to ensure that a watertight seal was achieved and the possibility of leaks into the basement could not occur. In addition, to provide further confidence, a bund was provided on the basement floor around the outside of the 700 mm casing, and installed with a leak detection water sensor. This sensor was linked to a telemetry system to allow immediate notification of the drilling team in the event of any water leaks. PDL was confident that no leaks to the basement would occur given the seal provided on the 700 mm casing, however

Proposed method of casing from road level to basement slab.

This process was not only expensive but practically difficult given the nature of working in a busy London street. The client requested a design and build solution for the drilling works which included the supporting of the rig whilst drilling through the vault arches.

PDL devised an engineering strategy which negated the requirement of the expensive steel supports and opted for and engineering solution which comprised of a sand and timber beam bed & opening small cores through the vault arches. This approach meant that the project was more financially and practically viable.

PDL used a 700 mm temporary casing to isolate the basement from the drilling works. The 700 mm casing was lowered using the rig winch and once seated through the basement slab (now broken out to expose the underlying made ground), it was sealed into the basement slab with concrete and was also welded

this leak detection system was intended to provide additional confidence to the main contractor. The 700 mm casing, once sealed into the basement slab, acted as the outer casing for the reverse circulation drilling.

Drilling to chalk A 670 mm diameter drill drag bit was lowered through the casing to commence drilling to the top of chalk. Once the chalk was encountered and proved, the drag bit was removed and replaced with a 670 mm tricone rock and roller (either steel tooth or tungsten carbide bit). Drilling continued for 3 to 5 m into competent chalk, to provide a seat for the casing.

It was estimated that drilling to this depth could be achieved used suction (supplied by a rig mounted pump) on the central drill rod string, to lift the drill cuttings. At depths deeper than this, airlift techniques needed to be used to pull the water flush and cuttings up the central rods.

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AWARD: WELLS & DRILLING Installation of the permanent casing Once the chalk had been proved, the permanent casing was installed. The casing was a 580 mm outside diameter steel casing with a 12 mm wall thickness and suitable spacers. The casing was lowered to the top of the chalk formation.

A grout shoe was installed at the bottom of the casing and the casing lowered to depth. A Tremie pipe was tied to the outside of the casing to allow grout to be pumped to the annulus at the base. Grouting continued until the full depth of the casing was sealed up to the base of the 700 mm temporary casing.

Once grouting was commenced it was continued until the works were complete to ensure a competent seal on the casing.

The grout was then allowed to set for a minimum of 24 hours. The grout used

Indicative drilling compound layout comprised sulphate resistant cement and samples were taken of the grout at regular intervals and placed underwater to assess setting times. In addition, PDL proposed to undertake a cement bond log as part of the geophysical testing programme. This cement bond log confirmed the integrity of the grout seal.

Drilling to depth After the grout had set, confirmed by the underwater sample setting time, drilling continued with a 450 mm diameter tricone steel-tooth rock roller drill bit until the full depth of the well was reached, at 200 m below ground level. Drilling at this depth required the use of airlift to pull the water and cuttings up the central rod string. In Reverse Circulation drilling, the rod had a twin wall arrangement, allowing air to be injected between the 10 The Groundwater Engineer Magazine Edition#2

outer and inner walls, which was then fed into the inside of the rod just above the drill bit. This air injection into the central rod annulus allowed the lifting of water and cuttings up the inner rod to surface from these depths.

Initial airlifting of the borehole

detailed method followes: A 2 inch plastic pipe was installed into the well to a depth of approximately 10 m below the permanent steel casing (which was assumed to be around 60 m below ground level). The 2 inch piping was connected to a wellhead assembly that was welded to the permanent 508 mm casing.

Once the full depth of the borehole was achieved, the initial phase of airlifting, which was anticipated to take one day, was used with the existing drilling rod string. As with the Reverse Circulation drilling method, air was injected in the annulus between the dual rod walls and injected into the inner rod annulus just above the drill bit. Airlifting using this technique was continued until the waters brought to the surface were essentially free of fines. Once airlifting

This wellhead assembly had a manual valve, a pressure relief valve, and a pressure gauge. It was proposed to acidise the borehole with 5 m³ of hydrochloric acid (32%). This acid was discharged into the borehole 1 m³ at a time. During this process, if evidence of a pressure increase was observed, the manual bleed valve was opened to control the release of pressure. Gas/fluids were discharged to the same partially waterfilled holding tank as referenced below.

was completed, the drill bit and rods were removed, and the drilling rig was demobilised from this location and relocated to the next borehole.

The discharge pipe was secured below water level to ensure any gas emitted was dissolved in the water. Once all of the acid had been discharged into the borehole and sufficient time had passed to accommodate any off-gassing pressure increase, the manual valve was opened, and the waters in the holding tank were neutralised with hydrated lime, as required. The pressure relief valve was set at 3 bar as this was considered to be a maximum acceptable pressure that borehole grouts could be subjected to.

In the event that, due to an unforeseen event, the borehole pressure increased to 3 bar, this pressure relief valve would open and gas and/or fluids would be discharged to the water-filled holding tank (with a minimum freeboard of at least 5 m³ to allow for collection of fluid volumes from the well should this be required). The wellhead assembly was pressure rated to 16 bar.

As part of this process, the 700 mm casing was disconnected from the base plate and lifted to the surface using the drilling winch. Both the base plate and the temporary 700 mm diameter casing were removed. Once the drilling rig had been demobilised from the location, the well was prepared for acid treatment.

Acidisation The main difficulty was using this controlled substance in a very public space. An incident in such a crowded space was not acceptable. The basic method was that a remote acid head was utilised and acid was then fed from street level in to the vault. More

AWARD: WELLS & DRILLING Post acidisation airlifting A 100mm plastic pipe was installed to the base of the well (1 m from the base of the well to prevent entrainment and blockage with sludge). An airline from a compressor passed from the outside of the airlift plastic pipe through the pipe wall into the annulus with an upturned fitting. This attachment was installed at around 120 mbgl. Compressed air, delivered through this attachment, allowed airlifting of waters from the base of the well.

“

Installation of the permanent pump, riser pipe and reinjection pipe While drilling continued at the second location, the permanent pump, riser pipe and reinjection pipe were installed in the first borehole. The wheel-mounted excavator and pipe clamps were used to lower the equipment to the required level in the borehole. Once installed, the equipment was connected to the wellhead assembly, and an equipment test was undertaken.

Turbidex is a natural mineral media that has a very high surface area and is very effective at straining fine particulates entrained in water

”

Airlifting continued until waters ran clear. During all airlifting activities, the abstracted waters were passed through a Turbidex filter, prior to discharge to sewer.

The Turbidex filter aimed to remove any residual fines down to a 5 um size. The use of this filter ensured that all waters were suitable for discharge to sewer.

The Nordmeyer DSB 3 rig ready to commense drilling operations in central London.

PROVIDING GROUNDWATER CONTROL AND PUMPING EQUIPMENT HIRE FOR CONSTRUCTION IN THE UNITED KINGDOM

Project Dewatering forms part of Hölscher Wasserbau GmbH, Europe’s largest dewatering contractor servicing construction projects throughout Europe.

Well/s Drilling Project of the Year 2023

DESIGN | SUPPLY | SUPPORT

Project Dewatering Limited. Unit 3, The Old Wireless Station, Great Bricett, Ipswich, Suffolk, IP7 7DS Tel: 01473 658 807 www.project-dewatering.co.uk Email: enquiries@project-dewatering.co.uk The Groundwater Engineer Magazine Edition#2 11

CASE STUDY: VAN TONGEREN WATERTECHNIEK

A monster job on the N631 Preparation of construction pit Rijen. This is part of the Oosterhoutseweg N631 tunnel project.

The Dutch town of Rijen is now home to a remarkable feat of engineering: a motorway running underneath it that seamlessly integrates with its natural surroundings. But what lies beneath the surface is just as impressive – a complex dewatering strategy that played a critical role in the project's success.

Company: Country: Client: Location:

Van Tongeren Watertechniek Netherlands Heymans Rijen

T

he heart of the project involved installing a massive, 4,800,000kilo concrete tub – the future itself. Imagine a 45-metre-long concrete tub with walls 7 meters high being pushed into place, millimetre by millimetre, within 26 hours. This feat allowed traffic on the N631 to pass calmly under the railway without waiting for passing trains. Achieving this required absolute dryness.

ProRail and Heijmans commissioned Henk van Tongeren Water & Techniek, in collaboration with Raaijmakers en Zn. Bronbemaling and Tjaden Adviesbureau to take on the challenge.

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A 45 metre long concrete tub with walls 7 metres high. A bin weighing 4,800,000 kilos pushed into place millimetre by millimetre within 26 hours. This will allow traffic on the N631 to pass calmly under the railway without having to wait for passing trains.

CASE STUDY: VAN TONGEREN WATERTECHNIEK Their well-orchestrated plan involved: • Pre-emptive pumping tests: Accurately gauging the flow rate allowed for precise planning and execution of the dewatering process.

• Thorough soil analysis: Tjaden Adviesbureau meticulously mapped the site's soil composition, ensuring no surprises during excavation and drainage.

• Sustainable water management: Dozens of strategically placed return wells filtered pumped water back into the ground, minimizing environmental impact.

• 24/7 monitoring: A network of monitoring wells provided real-time data, allowing for adjustments and guaranteeing the project's smooth progress.

• Electric focus: All pumps are electric at this project, from drilling to pumping, minimized the project's carbon footprint.

The sheer scale of water management involved was staggering. Henk van Tongeren and Raaijmakers extracted and returned over 500,000 litres of water per hour, ensuring a dry pit for the tunnel box installation. This "monster job" was crucial to keeping the project on track and allowing trains to resume service on time.

While drilling prowess was crucial, the true magic of this project lay in its collaborative spirit. Henk van Tongeren Water & Techniek guided clients

through every step, ensuring seamless execution alongside Raaijmakers en Zn. Bronbemaling's expertise and Tjaden Adviesbureau's insightful analysis.

This synergy resulted in: • Pre-construction location: Maintaining a flow rate of 50 cubic metres per hour per pit, a crucial feat for safe and efficient construction.

• Minimal environmental disruption: Respect for the surrounding wooded area was paramount, achieved through strategic water management and careful planning.

• A modern marvel: The final product – a 10-inch aqueduct seamlessly traversing the road while preserving the natural landscape – is a testament to the power of collaboration.

It's a captivating glimpse into the unseen forces that shape the world around us. The Rijen project is a true "hussar piece," where diverse phases, techniques, processes, and disciplines come together in perfect harmony. A dry tub, a smoothly sliding tunnel, and a traffic-calming solution – all made possible by the combined expertise of Henk van Tongeren Water & Techniek and Raaijmakers en Zn. This project is a testament to the power of collaboration and innovation, showcasing how engineering prowess can seamlessly integrate with and enhance the natural world.

Looking for the best drainage solution for your project?

Contact acquisition manager Marco Bouwmeester at m.bouwmeester@vantongeren.nl

More about Van Tongeren Watertechniek Van Tongeren Watertechniek is the specialist in source dewatering, soil investigation and sustainable infiltration techniques. With 7 offices throughout the Netherlands, we know the soil of our work locations like no other. Every day, we apply our specific knowledge of the environment and deliver innovative solutions in water technology.

Both for large companies and small, local authorities.

In fact, we do everything to keep projects moving.

Because if you want to work safely in a dry construction pit, dig a tunnel or sustainably infiltrate the natural environment, you need the right techniques, experience and manpower.

We have 75 years of experience in this field. For more information, visit www.vantongeren.nl.

The Groundwater Engineer Magazine Edition#2 13

INTERVIEW: LAURA FLOREA

TDI Young Professional of the Year 2023 Above: Laura on the right and her colleague Rikki on the left discussing infiltration and re-infiltration wells for the new project at the Metro in Copenhagen

Introducing Laura Florea, an exceptional Geologist and Project Manager at Hölscher Jensen A/A, who stands as the proud recipient of the prestigious TDI Award for Young Professional of the Year for 2023. Laura's remarkable journey within the dewatering industry in Denmark is a testament to her unwavering commitment to excellence.

H

ölscher Jensen is a renowned specialist in groundwater lowering and groundwater purification in Denmark.

Laura's role within the company has been instrumental in their core areas of expertise, including tailored solutions for groundwater treatment, construction site cleaning, and waste disposal. Her dedication shines through at every stage, from the meticulous design phase of dewatering projects to their execution and ongoing progress. Laura's handson approach involves crafting water management plans, collaborating with cross-functional teams, and ensuring seamless communication for the success of each project.

"What sets Laura apart is her sharp focus on health and safety, a commitment that extends not only to her team but also to those collaborating with Hölscher Jensen. Her role as a safety representative underscores her unwavering dedication to enhancing safety standards within the dewatering industry."

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Most of us have worked closely with Laura and we all have been struck by her approach to the tasks, how fast she solves them, with utmost quality says Jan Vognbjerg, CEO of Hölscher Jensen.... and one of the most liked and friendly colleagues imaginable. But also, tough, and powerful when needed,” Vognbjerg concludes.

Furthermore, Laura's commitment extends beyond her immediate responsibilities, as she actively engages in sustainable initiatives. Her passion for alternative energy production, particularly in geothermal energy, exemplifies her dedication to creating environmentally responsible solutions.

Laura is not just a deserving recipient

Above: Laura Florea

of the Young Professional of the Year award; she represents a new generation of professionals leading the way in the industry's evolution toward innovation and sustainability.

We interviewed Laura to learn more about her career thus far: Where do you find yourself currently in your career?

I find myself in the early growth stage of my career, where I am willing to develop my technical and geotechnical competencies. I have had the honour to achieve early progress during the first two and a half years of my career, where I have had the opportunity to develop project management skills as well.

How did you get into the dewatering industry and why?

The dewatering industry showed itself as a potential direction to me after graduation.

INTERVIEW: LAURA FLOREA One of my former peers had recommended this trajectory, and as I was open-minded to ideas of developing my career, I applied for a job in the dewatering industry for a project where juniors were sought after.

Were there projects that helped you kick start your career?

To my excitement, the very first project I embarked on was an international-scale project, the Baltic Pipe, meant to transport Norwegian Gas from the North Sea to Poland via Denmark. I enrolled in the Jutland section of the project, where I assisted Hölscher Wasserbau in their mission to dewater the entire stretch where the pipeline was built.

The experience on this project, first as an assistant and then as a project engineer, propelled me to receive the responsibility as a project manager over the Green Gas Lolland project, in Southern Zealand, Denmark. There, I have additionally carried out planning and engineering works for groundwater lowering along the expected 45 km of pipeline.

What do you foresee the biggest challenges within the industry in the near future?

Depending on the location, duration, and conditions of the project, I see a great challenge in attracting young talents to the dewatering industry due to the increasing tendency for flexibility in everyday life. However, I do think there are ways to counter such challenges by means of implementing rotation of shifts and balanced working hours over the duration of a project.

We live in a changing world that has also recently been impacted by a pandemic, which showed us that re-thinking the way we work is not something out of the question and is rather beneficial to everyone.

How do you see technology playing a part in the industry in the future?

Of course, technology plays a major role in the dewatering industry, however, implementation of the said technology in an efficient and sustainable way is more important. Overall, there should be a balance between the use of technology and manpower, while keeping a keen eye on the impact on the local environment where it is used.

Laura Florea assisting Hölscher Wasserbau as a project assistant in their dewatering project for Baltic Pipe Jylland.

From my experience, often in the dewatering industry, the focus is rather on the fast-paced production which leads to overplanning and overuse of resources such as fossil fuels. While more environmentally friendly and more efficient alternatives are emerging, it is good to keep an open mind to innovating our existing materials and focus on the quality of the work with the use of technology.

What was the greatest encouragement someone gave you while studying?

What aspects of the industry do you think need improving?

Therefore, it was not external factors that I relied on, but rather a self-conviction that by working professionally and being meticulous, I can exceed my limitations and eventually bring some positive contribution throughout my career.

I believe that the dewatering industry needs to improve in communicating and working together for improving the technologies used, developing and innovating the ways of executing works, as well as moving towards a greener transition.

Why do you think TDI is important for the industry and how it can help the industry develop?

TDI is bringing together experts and dewatering workers worldwide to facilitate communication, as well as to develop best practice models and to share efficient dewatering solutions among all parties. This way, the improvement in the areas mentioned earlier is much smoother, faster, and certainly exciting.

Moreover, TDI gives the opportunity to different companies, as well as individuals working with dewatering to bring up ideas, share their opinions, and be heard and considered. This works out as a good motivation and encourages people to join the industry and stay in it.

I believe that while studying, the main engine pushing me forward and encouraging me was my internal drive to learn.

I knew that I was highly interested in Earth sciences since early education, and that was the way to pursue it.

Being fluent in several languages is quite impressive. Do you feel it is beneficial when dealing with global companies in our industry?

Being fluent in more than one’s mother tongue is important while in the dewatering industry. The working environment is almost always international, and there are often at least four to five languages spoken by the people working on the project.

Therefore, to facilitate efficient communication between everyone partaking in a dewatering project, especially when one is in a managerial position, speaking at least a basic level of multiple languages is essential.

What is your life motto?

Everything happens for a reason, and the choices we make are building up to that.

The Groundwater Engineer Magazine Edition#2 15

ARTICLE: ROSCOE MOSS COMPANY

Functionality is consistenty

By Timothy Lynch President at Roscoe Moss Company

Casing and Screen for Dewatering Wells

D

ewatering systems should be designed and constructed to ensure desired functionality is consistent with expected project life. Unfortunately, this is not always the case. Premature system failures are often the result of technical and financial decision makers initially misunderstanding each other’s specific needs. This, despite the fact, all dewatering applications have the primary goal of pumping the most water at the lowest possible cost.

Collaboration between technical and financial decision makers is vital to a successful dewatering project.

Too often, misunderstandings and misconceptions regarding technical and financial objectives set the stage for project problems resulting in failure to accomplish intended goals.

Unfortunately, this is often due to a failure to communicate. It is vital for technicians to explain the benefits of proposed products to the financial team, not only from a technical aspect but also from an economic efficiency perspective. The ability to demonstrate a product’s value to the purchasing department, by life cycle cost analysis, can be the difference between use of the best available technology and something that may, or may not be even somewhat adequate..

Well screen, and to some extent well casing, is the heart of dewatering wells, selection of these products can make or break a project. Yet, difficulty in determining what type of casing and screen to use is an example of the failure of technical and financial personnel to effectively communicate.

The aforementioned goal of pumping the maximum amount of water at the lowest possible cost applies to both temporary and permanent dewatering systems. To accomplish this, it is vital to understand site-specific hydrogeologic conditions.

Along with determining how much water can be produced, it is also important to know size distribution of aquifer material along with water quality. This information will determine; well diameter, screen length, the requirement (if any) for formation stabilizer or filter pack, and optimum screen slot size. Water quality analysis of both chemical and biological 16

The Groundwater Engineer Magazine Edition#2

parameters will inform the designer’s selection of steel type regarding corrosion and future well rehabilitation.

With that in mind, let’s explore the features and benefits of common casings and screens with respect to selection of casing and screen for dewatering wells.

Products described are used in both temporary and permanent dewatering applications.

Dewatering well casing and screen can range in diameter from approximately 2”PS to greater than 24”. Available materials include PVC, mild steel, HighStrength Low-Alloy Steel (HSLA), and various grades of stainless steel.

Louvered screen Screen types include continuous slot screen, slotted pipe, and shutter screen.

Low Carbon

Copper Bearing

High Strength Low Alloy

SST 304L

Corrosion Resistance

X

X

9X

244X

Physical Properties

Iron > 98%

Minimum 0.2% Cu

Min. Amounts of Cu, Ni, Cr

18-20% Cr 8-13% Ni

Yield Strength

35,000 Ibs/in2

35,000 Ibs/in2

500,000 Ibs/in2

30,000 Ibs/in2

While many are familiar with characteristics of mild and stainless steels, some may not be aware of HSLA’s superior strength, corrosion resistance, and attractive price point. This material is an excellent choice for corrosive environments exceeding limits of mild steel yet not severe enough to require stainless.

Wire Wrap Screen

HSLA Louvered Screen

Careful attention must be paid to screen slot geometry. When maximum water production at minimum cost is the primary goal, slot geometry which precludes plugging and allows the free flow of water must be utilized. While slotted pipe is cheap, it is subject to plugging and inefficient flow.

ARTICLE: ROSCOE MOSS COMPANY Two key factors in product selection are strength and durability. It is important to choose casing and screen capable of withstanding the rigors of installation, development, and, in the case of permanent wells, future rehabilitation.

Besides mechanical properties, corrosion resistance must also be taken into consideration especially when designing wells which are expected to perform for decades. Thus, the importance of considering water quality when selecting casing and screen material. It would make little sense to select a steel type based on initial cost rather than investing more upfront to ensure well life to be equal to or greater than expected project life.

Threaded and Coupled Ends

Clogged Slotted Screen These limitations increase operation and maintenance costs. Studies have shown shutter screen and continuous slot screen are the most efficient options.. Besides shutter screen’s strength advantage, its smooth interior allows utilization of the most effective well development methods giving it decided efficiency and maintenance advantages in deep, gravel envelope wells

Estimated Present Cost of Well construction and Periodic Rehabilitation (Conceptual Well Design-500ft Depth, 10 3/4 in. OD Casing and Screen).

I am confident all in this industry are familiar with situations where projects have ended-up being required for many more years than originally anticipated.

Inside Louver. Below inside Wire Wrap Screen.

On the other hand, some dewatering projects are temporary in nature. In these cases, the contractor may decide to upgrade materials, having in mind the desire to reuse casing and screen multiple times. Certainly, strength and durability are concerns but selection of a joining methods is also important. Common end connections include, welded, threaded, spline lock, and solvent welded PVC. Welding is used in many situations.

It should be noted that use of a weld collar (rather than butt welding) is a faster and more reliable method.

Weld collars also facilitate faster removal of casing and screen should it be required. (Photo 10) Threaded joints generally provide speedy installation but are subject to galling. This is especially true with stainless steel threaded connections.

Weld Collar

Spline lock fittings offer users many advantages. They are quickly installed and have no galling issues. Should removal of casing and screen be required, splines can be quickly disassembled.

While slightly more expensive than threaded connections, this cost is more than offset by speed of installation.

Although the primary objective may be the same, dewatering systems are often complex.

The designer has many casing and screen options available to ensure all operational and economic goals are achieved. It is imperative the designer is aware of all options and Spline Lock Fittings can articulate both technical and financial justifications for final recommendations.

Most often, meaningful collaboration between contractor, designer, and financial advisor results in the best project outcome.

The Groundwater Engineer Magazine Edition#2 17

2023 TDI AWARDS 2023

TDI AWARDS 2023

The 2023 TDI Awards ceremony brought together a global gathering of dewatering and groundwater professionals from all corners of the world. A collective celebration of innovation, dedication, and with quality project management, within the industry, the TDI Awards shone a spotlight on the tireless efforts of professionals who work relentlessly to shape a more sustainable and efficient future.

The ceremony was presented by our master of ceremonies, Peter Brooke, Regional Director Strategic Sales & Marketing - Europe & Africa at Fugro and supported by Vivian Botha-Veldstra TDI advisory council member. Peter shared some inspiring words on the sustainability of the industry and the importance of recognising achievements in the dewatering industry.

A special mention goes to this years’ sponsors and award presenters: Timothy Lunch from Roscoe Moss, Owen Gilbert from NCS Fluid Systems and Robin Lomulder from Fugro.

Christoffel Botha of the TDI Advisory Council shared a key message on the future of the dewatering industry and the importance of young people joining the industry.

From the construction and mining sectors to groundwater engineering, the eight distinct award categories served as a backdrop for recognising outstanding contributions in the dewatering field. It was a year marked by exceptional accomplishments and groundbreaking initiatives, reaffirming our collective mission to drive positive change in the dewatering and groundwater control industry.

Congratulations to the 2023 award winners

18

Keller – North America Health & Safety Excellence Company of The Year

GEOSS South Africa Sustainability Excellence Company of The Year

Project Dewatering Limited Wells / Drilling Project of The Year

Griffin Dewatering Groundwater Treatment Project of The Year

Hölscher Jensen a/s Equipment or Material Innovation of The Year

Hoelscher Ferrer North America Dewatering Consultant Project of The Year

O2DIT Foundation Dewatering Contractor Project of The Year

Laura Florea - Hölscher Jensen a/s Young Professional of The Year

The Groundwater Engineer Magazine Edition#2

TDI AWARDS 2023

Enter now for the TDI 2024 Awards

In 2024, we will celebrate once again the fantastic achievements made by dewatering professionals from across the globe. We look forward to acknowledging those who are making waves in the industry.

sponsoring a TDI Award will generate exposure for the company and promotes staff members to feel awarded for their hard work in the last 24 months and published in the third edition of The GEM Magazine.

The Dewatering Institute Awards brings together the leaders in the industry to celebrate their achievements and showcase their projects and abilities. Participants can enter 8 different categories, covering a range of projects, services and products offered across the world and will be backed by a digital media campaign to generate as much exposure possible to all parties involved.

We look forward to introducing the 2024 judging panel, who collectively boast vast experience from all over the world. Be sure to sign up for the TDI newsletter to receive updates on when we’ll be rolling out the red carpet for the 2024 TDI Awards, the judging panel, and nomination deadlines.

Entries will be open to all companies in the dewatering and ground control industry, world-wide. Winning or

ENTER HERE

HEALTH & SAFETY EXCELLENCE COMPANY OF THE YEAR

SUSTAINABILITY EXCELLENCE COMPANY OF THE YEAR

WELL/S DRILLING PROJECT OF THE YEAR

GROUNDWATER TREATMENT PROJECT OF THE YEAR

DEWATERING CONSULTANT PROJECT OF THE YEAR

DEWATERING CONTRACTOR PROJECT OF THE YEAR

EQUIPMENT OR MATERIAL INNOVATION OF THE YEAR

YOUNG PROFESSIONAL OF THE YEAR

The Groundwater Engineer Magazine Edition#2 19

CASE STUDY: GRIFFIN DEWATERING

Carnotite Groundwater Treatment Treatment Plan & Groundwater Testing

Company: Country: Client: Location: Duration:

Griffin Dewatering USA FH Paschen City of Chicago Completed in 2022

T

he project site was a former elemental radium separation facility. Groundwater data indicated the presence of Uranium in the water which would require treatment prior to discharging per the permit requirements. The project included excavations of up to 15 feet below ground surface, with ground water being encountered approximately 9 feet below ground surface.

Sampling of existing groundwater monitoring wells was performed to better define the site’s water quality.

The information from water testing, and historical water quality data allowed Griffin to develop a preliminary design and estimate for treating the dewatering effluent.

Groundwater Treatment Solution Griffin designed and installed a water treatment solution that incorporated sediment filtration, bag filtration, adsorptive media, and ion exchange media. The treatment system had to be built on a containment pad with a dedicated sump system to handle spills/ leaks or precipitation that entered the area and was designed to handle a flow rate of up to 200 gallons per minute.

Gravity wells were designed and installed to lower groundwater.

The system operated for approximately four (4) months until deep excavation was complete.

Water Treatment System Design Discharge effluent was routed through a perimeter HDPE discharge system into a 18,000-gal settling tank to provide residence time for settlement of heavy particles & total suspended solids (TSS) reduction

› Next water was pumped through a series of bag filters utilizing 5-micron & 1-micron filter bags

› Specialty ion exchange resin was utilized to effectively remove the Uranium

› Water was then processed through adsorber vessels filled with granular activated carbon (GAC) to remove any organic compounds

› Treated water was directed into a 21,000-gal holding tank for testing before being discharged to the municipal storm drain manhole

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CASE STUDY: GRIFFIN DEWATERING The Griffin Difference Griffin was able to successfully design, install, monitor, and remove a fully functioning dewatering and water treatment system, allowing the Contractor to meet their excavation and construction requirements.

Griffin faced tight schedules, a rigorous review process, and multiple site logistic constraints due to the type and classification of the contamination.

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> Water Treatment

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The Groundwater Engineer Magazine Edition#2 21

COMPANY PROFILE: KELLER

Unlocking Excellence in Health and Safety:

Keller North America Joins TDI as a Founding Member

Above: Wharf project in Washington, DC where Keller performed dewatering, water treatment, and foundation/soil improvement work.

I

n the dewatering industry few companies can rival the experience and commitment of Keller North America. Recent winners of the TDI Award for Health & Safety Excellence Company of the Year, Keller has earned recognition not just for their impressive track record but for their unwavering dedication to setting industry benchmarks.

Keller's roots run deep in North America, with over a century of expertise in designing and executing groundwater control techniques, including dewatering, ground freezing, water treatment, and landfill and mechanical work.

This seasoned geotechnical specialty contractor has garnered a reputation for innovative, practical, and cost-effective solutions in diverse markets. By uniting global resources and expertise with localized knowledge and focus, Keller consistently delivers the optimal solutions to meet their clients' needs.

The Dual Role: Dewatering and Groundwater Treatment A hallmark of Keller's comprehensive capabilities lies in their unique ability to seamlessly integrate dewatering and groundwater treatment solutions with a holistic approach. Groundwater lowering and the treatment of contaminated sites are two sides of the same coin, and Keller excels in both areas.

The power of this dual role is evident in the efficiency and cost-effectiveness it brings to projects.

22 The Groundwater Engineer Magazine Edition#2

With Keller addressing these critical aspects under one roof, clients can expect not only superior service but also significant cost savings and expedited timelines.

The Pinnacle of Health and Safety Keller North America's unwavering commitment to health and safety is a beacon of excellence in the industry, and this dedication has earned them the Award for Health & Safety Excellence Company of the Year at the 2023 TDI Awards. It's an honor well-deserved, given Keller's relentless focus on the wellbeing of their teams and all stakeholders involved in their projects.

Keller's commitment to health and safety is multifaceted. At the core is a comprehensive approach to risk management that extends from meticulous planning to on-site execution.

Safety isn't merely a checklist for Keller; it's a fundamental principle that informs every decision and action, ensuring a secure environment for their teams and partners.

One notable aspect of Keller's commitment to health and safety is their safety representative's role. By actively engaging in constant communication with peers on safety matters, Keller's team contributes to improving safety not only within their organization but also for the broader dewatering industry.

Innovating for a Sustainable Future Keller's dedication to sustainability is another pillar that sets them apart in the industry. They're not content with merely meeting regulatory standards; they actively seek innovative ways to contribute to a sustainable future. This commitment to sustainable practices underscores their responsibility to the environment and the communities they serve.

The Science of Ground Freezing Among Keller's many specialized services, ground freezing stands out as a testament to their technical prowess.

Ground freezing is a construction technique with a wide range of applications, primarily used in the construction of shafts, mines, and tunnels. It serves as a vital method for providing temporary earth support and groundwater control when conventional methods such as dewatering, shoring, grouting, or soil mixing are not feasible.

The ground freezing process involves drilling and installing a series of closely spaced pipes and circulating a coolant through these pipes.

COMPANY PROFILE: KELLER

Above and below:The Wharf project in Washington, DC where Keller performed dewatering, water treatment, and foundation/soil improvement work.

This refrigerated coolant extracts heat from the ground, converting soil pore water into ice, resulting in an incredibly strong and impermeable material. Unlike some ground improvement methods, ground freezing is entirely chemicalfree, utilizing environmentally friendly coolants like glycols, calcium chloride brine, or liquid nitrogen.

Ground freezing for deep shaft excavation One of the most common applications of ground freezing is in the construction of deep shafts. The freeze pipes are drilled and installed around the proposed shaft's perimeter to the required depth. Coolant circulation creates a frozen zone that can range from one to ten meters deep, providing the necessary earth support.

Once the frozen zone is established, the inside of the shaft can be safely excavated and lined.

Ground freezing in the tunneling industry Ground freezing also plays a pivotal role in the tunneling industry, with applications that involve drilling freeze pipes around tunnel perimeters, providing earth support, and creating regional groundwater barriers. In tunnel construction, this method is particularly valuable when tunneling beneath roads, railways, or constructing safety cross passages between existing tunnels. Ground freezing is also used in conjunction with Tunnel Boring Machines (TBMs) to create pre-planned safe havens for tunneling interventions or emergency TBM repairs.

The Groundwater Engineer Magazine Edition#2 23

COMPANY PROFILE: KELLER Ground freezing to isolate groundwater from mining operations Additionally, ground freezing offers an innovative approach to isolating groundwater from mining operations.

Instead of large-scale dewatering operations with potential environmental consequences, ground freezing provides a regional groundwater barrier solution, effectively protecting the environment.

Keller's success in ground freezing is a testament to their extensive experience and advanced engineering capabilities.

The process is highly interactive and requires precise drilling and custom-made refrigeration and instrumentation equipment.

Keller has demonstrated time and again that their expertise in this field is second to none.

A Visionary Approach to Industry Excellence Keller North America's journey to becoming the largest geotechnical specialty contractor in the world has been marked by a visionary approach to excellence. Their impressive presence, with over 65 offices throughout the United States and Canada, is a testament to their commitment to serving local needs with global expertise.

An Asset to The Dewatering Institute The Dewatering Institute is thrilled to welcome Keller as a Founding Member in 2023. They are a valuable addition to the community with their dedication to creating environmentally responsible solutions and their commitment to sustainability, as well as their mastery of ground freezing techniques.

Greg Ziegler, Keller Vice-President says, “Keller is very proud to become a Founding Member of The Dewatering Institute. We look forward to engaging with other industry leaders and dewatering professionals from around the globe.”

Keller North America isn't just a leader in their field; they're a beacon of innovation, safety, and sustainability in the world of dewatering and groundwater control.

Their rich history and forward-thinking approach make them a company to watch and learn from in the ever-evolving landscape of environmental engineering.

In the coming years, Keller's continued dedication to excellence, health, safety, and environmental responsibility will undoubtedly shape the industry and inspire future professionals to follow in their footsteps. As we celebrate their achievements and look forward to their continued contributions, it is clear that Keller North America is a shining example of what can be achieved through unwavering commitment to excellence and a vision for a sustainable future.

24 The Groundwater Engineer Magazine Edition#2

Above and below: Kellers first street tunnel ground freezing

ARTICLE: MENTAL HEALTH IN CONSTRUCTION

Resilient Teams Prioritizing Mental Health in the Construction Industry

T

he construction sector, knownforits high-pressure and high-riskenvironment, sees workers experiencing higher rates of suicide than in any other industry.

Reports indicate that 1 in 4 construction workers have contemplated suicide and the suicide rate is 5 times greater than all fatal work-related injuries in the construction industry. This highlights an urgent need for attention to mental health in the field.

Shifting the Traditional Wellness Paradigm Traditional wellness programs in construction, often focusing on physical health and safety, overlook a crucial aspect: mental and emotional wellbeing. The industry’s demanding nature, with long working hours and challenging work conditions, necessitates a more wholistic approach to wellness that includes mental health.

At Kintla, we recognize the importance of providing tools for individual stress regulation while also building resilient teams to create construction workplaces where people can perform and thrive.

its effects on the brain to build longterm resilience. This model delineates how stress switches our brain function from logical, analytical processing to a primitive, reactive state, triggering our fight or flight reflex.

Understanding the Emotional Impact of Construction Work

Teams can use this model to recognize and regulate their emotional zones: the ‘red zone’ of high stress, characterized by anxiety, fear, and anger, which hampers ability to think analytically, creatively, or logically, the ‘grey zone’ of low stress which can lead to disengagement and safety risks, and the ‘green zone,’ where we’re engaged, alert, and energized, utilizing our thinking brains effectively.

Resilience is the ability to navigate and recover from stressors and challenges – which are inherent in construction.

The construction environment often pushes workers into high-stress states where performance and safety can be compromised. Balancing stress levels is crucial to maintain optimal performance where workers are engaged, alert, and focused.

Neuroeducation to Build Resilience Kintla’s Emotional Zones model helps teams understand stress and

Implementing regulation techniques, which can include physical activity, breathing exercises, mental exercises, and positive social interactions help teams to significantly regulate stress and contributes to better performance, safety, and quality.

The Groundwater Engineer Magazine Edition#2 25

ARTICLE: MENTAL HEALTH IN CONSTRUCTION

A survey of approximately 1000 construction workers revealed that those aware of these zones showed more positive responses in areas such as performance, collaboration, conflict management, and safety compared to those who were not.

Building Resilient Teams in Construction Resilient teams understand and support each other in stress regulation, creating a psychologically safe environment which enhances team performance but also supports the mental health needs of each team member.

Developing resilient teams in the construction industry involves four key steps: 1. Activating the Team: Establishing clear values, goals, roles, and responsibilities.

2. Emotional and Conflict Management: Training in stress and emotional regulation and fostering team routines that build trust and psychological safety.

3. Sustaining Performance and Support: Continual feedback, collaboration, and emotional regulation are essential as teams face ongoing challenges.

4. Adaptation and Training: Ongoing training in emotional regulation and integration into employee onboarding is critical for handling crises effectively.

Conclusion The construction industry facesunique challenges in mental health management, which we can manage through shifting the focus from traditional wellness programs to neuroeducation for personal resilience and resilient teams.

These teams are not only high-performing but also equipped to manage stress actively, support each other, and maintain a positive environment.

26 The Groundwater Engineer Magazine Edition#2

By embracing this model, we can create a cultural shift in the construction workforce, a critical step at a time when it is most needed. Through resilience and mental health awareness, we can ensure that our teams not only perform exceptionally but also thrive in a mentally healthy and supportive work environment.

Mental health issues are increasingly affecting the construction industry.

Author Laura is a consultant and executive coach at Kintla. She partners with engineering and construction industry business leaders to build cultures of performance, resilience, and inclusion.

Kintla work with companies across engineering, construction, and manufacturing to deliver programming, workshops and coaching in resilience, leadership, culture change, teamwork and safety. Laura.Aiken@Kintla.io https://www.linkedin.com/in/lauracaiken/ References 1. CIOB. Understanding Mental Health in the Built Environment. 2020. Available from: https://www.ciob.org/industry/research/ Understanding-Mental-Health-BuiltEnvironment 2. CDC. Partnering to Prevent Suicide in the Construction Industry – Building Hope and a Road to Recovery. 2020. Available from: https://blogs.cdc.gov/niosh-scienceblog/2020/09/09/suicide-in-construction/

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The Groundwater Engineer Magazine Edition#2 27

CASE STUDY: HÖLSCHER JENSEN

Sydhavens Metro Project

Hölscher Jensens crucial role in a major project in Copenhagen, Denmark

Company: Country: Location: Duration:

T

he Sydhavns Metro, a large infrastructure project in Copenhagen, has been a game-changer for the city's transportation network in the southwestern region of the city.

Connecting these regions to the rest of the metro system, this project was a massive undertaking, requiring precision, dedication, and the expertise of numerous professionals. One such professional is Friederike Wetter, who has been an indispensable part of the Hölscher Wasserbau/Hölscher Jensen team since 2009. Her involvement in the Sydhavns Metro project, which was successfully executed in March 2023, is a good example of the critical role she and her team has played in such a large endeavor.

The Sydhavns Metro: A Vital Link in Copenhagen The Sydhavns Metro, also known as Metro Line M4, is more than just a transportation project. It represents the growth and development of the southwestern region of Copenhagen, connecting it to the bustling heart of the city.

28 The Groundwater Engineer Magazine Edition#2

Hölscher Jensen Denmark Copenhagen 2018 - March 2023

This was necessary to facilitate the construction of various metro stations, including Havneholmen, Enghave Brygge, Sluseholmen, Mozarts Plads, and Ny Ellebjerg, as well as the new control center for the metro, located in Sydhavnen.

Dewatering Operations: A Crucial Task

Friederike Wetter The expansion of the metro system has been a significant step towards making public transportation more accessible and efficient for the population of Copenhagen.

Hölscher Jensen's Contribution Hölscher Jensen, a leading dewatering and project management company in Denmark, played a pivotal role in the successful completion of the Sydhavns Metro project. Their involvement in the project began in 2018, and they were entrusted with the crucial task of sustainably dewatering deep underground structures from groundwater along the metro line.

Lowering the groundwater body is a complex process that involves controlling the water table to ensure that construction sites remain dry during construction and later operation.

Hölscher Jensen's team, led by Friederike Wetter, managed this task on all six construction sites she was entrusted with over a period of approximately three years. Their expertise in maintaining water levels and preventing flooding during period of high groundwater level was critical to the project's success.

Innovative Methods of Monitoring with SCADA To accomplish the challenging task of effective groundwater dewatering, Hölscher Jensen utilized the most advanced technology available on the

CASE STUDY: HÖLSCHER JENSEN market, known as SCADA, which stands for Supervisory Control and Data Acquisition. SCADA is a fully automated system for monitoring, controlling, and collecting data. It able to handle large-scale processes across multiple locations, even over substantially large distances.

The SCADA system ensured round-the-clock monitoring of the construction sites and would trigger an alarm and initiate an automatic shutdown if water levels rose above predefined trigger levels. This rapid response system allowed Hölscher Jensen's team to be on-site promptly to prevent potential flooding, safeguarding both the construction progress and the safety of workers.

Water Remediation and Sustainability Prior to commencing the groundwater dewatering process, Hölscher Jensen produced 275 boreholes at the six construction sites to evaluate and remediate any groundwater contamination. Where necessary, they extracted the contaminated water, treated it on-site, and then returned it back to the natural ground body. This sustainable approach not only ensured the success of the project but also minimized its environmental impacts.

Looking Ahead The hard work and dedication of professionals like Friederike Wetter and the entire Hölscher Jensen team have been instrumental in the progress of the Sydhavns Metro project.

The five new metro stations and the control center are expected to open in 2024, marking a significant milestone in the growth of Copenhagen's transportation network.

In conclusion, the Sydhavns Metro project is a sound proof of the collaborative efforts of numerous individuals and organizations, with Hölscher Jensen's vital role in groundwater dewatering being an excellent example of their commitment to ensuring the project's success.

As Copenhagen continues to evolve, projects like these will be essential in shaping the city's future, and professionals like Friederike Wetter will continue to play a pivotal role in that journey.

The Groundwater Engineer Magazine Edition#2 29

COMPANY PROFILE: NCS FLUID SYSTEMS

NCS Fluid Systems: Leading the Way in Expert Dewatering and Fluid Management Solutions

I

n the field of dewatering, NCS Fluid Handling Systems shines as a top-tier designer and service provider. Our reputation for excellence is well-earned, particularly when complex, engineered solutions are needed for excavations extending beyond the groundwater table, demanding the deployment of reliable site dewatering systems.

For shallow excavations, the efficiency of single-stage well-point dewatering systems often surpasses all other methods when it comes to achieving the required drawdown. In instances of deeper excavations, our team can seamlessly introduce a second stage of well points or opt for the utilization of a deep well dewatering system, ensuring optimal results.

Our dedicated team of professional engineers are at the forefront of the dewatering industry. They meticulously review geological reports, collaborate with environmental consultants, and provide a holistic dewatering package that encompasses a methodically crafted dewatering plan, precise equipment specifications, expert recommendations, comprehensive water treatment, advanced filtration solutions, and vigilant groundwater monitoring. With NCS Fluid Systems, you can be assured that your dewatering needs are met with precision and a commitment to environmental stewardship.

In the realm of fluid management, NCS Fluid Systems offers innovative solutions tailored to unique demands. Our expert designers can create customized systems, whether it is removing particulate matter or addressing scenarios involving hydrocarbon sheens or their presence.

We take pride in enhancing efficiency and safety during our Dewatering and Water Management Projects. NCS Fluid Systems excels in seamlessly integrating automation, online operational data, telemetry, telematics, and remote operations, delivering our clients innovative and comprehensive solutions.

Project Highlight: Lower Mainland, British Columbia Water Treatment and Wellpointing In the summer of 2022, NCS Fluid Handling Systems rose to the challenge and accepted a project in Lower Mainland, BC, Canada. The project was for a pipeline Owner performing an integrity dig program to ensure the pipeline was in safe operating condition. NCS completed a wellpoint dewatering and water treatment project to support the Owner and ensure the dig areas were safe for workers and free of water for removal and re-installation of pipeline. This project was part of an extensive pipeline integrity dig program that aimed for minimal environmental disruption on a tight timeline due to a strict outage schedule.

Our team of experienced professionals demonstrated their engineering leadership by delivering high quality work within budget and on schedule without safety or environmental incident. Our project leaders worked tirelessly to complete the wellpoint dewatering and water treatment, with installation and commissioning taking place within a 14-day period in extremely high and sustained temperatures.

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This project demonstrates once more that any theoretically based conclusion must always be tempered with experience; a project can be conducted with confidence when the theoretical conclusions coincide with those of expert judgment and vice versa - A Ferrer

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COMPANY PROFILE: NCS FLUID SYSTEMS

We are proud of our team for their unwavering commitment to excellence, which has contributed significantly to our success and the success of this project.

The completion of this project included the discharge of water to the environment in an area that supplies drinking water to a city of 85,000 people over the course of 4 months. To ensure conformance with environmental regulations, rigorous testing and analysis was conducted on all treated discharges throughout the duration of the project and met the criteria for BC Water Quality Guidelines.

We ensured environmental quality by utilizing our innovative technology and expertise to maintain high standards of safety and sustainability. With these measures in place, NCS Fluid Systems project management team executed the project flawlessly and without incident.

Our experienced team of professionals conducted a variety of operations including water jetting and drilling for wellpoint installation to overcome changing terrain and subsurface soil conditions. We also provided conventional water treatment systems that had a maximum combined flow capacity of 9000 US gallons per minute. The total number of water treatment systems was nine and the wellpoint dewatering totaled over 6300 meters in distance, both of which spanned over an area of approximately thirty kilometers.

We are proud to have successfully completed this project, and we look forward to continuing our leadership in innovative fluid handling solutions with leaders like ours.

WELL-POINT DEEP WELL DEWATERING HYDRO-TESTING PRESSURE TESTING SEWER BYPASS RIVER DIVERSION CREEK BYPASS WATER MANAGEMENT INDUSTRIAL WATER TREATMENT & FILTRATION SPECIALIZED HEATING SERVICES NATURAL CONTAINMENT SOLUTIONS WWW.NCSFLUIDSYSTEMS.CA

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Conceptual schematic of the work packages along the western influence to the Sandvlei.

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Livable Urban Waterways Project – Hydrogeological Characterisation of the Sand River Catchment

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ater serves a broader purpose beyond meeting supply and demand. It plays a significant role in shaping the identity of a city, providing amenities, ecosystem services, and contributing to urban revitalization. Cities worldwide are exploring how their waterways can serve as conduits for building greater resilience and act as critical habitats, social spaces, commercial hubs, and transportation corridors (Kaner, 2019).

The issue of water scarcity in Cape Town brought attention to the challenges posed by an increasingly unpredictable climate. The growing demand for water services due to urbanization and population growth exacerbates the problem, leading to scarcity and potential conflicts in social, economic, and environmental aspects.

The City of Cape Town envisions a water-sensitive city that celebrates the interconnectedness of people, nature, and water, with a deliberate focus on design. In its Water Strategy (2019), the City has committed to transitioning to a water-sensitive city by 2040. While many of Cape Town’s waterways are currently in poor condition, there are some waterways that exhibit elements of livability.

The City of Cape Town have developed and defined the concept of Livable Urban Waterways, a concept that has parallel references and conceptual framings to sponge cities and water sensitive cities (World Future Council, 2016). In this Study within the Sand River Catchment, GEOSS has characterized the hydrogeological setting, and unpacked the opportunities and implications of design interventions.

These include the potential for the aquifer to accommodate flooding (by allowing interaction with the aquifer, and bank storage), for the channel to have acceptable water quality, have a functioning ecology and to be connected to the water table and floodplain (including environmental managed aquifer recharge applications).

32 The Groundwater Engineer Magazine Edition#2

Assessment of the shallow soil horizons were undertaken through hand augering, and the digging of trial pits.

However, water serves a broader purpose beyond meeting supply and demand.

It plays a significant role in shaping the identity of a city, providing amenities, ecosystem services, and contributing to urban revitalization. Moreover, water enhances property value, improves neighbourhood appeal, and fosters liveability, community health, and wellbeing. Cities worldwide are exploring how

their waterways can serve as conduits for building greater resilience and act as critical habitats, social spaces, commercial hubs, and transportation corridors (Kaner, 2019).

The City of Cape Town envisions a water-sensitive city that celebrates the interconnectedness of people, nature, and water, with a deliberate focus on design. In its Water Strategy (2019), the City has committed to transitioning to a water-sensitive city by 2040. This approach integrates the urban water cycle, enhances resilience, and protects the sensitive natural ecosystems of Cape Town. It optimizes the use of stormwater and urban waterways for flood control, aquifer recharge, water reuse, conservation, and recreational purposes.

While many of Cape Town's waterways are currently in poor condition (City of Cape Town, 2021), there are some waterways that exhibit elements of liveability. The City of Cape Town have developed and define the concept of Livable Urban Waterways, a concept that has parallel references and conceptual framings to sponge cities and water sensitive cities (World Future Council, 2016).

Sponge cities and water-sensitive cities share numerous similarities. Both aim to create interconnected waterways, channels, and ponds throughout neighbourhoods, fostering urban ecosystems, boosting biodiversity, and offering cultural and recreational opportunities. Various interventions, such as bio-swales, bio-retention systems, porous roads, and natural ponds and wetlands, are commonly employed.

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Schematic representation of the study methodology and purpose.

These sustainable drainage systems enable the gradual release of stormwater, facilitate groundwater infiltration, and provide habitat and ecological services.

Implementing the Livable Urban Waterways (LUW) Programme requires a paradigm shift in how we work. It demands collaborative planning and management of waterways, the development and implementation of incentives and regulations, direct investment in new and existing infrastructure, and the co-design of solutions.

When infrastructure investments are necessary, they should adhere to sound ecological and engineering principles, utilizing green infrastructure and watersensitive design.

The vision is to create a water-sensitive Cape Town with safe, healthy, functional, and productive waterways. This entails protecting waterways, restoring river corridors, and enhancing the quality of life for communities and the environment.

The LUW Programme aims to establish a collaborative and systematic approach to waterway rehabilitation throughout Cape Town. By employing water-sensitive design and innovative waterway management methods, the programme aims to achieve multiple benefits.

A Livable urban waterway consists of six elements, where each element has a key performance indicator that can be used to assess a waterway before and after a LUW project. In summary, the elements and their indicators include:

4. Connectivity to Water Table and Floodplain: Livable urban waterways are hydraulically connected to aquifers, floodplains, and wetlands.

This connection allows water to move naturally, recharge groundwater, and sustain wetlands. The indicator assesses the percentage of permeable area enabling connectivity to the floodplain or aquifer.

Schematic diagrams for a gaining surface water interaction with shallow groundwater (Woessner, 2020).

1. Water Quality: Livable urban waterways maintain acceptable water quality, free from sewage, litter, and invasive species, while supporting indigenous aquatic life.

Indicators include E.coli concentrations per 100ml, nitrogen and phosphorus nutrient concentrations, litter and sediment levels, and other relevant factors.

2. Flood Management: Livable urban waterways are designed to accommodate flooding and effectively manage floodwater without posing risks to surrounding communities. The indicator is the ability to accommodate return period storm events.

3. Ecological Functioning: Livable urban waterways provide a diverse habitat structure that supports a healthy biodiversity of indigenous aquatic life.

They also promote connectivity for the movement of plants and animals.

The indicator measures the present ecological status or habitat integrity.

5. Community Engagement: Livable urban waterways serve as linear pathways connecting communities and are enjoyed by people for recreational, educational, and exercise purposes. The indicator measures the number of amenity uses and their frequency.

6. Ecosystem Services and Benefits: Livable urban waterways act as green infrastructure, utilizing natural processes to treat water, reduce flooding, enhance biodiversity, trap sediments, recycle nutrients, reduce heat, and sequester carbon. They can also provide economic benefits and ecosystem services. The indicator measures the number of additional ecosystem services, economic benefits, or social benefits provided.

GEOSS South Africa (Pty) Ltd were appointed by Lukhozi Consulting Engineers as the hydrogeological specialists on the project, tasked with characterising the hydrogeology of the Sand River catchment, as well as howthe site could be improved in terms of its functioning as a Livable Urban Waterway from a hydrogeological perspective.

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AWARD: SUSTAINABILITY EXCELLENCE Discussion: The data shows a relatively thin layer of <2 meters of dry sand.

This is underlain by semi-saturated to saturated sand and possible clay-rich unconsolidated material to a depth of 8 meters. At depth >8 meters the profile is likely dominated by saturated sand. The zone of lower resistivity around stations 96 - 116 is likely indicative of the wetland edge, visible on the surface. This correlates well with subsurface materials extracted during the installation of the piezometers and is consistent with the geological setting.

Resistivity traverse across the study site, with interpreted lithologies. Panoramic photo of the lower most study site within the Sand River catchment.

Hand augering facilitated the logging of the shallow subsurface, and the installation of shallow piezometers for water level and field chemistry measurements.

The study included the installation of piezometers for assessing groundwater elevations and flow directions to assist in characterising the nature of groundwater – surface water interaction through the catchment. While the type interaction varied through the catchment, it generally transitioned from a losing stream in the upper reaches, to a flow through system in the middle reaches, to a gaining stream in the lower reaches.

Extensive water sampling for stable isotope and inorganic chemical parameters was undertaken at identified target sites throughout the catchment, enabling characterisation of the catchment and identification of areas of potential concern.

Resistivity surveys were undertaken across the channels of the various tributaries, in addition to trial pits and augering, allowing for assessment of the aquifer, its characteristics, and ability to receive and contribute water. This information is also useful in assessing constraints in terms of the potential interventions at the various target sites. At certain locations through the catchment, groundwater interaction with surface water is limited on account of the lined canalised river. In these instances, the implications of removing the canal lining could be assessed.

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The hydrocensus included the measurement of field chemistry at boreholes surrounding the study sites to assist in developing the hydrogeological conceptual model.

Cross section 4 Indicating Water Level and Surface Elevation from WP7_PZ10 to WP7_PZ12.

AWARD: SUSTAINABILITY EXCELLENCE From the assessment, it was determined that the Sand River (and its tributaries) could be improved in terms of its suitability to be a Livable Urban Waterway (LUW), particularly regarding the ability to:

• Have a functioning ecology (Groundwater can limit low flows, and potentially allow for increased wetland area using MAR techniques).

• Accommodate flooding (by allowing interaction with the aquifer, and bank storage)

• To be connected to the water table and floodplains (by removing the canal lining, and using MAR techniques).

The detail of the various specialist studies was then used to conceptually design interventions that can be implemented at strategic locations throughout the catchment.

• Have acceptable water quality (better interaction with the aquifer would likely limit the variability in surface water quality)

Summary: The data shows a relatively thin layer of transported sand varying between depths of 0 – 2 mbgl across the profile, which is underlain by saturated clays to depths of approximately 6 mbgl. Around stations 56 – 62 at <6 mbgl the channel position and saturation can be seen. From stations 28 – 38, 68 – 80 and 88 – 96 weathered to competent granite core stones occur from 2 – 12 mbgl.

Below: 2 mbgl it is anticipated that the subsurface comprises unconsolidated, clay-rich material grading into weathered granite bedrock with depth. This correlates well with subsurface materials extracted during the installation of the piezometers and is consistent with the geological setting.

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Problem? Analysis and Solution Orillia Sanitary Sewage Pumping Station Low-Capacity Wells Dewatering in Ontario, Canada Project overview The town of Orillia, located on the shores of lakes Couchiching and Simcoe, is growing at a fast pace and requires, among other municipal services, the expansion and upgrading of its sewage systems.

Company: Country: Client: Location:

Hoelscher Ferrer North America Canada JB Enterprises Ontario, Orilla

In response to this growth and as part of a larger project, the Orillia municipality awarded the contractor JB Enterprises the development of a sewage pumping station, which would replace the one that had been in use for over 90 years and with insufficient capacity for today's needs.

Construction work began early last year 2021 but was interrupted for more than a year due to problems associated with water table control that prevented progress in the excavation. Initially, by a local company and as a subcontractor of JB Enterprises, inefficient Eductor and Sumps technologies and means were applied, which, by design and pumping incapacity, failed to cause a lowering of the water table by more than 6 meters.

In late September 2022, the contractor JB Enterprises requested design and execution support from HOELSCHER FERRER NORTH AMERICA, Inc. (HFNA), who after a thorough analysis and calculation proposed a dewatering system based on 10 low-capacity deep wells (LCW). The proposal was justified with a three-dimensional numerical calculation model (FEFLOW code) and accepted by JB Enterprises. The trust, support and collaboration demonstrated by the contractor resulted in the resolution and control of the problem in 45 days, which allowed the construction of the pumping station to proceed.

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1. Photograph taken during excavation works.

2. Site location

AWARD: DEWATERING CONSULTANT

Fundamental description of the pumping station structure The project consists of a sewage pumping station as part of the renovation and expansion plan of the Orillia city sanitation project.

The pumping station, with construction dimensions of approximately 200 m2 (16.5 x 12.0) m, requires excavation at two depth levels, zone 1 (green) and zone 2 (yellow). See Figure 3.

3. Plan and Section of the pumping station Zone 1 was to reach a depth of 4 meters, and Zone 2, 11 meters.

Subsequently, it was decided to increase the excavation of Zone 2 by an additional one meter in depth.

Based on the above, it was conclusive the need to apply a pumping system based on low-capacity deep wells. The proposal was endorsed, at least by: (1) The significant energy savings that this option represented compared to other previously used systems.

(2) The versatility and ease of adaptation of the pumping system to possible deviations of the real (measured) flow rate from the theoretical (calculated) one.

Both zones are confined by a 17-meter-deep secant pile screen, highlighted in red.

(3) Robustness of the discretized and independent pumping system that, in the event of a pumping well failure, it would maintain the rest of the system operational.

Conceptual analysis of hydrogeological and boundary conditions

(4) Ease of excavation, because although the HFNA design envisaged locating the wells inside the enclosure, its infrastructure is less than other systems previously used.

The conceptual analysis of the problem already showed the need to (1) apply a deep pumping system that would guarantee the stability of the bottom of the excavation, (2) select a system that would allow pumping a minimum of 50 to 60 l/s, and (3) consider a geometric elevation of the pumped water of 14 to 15 meters.

(5) Quick execution and installation of the system, except that, for its implementation, the excavated area had to be backfilled to allow access to the drilling machines and operators.

This approach was presented and explained to the contractor JB Enterprises, who accepted the conditions.

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AWARD: DEWATERING CONSULTANT Theoretical sizing and quantification using Feflow numerical code Once the system to be used (LCW) was determined, it was time to design it. To do this, the first step would be to quantify the expected flow and distribution as an extraction route, determining the number of pumping wells and their depths.

Due to the complex geometry, the heterogeneous conditions of the soil and its markedly anisotropic flow behavior, it would be necessary to use a numerical calculation model, simplified analytical calculations not being valid.

For the calculation of the flow in porous

media, the three-dimensional numerical computer code FEFLOW, based on Finite Elements, was used under license. Table 5 shows the adopted values with which the model was input and their description.

After the calculation meshes, successive iterations and the application of the boundary conditions (recharge edges), the model was presented as shown in Figure 4.

The optimal iteration resulted in the operation of 10 deep wells in a permanent regime, with the calculated result shown in Figure 6.

5. Elevations, values and description considered in the numerical computation model 4. Numerical-computation-model generated meshes

6. Calculated values (steady state). Total pumping flow rate and flow distribution in each well.

7. General and specific calculated drawdowns in virtual wells and piezometers.

Figure 7 shows the generic curves of calculated water table drawdowns, both in the pumping wells and in the series of "virtual piezometers". It can be seen for example that, mathematically, piezometer number 21, located in the center of the excavation, shows a drawdown of 11.51 meters. Therefore, the target drawdown would be achieved.

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8A. Calculated water table drawdown section 8B. Calculated 3D drawdown

Execution and installation of low-capacity well system

Figure 8A above shows a section of the computed downslope (white line), and 8B below its three-dimensional image, with the sole intention of better approximating the understanding of the effect.

At the time of our intervention (HFNA), the excavation had a depth of around 6 meters. Prior to the execution of the pumping wells, it was necessary to backfill the excavation to surface level for safe access of machinery and work equipment.

Final considerations and results

Once the excavation was backfilled and in accordance with the theoretical design, the 10 low-capacity wells were constructed.

According to the design shown in Figure 9 above, diameter 244 mm (10"), casing 140 mm (5.5"), filter pipe, centering devices and bottom cover, the wells were equipped with 4" submersible electric pumps. The drilling system used was roto-percussion with hammer at the bottom, dual, with simultaneous advance of auxiliary pipe and drill string, with cleaning sweep with compressed air, avoiding the use of muds that could alter the natural permeability of the ground. The equipment used is shown in Figure 9 below.

9-Above. Well design. Stratigraphy; 9-Below. DUAL system drilling rig.

- The construction of the wells became extremely complicated, given that the soil on which they were working had been backfilled, without compaction or natural cohesion, which caused excessive differential settlements of the rig.

9-Above.

- Due to schedules and job award dates, there were days of work at temperatures below - 20°C (- 4°F), which conditioned some of the processes and undoubtedly reduced production.

- The wells made inside the enclosure confined by the screen piles are not intended and designed to cause a lowering of the level outside the enclosure. It so happened that occasional, but significant, water leaks also manifested themselves through the secant piles. To compensate for this effect, a series of boreholes were drilled outside the perimeter.

- The theoretical flow model (calculated) resulted in a pumping flow rate somewhat lower than the actual (measured) flow rate, evidently and at a minimum, due to contributions from vertical preferential pathways and seepage through the screen piles.

Against all hindrances, the pumping flow rate was kept within the limits of the project permits. The system operated correctly and water table control was achieved on schedule, resolving any unforeseen issues that arose with the collaborative solutions between JB Enterprises and HFNA. The Groundwater Engineer Magazine Edition#2 39

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The dewatering project in Orillia, Canada, aimed at constructing a new sewage pumping station, stood out because of its unique characteristics and the execution strategy employed.

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This project The construction of the pumping station presented several challenges due to proofs once again that its location, the significant depth of any theoretically based excavation, the shallow water table, and the hydrogeological connection with a conclusion must always lake. After initial progress, the previously subcontracted dewatering methods be supported by with failed, causing flooding and risking the experience; a project can be stability of the excavation, and ultimately undertaken with confidence leading to a year-long halt. when the theoretical It was notable the need to implement additional measures to control erratic conclusions coincide with water flows (lack of predictable patterns) due to a typical heterogeneity and those of expert judgment anisotropic behavior along the media and vice versa. with a strong vertical component.

– A. Ferrer

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To overcome these obstacles, JB Enterprises Construction entrusted the assistance of HOELSCHER FERRER NORTH AMERICA, Inc. (HFNA) who, through meticulous analysis and a three-dimensional numerical model, conceptualized and implemented a tailormade deep pumping system utilizing low-capacity wells (LCW).

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The satisfactory execution of HFNA's dewatering plan enabled the construction of the pumping station to proceed, ultimately meeting the project's objectives. JB Enterprises' trust in HFNA and their support played a crucial role in this project's success.

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O2DIT are committed to the most sustainable technology in rainwater Company: O2DIT Foundation Country: Netherlands infiltration and return Location: Apeldoorn Duration: 2022 - Ongoing drainage.

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here are many possibilities to cope with rainwater problems within the urban environment.

However, most of the solutions solve the problem, but are not sustainable. With direct discharge to surface water the sweet water cannot be used in future. Slow filtration, till now done without any pre-treatment, will at the end pollute the underground water bodies. The water that will be infiltrated

by FHVI is pre-treated. It can be used in future on the spot. But more important, although the investments are higher, the maintenance of FHVI systems is lower than other systems. During the project different innovations have been carried out. The filters have been optimized, and the pre-treatment system is developed.

The workforce conditions have also been optimized. FHVI has become a grown-up technology, and the system is demonstrated on a big scale.

FHVI prevents urban pluvial flooding In the project ‘Adaptation to extreme rainfall; demonstration of FHVI to prevent damage by urban pluvial flooding’ the technique FHVI (Fast High Volume Infiltration) was tested in the Netherlands.

The results show that the technique is an excellent way to rapidly discharge excessive rainwater into the underground, and therefore to prevent pluvial flooding.

1. Problem More extreme rainfall Climate change scenarios predict more frequent and larger extremes in rainfall.

Pluvial flooding will increasingly cause damage because of climate change and continuing urbanisation.

Another possibility, and the economic one, is direct discharge to surface water.

However, there is not always surface water available. A further disadvantage is that the water (freshwater!) cannot be used locally in case of drought at a later time.

New solution: FHVI

Existing solutions have disadvantages

Another possibility is Fast High Volume Infiltration (FHVI). A deep infiltration well, such as FHVI, can be a feasible solution to rapidly discharge rainwater in places with limited space. Additional benefit is that the water replenishes the groundwater, and therefore stays available in dry times.

FHVI allows a rapid infiltration of large volumes of water. It is an innovative technique, with no pump or moving parts, so very low-maintenance. Its installation takes up little space. If it is carried out simultaneously with infra technical adjustments and/or works, it does not cause any inconvenience to the surrounding area. The FHVI system is designed to last for decades.

Nowadays, there are many solutions in the market to cope with the problem of pluvial flooding. Systems like buried crates, wadis, or permeable road surfaces are used. These systems are all based on slow infiltration into the underground.

But since the infiltrated water is not treated, there is a considerable chance of clogging. This can only be solved by high maintenance costs.

The FHVI technique was first developed

by German geo-hydrologist Werner Wils for lowering the groundwater table at construction sites. Here huge quantities of groundwater are pumped up and infiltrated again in groundwater layers.

Wils performed intensive research and discovered that large quantities of water can be discharged quickly into an underground aquifer.

Limited means of discharge in cities Many cities in the EU have combined sewer systems, with capacities much too small to cope with extreme rainfall.

Separated sewer systems have a limited capacity and often costs are prohibitive.

Natural infiltration of rainwater is constrained by the relatively limited permeable surface in cities.

2. Solution

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AWARD: DEWATERING CONTRACTOR He discovered that, by using the right infiltration layer, more water can be infiltrated than would be expected by normal infiltration. Although this technology was patented, the scientific proof had not yet been delivered. Scientific research has led to two thesis studies at two Dutch universities. For that reason there is, since 2020, solid scientific proof for this phenomenon. FHVI for rainwater infiltration This scientific proof has led to the search for other applications. The hypothesis was that this would also work for infiltration of rainwater. During heavy rainfall, large amounts of rainwater have to be discharged. The last years many technologies have been developed, mostly based on infiltration. The difference with FHVI is that, although FHVI is higher in construction costs, it is considerably lower in maintenance costs.

Infiltrated water is treated The most important point however, is that the infiltrated water is treated, and that it can be used at a later stage (dry times, cooling the city etc.). The pre-treatment is very simple, small and cost-effective: it is a container of about one cubic meter made of plastic or concrete, filled with sand and/ or gravel. It mimics the passing of water through layers of soil. The composition of the sand and gravel can be adapted to the situation. Rainwater is fed into it from above from the street level drain, and drains out at the bottom through a perforated drainage pipe. The bed of sand and gravel catches virtually all solid particles without becoming clogged. It even filters out many dissolved substances.

We can summarize FHVI for rainwater discharge as follows: 1. rainwater goes from street level to the drain, where the largest pollutants are already stopped: coarse leaves and litter; 2. the pre-treatment catches solid particles without becoming clogged; 3. the water goes into the infiltration well: a deep pipe with a perforated section at the bottom at the level of an aquifer (sometimes 15-30 m).

See also our animation of how an FHVI works. https://aerfit.eu/en/fhvi/

3. Research on practice scale The technology was already used on a small scale in several places in the Netherlands and Germany. In 2018, it became clear that it was time for a bigger scale. In the Municipality of Apeldoorn, the Netherlands, 150 FHVI infiltration systems were installed from 2019 to 2022.

The municipality wants to be climate robust by 2050, and has been disconnecting as much rainwater from the sewer system as possible since 2006, using several earlier techniques. However, in several places, where the rainwater sewer 42 The Groundwater Engineer Magazine Edition#2

Illustration demonstrating how infiltrated water is treated

had been disconnected, flooding occurred again after heavy showers.

A consortium (Municipality of Apeldoorn, the Netherlands, Foundation O2Dit (member tdi), Van Tongeren Watertechniek, the Netherlands (member tdi) and Hölscher Wasserbau, Germany (member tdi)) proposed a project of 4.2 million euro, which was endorsed by the EU LIFE+ programme. In the project, 150 infiltration wells were constructed in different parts of Apeldoorn.

In a desk study, the expected drilling depth was estimated. During drilling, the exact depth was then determined, ranging from 15 to 30 metres. During the project phase, the wells were placed in several types of locations: in parks, in lawns or between buildings, to provide as much diversity in the locations as possible.

The technique was tested under conditions of extreme rainfall in Germany and the Netherlands. This is a so-called T10 rain shower, corresponding with a peak intensity of 5.25 l/s for an area of 250 m²: a total volume of 36 mm/h. The FHVI technique passed the tests well, so the step toward a more extensive pilot phase could be taken in this project.

4. Results In Apeldoorn, the 150 wells were constructed and tested. A monitoring system was developed to follow the infiltration capacity of the wells for two years.

A decrease in infiltration capacity can be the result of a non-optimal functioning of the pre-treatment. In some cases, it was possible to correct the pre-treatment by changing the sand composition. Most of the wells are now more than two years in use. In only three cases, it was necessary to clean the well. The pre-treatment is cleaned regularly (once a year), by removing the sand/gravel and replacing it by new sand/gravel.

There has been some cases were the FHVI system could not be applied. That was when it was not possible to find a suitable layer in the underground to infiltrate the water. For example, this was the case when the subsoil had been heavily disturbed.

In combination with the quantitative monitoring, there is also monitoring on the quality of the infiltration water. In the Netherlands there are, until now, no requirements regarding the quality of water that is infiltrated. Nevertheless, we decided to make a robust system that is also able to remove nearly all kinds of chemicals. This was not a part of the original project proposal.

However, it is our vision that, although no one is asking for it, this technology can only survive when it does not pollute the underground.

The project runs until mid 2024. All infiltration wells are now constructed. 2022 and 2023 are used for intensive monitoring.

AWARD: DEWATERING CONTRACTOR In 2024, the project will be concluded with a final report.

In the meantime, a spin-off of this project is a project in Lithuania. In Lithuania, with comparable rainwater problems, there is a demonstration project with six FHVI wells and pre-treatment systems. The pretreatment is part of that project from the beginning. The authorities in Lithuania are much stricter on the quality of the water than Dutch governmental parties.

very well, but were too heavy to handle for the workers. In the end, we were able to develop a pre-treatment that could easily be handled (in most times a cleaning not more than once a year). This was necessary for healthy and safe working conditions.

The drilling activities have been done, according workers’ safety regulations, always with at least two persons.

Therefore, from the drilling, there were no extra CO2 or nitrogen emissions. The sand/gravel of the pre-treatment is reusable. It goes back to the factory and is cleaned. After that, the sand/gravel can be used again. The environmentally most important step is the purification of the infiltration water. By doing so, there is no harm to the environment or underground water layers.

7. Conclusions FHVI is an excellent technique to prevent pluvial flooding. In short:

5. Technical risk identification During the project many adjustments and mitigation has taken place. When a project starts, everything is only on paper. In practice, many things turn out differently. It turned out that FHVI was not applicable on all project spots. Within the project, we searched and found other suitable locations. The biggest change in the project plan was the introduction of the pre-treatment. It was necessary to protect the infiltration well. Without this protection, it was necessary to clean the well twice a year to maintain its capacity.

With the pre-treatment, the cleaning of the well every two years was more than enough.

In addition, the working conditions have led to adjustments. The first prototypes of the pre-treatment were functioning

• It is higher in construction costs, but much lower in maintenance costs • The construction occupies little space • FHVI discharges water very rapidly, in most cases • A simple pre-treatment system prevents clogging of FHVI • The pre-treatment protects not only the quality of the groundwater, but also the well itself

6. Sustainability Sustainability and environment were important points within this project. We were able to carry out the drilling with an electrical drilling machine. The batteries were filled with electricity from green sources (wind, solar).

• FHVI discharges rainwater into the groundwater supply, and therefore makes it possible to re-use the abundant rainwater in dry times • FHVI cannot be used when the subsoil has been disturbed too much in the past.

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The Groundwater Engineer Magazine Edition#2 43

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North East Scarborough Community Company: Aquatech Dewatering & Child Care Centre, Country: Canada Toronto, Ontario Location: Toronto, Ontario

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he site for this project is located in a densely populated area in an east Toronto district referred to as Scarborough. The site itself, once a soccer field and children’s playground, is nestled between a public works yard and a firehall with access to the south side of site off a busy feeder roadway and from a subdivision side street to the northeast.

The project requiring dewatering comprises the construction of a 3-storey community centre with a partial deep basement, parking areas, site servicing, installation of four chamber systems to manage stormwater and permanent site drainage. The facility design boasts a 25-lane indoor swimming pool, leisure pool, recreational gymnasium space large enough to accommodate an indoor cricket pitch, community rooms, a childcare facility and outdoor rooftop green spaces for leisure activities. An outdoor skateboard park and multiple play spaces is also offered by this facility space. The North East Scarborough Community Recreation & Child Care Centre will be the City of Toronto’s first Net Zero Energy and Emissions Community Recreation Facility.

The dewatering design challenges posed by this project included:

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a shallow unconfined aquifer atop Till and Silty Clay soil at inverts above the footing depths of the principle structure proposed swimming pool; the project specified a requirement of “dry” construction conditions at the base of the excavations;

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Duration: • • • •

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30 June 2022 - July 2025

the general contractor did not want to perform supplemental sump pumping; settlement of any kind was not permitted so the dewatering system must not pump fines of any kind; the general contractor and consultants elected to open cut the excavation (without shoring); groundwater is encountered at

a complete cut-off to groundwater infiltration to prevent the silts from dilating as construction progressed.

Notably, the site investigation documents stated

approximately 4.6 meters below ground surface (BGS) with the lowest depth footings at 10.5m BGS; set back from the excavation around the perimeter for dewatering must be 12.5 to 20.5 meters; sub-cuts or benching not an option due to limited space and need for construction access around the excavation.

The critical considerations for the design of the dewatering system included ensuring the functionality of the system with well placement as far away from the excavation as deemed practical while ensuring that all soils would be adequately impacted.

Knowing that preservation of the bearing capacity of the soils was of paramount importance for both the structural design and to support the crane on site during construction, the dewatering design needed to ensure that the system created

“Dewatering will be required prior to any excavations below the groundwater table.

Otherwise, it will result in an unstable base and flowing sides.”

Wells needed to be installed without being problematic to the sequencing of construction by other trades. Initially, zonal wellpoints were considered to save cost but the proposed distance of ±12.5M from the footings was outside of the range of influence to guarantee adequate dewatering.

AWARD FINALIST: DEWATERING CONTRACTOR Approaching localized system implementation in sequence to facilitate the installation of the footings was suggested by the architectural consultant, but due to the existing interface condition, drawdown would be restricted to a point well above the final excavation depth, so a typical dewatering plan did not make sense. Ultimately, a unique strategy was proposed.

Considering the range of influence across an interface condition for adequately dewatering the soils is limited such that the further away from the well, the less dry the excavation will be, that groundwater identified atop the Till/Silty Clay layer would need to be removed and recharge or re-infiltration from the surrounding aquifer would need to be cut off to prevent the excavation from continuously re-filling, our system was designed to ensure that pumping rate for dewatering exceeded the recharge rate.

In essence, the dewatering system would need to create a cut-off similar to what would have been provided by shoring while also drying out the internal soils to preserve the bearing capacity of the founding soils and ensuring a safe, dry excavation.

Aquatech Dewatering installed a perimeter ELECTRIC EDUCTOR system comprising ±378LM installed 12.5M from the foundation at the east, south and west wall alignments and approximately 20.5M at the north end. Pre-drilling and jetting methodology was used to Wells were spaced at ±3M C-C with screens at the Silty Clay interface at Elev.±133.3m ASL, wherever the interface condition existed.

If the interface elevation varied, the screen located also varied to ensure there would be no bleed across into the excavation.

The system was fully commissioned June 30, 2022, and is expected to be decommissioned July 2023.

A temporary trench was excavated at the north end of the site to confirm the groundwater level.

Above: the system functions very well to capture the groundwater across the interface.

The excavation is completely dry and did not require any localized systems (i.e.: interior wellpoints) for the crane pad.

Three 50hp turbine pumps are installed in an 18k Gallon Weir tank to power the eductor system. Essentially, two pumps run the system with built-in redundancy to ensure that if one pump fails, the third will back up to permit time for response

by Aquatech personnel to perform maintenance/repairs without jeopardizing the site.

Drilling and jetting is performed in a small trench located outside of the proposed building footprint to control the water and spoils. Tracked mud is not permitted from site access roads to City of Toronto roadways.

Severe weather is inherent to projects located in Ontario, Canada. The winter season typically begins in November and lasts until the end of April so measures must be taken to ensure that components do not freeze. At this site, glycol heaters, insulated tarps and pea stone gravel bags are installed to keep the header pipes and tank (including the pumps) nice and warm despite overnight temperatures averaging -15°C throughout the season.

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Project Prinses Amaliahaven Emission-free drainage in port of Rotterdam

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he Prinses Amaliahaven is part of Maasvlakte II in Rotterdam. For the expansion of the container terminals, 2.4 kilometres of new quay wall are being built here.

To realise this on dry ground, Henk van Tongeren Water & Techniek provides drainage. For this, they use 138 electric piston pumps, which are powered by green energy, with additionally installed onsite solar panels and wind turbines. As a family business, they attach great importance to sustainability.

That is why this project touches the heart of their business.

The project summarised • 2.4 kilometres of quay wall will be built • 138 electric piston pumps pumping the area • 12,000 kWh generated per Green PowerBox® per year • 10 million m3 of water pumped per year • 67 monitoring wells with realtime groundwater level registration • Start installation of drains: summer 2021 • Pumping operational until April 2024

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Company: Country: Location: Duration:

Van Tongeren Watertechniek Netherlands Port of Rotterdam 2021 - 2024

About the project It is complex to build several kilometres of wall in a place that is currently sea. Yet Henk van Tongeren Water & Techniek realises the optimal conditions for this. And without any CO2 emissions either! Many kilometres on both the land side and the water side are provided with drains connected to piston pumps.

This will pump around 10 million m3 of water entirely electrically every year, so that the quay wall can be realised on dry land.

Real-time monitoring keeps an eye on everything and allows for quick adjustments. By realtime monitoring is also prevents unnecessary groundwater withdrawals. This is better for the environment and costs less energy!

AWARD FINALIST: DEWATERING CONTRACTOR Environmental concerns Henk van Tongeren Water & Techniek is using only electric pumps for this project. That makes a huge difference in terms of CO2 emissions. When pumping, water management is of course always important. The less water is pumped, the better it is. Thanks to its knowledge of the subsoil, drainage techniques and pumping techniques, the family business always looks for an optimal installation so that as little water as possible is extracted.

Water is always discharged first via infiltration into the soil in the immediate vicinity. If that does not work, the preferred method is discharge into nearby surface water. Only if this is not an option will discharge to the sewer be considered. As patent holder of DSI return drainage (FHVI – Fast High Volume Infiltration), the phenomenon to infiltrate water in a sustainable way, Henk van Tongeren Water & Techniek likes to be at the forefront in this field.

The Green PowerBox® is used to drive the electric pumps in the self-sufficient construction site. This box can generate sustainable, green energy at (remote) locations where large amounts of energy are required. Perfect for working emission-free as well as significantly reducing total energy costs on site. The Green PowerBox® is an intelligent, mobile energy solution that allows Henk van Tongeren Water & Techniek to meet their project’s energy needs quickly, green and sustainably. The box provides electricity based on solar and wind energy.

Reuse of dewatering materials is important for waste reduction.

Filters can last up to 10 times. Another point of attention is standardisation of materials, so that components can be exchanged easily between drainage systems.

Repairing dewatering materials is also done regularly in the company’s own workshop. Many pumps are overhauled; the pump housing and frame can sometimes last 50 years with a new motor!

See how we put water to work at www.henkvantongeren.nl

People come first When it comes to social sustainability, Henk van Tongeren Water & Techniek has also been making great strides for years. For example, by setting up an education programme for lifelong learning. From primary school (What is ‘Holland waterland’? How do we ensure a bright future together?) to secondary school and practical education. It is also an ideal way to reach people from other professions who want to retrain.

Through the partnership Draisma Dynamo Verbindt, Henk van Tongeren Water & Techniek organises activities in the broadest sense for various target groups, including people with disabilities. In this way, the company wants to contribute to people in Apeldoorn society. In addition, the family business sponsors various local (sports) initiatives, as well as initiatives that help the unemployed or people with disabilities.

Because everyone deserves a place in society!

The Groundwater Engineer Magazine Edition#2 47

INTERVIEW: OWEN GILBERT

Experienced Leader appointed as TDI Advisory Council Member Owen Gilbert, President and CEO says that the success of NCS is not a solitary triumph, but a collective achievement, fuelled by the invaluable contributions of a diverse group of stakeholders, including our exceptional team, dedicated suppliers, and trusted business partners, among others. It is remarkable that we extend our thanks to all those who have played a pivotal role in achieving the highest level of excellence within our industry. Your unwavering support and steadfast commitment are highly appreciated.

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wen's entrepreneurial spirit has led to the founding of two exceptional companies: NCS Fluid Handling Systems, a Canadian-owned and operated business, and NCS Environmental Solutions Ltd. These companies are dedicated to supporting the growth of the Canadian energy sector, municipal infrastructure, and environmental integrity through principled, natural, and cost-effective solutions in fluid handling, water management, and environmental services. Owen's leadership has shaped these ventures, delivering innovative solutions while respecting the environment and regulatory compliance.

Can you tell us more about your work history and how you got into the dewatering industry?

Owen Gilbert NCS Fluid Systems President CEO

I see solutions and I don’t dwell on obstacles; I embrace opportunities.

In my career journey, I've evolved from a Draftsman to a VP of Sales and Marketing, where I played a pivotal role in the company's sale to a US public corporation.

I introduced novel sales approaches, mentored personnel, and presented to over 500 industry professionals.

As VP of Operations, I managed four manufacturing facilities, formulated budgets, and implemented a strategic sales strategy. I then assumed the role of President and COO, leading significant organisational changes and driving growth in challenging economic circumstances. Subsequently, I became COO at a different organisation, focusing on cost-reduction initiatives and forwardlooking assessments. As VP of Operations for a transitioning business, I oversaw cultural shifts, refined product offerings, and introduced a comprehensive training program.

Today, I proudly serve as the President and CEO of NCS Fluid Handling Systems Inc., a company founded to address the growing importance of responsible water management. Our services encompass Dewatering, Water Management, Hydro Testing, and more, with a commitment to comprehensive knowledge and environmental responsibility, safeguarding our natural resources for future generations.

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What are your favourite projects that you’ve worked on in your career?

Some of my favourite projects throughout my career have involved testing the largest LNG and LPG tanks in North America. I’m equally passionate about responsible water management in industrial settings, recognizing our role as stewards of this vital resource in our industrial applications. It’s a source of pride for me that we’ve played a pivotal role in treating and testing water, as well as managing it, for the two largest hydrotest tanks in North America.

What are some of the biggest challenges you’ve seen in the industry?

The most significant challenge within our industry revolves around knowledge sharing, particularly among newcomers.

Ensuring that industry expertise reaches those new to the trade remains a hurdle.

Furthermore, there’s a pressing issue of attracting more individuals to join our field. I strongly advocate for promoting dewatering as a viable career option and emphasising the substantial career growth opportunities within our industry.

To address this, I’ve initiated a program called Tier Training, modelled after the Canadian apprenticeship program. This training aims to establish dewatering and water treatment as fundamental competencies while showcasing the promising career paths available within our industry. At a very high level it mimics the 4-year apprenticeship-type trade programs where an entry level employee would learn safety, small tools, and general duties in the first year.

To advance to the next tier they must demonstrate competency and complete 2,000 hours on the job, gain practical experience where the tasks gradually become more difficult and add a level of responsibility and accountability.

At a certain point, we’ll attempt to add the mentoring of a PM to those at a 3rd or 4th level to advance to new emerging leaders. In all cases, 1st and 2nd level employees always work under the supervision of a 4th level or higher.

How have you seen the industry develop over the past decades?

Over the past decades, I have witnessed significant transformations within the industry, marked by a remarkable shift towards automation and the integration of technology-driven solutions.

Automation: One of the most prominent trends has been the widespread adoption of automation in production processes and operations. Industries have increasingly turned to robotics and advanced machinery to streamline workflows, improve efficiency, and reduce human error. This has not only boosted productivity but also enhanced safety standards in many sectors.

Online Operational Information: The advent of the internet and the proliferation of digital technologies have allowed companies to access real-time operational data from remote locations.

This has revolutionised decision-making processes by providing up-to-the-minute insights into various aspects of a business, from inventory levels to equipment performance.

Telemetry and Telematics: The use of telemetry and telematics systems has become commonplace in the industry.

These technologies enable organisations to monitor and manage assets in realtime. Telematics has not only improved asset utilisation but also enhanced safety and security.

Remote Operations: The concept of remote operations has gained significant traction, allowing companies to manage critical tasks from a distance.

Overall, the industry’s development over the past decades has been marked by a relentless drive toward efficiency, cost reduction, and improved safety.

The integration of automation, online operational information, telemetry, telematics, and remote operations has played a pivotal role in achieving these objectives. As technology continues to advance, it’s likely that we will see even more innovative solutions emerge, further transforming the landscape of the industry.

How do you see technology playing a part in the industry in the future?

Technology undoubtedly holds the key to the future of the dewatering industry, as it does for all industries. One of the most significant challenges we face in the industry is effective information and data management, with a particular emphasis on information sharing.

In the coming years, I foresee technology playing a pivotal role in addressing this challenge. Advanced data management systems, cloud-based platforms, and digital tools will revolutionise how we collect, store, and share critical

information. These technologies will streamline processes, enhance collaboration, and improve decisionmaking.

only do you have the chance to make a meaningful impact on the world, but you can also enjoy a promising and satisfying career in the process.

Moreover, we can anticipate the integration of cutting-edge technologies such as sensors and predictive analytics into dewatering equipment. This will enable real-time monitoring of systems, predictive maintenance, and more efficient resource allocation.

In essence, a career in the dewatering industry isn’t just about securing a job; it’s about becoming a steward of one of our planet’s most critical resources and ensuring a sustainable future for generations to come.

Additionally, as environmental sustainability becomes increasingly important, technology will empower us to develop and implement greener dewatering solutions. From more efficient water treatment processes to reduced energy consumption, technology will drive innovation in sustainability.

Ultimately, technology’s role in the dewatering industry’s future is not only about increasing efficiency and effectiveness but also about addressing the broader global challenges of water resource management and environmental responsibility.

Why would you recommend younger generations a career in the dewatering industry?

I would highly recommend younger generations consider a career in the dewatering industry for several compelling reasons: First and foremost, water is a fundamental necessity for life itself. Our planet’s future depends on responsible water management. Without effective dewatering practices, we risk wasting this precious resource, which is something our world cannot afford.

Furthermore, water has become a valuable commodity, and its efficient management is of utmost importance.

As a professional in the dewatering industry, you would be at the forefront of ensuring that this invaluable resource is conserved, treated, and utilised efficiently.

Beyond the environmental and ethical aspects, a career in dewatering offers a pathway to a rewarding and fulfilling profession. The industry is ripe with opportunities for growth and innovation, with a constant demand for skilled individuals who can contribute to sustainable water solutions. So, not

What aspects of the industry do you think need improving?

I see two critical areas for improvement within the industry: 1) Enhanced Knowledge Sharing, and 2) Promoting Industry Careers: We should actively encourage more individuals to explore and pursue careers within the industry.

Why do you think TDI is important for the industry and how it can help the industry develop?

The dewatering industry, on a global scale, should prioritise the sharing and dissemination of information. Certain regions, such as Europe, are pioneering various dewatering technologies, and it’s essential that this knowledge is distributed worldwide. Differences in information accessibility exist both regionally and internationally.

TDI plays a vital role in our industry by serving as a platform for global information sharing. It facilitates industry development through education, the exchange of research and knowledge, the availability of literature and best practice guidelines, and, importantly, by fostering networking opportunities.

What was the greatest encouragement someone gave you regarding business?

“Be a leader, forge your own path, don’t follow the herd, look past the present and look upon the horizon because that’s where we're going.”

What is your life motto?

I live by these life mottos: “I’ve never set out without the goal of winning, however I am willing to accept the outcome if we brought our best that day.”

“I see solutions and I don’t dwell on obstacles; I embrace opportunities.”

The Groundwater Engineer Magazine Edition#2 49

CASE STUDY: GRIFFIN DEWATERING

SLC Airport Central Tunnel Project Challenges A deep 35 ft. excavation with sheet pile shoring was required for this project. Highly stratified soils and underlying alluvium caused difficult dewatering conditions and the risk of unstable soils near the planned excavation depth. High piezometric water tables required specific drilling techniques for borehole stability.

Water treatment for hydrocarbon contamination was also required for several wells.

Company: County: Location: Duration:

Griffin Dewatering USA Salt Lake City, Utah 2021-2022

Deep Well System Design Griffin designed and installed a deep well dewatering system to target the coarse alluvium from 45-ft. to 85-ft. below grade.

Large diameter wells were drilled up to 85-ft. below the excavation depth to depressurize the underlying soils and pump high volumes of water.

The system produced approximately 550 gpm and the depressurization of the formation provided a successful project with limited sumping. Elevated casings and specialized drilling rigs were employed in order to safely and effectively drill the wells to the design target depth.

Temporary Water Treatment System Temporary water treatment was required to remove hydrocarbon contaminants from the effluent of several wells.

Griffin designed and installed the temporary treatment system to remove the contaminants and allow discharge to continue.

The Griffin Difference Griffin provided a turn-key solution and completed all dewatering permitting, design, submittal, and installation.

Griffin’s design to depressurize the underlying alluvium formation performed very well and helped maintain an aggressive project schedule.

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• Thickening – improved settling fluxes and densities.

• Tar gets clays and ultra-fine particles for improved solid-liquid separation.

• Filtration – improved cake permeability.

• Effective coagulation of ultra-fines for better flocculation and fines capture.

• Storm water quality management – control of suspended solids in runoff.

• Thickening – flocculant dose reduction.

• Tailings Storage Facilities – improved return water quality.

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COMPANY INFO: EAST COAST DEWATERING

Sock Drain Installation How do you dewater?

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hen it comes to living on the coast, high groundwater levels and coastal tides make dewatering almost always necessary when working below grade. Having been around numerous wellpoint systems, deep wells, and Kelly wells, we knew that there had to be a way to dewater that was less labor intensive, more cost effective, and overall, more efficient.

However, there is a time and a place for each, I would argue that sock drain systems are pound-for-pound the better option from a cost-effectiveness and labor standpoint. This is where East Coast Dewatering was born.

Michael Bryant started East Coast Dewatering in 2023 with the purpose of making dewatering more efficient. Located along the South Carolina Coast the idea was to services local utility contractors. With the purchase of their sock trencher, word has quickly spread to Virginia, North Carolina, Georgia and even parts of northern Florida.

Here’s a deeper look at sock drains and how they stack up against wellpoint systems.

What is Sock Drain Dewatering?

By rapidly draining the groundwater from the saturated soil, sock drains enhance the stability of the ground and make it safer for contractors to work below grade. Sock drain dewatering systems are a relatively simple concept.

A specialized trencher digs and installs a flexible corrugated pipe, that has small holes in it, with a fine mesh cloth around it, under the construction area. This is typically done for pond construction, utility installation, or for general site dewatering.

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The length of the sock run is determined by the soil conditions and the depth of the water table. It is usually installed in 300ft600ft runs around 18ft deep with the two ends coming out of the ground (the header) where contractors can connect a pump.

After subsurface construction is completed, pumps and header can be removed from the system allowing the water table to return to normal. Sock underdrain is capped for future use or abandoned in place.

Wondering about the advantages of using sock drains? There are many. Not only does the use of sock drains rapidly dewater an area, it can prevent settlement issues and be a long-term solution with minimal environmental impact.

Advantages of using Sock Drains Accelerated dewatering Sock drains have a high hydraulic conductivity, allowing water to quickly flow through the geotextile material. Installation time is fast compared to other methods. Our trencher can install up to 2,200ft per day depending on the soil conditions.

Improved soil stability Sock drains help decrease pore water pressure, which reduces the risk of soil liquefaction, slope instability, and potential settlement issues.

Increased bearing capacity By accelerating the dewatering and consolidation of soils, sock drains can improve the bearing capacity of the ground. This is beneficial for supporting heavy structures and loads, reducing the risk of settlement or differential settlement.

COMPANY INFO: EAST COAST DEWATERING Cost-effective solution Sock drains are typically cost-effective compared to alternative dewatering methods such as wellpoint systems and Kelly wells (or whistle pipes). Less equipment, less labor, resulting in potential cost savings for construction projects.

Ease of installation Installation is quick and easy. East Coast Dewatering has a specialized trencher that can install up to 1,800ft of sock per day with limited disturbance to the site.

Other systems will always have their place in the dewatering world but for utilities installation, pond excavation, and general site dewatering, a sock drain system installed by East Coast Dewatering will always be the better choice

Let’s compare the estimated cost difference: Wellpoint System Cost You the contractor are installing this system with your crew and your equipment. 500ft straight run installing every point (about 125 points) Equipment: Excavator ($800/day), skid steer ($300/day), jet pump ($400/day), jet rod ($100/day), jet hose ($200 day) Equipment total for 1 day: $1,800 Sand: 2 dump trucks with wellpoint sand: $2,000 Header pipe, points, swing arms 1 month rental (no wellpoint pump or hoses): $2,500 Labor: 4 crew, 10-hour day, at an average hourly rate of $19 per hour: $760 Fuel and Freight: $1,200 Removal of system when complete: $800 Wellpoint Total: $9,060

- Michael Bryant

$8,260/500ft = $18.12 per linear foot

Compatibility with various soil types Sock drains are suitable for a wide range of soil types, including silts, clays, and sandy soils. They are versatile and can be used in different ground conditions, making them a flexible solution for dewatering projects.

Sock Drain System You hire East Coast Dewatering to come install the sock drain system 500ft of installed sock at $10 per foot: $5,000 Mobilization total: $1200

Environmental benefits Sock drains are often made of geosynthetic materials that are resistant to degradation, offering long-term performance.

They can be environmentally friendly alternatives to traditional drainage methods, as they minimize the need for excavations and the use of aggregate materials.

Site benefits No above ground piping except the header that connects to the pump. Depending on soil conditions, sock drains can dewater a 20ft-30ft radius Air leaks or vacuum loss are minimal because everything is below ground except the header pipe.

Sock Drain Total: $6,200 $6,200/500ft = $12.40 per linear foot In addition to the costs above, you must account for two other efficiency issues: 1) If your crew that installed the wellpoints had to stop work on another job to come do this wellpoint system install, how much production did they lose by leaving that site for a day?

2) What wear and tear happened to your equipment?

Now let’s look at a scenario wherein you have the option to use a sock drain or wellpoint system. Let’s assume that you are laying a 500ft run of sewer 15ft deep for a new housing development. For the sake of comparison, the soil is sandy with some silt mixed in, and the water table is at -5ft.

You own the excavator, wheel loader or skid steer, but you must rent the wellpoint system (excluding pump and hoses).

You also must rent the jetting equipment for your crew to install the system.

The Groundwater Engineer Magazine Edition#2 53

TDI MISSION STATEMENT

Unifying the World of Dewatering: The Dewatering Institute's Global Impact

TDI's Fundamentals The core fundamentals of The Dewatering Institute revolve around Education, Knowledge Sharing, Best Practices, and Networking. We translate these principles into tangible action through an array of initiatives, including webinars, training courses, case studies, concise guides, and continuous professional development opportunities.

In addition to fostering personal and professional growth, we offer extensive networking and brand exposure possibilities, granting our members access to an expansive platform for engaging with a broader audience.

This outreach spans diverse avenues, encompassing social media, events, blog posts, and newsletters. Christoffel Botha, a valued member of TDI's Advisory Council, underscores the significance of our events and training courses, emphasizing their pivotal role in expanding knowledge and connecting with industry peers worldwide.

At TDI, our mission is clear: to bring together unwavering support to all members and collabrators across the entire project life cycle, says Christoffel.

TDI Advisory Council TDI’s diverse Advisory Council is made up of leading experts in the industry to ensure all aspects of the institute are covered. In order to deliver effective dewatering solutions, an in depth understanding of the external factors and parameters that may impact an operation is essential. Therefore, we believe in promoting best practices directly from professionals.

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This year we welcome two new experts to the Advisory Council: Andres Pinto: Regional Technical Lead Ground Engineering for Stantec, Andres is a Civil Engineer based in Qatar.

Andres also holds a Masters Degree in Geotechnical Engineering. With 21 years’ experience in ground engineering, Andres has worked in geotechnical roles in mountainous and seismically active areas as well as management, design, procurement, and construction of geotechnical and tunneling large-scale underground projects.

Owen Gilbert: Chief Executive Officer at NCS Fluid Handling Systems Inc and NCS Environmental Solutions Ltd. Owen is based in British Columbia, Canada.

He holds an MBA from Royal Roads University. Since beginning his career as a draftsman, Owen has enjoyed a fruitful career in various roles from operations management to sales and marketing. Owen’s keen awareness of the growing importance of responsible water management, prompted him to establish NCS. . By becoming a TDI member, you gain exclusive access to a wealth of resources and case studies, ensuring the continued growth and knowledge-sharing vitality of our industry.

TDI Members The TDI community wouldn’t be what it is without our founding members: Griffin Dewatering LLC, Roscoe Moss Company, Van Tongeren Watertechniek, Carl Hamm Pipes and Pump Solution, Stuart Wells Ltd, Holscher Group, Hydroserv International and Layne ‘A’ Granite Company and Keller North America.

Our global community is well distributed across The United States (27%), Canada (6%), Europe (40%), the Middle East (10%), Africa (11%), New Zealand (3%) and Australia (3%). Members are from various disciplines within the industry; namely civil engineering (30%) dewatering contractors (20%), facility services (9%), suppliers (20%), main contractors (10%), environmental services (6%) and education institutes (3%).

The community consists of 8 founding members, 6 contributor members, 37 company members and 10 individual members.

In 2023, we welcomed a number of new members to our community, namely Kaveh Zamani - Aquatech, Giwrgos Syllignakis - Whelve Energy, O2DIT, NCS Fluid Handling Systems, PowerFlo Pumps and Systems, A PowerFlo Technologies Company, Clark Foundations, Johanne Bendix - Ramboll Group A/A, HBC Construction, Angus Flexible Pipelines, Piteau Associates LTD, Mersino and Keller North America.

Our Plans for Future Growth In 2024, at TDI we aim to continue to focus on education, training, best practices, and the development of dewatering industry guidelines. Our primary mission is to empower our members and industry professionals with the knowledge and skills essential for success in the evolving landscape of dewatering. We've listened to the needs and aspirations of our members and the wider industry, recognizing a shared desire for more extensive training opportunities and insights into innovative practices. To meet these demands, we aim to take action on a diverse range of educational avenues, including webinars, hybrid events, online live training, recordings on specific topics, and in-person training sessions.

This multifaceted approach not only equips individuals with valuable expertise but also facilitates networking and the exchange of ideas among our members and clients.

We will once again honor outstanding achievements and innovative contributions within the industry with the 2024 TDI Awards, an annual virtual celebration of excellence. As we look to the future, we are committed to continue growing our member base as we work towards full establishment of TDI as a legitimate entity capable of providing accreditation resources, thereby setting new standards for excellence within the dewatering community.

TDI MISSION STATEMENT Why become a TDI member?

To stay up to date

Embracing TDI membership extends an invitation to join a flourishing and expanding community of industry experts. As a member, you gain access to a wealth of opportunities, from knowledge-sharing and educational resources to the exchange of best practices and networking with fellow professionals in the dewatering industry.

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TDI is driven by the mission to cater to the diverse needs of all its members and collaborators, which encompass a wide spectrum of stakeholders, including project owners, governmental entities, engineers, contractors, manufacturers, and suppliers. To register as a member contact TDI on admin@dewateringinst.com

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The Groundwater Engineer Magazine Edition#2 55

TDI EVENTS

TDI Events iFLUX Pre sentation

arl Hamm ongress C IAH 50th C ber em m founding

Young Professionals of the Year

TDI Awards 2023

TDI Awards 2023 Young Professionals of the Year Nominees

seph Sopko ntation. Jo Keller prese Riette Laas. and

O2DIT Founda tion Pre sentatio n

TDI visits IAH 50th Congress in Cape

Town

Christoffel Botha, Executive member visit to Tim Roeder

Smartrek Technologies Webinar

TDI Awards Ceremony Webinar

Griffin Dewatering Webinar

Smartrek Technologies will be discussing the proprietary spidermesh protocol, assessing the pain point and their atrax web application solution and the benefits they can provide.

Celebrating the achievements of the professionals in the TDI community.

25 January 2023

22 June 2023

Enhance Your Water Treatment Project with Griffin Dewatering’s Expertise, concluding the webinar with TDI award winning Groundwater Treatment project of the year - Carnotite Reduction Remediation Project, Chicago, Illinois 25 October 2023 WATCH HERE

WATCH HERE

WATCH HERE

DHI – The expert in water environmental Webinar

Vietti Slurrytec Webinar

Enhancing mine-water management with groundwater simulation using FEFLOW.

Enhanced Dewatering by Process Water Conditioning” Understanding slurry means designing the process to suit the properties of the slurry.

22 February 2023

26 July 2023

WATCH HERE

WATCH HERE

Roscoe Moss

BBA Pumps Webinar

Principles of Efficient Water Well Design Dewatering with less energy consumption, more environmentally friendly equipment, and lowest cost of ownership pumping solutions.

24 May 2023

WATCH HERE

23 August 2023

WATCH HERE

O2DIT Foundation Webinar The DSI/FHVI technique and the history.

Applications of the DSI/FHVI technique (dewatering and rainwater infiltration).

Applications of the technique in the future; DSI/FHVI as a solution of climate change (intensive rain showers and drought).

29 November 2023

WATCH HERE

iFLUX Webinar Real-time iFLUX sensors reveal rapidly changing groundwater flow dynamics in wetland ecosystems. Sustainable and resilient groundwater abstraction facilitated by real time groundwater flux monitoring: A field case at a Dutch coastal drinking water utility.

13 December 2023 WATCH HERE

Royal Eijkelkamp Webinar

Keller Webinar

Upcoming 2024

Introduction to Sonic Drilling, Tooling, Sectors and Case Studies.

The Importance of Artificial Ground Freezing (AGF) for Shaft Sinking and Tunneling.

7 June 2023

27 September 2023

To find out more about our upcoming, webinars, presentations and events click on the link below or contact riette@dewateringinst.com if you and company would like to get involved.

WATCH HERE

56 The Groundwater Engineer Magazine Edition#2

WATCH HERE

TDI MEMBER TESTIMONIALS

Robin

o Lomulder – Fugr

ustry in a better TDI helps the ind is a fantastic cooperation and ed about new orm inf t medium to ge en developm ts.

ller Joseph Sopko - Ke rials. ible learning mate TDI provides incred ine az ag m w s and ne The webinars serie rtunity le like me anoppo op pe e giv ly on t no a ide ov pr t ology bu to share our techn rs at be em m for ing rn great source of lea careers. all stages of their Systems S Fluid Handling Owen Gilbert – NC ustry, on a global The dewatering ind d itize the sharing an scale, should prior Certain . on ati orm inf of dissemination ng various rope, are pioneeri regions, such as Eu sential es ologies, and it’s dewatering techn rldwide. wo ed ut ge is distrib that this knowled exist ity ation accessibil Differences in inform y. all on ati ern d int both regionally an ies artrek Technolog Martin Carrier – Sm e th for ch as TDI allow Organizations su e th d an on ati inform dissemination of ; the entire industry advancement of ng izi tim op of al a go this is essential in essential in a world resources and is ited. are increasingly lim where resources au lscher Wasswerb Joe Dreissiger – Hö ote om pr to t en m as an instru TDI can function uired req ing th ery ev of on the overall educati dy to d it can act as a bo for dewatering, an required be ll wi at th s es oc pr participate in that mate ure to mitigate cli in the very near fut see that n ca I ere wh s at’ change. I think th at ce very easily in th TDI will find its pla e. ur fut e th in discussion

rvices M Consulting Se Kym Morton – KL s very well s initiative and fit TDI is a marvellou ormation inf ore m to spread with my ambition ve more agement and ha about water man should be ere Th . e industry transparency in th , but at the try us ind e th in good competition boration. needs to be colla same time there

- DHI Rivera Villarreyes Dr. Carlos Andres as a rks wo I ongly that TD I do appreciate str in all ers ion tit ac pr n twee strong bridge be tering rs related to dewa the multiple secto elling, od m l ca eri m nu try, from pump indus at th ers ng, among oth monitoring, drilli ation orm inf of n tio mina allow for the disse industry. ent of the entire and the advancem

ational – Hydroserv Intern Barry O’Sullivan to bring has ever managed No organization tering wa de e th ers from so many practition an is it so e, for be industry together vement. exceptional achie ring – Griffin Dewate Bronson Gerken educating rfect platform for TDI provides a pe eers on gin ultants, and en contractors, cons many are ere Th . ing dewater the intricacies of pact im e th ing system and facets to a dewater e of typ e th m fro n, excavatio to it can have on an w ho en ll design, and ev system, proper we posal. dis to ior pr ter the wa temporarily treat n n – Van Tongere Guido van Tongere Watertechniek t fun initiative. It’s grea TDI is a very good ork like this tw ne al on ati ern to be in an int just le. People who are with similar peop . are we watering as as addicted to de

Company Layne A Granite James Cooper – er nt to bring togeth I think it’s importa er the world ov all m fro rs de industry lea an me page. We have and get on the sa n and tio iza an ape this org opportunity to sh nice to It’s . es tic ac pr st be the future of our I’ll be are involved, and have people who . more involved too

Hölscher Jensen Jan Vognbjerg – the nt that we share I think it is importa solutions ht rig e th t ge d an best knowledge have. the resources we so that we protect ge is led ow kn ng ari sh Online webinars– ed more of it. very helpful. We ne uart Wells David Wright – St where globally we TDI is a platform ments, successes, can share develop view to reducing a th wi and failures as oting dewatering carbon and prom ly an environmental . try us ind ly nd frie Roscoe Moss Timothy Lynch – e of the most In my opinion, on things TDI g game changin would be to sh pli m co ac t migh ponsible for res e influence thos to base their s ion cis de ing purchas life-cycle cost on ns recommendatio an initial cost. analysis rather th tti Slurrytec Andrew Vietti – Vie for information TDI is a platform r we can reach a sharing – the bette en outside of the (ev e nc larger audie the better we can mining industry) tering sector. wa de e serve th The Groundwater Engineer Magazine Edition#2 57

FUN FACTS

Fun Facts about Water Dewatering is a process of

removing water from materials and soil.

400 BILLION

Approximately 400 billion

gallons of water are used in the United States per day.

Deep Wells typically consist of boreholed fitted with slotted linings and electric submesible pumps.

40%

About of the US population uses groundwater as drinking water.

Did you know?

On a global scale the amount of water evaporating is about the same as the amount of water precipitating.

3%

Only of Earth’s water is fresh water.

Only 1% of the water on earth is useable, 99% of which is groundwater Fresh

uncompacted snow is usually 90-95% air

We use about the

same amount of water that the rains on the aquifer in a year!

Each year, about 237, 250 million gallons

recharges (fills up) the aquifer

80% of the earth's surface is water 97% of the earth's water is seawater Water is needed to create nearly everything we eat. An egg

takes about 120 gallons of water! Think about it. You have to raise the chicken and grow the food for the chicken before you can ever get an egg. (Source: USGS) 58 The Groundwater Engineer Magazine Edition#2

The Groundwater Engineer Magazine Edition#2 59

Masters of dewatering

From Holland. Home of dewatering | www.vantongeren.nl 60 The Groundwater Engineer Magazine Edition#2