Hölscher Solution _ #01
Groundwater management

GROUND WATER MANAGE MENT

Water is essential, but on construction sites, it can pose significant challenges. That’s where we step in. Through targeted lowering of groundwater levels and advanced dewatering systems, we keep construction sites dry, whether for linear projects, tunnels, or subway developments.

Dry excavations for your project

For more than 65 years, Hölscher has been ensuring dry construction sites through targeted groundwater lowering and innovative dewatering techniques. We offer customised solutions for every construction project – private or industrial – to protect against groundwater and precipitation. Depending on your specific needs, we employ the most advanced techniques to make your project possible. Our portfolio ranges from simple excavations, underground garages, pipelines, and cable routes, as well as highly complex excavation pits for wind farms, shopping centres, deep railway stations, and subway projects at depths of over 40 meters.

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Services and methods

Groundwater management for linear construction sites

Linear construction site dewatering is designed to lower the groundwater table along the axis of extended construction areas. This applies to projects such as pipelines, cable routes, roads, and railways. Wells or drainage systems are installed at regular intervals to efficiently redirect water, ensuring dry working conditions and enabling the safe installation of utilities like power lines or pipelines. Modern pumping and filtration systems ensure that extracted water is returned to natural watercourses or reinfiltrated into the ground, minimising any disruption to the natural groundwater balance. This method is particularly vital for long and linear construction projects.

Gravity wells

Gravity well dewatering begins with a borehole of 300 to 2,000 mm in diameter. Depending on the depth of the excavation and geological conditions, these boreholes can range from a few meters to several hundred meters deep. Once drilling is complete, the well is equipped with a slotted filter pipe and a solid pipe. The space between the borehole and the well casing is filled with filter gravel and bentonite, depending on the soil conditions. A submersible pump is then used to extract groundwater from the well to lower the water table to the desired level.

Horizontal dewatering

Horizontal dewatering is primarily used for linear structures and large excavation sites. Drainage pipes with a diameter of 80–100 mm are installed up to 6 meters deep into the ground. A drainage trencher creates a trench approximately 30 cm wide, where the drainage pipes are laid and then refilled. Depending on soil conditions, additional filter gravel may be placed above the drainage pipe. A gravel hopper attached to the trencher ensures the trench is filled with clean filter material from bottom to top during the process. A vacuum system with a piston pump generates the necessary vacuum to extract groundwater and direct it to a discharge point. This method is considered to be the most environmentally friendly way of lowering groundwater levels.

Vacuum deep wells

Vacuum deep wells are used to lower groundwater levels in low permeability soils. These wells are constructed using boreholes with diameters of 300-700 mm and depths of up to 50 metres. Depending on soil conditions and depth, either dry or wash drilling is used. After installing a filter pipe and filling the annular space with filter gravel and a clay seal, a submersible pump is used to extract the groundwater. A vacuum unit is also used to create a vacuum to enhance water extraction and improve soil stability.

Infiltration systems

To minimise the impact of groundwater lowering on the surrounding environment and maintain groundwater balance, we use various infiltration systems, including our patented hw-dsi® injection system. This innovative method allows up to 100% of extracted water to be reinfiltrated into the ground. It reduces the extent of the drawdown area and protects sensitive areas such as wetlands or structures at risk of settlement from the adverse effects of groundwater lowering. Additionally, suspected groundwater contamination can be contained and isolated by establishing a hydraulic barrier around the pollution source.

Efficient water discharge systems

Beyond groundwater extraction, safe discharge plays a crucial role in groundwater management. We offer a wide range of pipes in various diameters, materials, and flow capacities. For complex urban projects, we employ pipe bridges and elevated pipelines to manage height differences and allow roads to be crossed safely. Our patented Vario Supports enable spans of up to 25 meters to be bridged quickly and efficiently. These systems are complemented by booster pump stations and frequency controlled pumps to ensure precise and flexible water flow management.

Water treatment

In an era of climate change, our natural water resources are becoming increasingly scarce and pollution from pharmaceutical residues, microplastics, fertilisers and pesticides is on the rise. This is why we are committed to reusing water that has been removed from the cycle. We recycle the groundwater we extract by dewatering.

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Facts and figures

2000

dewatering wells installed annually

1280

piston pumps keep construction sites dry

100

kilometres of drainage installed per year

65

more than 65 years of expertise in dewatering

1

Europe’s #1 leading expert in groundwater management

Good reasons for Hölscher

Just a few reasons why our customers enjoy working with us.

Expert advice and construction dewatering designs

Extensive experience and proven track record in large-scale projects

Dewatering and treatment for managing water volumes of up to several thousand of cubic meters per hour

Continuous 24/7 water level monitoring for precise pump control

Water treatment and environmental protection to conserve water as a resource

Recording and tracking water levels, volumes, etc.

Expert teams in every branch

In-house equipment fleet

Hölscher as an employer

Trenching machine operator and Emsland-Original

Trenching machine operator Hermann Geres, an original Emslander and Hölscher veteran, has been working in groundwater management at Hölscher for over 30 years. With his extensive experience, he masters the art of reading soil conditions and uses a 30 meter long trencher to lay a narrow 15 cm line up to 4 meters deep into the ground.

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Holistic approach

For the construction industry, municipalities, and industrial companies, we are the national and international partner of choice for demanding groundwater projects. Our company combines in-depth expertise, decades of experience, and technical excellence in groundwater management to provide safe, sustainable, and intelligently connected solutions in the areas of groundwater management, water treatment, well drilling, geothermal energy, reinfiltration and monitoring. We employ both proven methods and proprietary, patented procedures. Our services cover all necessary steps – from consultation and planning to developing customised solutions and professional implementation with computer-controlled monitoring and documentation.