Our country is full of sheet piling: near canals, ports, canals, levees, construction pits, flood defenses and soil pollution. They remain or are removed after the completion of a work. They are made of wood, steel, concrete or plastic. They are driven, vibrated or pushed into the ground. They are anchored underground or without an anchor.
Especially along docks and the banks of our waterways, sheet piling stands shoulder to shoulder. The Dutch waterways are among the busiest in the world and our country is the European center for water transport. With good management and maintenance of our waterways, we can maintain and further develop this powerful position. Includes sheet piling.
†Where before there was no water, now there are many canals. Canals are man-made for transportation over water. And for good accessibility‘, explains environment manager Saskia Janssen in plain language.
†If you don’t use sheet piling on the banks, you need embankments and dikes to keep the water in. They take up much more space than sheet piles alone. Also, shoulders, slopes and embankments collapse, allowing sand and material to end up in a channel.†
†Old sheet piles with holes and cracks also cause leaching. So the channels become shallower and maritime traffic can flow less. By the way, this cannot be compared one on one with the Mosa. With a river or stream you want that in some cases because it’s part of nature. Therefore, maintenance is still necessary for a smooth and safe flow.†
If you don’t use sheet piles, you need embankments and dikes
The Hakkers-Beens consortium carries out maintenance and repair work on the banks of various canals in Limburg and North Brabant. Rijkswaterstaat awarded the contract for this at the end of 2020. The water works started in 2021 with the execution of the bank works. This happened in the Mark Canal and parts of the Wilhelmina Canal (near Oosterhout), and in a small part of the Zuid-Willemsvaart (near Someren-Eind). The work is expected to be completed in 2023.
Mike Ripzaad works for Hackers-Beens Combination. He lives in Werkendam, the cradle of many hydraulic engineering companies. Hakkers works in the development, production and execution of earthworks, dredging, construction, foundations, coastal and river works. Beens operates in the field of bank and wharf construction and dredging works.
†Every day to and from Oosterhout. We start at 7:00 AM and continue until 4:00 PM‘ says Mike. †2 foremen, 19 people in construction and a project team of 8 inside.’ No women? ‘The work is hard, wet, cold and dirty, but we had an internHe says apologizing.
Steel sheet piles are more sustainable
The 50-year-old sheet pile construction has been removed over a length of more than 4 km. Damaged concrete walls with wooden shoring are removed and anchors are cut. The work will be done from pontoons (floating platforms) on the water. With a big hit.
†We are replacing the old ones with steel sheet piles from 4 to 13 meters. They are also more durable because they last longer. We make them vibrate in the ground at a high frequency, so that the structures are not damaged. We can place from 50 to 90 meters per day† Noise pollution is limited.
The contractor communicates with the well-known BouwApp and informs the environment through newsletters. †We keep local residents well informed about our work and planning. We can then immediately address complaints and questions.†
The biggest challenge for the contractor is logistics. The supply and removal of material, equipment and supplies. All this must be done via water so as not to cause inconvenience due to the traffic of the work. †There is little public space, which means we have to coordinate well with businesses and municipalities to get suitable locations.† Mike loves his job, that’s for sure. †The variety, working on land and water, improving navigation. Handsome!†
Environment manager with many hats
Saskia Janssen is an engineer and studied Environmental Hygiene at Wageningen. In 1990 she started to work for the Rijkswaterstaat in Limburg. She was environmental manager at the Grensmaas project since 2008. In 2017 she moved to the canal bank works in the south of the Netherlands, also as environmental manager.
†As an environmental manager, you wear many hats. Surveillance of the relationship between the project and the environment, permits and legal issues, cables and pipes, communication with neighbors and the press, flora and fauna, technology. It is precisely this interaction that makes my work so exciting.†
The project involves more than replacing sheet piles. Saskia: ‘The work must meet 3 requirements: 1. Maintain the passage for inland navigation in the future, 2. Reinforce the banks in the context of high water security and 3. Create and maintain Fauna Exit Places (FUP). This to avoid the drowning of (terrestrial) animals that ended up in the canal.†
Good preparation is half the battle
Several studies were carried out in the preparation phase. To the location of important cables and pipes (gas, water, electricity, data), ancient explosives, archaeology, flora and fauna. Naturally, there were also consultations with interested parties, such as the municipality of Oosterhout, the province of Noord-Brabant and the water boards. Stakeholders, businesses and local residents understand very well that maintenance is necessary.
Saskia: ‘Good preparation is half the battle. Fortunately, we did not find any special or ‘cool’ cases in the preparation, planning and design phase. Very special was that due to the corona we had to make the tender completely digital†
Flora and fauna
Protected areas, forests, and plant and animal species must also be taken into account during maintenance and repair work on banks. This is established in the Nature Conservation Law (2017) which replaces the 3 previous laws ‘Nature Conservation Law’, ‘Forest Law’ and ‘Flora and Fauna Law’.
The new law is to protect biodiversity. Previous research has been carried out on the presence of protected flora and fauna. Think of martens, beavers, squirrels, water shrews, bats, breeding birds, fish, amphibians, and reptiles. And protected plants, of course. With the exception of bats, we did not have to take additional measures for other animal species.
†Here is a satisfied environment manager‘, concludes Saskia Janssen. †No channel blockages during work, limited environmental disturbance, work goes well, few additional measures for flora and fauna. And I’m proud of the animal outlet places.†