Creative with well drilling

In many situations this requires creative solutions in well drainage. This also applies to the development of the Eindhoven Northwest area, especially at the viaducts over the Beatrix Canal. Leave that to Ockhuizen, a specialist in dewatering since 1938.

"Initially, we were approached by combination Heijmans - Ploegam to provide trench drainage for the construction of the sewer system," says project manager Maikel van Steensel of Ockhuizen, part of Hurkmans Group. "We installed drainage strands with filters and a pump. We discharge the extracted water to surface water. As the project progressed, our scope expanded and we became involved in the civil side. With our well drainage we create a dry work floor on which the contractor can realize the foundations of the viaducts, tight against the sheet piling of the Beatrix Canal."

Good contacts at water boards

Ockhuizen was called in at an early stage to advise on the deployment of the right type of drainage on either side of two engineering structures across the canal. Van Steensel: "We mapped the soil structure and used this as a basis for a geohydrological model to visualize the sphere of influence of the drainage and the effects on the environment. Based on this, a drainage plan was written. One structure is located against a protected nature reserve. This entails the necessary restrictions regarding the extraction of groundwater. In close consultation with the water board, however, it was decided to discharge almost everything into the canal. The good contacts with water boards and permit providers are characteristic of Ockhuizen. That is where we really do stand out," Van Steensel emphasizes. "Together we always arrive at the best solution."

Gravity drainage 

Based on the local soil structure, Ockhuizen opted to use gravity drainage. "The Eindhoven soil is characterized by a structure with a great diversity of material: loam, fine sand, loam, coarser sand, loam fine sand, and so on," Van Steensel explains. "In order to properly dewater all these layers, gravity drainage is preferred to vacuum drainage. Because we were already involved in the preliminary project, we were able to design the dewatering in such a way that it did not form an 'obstacle' during the excavation, which was carried out in two stages. For example, we are using filters specially manufactured for this project. In addition, in the preliminary phase we placed monitoring wells with loggers at strategic locations to monitor the groundwater level so that the dewatering could be called at the right time. These loggers also hang at the temporary groundwater withdrawals at the structures, so that we can see remotely whether the groundwater level has been lowered far enough and the dewatering is doing what we intended."

Ockhuizen is a club with great clout. "Excelling with our modern 'machinery' and loyal and hardworking employees who are ready 24/7. With pumping you always run into surprises, that is inherent to the profession and the charm of our work. Thanks to many years of knowledge and experience and the necessary creativity, we always arrive at the most efficient solution while pumping as little water as possible," Van Steensel concludes.