City of Gouda draws up plan to combat waterlogging
The soil underneath the Gouda city centre has been subsiding for centuries. As a result, during severe downpours, many residents are faced with waterlogging and moisture issues. In order to reduce this trouble, the municipality has drawn up a plan in collaboration with the district water board. This plan is entitled Gouda Stevige Stad – Ontwerp Kaderplan Bodemdaling Binnenstad. It proposes that the water level in the lower parts of the city centre be lowered by 25 cm. The plan has not been finalised yet; residents have until 12 April 2020 to react.
Why this plan?
The soil in Gouda continues to subside and residents are experiencing increasingly more waterlogging issues. Since 2014, the municipality and the district water board have been exploring ways to best tackle this increasing waterlogging, in consultation with residents and with support from national research institutes, the Province, and Rijkswaterstaat. The study has shown that moisture issues and waterlogging during rain will decrease considerably if the groundwater level is reduced by 25 cm. The northern and eastern parts of the city centre are situated substantially lower than the rest of the city. That is why the plan envisages lowering the groundwater level in those sections by 25 cm.
How will the plan impact wooden pile foundations?
Some thirty buildings in the lower-lying part of the city centre rest on wooden pile foundations. If the water level is reduced, the owners of such buildings may be forced to advance the maintenance of the foundations. In the plan, the municipality and the district water board propose drawing up a compensation scheme, which would qualify these owners for a grant to compensate for foundation damage that would not have developed if the water level had not been reduced. For the future, the municipality and the district water board additionally intend to explore ways to cope with the increasing differences in elevation in other parts of the city centre, which are also caused by soil subsidence.
When will this happen?
If the plan is adopted, it would still be another five to ten years before the municipality and the district water board can actually lower the water level, because this would first require adaptation of the water system and the sewer system. Consequently, the lower water level will not take effect until 2025 at the earliest.