Clean waterways 2026
The municipality will again clean (dredge) waterways and ponds in 2026
Too many aquatic plants, boarded or collapsed banks, dirt, dead plants, fallen leaves and overhanging vegetation. If we don't remove these, the waterways eventually silt up. The possible result is that water can no longer flow through them adequately and water quality declines. Ditches and ponds ensure the supply and drainage of fresh water, thus maintaining the water levels. They also provide initial collection of rainwater. To keep these bodies of water neat and functioning, waterways need regular maintenance.
By dredging, we provide:
- Plenty of room for water
- A clean soil
- Oxygen-rich water
There is a difference between ordinary maintenance and extraordinary maintenance.
Ordinary maintenance
- removal of (excess) aquatic plants (including at culverts, fences and drainage ditches);
- removing debris, duckweed, leaves, objects and overhanging vegetation that impede water transport, storage or maintenance. Avoid duplication of effort: removing means removing, not just mowing!
- retrieving shore parts that have sunk or stepped in the water;
- keeping the inside of culverts clean so that they continue to function.
Extraordinary maintenance
Extraordinary maintenance serves to maintain the width and depth of the waterway. The minimum required water depth (intervention size) of each watercourse is also mentioned in the legger oppervlaktewateren (surface water regulation). By removing the silt from the bottom (dredging), the watercourse regains the depth prescribed by the legger.
How is dredging done?
First, the ditch is measured. We measure the depth of the solid bottom, the dredging layer and the water level. Then we compare the depth of the ditch and the thickness of the dredging layer with the 'legger' of the Hoogheemraadschap van Rijnland. This indicates per watercourse what the profile of the watercourse should be. We use this information to determine whether dredging is necessary. The contractor carrying out the work determines which dredging method (boat and/or crane) best suits which water. This can differ for each pond or watercourse. To determine the quality of the dredge, a water bottom survey is performed. The dredged material is removed to an approved dredging contractor.
A QuickScan flora and fauna will be conducted, which consists of an exploratory field visit that provides insight into any protected animal and plant species.
Dredging 2022-2026
In 2022, the municipality started dredging. This project runs for several years. In 2022 and 2024, the most urgent waters were dredged. The last part will be carried out next year (2026). Among others, the municipality will dredge the Paauwvijver and several surrounding waterways.
Maintenance obligation in dredging
When dredging, the cadastral owner is liable for maintenance. In most situations, the municipality or the Water Board has the maintenance obligation, but there are many waterways for which the owner has the maintenance obligation. On the site of the Water Board you can see the "Legger" in which the maintenance obligation is mentioned per watercourse.
Planning
- Preparation (water bottom surveys and surveying): Q1 and Q2 2025.
- Communications: Q3 and Q4 2025.
- Start of implementation: Q1 2026.