Two new weirs at Hooiweg
22 September 2025
The first work on the balancing lake in preparation. In the coming months, we will be constructing two new weirs Hooiweg and modifying the Doolhofstuw. The weirs expected weirs completed in the spring of 2026. Read more about the work, the schedule, and the measures we are taking to protect nature.

Planning activities
New weirs
Contractor Oosterhuis has started preparatory work for the construction of two new weirs Hooiweg/Matsloot. The weirs named Vischluststuw (northern weir) and Rowolderstuw (southern weir). Under normal circumstances, the weirs lie weirs , allowing the water to flow freely.When the extra balancing lake is used, these weirs balancing lake weirs to retain water.The plan is for the work on the weirs to be so far advanced weirs the first half of 2026 that we will be able to operate the northern weir and close off the southern channel. If necessary, the extra balancing lake will balancing lake already be partially operational.
Modification of the Doolhof weir
In addition to the construction of the new weirs, we are modifying the existing Doolhof weir at the Peizerdiep (see photo below). It will be raised and fitted with a new valve. The quays on either side of the weir will also be weir .

Construction work is expected to be completed in 2026 before the breeding season.
In the first quarter of 2026, we will also start raising quays and implementing nature measures and additional measures. The full expansion of the balancing lake completed in 2027.
What can you see and notice about the work?
- In the coming weeks, a follow-up to earlier archaeological research will first take place. It is possible that remains of peat mounds/house sites or other features will be found.
- The contractor will then begin removing obstacles and mowing the grass. From week 41 onwards, the excavation of peat and the application of sand will commence.
- The contractor takes nature into account during the work (breeding season, animal safety, and other measures). Ecologists from the water authority involved in the work. View the ecological work protocol.
Transport routes during work
Peat weirs removed and sand brought in for the two new weirs . Soil will also be needed to raise the quays at the Doolfhofstuw. In addition, equipment will be brought to the construction site.
The transport routes are indicated on the map below. Trucks will travel via the Hooiweg/Matsloot (the red line) with materials for the construction of the weirs. Soil will be transported via the Cosun path and the Roderwolderdijk (purple line).
During the work on the weirs, public roads will remain accessible to other traffic. However, traffic may experience some disruption from freight traffic. Local residents will receive additional information about this.
