Work activities

Read the latest information about the work to expand the balancing lake Onlanden balancing lake here. The work will continue until 2027.

Build weirs

In the coming months, we will be working with contractor Oosterhuis to build two new weirs Hooiweg and modify the Doolhofstuw.  

  • The new weirs Vischluststuw (northern weir) and Rowolder weir southern weir). Under normal circumstances, the weirs lie weirs , allowing the water to flow freely. When the additional balancing lake is used, these weirs balancing lake weirs to retain water. The plan is for 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. balancing lake the balancing lake will balancing lake be partially operational, should this be necessary.
  • The existing Doolhof weir will be raised and fitted with a new gate. The quays on either side of the weir will also be weir . 
Location Rowolder weir Matsloot-Hooiweg
Location Roderwolderstuw - Matsloot/Hooiweg

What can you notice about the work?

  • Repair work on Matsloot pavement – road closure from January 12 to 16 (weather permitting)
    The pavement at the northern weir subsided. To prevent damage to the bridge, we will be repairing it in early January. This will involve closing Matsloot/Hooiweg from the Sandebuur/Matsloot/Hooiweg intersection. The closure does not apply to cyclists.
  • The reinforcing steel and concrete floor at the northern weir now complete; next up are the walls and a 6-meter-wide sluice gate.
  • 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. Read the ecological work protocol here. 
Work on the northern weir Matsloot - Photo by Eelko Wester of Macadam.

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 path along Cosun 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 the freight traffic.  

You can zoom in on the map via this link.

Planning

  1. Currently underway: Construction of new weirs - Fall 2025 – Spring 2026

    • Start construction of two new weirs Hooiweg/Matsloot

  2. Still to be done: Doolhofstuw - End of 2025 – spring 2026

    • The existing weir raised and fitted with a new gate. The quays on either side of the weir will also be weir .

  3. Still to be done: Raising quays - Early 2026-2027

    • We will ensure that more water can be stored within the existing embankments of the balancing lake, which will be raised.
       

  4. Remaining tasks: Nature conservation measures - Mid-2026 - 2027

    • Placing refuge islands for animals, filling in ditches, and rewetting the area by constructing channels.

  5. Still to be done: Measures for homes - Mid-2026-2027

    • Measures for water management in homes

  6. Still to be done: Modification of pumping stations End of 2026-2027

    • The pumping stations capacity of the pumping stations and Zanddijk pumping stations will be adjusted.

  7. Remaining tasks: Completion of additional balancing lake 2027

    • The complete expansion of the balancing lake now complete.