Why
If the Wadden Sea is lower than the IJsselmeer, we drain the excess water from the IJsselmeer using the discharge sluices in the Afsluitdijk. We can drain less water because of the rising sea level. The water supplied to the IJsselmeer by rivers and adjacent areas increases as well. We need to drain more water than the current discharge sluices are able to.
How
Reinforcing existing discharge sluices
We will be reinforcing the construction of the existing discharge sluices in Kornwerderzand and Den Oever. We will be replacing the lock gates and drives in each sluice channel. We will also be improving the stability of the discharge sluices at Kornwerderzand.
Additional discharge sluices
Two new discharge sluices (eight new drainage shafts) will be installed in the islands of the sluice complex at Den Oever. This enables us to drain more water from the IJsselmeer to the Wadden Sea.
Pumps
We cannot use the discharge sluices in case of high tide on the Wadden Sea and strong north-western wind. We will also build two large pumping stations with three pumps each at Den Oever to be able to drain water in these conditions. This allows us to work against gravity. We will be able to drain large quantities of water in all weather conditions: the pumps have a joint capacity of 235 m3 water per second.
The pumps are fish-friendly and energy-efficient. The energy used by the discharge sluices and pumps at Den Oever will be generated in a sustainable manner using solar power on and around the Afsluitdijk. In order the reduce the energy usage even more, a guiding principle is: “We drain when possible, and pump only when necessary.”
When
The work on the discharge sluices and the pumps has started in 2019.