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IJssel Delta phase 2 Reeve Lock complex Infra

The IJssel Delta project is the closing project of the Dutch government’s ‘Space for Rivers’ programme, delivering improved flood prevention for the city of Kampen and its surrounding area. The Isala Delta combination (Van Hattum & Blankevoort and Boskalis) has been commissioned for this project by the Overijssel provincial authority and Rijkswaterstaat. The basic idea is to create a water connection between the River IJssel and Lake Dronten (Drontermeer) to be able to lower water levels in critical situations. The project furthermore includes making the River IJssel deeper and building new dikes. Along the eastern side of this overflow channel, the lock for recreational vessels was built in phase 1, for which Hollandia Infra built the water-control structures and gate operating mechanisms.

This Reeve Lock will replace the Roggebot Lock and become part of the primary water defences, i.e. the Reeve Dam, which connects the dike rings of Flevoland province and the IJssel Delta and separates the lakes along the edges of Flevoland province (such as Lake Dronten) from the Lake IJssel (IJsselmeer) system (Verlengde Vossemeer). The complex is made up of a lock, a scour sluice, and a fish pass.


In 2019, Hollandia designed, built, and installed the hydraulic operating mechanism for the lock, as well as 2 single gates (one gate at each lock end) and a set of spare gates for contingency situations. The water-control structures of the Reeve Lock complex will be part of the Netherlands’ primary water defences. As a result, the design had to meet higher standards than normal. When closed, the lock gates are secured using a heavy mechanical bolt that makes that the gates can keep out high water levels from both directions, while also protecting the water-control structure against possible high-impact collisions.

Scour sluice and guard lock

For the scour sluice, we designed and built the 4 gates and 8 cylinders. These 4 gates were hoisted into place in early July 2020. The scour sluice is intended to control water levels, as it will discharge ‘surplus’ water from Lake Dronten to the adjacent lake (Vossemeer), and let water into to the Kampen area in a controlled manner. Aside from that, the scour sluice will also be used as a guard lock to keep out high water from Lake Dronten (pushed up from the south west) and provide flood protection for Kampen. The scour sluice will be equipped with a separate facility for fish migration.

The scour sluice is made up of 2 parallel orifices that can be opened and closed individually depending on the required sluice capacity. Both orifices are fitted with 2 gates that can be used alternately and redundantly. The gates are moved up and down while suspended from hydraulic cylinders.

Fish migration

The orifices are located almost entirely below the water level, underneath the concrete sluice construction. Next to the orifices, a separate fish migration channel has been created, complete with fish chambers with partitions through which fish can pass. This channel will, in principle, always be open, but can be closed using a gate as and when necessary.