IJssel Delta is a project of the ISALA DELTA combination (Van Hattum & Blankevoort and Boskalis). For Phase 1, Hollandia Infra built the water-control structures and operating mechanisms for the lock for recreational vessels. The IJssel Delta project is the last in a series of projects as part of Rijkswaterstaat’s long-running national ‘Space for Rivers’ programme. The first lock was inaugurated by King Willem-Alexander in a festive ceremony on 14 March 2019.
Rijkswaterstaat’s national ‘Space for Rivers’ programme
IJssel Delta is one of the 34 projects that make up Rijkswaterstaat’s national ‘Space for Rivers’ programme that is intended to make the Netherlands’ river delta safer and more beautiful. To reduce the flood risk, a decision was made to lower water levels in the rivers by giving rivers more overflow space and creating extra space for the water when water levels rise.
The Dutch government has laid down the measures as part of this programme in a key spatial planning decision entitled ‘Space for Rivers’. Seeing as high water levels in the River IJssel create a flood hazard for the cities of Zwolle and Kampen, as well as for the hinterland, the River IJssel will be given more overflow space. This project was combined with the Overijssel provincial authority’s plans for the creation of a bypass waterway around Kampen (the Reevediep), which is intended to drive future area development in the southern part of the IJssel Delta. As a result, the project comes under the joint authority of the Overijssel provincial authority and Rijkswaterstaat.
The idea behind deepening the summer bed is to lower the water levels, so as to protect the area around the River IJssel when water levels rise. The summer bed of the (Lower) IJssel will be deepened along a stretch of over seven kilometres, between Kampen and the Eiland Bridge (Eilandbrug), near the estuary. This will be done by excavating the river bed, which will lower it. The Reevediep will be the new waterway connection between the River IJssel and Lake Dronten (Drontermeer), which in extreme conditions will discharge water from the River IJssel to Lake IJssel via Dronten Lake and the neighbouring Lake Vossen (Vossemeer). Along the dike that has been erected on the IJssel side runs a road called Kamperstraatweg. Dikes have also been built along the southern and northern side of the channel.
The creation of three floodplains between Kampen and Zwolle helps realise the objective from the key spatial planning decision, as it improves the spatial quality of the river area. This concerns mainly the preservation and strengthening of the special ecological value of the IJssel river delta and its accessibility. Along the Reevediep waterway, 400 hectares of new wetlands with properties that are typical of a river delta are being developed, which will be home to new cycling, walking, and exploration paths.
Structure and scope description
The IJsseldijk lock creates a connection between the River IJssel and the Reevediep waterway for recreational vessels. This lock is located in the northern part of the connecting IJsseldijk water defence, and therefore part of the primary flood control system in phase 1. At the level of the lock bay, Kamperstraatweg runs across the lock on the IJssel side.
The structure includes, besides the lock chamber and the lock bays, several water-control structures and operating mechanisms, electrical systems, lock approaches including guard and guide walls, river bed and bank protection, the control building, and site layout.
Building water-control structures and operating mechanisms
The scope for Hollandia during phase 1 extended to the design, manufacturing, and installation of the water-control structures and operating mechanisms (electromechanical drive systems). The water-control structures for this lock consist of 2 high and 2 lower mitre gates. We also supplied the stoplogs that are used to keep water away from the lock gates to enable maintenance or deal with a contingency.
Phase 2 is meanwhile also under way. This Reeve lock complex is 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 system (Verlengde Vossemeer). The complex is made up of a lock, a scour sluice, and a fish pass. For the lock, Hollandia has been tasked with designing and building the hydraulic operating mechanism, 2 single gates (one gate at each lock end), and a set of spare gates for contingency situations. The gates will be installed in April 2019.
For the scour sluice, we are in the process of designing 4 gates and 8 cylinders. These are scheduled to be installed in the spring of 2020.