Many Dutch growers are in favor of having a special valve installed in their reservoir to make room for new rainwater in the event of extreme rainfall, as it turned out during the Rainlevelr Event organized by the Delfland Water Board on 19th of November. At the same time, not all growers are aware of the project, and growers would like to see that the installation of a drain valve in existing reservoirs would be possible soon.
A well-attended event
View the photo report here.
Many hands were raised when asked whether growers were present.
With the voice of newsreader Noraly Beyer and images of a flooded De Lier (Westland) in September 1998, the importance of water control became immediately apparent in the World Horti Center. Tomato grower Jack Groenewegen could effortlessly reminisce about hastily putting his crops on boxes to save what could be saved. The floods were good for the solidarity in the sector and beautiful stories afterwards, yet everyone in the hall agreed that a repeat of 1998 should be prevented, especially after a light version after a heavy rainfall in May this year.
The introductory film was closely watched by the vast majority of the speakers in the front row and the rest of the attendants.
At the invitation of the Delfland Water Board, a remarkable number of growers from Westland, Oostland and even from further away, but also suppliers, advisers, insurers, governments and interest groups gathered to raise awareness of the Rainlevelr project and, above all, to share knowledge and experiences. The Water Board calls on growers in the project to place a special valve in their reservoir in order to make room for new rainwater in the event of extreme rainfall. By the end of this year, the system should be in operation at some twenty companies.
Jack Groenewegen took the hall back to 1998 when he had to try and save his crop by putting it on crates.
Freeing up the required capacity with an increasing number of growers
The event consisted of three rounds around the themes of 'Flooding', 'Drought' and 'Measures'. During the first round, Hugo Vreugdenhil, account manager for the Rainlevelr project, gave an introduction to the system. He pointed out that ultimately the installation of special valves, as far as the Water Board is concerned, would as quickly as possible be the standard procedure for new reservoirs and when replacing the reservoir lining. This was followed by a question from the attending growers in the hall: why the existing reservoirs are for now excluded from the project. At the moment this is the case, because in the initial phase of the project the Water Board does not want to run the risk of failing to install such a valve in an existing reservoir.
Soon it was about the next steps such as using underground water storage to survive periods of drought. Jacco Vooijs of LTO Glaskracht Nederland revealed that this matter is addressed in the project COASTAR. Wilko Wisse from tomato grower Lans, one of the first with a special valve, warned against taking all kinds of follow-up steps too fast. He emphasized that first more growers should join the project in its present form. That means that the capacity that has to be freed up in the run-up to heavy rainfall could be better distributed among the growers. The fact that the Water Board can now view the degree of filling of the reservoirs is, according to Wilko, important, because these data are more accurate than the data from the water level management. So there is less reason for panic and growers no longer (afterwards) have to release water needlessly.
Jaap Bij de Vaate gave an introduction to the theme 'Drought' and showed how growers of different crops with different water demand can help each other.
3500 m3 and 2022
Besides water also attention was paid to drought, inevitable after last summer. Drought that will most likely happen more frequently. Growers and neighbors with different water needs such as tomato and orchid growers could help each other in these periods, Jaap Bij de Vaate from Delphy showed this in his introduction to the second theme on the basis of a few figures. Ewald de Koning of Ter Laak Orchids was given the opportunity to talk about his experiences with underground water storage, while Wim Voogt from Wageningen University, in respect of salinisation, told growers in the hall that many crops could probably withstand more sodium than first thought. In addition to the number 3,500 (the average number of cubic meters of reservoir required per hectare), also the year 2022 was mentioned repeatedly. From 2022 on, brine water may no longer be discharged as a result of reverse osmosis, which means that growers will have to look even more for other water sources than is currently the case.
Many questions from growers in the hall. Photographed: Frank van de Burg of Solyco speaking.
After a break to catch up on the first two rounds, during the third round it was about measures. Among other things, the notorious price tag was discussed, for example with regard to the transport of water from the built environment. In the same built environment, the planting of roofs could also contribute to the dosed drainage of rainwater.
Corné Zwinkels after the conclusion of the event in conversation with chairman Maurice Wubben
At the end of all three sessions, Saskia Jouwersma of the Water Board used the opportunity to thank all those present and, above all, to call on everyone to contribute to the further development of the Rainlevelr project. In doing so, she knew from experience that just changing a policy is not easy, but that many innovative ideas can be tested under the term 'pilot'. Also that existing ideas, such as transferring water from existing reservoirs, should definitely be reviewed and recalculated on the recommendation from the attendants.
There were many growers present from both vegetable cultivation and floriculture: Paul Sonneveld (Passion for Lilies), Paul Zwinkels (TOVs Nursery P. and R. Zwinkels), Leon Schenkeveld (Schenkeveld Tomatoes) and John van Mil (Looye Growers).
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