Bart Schultz
This was celebrated, among other things, with the publication of an interesting and beautifully designed book, The Lisserpoelpolder 1624-2024, produced by the Cultural-Historical Association Oud Lisse. The book was presented at the Lisse library on September 9, 2024. The library also hosted a temporary exhibition dedicated to the Lisserpoel Polder. The Rooversbroek Polder lies between the Lisserpoel Polder and the ring canal. Including the Rooversbroek Polder, which has been connected to it since 1974, the Lisserpoel Polder covers 267 hectares.
The Lisserpoel Polder was flooded and drained again in 1625 and 1675. The polder is surrounded by a regional dike, which borders the ring canal on the landward side and the Haarlemmermeer ring canal on the east side, including the Rooversbroek Polder. The dike provides protection against the water in the collection system of Rijnland, which is currently maintained as much as possible at a level of 0.61 metres below NAP (Normal Amsterdam Ordnance Datum) in summer and 0.64 metres below NAP in winter.
A safety level of 1 in 300 years is currently used for the dike, based on the Interprovincial Consultation (IPO) damage class IV. However, it is currently being assessed whether and, if so, which adjustments may be necessary in the future.
The excess water is pumped out onto the collection system of Rijnland. The Lisserpoel Polder was reclaimed by a series of two paddle-wheel windmills. In 1645, excess water from the polder was pumped out by two windmills with Archimedes screws. This was probably the first application of windmills with Archimedes screws in a drained lake.
From 1917 onwards, excess water from the polder was pumped out by a suction gas engine. This was replaced by a diesel engine in 1960. This pumping station was replaced by an electric one in 1997. This pumping station was subsequently replaced by a new electric one in 2020. As part of urban development in the polder, a second electric pumping station was installed along the ring canal near the waste water treatment plant in 1992.
The total pumping station capacity in the polder is now 24 cubic metres per minute, which means that a water level of 14.4 millimetres can be pumped out per day across the entire polder, which is a normal discharge capacity for such a polder. If necessary, the windmill can still be used during extremely wet periods.
The Lisserpoel Polder was reclaimed for agricultural use and was used exclusively for this purpose for many years, until housing was developed on the north side of the polder in the 1960s. There are now four preferred water levels in the polder, one in the urban area and three in the rural area. The polder levels are approximately four metres below NAP. In one of the sections the same water level is maintained year-round. In the other sections a summer and a winter water level are maintained, with the winter water level being ten to twenty centimetres below the summer water level. Within the water levels, the water level is raised in several places by means of weirs.
Excess water from the Rooversbroek Polder was originally discharged via the ring canal of the Lisserpoel Polder. Since 1974, the Rooversbroek Polder, which is situated on a higher level, has discharged excess water over a weir into two sections in the rural area of the Lisserpoel Polder.
After many problems, especially in the early years, the Lisserpoel Polder has evolved over its 400 years history from a purely agricultural polder to a prosperous urbanized polder. The value of buildings and infrastructure, as well as the number of residents, has increased dramatically, especially since the 1990s. Given the increasing activity in the Randstad, it is expected that the value and perhaps the number of residents will increase even further in the near future. Due to the size and depth of the polder, careful water management and flood protection are paramount. This responsibility lies with the Water Authority of Rijnland. The Dike Reef was therefore the first to receive the anniversary book.
