Posted on 14 August 2013
Chris van Vliet (team leader of Sample Taking at HHRS of Rijnland) explains why this project was carried out: “The most important aim of the project was to provide more insight into the polder levels. Up-to-date information on basic levels was already available from the existing ‘bosbo’ system, which is necessary in order to be able to regulate the water system management in case of rain or drought. The possibilities for regulating have been increased considerably now, which is of particular importance for short, heavy, often very local rainfall. The Rijnland District Water Control Board is now better able to satisfy its ‘dry feet’ objective, which is very important in a densely populated area like the Randstad conurbation.”
What equipment did Eijkelkamp supply?
Besides the supply of the necessary e+ WATER L® (surface water) sensors and e-SENSE ® (telemetry) modems, Eijkelkamp also took care
of the other tasks in the field. These tasks consisted of, among others, dredging and surveying all the level reference points and the complete installation of the equipment. The project was handed over, fully operational, in June 2009.
Rijnland District Water Control Board about Eijkelkamp
According to Chris van Vliet, high demands were made of the equipment: “In addition to a warning system in case of theft, low energy consumption and low maintenance were also important. It was possible to satisfy all these requirements, and as a result a low maintenance system was installed that is very frugal in its energy requirement. This was important, not only in view of ‘business security’, but also in order to keep the costs low. Many measuring points are located in out-of-the-way polders, where regular visits would involve a heavy financial burden for this system. Now just a single annual visit will suffice.”
In combination with the e-SENSE telemetry system, measurement data and any alarm signals are sent directly to the central Rijnland database using the GSM network. Thus it is possible to monitor and manage water levels from a distance and over a longer period of time. Alarms warn the water level controllers at an early stage for impending inundations or water levels that are too low. Trends are also revealed and, in part as a result of this information, it is possible to estimate the fluctuation of surface water in the future.