Electricity and Control May 2022

SENSORS + SWITCHES

Reliable water level readings from remote areas Prolonged periods of drought, sudden downpours or violent thunderstorms – all over the world once familiar weather patterns are becoming increasingly erratic and unpredictable.While this has a significant impact on the natural environment (and in some cases on people and property, as we have witnessed recently in South Africa), it also calls for innovative actions to be taken by affected municipalities. In Belgium,VEGA’s compact radar level measuring instruments provide reliable readings for ecologically friendly water management.

W hen rivers suddenly overflow their banks, or drink ing water becomes scarce, or a nature reserve struggles with a drought, water distribution strat egies have to be rethought. In Belgium, this task is carried out by the Flanders Environment Agency VMM ( Vlaamse Milieumaatschappij ). Although the authority can do little to change the volatility of the weather, it does plays a decisive role in a holistic water policy. The environmental agency measures and monitors wa ter quantity and quality, manages water systems and levies fees on water pollution and groundwater extraction. It also advises on environmental permits and supervises infra structure planning, as well as the monitoring and supply of drinking water. For rivers or any other form of flowing water, VMM relies on IoT solutions and adopts an integrated ap proach focused on limiting the risk of flood damage and achieving a high ecological status. VMM looks to ensure that no user or consumer in the complex system of water distribution is neglected. Howev er, effective monitoring relies on accurate measurement. User-friendly and low-maintenance Initially, ultrasonic sensing was used to measure the water level in non-navigable streams, canals and rivers. The major drawback of this measuring method, especially outdoors, is that the sound propagation time depends on the temper ature, which can result in considerable measurement errors due to temperature changes or solar radiation. Thick fog, wind and rain, as well as a build-up of dirt, also influence ultrasonic measurement. Even cobwebs can cause inaccu rate readings: as they gather debris, they interfere with the measuring signal, resulting in an increase in the blocking distance, or dead band, typical of ultrasonic sensors. In addition, there were ongoing maintenance problems. Radar sensors, by contrast, are unaffected by dirt, sun light, fog, wind or rain. And they do not require mechanical protection from high floodwaters. For that reason, the deci sion was made, over 15 years ago, to change the type of sensor used and since then the agency has relied on radar technology from VEGA. VMM first worked with the radar level sensor VEGAPULS 61 with PVDF antenna for several years,

and subsequently with VEGAPULS WL 61. In the course of the ongoing collaboration between VMM and VEGA, the agency especially appreciated the solution-oriented approach of the Schiltach-based company, as Johan Eylenbosch, hydrographer and electrical mechanic at VMM, notes: “Whenever a problem arose, the service and additional information provided by VEGA was helpful.”

To date, 50 VEGAPULS C 11 level measurement modules have been installed in five Belgian provinces, to monitor water levels continually. A real-time overview Due to climate change, a new challenge arose. VMM needed to find a way to obtain a com prehensive overview of water levels at various locations at any time of day. The agency’s intention was to build a fine meshed network of real-time level measuring points. Impor tant measuring points include, This was confirmed again in the next project the agency undertook.

MAY 2022 Electricity + Control

17