The Grift is a stream that has its source just outside Apeldoorn. The Grift picks up water from several branches and channels it through the landscape. As there are lots of changes going on in the urban area of Apeldoorn, Regional Water Authority Vallei en Veluwe has worked in cooperation with Royal Eijkelkamp to install a flow rate meter.
Hydrologist Harmen van de Werfhorst works for the Regional Water Authority. He tells: 'As a hydrologist at Regional Water Authority Vallei en Veluwe, I deal with water management. Our department makes sure this is done well. After all, as a water authority, our job is about meeting standards on a daily basis. One of those standards is that we have to keep people’s feet dry. In the urban area this means: not letting houses get flooded. We use several mathematical models to monitor this. Those models involve various formulas for calculating water level and discharge. We want to check the calculated outcomes with actual measurements. If the calculated water level or discharge deviates too much from the measured water level or discharge, we have to adjust the model.'
'The project on the Grift is a great example of this. The Grift has its source just outside Apeldoorn. The Grift picks up water from several branches in Apeldoorn and channels it along here. There's a lot of upheaval right now in the urban area of Apeldoorn. Streams are being rerouted above ground, and rainwater is being redirected off various hard surfaces, such as roofs, car parks and roads. The water used to drain from them via the sewers to the purification station. However, the precipitation that falls is relatively clean, so we want to segregate it as far as possible. Of course, the rainwater can also end up in the surface water, but we want to keep a close eye on things to make sure it's all working OK.'
In the long term, you might even be able to see the effects of climate change
'We’re now doing live measurements, so we can monitor water level and discharge realtime. There's no alert linked to it, but that's certainly a possibility for the future. We installed the flow rate meter in September. So we now have data from the autumn period and some of winter. It's still too soon to spot trends, but we are seeing seasonal influences. In September, for example, the discharge was lower. And we had a lot of rainfall in the autumn, which also increased the discharge. In the long term, you might even be able to see the effects of climate change.’
'As well as installing the meter, Royal Eijkelkamp advised us on the choice of location. We really enjoyed working with Royal Eijkelkamp, and we're happy with the equipment. It's robust and, so far, we haven't had any faults or other issues.'
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