Study of salt content in Dutch canals

Commissioned by the municipality of Harlingen, Antea Group measured the salinity of the Harlingen canals in Friesland, The Netherlands. A motorboat with an advanced mobile multiparameter probe, purchased at Eijkelkamp Soil & Water, was used to travel the length of the canals and conduct the measurements. Project Manager Jeroen Kruse talks about the project, the outcome of which will save the municipality of Harlingen a lot of money.

‘The municipality of Harlingen was curious to know the salt content of the water in the canals and harbour, and where the salt came from. This is important because surface water salt content is a determining factor for the rate of silt deposition. And the faster silt builds up, the more often a canal or harbour has to be dredged. In other words, the presence and amount of salt in the surface water has a direct impact on the maintenance costs for the canals and harbour.’

 ‘We did two rounds of measurements with a measuring boat for this project, at high and low tide. We wanted to know whether the tide also affected the amount of salt in the water. The boat was equipped with an AP-5000 water quality probe that stored the values every half minute. We then imported the data in GIS and used it to generate a comprehensive chart showing the amounts of salt in the water.’
As it turned out, the gate valve at the end of this watercourse was leaking. As a result of our measurements, the municipality of Harlingen replaced this gate valve. In December 2018 we conducted another round of measurements to see if the replacement had the desired effect. The results did, in fact, show that both in the Zoutsloot and other watercourses the surface water salt content was significantly lower.’

‘The use of the advanced AP-5000 has proved to be a huge boon. It's much faster than taking samples, sending them to the lab, and receiving the results a few weeks later. This way the measurement values are available straight away, it's much less expensive, and it's easier too. In this case, the measurement rounds were performed by just one person. We see this as a nice addition to many other types of work we do for the municipality of Harlingen, such as water bed research in connection with dredging of the harbours. We use Eijkelkamp Soil & Water equipment, such as piston samplers, for that too.’

‘We feel that now that we have this measuring equipment the door is open for doing more projects of this kind – perhaps with our new underwater drone. We've adapted it so the measuring equipment can be attached to it too, making it possible to measure at various depths. It's a great instrument that offers a new sea of possibilities.