The document describes several uses of underwater drones to monitor water quality by Dutch water authorities and municipalities. Applications included using drones to search for pollution sources in canals and culverts, measure dissolved oxygen and turbidity in lakes, measure conductivity in a canal experiencing saltwater intrusion, assess the effectiveness of filters and fountains, monitor water quality near houseboats, and inspect floating gardens and urban aquaculture systems. Water quality parameters like dissolved oxygen, temperature, conductivity and turbidity were measured at various depths and locations to map conditions and identify issues.

1. INDYMO

2. Waterboard - Delfland
Surface water check, to search for possible polution sources or illicit discharges that could explain the poor water quality of
the water system (very low dissolved oxygen concentration values)
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Temperature (C) Conductivity (mS/cm)
https://www.youtube.com/watch?v=fAJn3mAfvFw

3. Waterboard - Delfland
Inspection of a culvert in a greenhouse area to search for illicit discharges or
other possible causes for suspicious water quality parameters concentrations
previously measured with grab samples by the water authority. Underwater
drone succeeded in entering the culvert for up to 20m.
https://www.youtube.com/watch?v=fAJn3mAfvFw

4. Waterboard - Waternet
Research about the ideal conditions for the presence of mussels at Sloterplas, Amsterdam. The underwater drone was used
to collect water quality data (e.g. dissolved oxygen) and to collect underwater images of the mussels laying on the bed of the
lake. This was performed at several different regions of the lake, and at water depths reaching over 30m. The visual data was
used to assess about the representativity of the samples collected with traditional methods.
https://www.youtube.com/watch?v=jvjokW0TFj8

5. Waterboard – Hunze en Aa’s
Water quality measurements in lakes with high turbidity, to infer about the possible causes, which could be due to high
algae concentrations, or mostly due to inorganic sediments in suspension.
https://www.youtube.com/watch?v=D4fom8HXAvE
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Averages of Turbidity (FNU)

6. Waterboard – Hunze en Aa’s
Conductivity measurements in a canal with reported salt intrusion problems. A longitudinal profile of the variation of
conductivity allowed to clearly visualize the variations in the salinity along a distance of 8km from the sea (dike) until a lake.
https://www.youtube.com/watch?v=MeQ7rxXKOzo
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Conductivity(mS/cm)
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Conductivity Profile
Down CTD
UP CTD

7. Waterboard - Reest en Wieden
Study of the effectiveness of selected parameters in large scale filters (Wetlands / Halophyte filters / Reed filters), and their
spatial variation within the filter. Insight into the underwater life.
https://www.youtube.com/watch?v=YS1t6IJqzxM
Hoogeveen – Oude Diep
Drieland (Groningen)

8. Groningen Municipality
Water quality measurements nearby and underneath houseboats in the Noorderhaven,
Groningen (measurements simple to perform using underwater drones). This location is
of high interest due to the high coverage with the boats (over 60% covered), and due to
the fact that most houseboats are not connected to the sewer..
https://www.youtube.com/watch?v=QYvWB8ybIV0

9. Groningen Municipality
Assessment of the efectiveness of a fountain that was installed to stimulate the aeration of an eutrophicated pond in
Groningen. For this, an underwater drone equipped with water quality sensors was used, allowing the collection of
dissolved oxygen concentrations at several regions around the pond.
https://youtu.be/QYvWB8ybIV0?t=234

10. Urban Farming, Rotterdam
Monitoring of water quality parameters in tanks used to breed fish (catfish and telapia), and in the basin where
vegetables are grown. Both the tanks and the basins are part of a cycle where the water is recirculated. The vegetables
and algae remove the nutrients from the wastewater coming from the fish tanks, and then the purified water is pumped
again to the fish tanks.
https://www.youtube.com/watch?v=REhnLbxgjJ4

11. Urban Green
Underwater visual inspection of a floating garden, and water quality measurements in the surrounding water. This
floating garden is an inniciative of the start-up Urban Green, and this first prototype is located at the RDM Campus,
Rotterdam.
https://www.youtube.com/watch?v=AyHVVEfTLvE