Monitoring the salinity of surface water in the Netherlands with Acacia

Acacia is a groundwater consultancy firm with a mission to improve the access to clean and safe water worldwide using smart, sustainable and practical solutions. With projects around the globe, Acacia puts the owners and users of water, from governments and citizens to villagers and village elders, at the forefront.

TexelMeet is one of Acacia’s projects in which farmers and water managers unite in order to control water quality using innovative technologies.

Above: A farmer testing the salinity of water using Akvo Caddisfly, Texel, 2015.


The Netherlands



Water resource management (WRM)


Tool training

Technical consultancy

The challenge

On the Wadden Island of Texel in the North Sea, 17% of which consists of water, maintaining water quality is a continuous challenge for the local water board. In particular, the salinity of the water needs to be regularly monitored. When seawater seeps into the surface water, it becomes saline. Farmers then use this water to irrigate their crops. The resulting damage can be detrimental to entire crops, and accountability can be hard to pin down.

In order to ensure that the water used for irrigation is fresh, real-time testing needs to be done and the water boards responsible for the region need to be notified.

A farmer testing the salinity of water using Akvo Caddisfly, Texel, 2015.

The partnership

Management of water quality requires data and that’s where Akvo’s cooperation with Acacia Water comes in. Together with Acacia, Akvo has been working with the water board responsible for North Holland, Hoogheemraadschap Hollands Noorderkwartier (HHNK) on combining sensors with smartphones for mobile data collection on water quality.

Farmers on the island of Texel use Akvo Caddisfly, a water quality testing system on a smartphone, and Akvo Flow, an app which collects and transmits the data to an online dashboard. Akvo also trained the farmers in data collection and water quality testing in order to ensure high quality, reliable data. Data collected is immediately uploaded and shared online on a map through the phone’s GPS. It can then be used by members of the public, the agricultural community, knowledge institutes, and waterboards to make informed decisions.

The change

Since November 2015, farmers have been testing the electro conductivity (EC-value) of the surface water surrounding their lands. Most of them collect data weekly which is immediately shared online on via an easy to use map visualisation. By simply looking at the map, you know which part of the island faces challenges with saline surface water. If the salinity of the water is too high, HHNK are notified and take measures to increase the level of freshwater in the area in question.