Belgium ranked 23rd globally in the 2019 National Water Stress Ranking. Recent dry years have created a high sense of urgency – at all levels – to work towards more robust water systems. Several concepts are currently explored by the B-WaterSmart partners, including the treatment of wastewater for high-end reuse and stormwater retention and reuse for agriculture.

The key water-smart challenges are high drinking water demand due to dense population, high water demand for agriculture, groundwater overexploitation, water quality deterioration, water scarcity due to droughts, climate change, and urbanization. The main water-smart opportunities therefore are to establish regional circularity in the water system. One way is to improve the existing drinking water production and use alternative water sources such as treated wastewater. Another is securing irrigation and groundwater recharge by interaction with the urban reuse cycle. A special focus is lying on the development of regional concepts for improving and monitoring water-smartness and a more robust water system, with a focus on safe water reuse.

The coupling of agricultural needs with the urban stormwater is done in our living lab at Hombeek. For urban water safety reasons, a buffering basin was going to be build next to agricultural area. Whitin this project and with help of the city of Mechelen, the design was changed so storage and reuse of water now is enabled. During 2023, two basins were dug: one smaller for possible slightly polluted water and one bigger for clean stormwater. This stormwater retention basin will work somewhat different form traditional ones: to enable storage and reuse of water, this basin is equipped with a smart valve. Instead of releasing excess water when heavy rain events are over, it will retain water as long as possible. Only when rain is predicted and the remaining buffering capacity is insufficient, water will be released and lost to the river system. The retained water is applied at nearby crop fields under two main scenarios. Firstly, during dry periods, water from the basin is slowly infiltrated through the drainage systems in the fields. This way, the soil remains moist and suitable for plant growth while the wateris used economically. Secondly, when the basin must be emptied, water is pumped into the fields at maximum possible rate to maximize local infiltration and groundwater recharge and minimalize water losses. With this solution, local urban runoff can benefice the local agriculture and environment whilst urbanisation related water problems are mitigated.

Here are some pictures of the construction of the basins.