Climate Adaptive Drainage (CAD): developments, experiences from 2010 to present, and application in Flanders

Agricultural water management in terms of drainage and irrigation serves agricultural crop production. At the field scale, in delta areas of the world, drainage is often needed to prevent water logging and to reduce oxygen stress. Subsurface drainage has been one of the most-applied ways to control the groundwater table at the field scale. There have been technical and drainage design developments to move from conventional subsurface drainage to controlled drainage.

Ongoing climate change induces more extreme dry and wet conditions that have impact on crop growth and agricultural crop yield, it is important to anticipate on these amplifying soil moisture conditions. Technically advanced controlled drainage systems like the Climate Adaptive Drainage system allow for such anticipative water management. Climate Adaptive Drainage (van den Eertwegh et al., 2013) is future-oriented and is promising, and can be remotely managed the field and regional scale. Also, subirrigation features with pump systems have been added.

Climate Adaptive Drainage (CAD) is a controlled drainage system with connected subsurface drain tubes, that allows to remotely manage the drainage basis by telemetry. The Climate Adaptive Drainage system consists of subsurface drains, coupled by one or two collector drains, a drainage pit with a mechanically manageable drainage basis, an electronic solar-powered control unit, and hydrological field monitoring by sensors. The drainage basis can be controlled remotely. The equipment installed allows remote and continuous management of the drainage basis, to control the water discharged to the surface water by the outlet of the CAD-system. All is coupled with by a two-way telemetry system for control, visualization of information, and data management on operations and hydrological effects at the agricultural field. The feature of the automated control of the drainage basis provides opportunities for continuous and online control of the field soil moisture pressure head conditions.

The first CAD system was designed, implemented, and tested at three agricultural field sites in The Netherlands in 2010-2012. Since then, we have operated one of the three systems until today, which we extended in 2016 with subirrigation, using treated waste water from a municipal WWTP. We moved a second system to a new test site in 2018. Also this system was extended with subirrigation, all running on solar power, using an integrated pumping system for fresh surface water supply. Its management is fully automated. We designed a new system in 2020 with integrated water pumps as well. We have been executing several applied research projects using the CAD systems, including monitoring and 1D/2D-modelling of both management, as well as hydrologic effects, and agricultural crop production (de Wit et al., 2021).

We will present our experiments, data and information, and farmers’ experiences and capacity building needed. We will discuss on effectiveness of CAD applications, the do’s and the don’ts. We will put local to regional scale applications of the systems in perspective of water management targets and water availability. These are ingredients for a field introduction of CAD systems in Flanders in 2023.