Not to mention the unsustainable and hazardous runoff of soluble agricultural byproducts, conventional water management in agriculture is in the direction of fast drainage for arable land through traditional systems. Rainfall can cause flooding, on the one hand, due to high flow rates, but on the other hand mismanagement can trigger, even with sufficient annual rainfall, damage to crops due to drought in warmer seasons.
The active regulation of the basins outlets can be made via controlled drainage by a controlled infiltration or outlet structures. It is important to properly coordinate flow and water level within the basin for a balanced degree of flood protection and water availability for irrigation. Maintenance and operation are crucial for a proper functioning as required routine work includes quarterly inspections of inlets and outlets as well as sediment and trash dredging.
The design features of a controlled drainage consist of: drain-storage-pipes, control manholes, drainage pipes and a control center. The drain storage lines has retentive plastic hollow bodies that are coated a water-permeable, fines geotextile. The lines essentially follow the contour lines having a base slope of approximately 0.1% within the discharge direction. The distances between lines result from the hydraulic calculations that help also in dimensioning the hollow body sections.
Each Drain storage line is connected with a control shaft. The terrain slope towards successive wells that are connected to drain pipe leading to open outfall. The control center is equipped with a receiver device that is able to receive wireless signals. It is linked externally via the NA model using current predictions of rainfall and other meteorological parameters.
The application of a controlled drainage systems is limited by the topography factor. Optimally, it is implemented for surfaces having a gradient of less than 1%.