The flood retention basin is 8.5 km above the Haaren estuary at the confluence of the Haaren and the Putthaaren.
With a maximum water level of +6.50 m above sea level, around 650,000 m³ can be stored in this valley on a flooded area of 70 ha. The backwater level is generally limited by the natural slopes. In the east, across the Haarental, a dam with a crown height of NN + 7.50 m and in the south to protect against the road "Woldlinie" a dam has been partially built to NN + 7.00 m.
The dam crown of the main dam is paved for maintenance work and repairs in a width of 3.00 m. Public transport is not permitted on this route.
The annual summer flood of the hair has a peak discharge rate of around 70 l / s · km². A peak discharge rate of 127 l / s · km² must be expected every 10 years.
With a backwater level of NN + 5.00 m, the basin holds 165,000 m³ with 17 hectares of flooded area. At a water level of 6.00 m above sea level, the basin capacity increases to 360,000 m³ with 45 ha of flooded area, and at the maximum storage level of 6.5 m above sea level, 70 ha are flooded with a basin capacity of 650,000 m³.
The entire system and the weir structure are designed in such a way that a maximum storage target of NN + 6.75 m with a basin volume of around 850,000 m³ could be achieved.