The dams on the upper part of Brejlský potok create an intensified cascading swale.
Its function is primarily:
- Slowing down and temporary retention of surface and drainage runoff of rainwater from surrounding agricultural areas,
- capturing the sediment that is washed away and then returning it to the agricultural land.
The swale forms a sunken place with a total area of 280 m2 and a water retention capacity of 53 m3. Its construction protects the main drainage channel, which receives surface and drainage water, from siltation. The main drainage channel was transversely dammed with ten dams to temporarily collect surface and drainage runoff. The dams will create shallow and temporarily flooded pools of roughly half a metre in depth, which will be dry for most of the year, for now. When the local drainage system is restored, the frequency of flooding of the pools will be significantly higher.
In addition to the swale itself, the surface runoff of rainwater from this agricultural land is slowed down by longitudinally adjacent strips of meadow vegetation three metres wide. They also provide important habitat for grassland insects and other animals in the agricultural landscape.
