Drainage or dewatering is the removal of water over and through the ground in order to decrease the groundwater level. In wet meadow or forest shallow ditches (swales) were dug for this which led at the plot boundaries in deeper canals. Nowadays for this with coconut (machine) wrapped perforated pipes are buried. You can also fill a ditch with fagots or gravel (with bitumen cloth as soil retaining walls around it). It will silt and clog again. Also swales and canals should be cleaned or deepened every few years.

zouwen(A swale is wide and shallow, slight trough with very blunt edges. You can even mow in it. It can be grazed and run over without stumbling. Only at much precipitation there is some slowly runoff water in it. The higher part remains dryer and passable. They were used in pastures and woods.)

A meadow or wetland is the toponym (field name) to indicate grassland plots in a stream valley.
In stream valleys swales were also used to irrigate and bring minerals in the hayfield. There was no fertilizer, and livestock remained predominantly in the stable (or was herded). Brooks were dammed up, and the overflow was used to transfer (the ”watering’) (alternating) nutrients (which were removed by haying) to the plot.