**2.1. Traditional water meadows in Europe**

Traditional irrigation techniques in grasslands were widely used until about the middle of the twentieth century [8], this is, when the techniques were replaced with modern systems using electric power supply and sprinkler irrigation and liquid manure or mineral fertilization to improve economic output of grasslands. Traditional methods of intensification, like traditional meadow irrigation techniques, are based on gravity and the natural movement of water from a river or stream [8, 9]. Meadows are either deliberately inundated by the damming of adjacent streams or ditches or the water slowly trickles over the surface of a slope. The time of inundation is usually kept short ("flash inundation"). The relief of the irrigated area is crucial to allow fast drainage, to avoid adverse effects of stagnant water [8, 11].

The widespread use of traditional meadow irrigation throughout Europe was by far not focused to dry areas only [8]. The positive effects found are not only restricted to the water supply but also to soil quality, making available of nutrients, pest control or elongating the growing period [9]. From Finland and Sweden in the North to Southern Spain or Sicilia in the South as well as from France in the West to Eastern Romania, traditional water meadow techniques were applied [8].

There is a large variety of management practices depending on region and natural settings. A rough separation of the techniques can be done into practices used in mountainous regions in contrast to techniques applied in valley floors and flat areas [8]. The application of traditional meadow irrigation in mountainous areas is often especially straightforward as the water is directed into ditches that follow the contour lines and the natural inclination of the hillslope which is sufficient to avoid stagnant water conditions. Irrigation systems in flat areas often were constructed with major effort as the surface level had to be adapted thoroughly. A ditch system allowing water division as well as a drainage system has to be constructed.

Traditional meadow irrigation clearly differs from modern sprinkler irrigation. The soil is not just wetted from above but soaks thoroughly. Above ground plant parts are often not even wet after irrigation, but soil water is effectively filled up to the local water holding capacity. The negative effects of large water drops splashing onto the soil surface closing soil pores, compacting the soils, and eventually leading to soil erosion—which are often problems under sprinkler irrigation—are avoided. Further, large water losses by the evaporation from the plant surfaces are reduced. It could be shown that traditional irrigation techniques are leading to a renewal of ground water resources [8] and increases water retention in the landscape. The potential negative argument traditional irrigation methods would be a waste of water that do not necessarily hold, if such secondary effects are included into the evaluation [8, 12, 13].
