Water erosion in the catchment basin of the Jeleni Brook The study on water erosion in the catchment basin of the Jeleni Brook was carried out in the years 1995-1999. The catchment of the Jeleni Brook has complex relief, receives frequent precipitations and thus is more threatened by water erosion. Soil cultivation and water from quickly melting snow can also be the factors affecting soil erosion. Waters from the melting snow produce rills of the following dimensions (mean values): width from 11.5 to 13.6 cm, depth - from 6.4 to 7.1 cm and length - from 39 to 112 m. The mean values of soil losses vary from 0.5 to 2.02 t·ha-1. Erosion caused by intensive storm precipitation occurs less frequently but makes much higher soil losses. One of the registered incidents shows that 51.6 t·ha-1 (4.5 mm of soil layer) can be washed out from the area of 0.66 ha. Combined effect of outwashing and ploughing in lower parts of slopes created new forms of relief such as agricultural terraces (escarps). Agricultural terraces assume the shape of scarps up to 2 m high and of different length (e.g. 150 m) along with the land use border-lines between e.g. forest and field or field and grassland. Agriculturally used soils within this catchment need protection based mainly on agrotechnical measures or on alteration of land use. Some areas should be afforested.