Hydrogeomorfologia obszarów źródliskowych (dorzecze Parsęty, Polska NW)

The chief aims of the research conducted in the southern part of the Parsęta drainage basin NW Po¬land are to characterise the organisation of the river system in channel heads and to determine the role of groundwater outflows in their development. The geomorphological, lithological, hydrological and hydrochemical studies performed made it possible to obtain a picture of how channel heads operate in the postglacial zone of the Polish Plain. In the 88 channel heads, zones of occurrence of the following processes were identified: seepage erosion; falls, dry ravel events and slides; creep, solifluction, surface runoff and erosion; channel processes; and landforms created under the impact of plants, animals and humans. The co-occurrence of several morphogenetic processes creates a variety of depositional conditions in alcoves, leading as a result to the accumulation of several sets of deposit. They are a record of headwater erosion and accumulation, fluvial deposition and redeposition, chemogenic and biochemogenic sedimentation, biogenic sedimentation, and sedentation. Headwater areas can be divided with respect to landforms of a higher taxonomic order initial morphological surfaces into slope, inserted, and scarp types. Each of those three types of headwater alcove has a different mechanism of initiation and development as well as its own way of joining the permanent river network. The development of a river network can proceed towards higher-order channels downslope development with a stream extending towards a watershed divide in the case of slope and inserted alcoves, and from a higher-order channel towards the watershed divide upslope development in the case of scarp alcoves.