In result of considerably diminished retention abilities of catchment area as well of river and stream inundation areas, increased high water flows occurred, particularly in the watercourse mouth sections. It poses a considerable flood hazard for the urbanized areas. Registered flood of July 1977 and June 2001 caused by high waters confirmed significant flood hazard in the areas of Carpathian tributaries of the Vistula River. In the Carpathian Foothills area, because of high water culmination times are shorter, watercourse regulation in closely built-up areas is necessary. Strong urbanization of the riverbank terrains resulting from historical location of towns gives no possibility to design riverbed in character close to natural. One of the main solutions, which is the most frequently applied and guarantees conducting high water flows is heavy consolidation of bed constructed in a shape of a trough. An example of this type of regulation is applied the mouth section of the Naściszówka stream. The Naściszówka inflow to the Łubinka river is situated in the Nowy Sącz city area. The streambed runs along Barska street. The adjacent terrain is characterised by a close urban building. The trough discharge capacity was assessed. According to the design guidelines in „Mountain stream consolidation”, ...