Dynamics of the Surface Water Circulation between a River and Fishponds in a Sub-Mountain Area

Assessment of river-fishpond surface water circulation is recognised as to be of critical importancein the Upper Vistula river catchment (southern Poland). The Vistula river is characterised by a high flow inspring, partly retained in numerous fishponds, and a low flow in autumn. Evaluation of the water circulationcycle is based on an equation of pond water balance. Water balance components include regulated inflow tothe ponds and regulated outflow from the ponds, precipitation, and evaporation. Results have been obtainedduring four-year monitoring period. Waters circulation between the ponds and the river has been computedfor the annual hydrological cycle and for three periods; November – April, May – September and October.The three periods differ in the absolute magnitudes of the water balance components and, in the relativemagnitudes of the components. Deviation from the normal pluviometric conditions during the consideredyears has been evaluated by comparing the current results with results of a thirty -year precipitationmonitoring.q