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EN
Premises for the construction of balance equations of water reserves in the saturation zone of forest soil are presented in this paper. Changes of soil water reserves are dealt with as an effect of the atmosphere-tree stand-soil balance at the assumption of constant ground water flow and negligibly small losses for infiltration down the soil profile below saturation zone. These assumptions are met in permeable lowland forest soils, particularly in areas where the aquifer is situated on relatively shallow impermeable substratum. Then, for snow-free periods, it is possible to: 1) combine the increment of soil water reserves with precipitation above tree crowns and with plant and litter interception and 2) combine the losses of soil water reserves with plant transpiration and evaporation from the soil surface. The periods of increments and losses of soil water reserves are determined from limni-graph records of ground water table depth in piesometers. Examples are given in the paper of equations identified by long term data from 13 soil profiles localised in pine forests on Pleistocene floodplain of the Dunajec River. The data included: ground water table depth, physical properties of grounds in soil profiles, and hydro-climatic conditions. The equations combine increments and losses of water reserves in the saturation zone with rainfall and deficits of air humidity measured on a mid-forest meadow.
PL
W pracy przedstawiono przesłanki do konstrukcji równań bilansu wody w strefie saturacji gleb leśnych. Zmiany zapasu wody w glebie są traktowane jako wynik bilansu atmosfera-drzewostan-gleba, z założeniem ruchu ciągłego wody gruntowej, oraz zaniedbywalnie małych strat na infiltrację w głąb profilu, poniżej strefy saturacji. Założenia te są spełnione w wysokim stopniu w nizinnych glebach leśnych, przepuszczalnych od powierzchni, szczególnie na tych obszarach, na którym warstwa wodonośna znajduje się na stosunkowo płytko położonym stropie utworów nieprzepuszczalnych. Wówczas w okresach bez pokrywy śniegowej możliwe jest: (1) związanie przyrostu zapasu wody glebowej z opadem nad koronami drzew i intercepcją roślin oraz ściółki, (2) związanie ubytków zapasu wody glebowej z transpiracją roślin i parowaniem z powierzchni gleby. Okresy przyrostów i ubytków zapasu wody glebowej są wyznaczane na podstawie zapisu limnigraficznego głębokości zwierciadła wody gruntowej w piezometrach. W pracy podano przykłady równań opracowanych na podstawie danych z wieloletnich pomiarów w 13 profilach glebowych zlokalizowanych w lasach sosnowych na plejstoceńskiej terasie Dunajca, tj.: 1) głębokości zwierciadła wody gruntowej, 2) właściwości fizycznych gruntów budujących profile glebowe, 3) warunków hydroklimatycznych. Równania te wiążą przyrosty i ubytki zapasu wody w strefie saturacji z opadami deszczu i niedosytami wilgotności powietrza, pomierzonymi na śródleśnej łące.
EN
Sąspówka is a right-hand side tributary of the Prądnik River in the Ojców National Park. This catchment is characterized by several features which could substantially influence its water balance: the upper part of the catchment, located in a plateau, is utilized for agriculture, while he lower part consists of steep slopes, largeIy covered by forests (Fig. I, Tab. I). The topic of this paper is developing a crude water balance for the entire catchment and for its parts; upper one and lower one, the latter one treated as a difference between entire catchment and the upper part. The detailed goals of this study were: presentation of the basic features of the water balance for different parts of the catchment and comparison of the balances for the forested and non-forested parts of the catchment [8]. The climate of the study area was characterized on the basis of data from climatic stations in Kraków and in Olkusz. In both stations precipitation is usually larger the evaporation.In Kraków for 19 analyzed years oni y in 7 the precipitation was lower than the potential evaporation; the situation in Olkusz (Fig. 2) was similar [8]. During this study, the first and third year were drier than the average, while the second year was very close to mean values. AlI components of the water balance were calculated as mean monthly values for the entire catchment and for its parts - the forested and non-forested ones (Tab. 3). The water losses (evaporation form the catchment area and runoff outside the main river bed) were calculated on the basis of the balance equation. The water losses were not correlated with the evaporation estimated on the basis of measurements conducted with the Piche's evaporimeter; we can assume this to be a characteristic feature of the karst regions (Fig. 4). Taking that into account, we can reasonably assume that mean monthly runoffs from the forested and non-forested parts of the catchment are not correlated (Fig. 5).Thus, the much larger runoff from the forested part of the catchment should be interpreted rather as a product of many additional water springs, located along the stream bed in the lower part of the valley and fed with the water infiltrating in the upper part of the catchment deep into the bedrock, than as a result of differences in land use between two parts of the catchment. In comparative studies on the influence of forest cover upon the amount and dynamics of water runoff from a catchment the effect of the leak tightness of the catchment upon the study results is usually underestimated. That was clearly shown in this study, conducted in a karst type catchment.
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