Hydrological Impacts of Various Land Cover Types in the Context of Climate Change for Zala County

Abstract

Abstract The water balance of Zala County was analyzed using remote-sensing based actual evapotranspiration (ETA) (Kovacs 2011) and runoff (R) in the context of land cover types. The highest mean ETA rates were determined for water bodies (658 mm/year) and wetlands (622 mm/year). Forests have higher values than agricultural areas, and the lowest rates belong to artificial surfaces. Mean annual runoff is the largest on artificial surfaces (89 mm/year), and it decreases on the other land cover types. For climate change impact analysis a Budyko-model was used in spatially-distributed mode. The parameter of the Budyko-model (α) was calculated for pixels without surplus water. For the extra-water affected pixels a linear model with β-parameter (actual evapotranspiration / panevapotranspiration) was used. These parameters (α and β) can be used for evaluating future ETA and R in spatially-distributed mode. According to the predictions, the mean annual evapotranspiration may increase about 27 mm while the runoff may decrease to the one third to the present amount by end of the century Kivonat Kulonboző felszinboritasok vizforgalomra gyakorolt hatasa a klimavaltozassal osszefuggesben Zala megye peldajan. Zala megye teruleti vizmerlegenek elemzese taverzekelesi adatokon alapulo aktualis evapotranszspiracio (ETA) (Kovacs 2011) es lefolyas (R) alapjan, a felszinboritas fuggvenyeben tortent. A legmagasabb atlagos parolgasertekek a vizek (658 mm/ev) es a vizenyős teruletek (622 mm/ev) eseteben jelentkeztek. Az erdők magasabb parolgassal jellemezhetők, mint a mezőgazdasagi teruletek, a legalacsonyabb ertekek a mesterseges felszinekhez tartoznak. Az eves atlagos lefolyas a legnagyobb a mesterseges felszineken (89 mm/ev), es egyre kisebb a tovabbi felszinboritasi kategoriak eseteben. A klimavaltozas hatasanak vizsgalata egy terben osztott Budykofele modell hasznalataval tortent. A Budyko-modell kalibracios parametere (α) a tobbletvizhatastol fuggetlen pixelekre kerult kiszamitasra. A tobbletvizhatasu pixelek eseteben egy linearis β-parameterű modellt (aktualis parolgas / kadparolgas) vezettunk be. A ket parameter (α es β) segitsegevel becsulhető a jovőbeli ETA es R, terben osztott modon. Az előrejelzes alapjan az eves atlagos aktualis parolgas 27 mm-el novekedhet, mig a lefolyas a harmadara csokkenhet a szazad vegere