Temperature-Driven Evaporation Analysis Over Ballikaya Catchment

Abstract

Hydrometeorological analysis such as terrain characteristics, flood forecasts and water potentials have become possible through computer models today in parallel with rapidly ever-evolving technology. While the surface-runoff during a storm has linearly and highly correlation with effective precipitation, it is inversely proportional to hydrological losses, including interception, infiltration, transpiration and evaporation. However, flood estimation analysis, in especially rural areas in Turkey, is still not widely and accurately usable, due to difficulties in accessing the necessary ground-based data records such as evaporation, which affects much of the rainfall. Although direct measurement of evaporation is not available now, indirect methods such as evaporation pans have been developed to give acceptable results. On the one hand, observation networks are built by Turkish State Meteorological Service for the estimation of evaporation from open water bodies; these measurements, on the other hand, are only obtained at large climatological stations such as city centers and generally for only six months of the year. In this sense, evaporation values, in order to apply rainfall-runoff analysis, were estimated by Kharrufa, Blaney-Criddle, and modified Blaney-Criddle methods to be used in Monthly Average models. While the highest underestimations were obtained in modified Blaney-Criddle method, Kharrufa method outperformed the other two Blaney-Criddle products. The results, confirmed by analysis of the temperature-based Kharrufa approach in two urban areas close to the study basin, show to be appliable for estimation of long-term hydrographs. The analyzed method can be applied over rural watersheds lacking in-situ evaporation measurements as well as enables more accurate rainfall-runoff simulations processes with calibrated and verified hydrological models.