Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 8 6 2004 10.5194/hess-8-1200-2004 http://www.hydrol-earth-syst-sci.net/8/1200/2004/ http://www.hydrol-earth-syst-sci.net/8/1200/2004/hess-8-1200-2004.html http://www.hydrol-earth-syst-sci.net/8/1200/2004/hess-8-1200-2004.pdf 1200 1209 0000-00-00 Research Note: Determination of soil hydraulic properties using pedotransfer functions in a semi-arid basin, Turkey M. Tombul Z. Akyürek A. Ünal Sorman Anadolu University, Civil Engineering Department, 26470 Eskisehir, Turkey METU Geodetic and Geographic Information Technologies Division, 06531 Ankara, Turkey METU Civil Engineering Department, 06531 Ankara, Turkey Email for corresponding author: mtombul@anadolu.edu.tr Spatial and temporal variations in soil hydraulic properties such as soil moisture q(h) and hydraulic conductivity K(q) or K(h), may affect the performance of hydrological models. Moreover, the cost of determining soil hydraulic properties by field or laboratory methods makes alternative indirect methods desirable. In this paper, various pedotransfer functions (PTFs) are used to estimate soil hydraulic properties for a small semi-arid basin (Kurukavak) in the north-west of Turkey. The field measurements were a good fit with the retention curve derived using Rosetta SSC-BD for a loamy soil. To predict parameters to describe soil hydraulic characteristics, continuous PTFs such as Rosetta SSC-BD (Model H3) and SSC-BD-q33q1500 (Model H5) have been applied. Using soil hydraulic properties that vary in time and space, the characteristic curves for three soil types, loam, sandy clay loam and sandy loam have been developed. Spatial and temporal variations in soil moisture have been demonstrated on a plot and catchment scale for loamy soil. It is concluded that accurate site-specific measurements of the soil hydraulic characteristics are the only and probably the most promising method to progress in the future. Keywords: soil hydraulic properties, soil characteristic curves, PTFs