Estimation of the Soil Saturated Hydraulic Conductivity and Soil Sorptivity of Terraced Soil Using Four-Term Expansions of the Haverkamp Model

Uzunçayır water retention Dam is located in the Tunceli province. This semi-arid mountainous region ineastern Turkey is prone to erosion. To combat this phenomenon, terraces along the edge of the MunzurUniversity campus were built on sloping ground with pine plantations. The objective is twofold, on theone hand to mitigate soil erosion and protect the dam from sediments deposits, and on the other hand topromote the infiltration of rainwater and the vegetation of the sloping soil. However, the so-called ecofunctions of the terraces over the time are not proven. Monitoring the infiltration capacities of the terracesover time and space will allow a better understanding of their contribution to the hydrology of thewatershed and their effect on soil erosion. The Beerkan infiltration technique offers simple andinexpensive experimental protocols. In addition, treatment methods are constantly improving. Morerecently, the four-term expansion of the implicit Haverkamp cumulative infiltration equation has beenproposed. This complicated but robust formulation was used in this study to estimate the soil sorptivity Sand saturated hydraulic conductivity Ks of terrace soil at Tunceli. The average Ks value of studied site wasestimated to be 0.0852 mm/s with a standard deviation of 0.0112 mm/s. The soil sorptivity values weremore extensive with mean value of 2.1227 mm/s0.5 and a standard deviation of 0.5855 mm/s0.5. The fit ofthe model used was perfect, showing that fast and robust estimation of S and Ks are possible using thenew model.