Application of Runoff and Sediment Yield Models by Geographic Information System

What is it about?

In this study, commonly used rainfall - runoff - erosion models which AGNPS, SWRRB and GLEAMS were examined by means of GIS. Efficacy of GIS and validation of these models were also considered. Beside determination of watershed area and subbasin boundaries, also contributing cell, subbasin which cell include, cell area, average elevation, slope, aspect, topographic factor, flow length, flow slope, concentrated slope and concentrated length was determined by GIS in Ankara – Yenimahalle – Güvenç watershed. The predictions of models were compared with measured data between 1989 and 1997, after 464.4 mm annual rainfall, 100.0 mm flow and 29.6 mm runoff was occurred, but SWRRB 39.8 mm flow, AGNPS 48.5 mm and GLEAMS 34.5 mm runoff modelled. Although annual average sediment yield of watershed was calculated as 3.6 t/ha, AGNPS modelled as 19.9 t/ha, (min. 5.5, max. 33.0 t/ha), SWRRB 19.8 t/ha (min. 0.1, max. 63.9 t/ha) and GLEAMS 1.3 t/ha (min. 0.2, max. 2.2 t/ha).

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