SELECTION OF APPROPRIATE TRANSPORT FORMULAS FOR ESTIMATION OF TRANSPORT AND DEPOSITION RATES AT BABREKA CANAL

Апстракт

Siltation is a significant factor, affecting the efficient operation and maintenance of the irrigation canals which influence the hydraulic behavior of the canals and economic benefits of irrigation. In last 25 years a tendency of silting up at the irrigation canals in Bulgaria is observed due to the following reasons: decreased area under irrigation, fluctuation in supply, non-regime section, ”berming” of the canal, economic, crime and safety situation. The large number of available bed load and permissible velocity formulas and the significant differences between obtained results enforce selection of appropriate sediment transport formulas in each particular case. In this study discharge and velocity approaches are used for estimation of sediment transport and deposition rates at Babreka Canal, Malka Vitska Irrigation Project in Bulgaria. Seven equations for prediction total bed load transport rates and five equations for minimum permissible velocity are compared. The results show substantial differences in performance. Two formulas for total bed load and two formulas for minimum permissible velocity are selected as appropriate for the studied canal.