Application of the M5 Model Tree in Energy Dissipation Prediction over Gabion-Stepped Weirs

Gabion structures are commonly used in water- related projects، especially as weirs. The unique structure of these weirs increases the rate of energy dissipation and reduces the construction costs of stilling basins. The permeable gabion weirs might have less negative impacts on the environment than most of the solid weirs. In this paper، the ability of M5 model in estimating energy dissipation over gabion-stepped weirs has been assessed. The M5 model has two options: M5P and M5Rule، although very similar، they differ in the manner of yielding of outputs. To assess the precision of these 2 models، the data collected on energy dissipation over 8 physical models were analyzed. Results showed that the M5Rule model، as a technique of data mining، had a good performance in predicting energy dissipation over gabion-stepped weirs. Moreover، the discharge and the height of the weirs were the most effective parameters in energy dissipation. Comparing the results of M5 model and the logistic linear regression method proved the rigorous power of M5 method in predicting energy dissipation over and through gabion-stepped weirs.