Correction: Combination of Discrete Element Method and Artificial Neural Network for Predicting Porosity of Gravel-Bed River. Water 2019, 11(7), 1461

We have found one error in Equation (2) (duplicate with Equation (1)) in our paper published in the Water Journal [1]:

$${\mathrm{m}}_{\mathrm{i}}\frac{{\mathrm{d}\overrightarrow{\mathrm{u}}}_{\mathrm{i}}}{\mathrm{dt}}={\mathrm{m}}_{\mathrm{i}}\overrightarrow{\mathrm{g}}+{\displaystyle \sum }_{\mathrm{k}}{\overrightarrow{\mathrm{f}}}_{\mathrm{i},\mathrm{k}}+{\overrightarrow{\mathrm{f}}}_{\mathrm{i},\mathrm{f}}$$

(1)

Equation (2) is corrected to:

$$\mathrm{I}\frac{{\mathrm{d}\overrightarrow{\mathsf{\omega }}}_{\mathrm{i}}}{\mathrm{dt}}=\frac{{\mathrm{d}}_{\mathrm{i}}}{2}{\displaystyle \sum }_{\mathrm{k}}\left({\overrightarrow{\mathrm{n}}}_{\mathrm{i},\mathrm{k}}\times {\overrightarrow{\mathrm{f}}}_{\mathrm{i},\mathrm{k}}\right)$$

(2)

These changes have no material impact on the conclusions of our paper. We apologize to our readers.