At a section of a 10 -ft-wide rectangular channel, the depth is \(0.3 \mathrm{ft}\) for a discharge of \(20 \mathrm{ft}^{3} / \mathrm{s}\). A smooth bump \(0.1 \mathrm{ft}\) high is placed on the floor of the channel. Determine the local change in flow depth caused by the bump.