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The semiarid areas of the Spanish Mediterranean region are environments that are severely threatened by desertification. Hydrological-forestry restoration is a very useful tool to fight these processes in programmes and projects of basin management. Check dams particularly can control bed erosion in ephemeral channels, among other things. The main aim of this study, then, is to evaluate how much check dams influence the degree of transitory general scouring in dry alluvial channels that function only sporadically and as torrents. Two areas were chosen: the Carcavo and Torrecilla catchments (River Segura basin), both drained by ephemeral gullies and both having undergone hydrological correction projects during the 1970s. Equations based on grain bed movement commencement criteria were applied for floods of different water depths, bearing in mind bed texture changes and slope adjustment brought about by dam construction. The results are contrasted with the critical velocity values, which in turn depend on the flow depth and the cross-section area before flooding. Finally, a comparison between real and predicted scouring is established for the cases analysed, including bankfull flow. Especially, the usefulness of Neill’s method has been tested in relation to net erosion values measured in the field with successful results.