Check dams in gullies in Northern Ethiopia were studied to see how they affect runoff. The researchers measured runoff in different gullies with and without check dams. In sandy areas, check dams delayed runoff reaching the lower part of the gullies. In limestone areas, different gullies had varying delays regardless of treatment. Gullies with check dams and vegetation reduced peak runoff more than untreated gullies. Overall, check dams can slow down runoff and reduce peak flow in gullies.