Check dams: Distribution, purposes and effectiveness

In recent years the installation of check dams has increased markedly in many environments worldwide. Construction materials, dam size and main purpose/s vary greatly between locations within and between countries, but all dams modify the flows and stores of water, sediment and nutrients. For this reason, check dams are often intended primarily as a component of soil erosion control within watershed management more broadly. This leads to check dams being installed in locations characterized by widely disparate biophysical environments, catchment area, land use/land cover and human requirements. Although the positive impacts of check dams are frequently reported, debate around the effectiveness of check dams become intensified following instances of dam failure. A review of recent literature is needed to examine the reported outcomes of check dam installation and to identify future directions. This broad overview classified 130 (out of 202 reviewed) papers into three main functional groups of soil erosion control: geomorphological, hydrological and ecological, comprising 40 %, 27 % and 8 % respectively of the reviewed papers. The remaining 25 % of contributions either included all functions or did not identify a main purpose for the dams. Results indicated that there is no clear conception of the geomorphological, hydrological and ecological outcomes of the check dam installations, that cost-benefit analysis was rarely undertaken, and that consideration of economic effectiveness was generally restricted to biophysical elements with social costs and benefits being absent. In future studies, evaluations of effectiveness would be assisted by published documentation of planning which detailed outcomes and maintenance over the expected lifetime of individual check dams.