French Experience With Open Check Dams

Debris Flows, Boulders and Constrictions: A Simple Framework for Modeling Jamming, and Its Consequences on Outflow

“…This is preferable to having a slit which is too narrow and persistently clogs up even for small events, causing large ongoing maintenance costs (Ballesteros‐Cánovas et al., 2016), or requiring a complicated cutting operation (Chiu et al., 2021). For instance, around a third of debris basins designed in France lead to either excessive maintenance costs or even abandonment of the structure (Carladous et al., 2022).…”

“…The extent of filling before an event , which depends on past events and maintenance policy (Carladous et al., 2022; Chahrour, 2021). It is often impractical to regularly assess sites, so the basin condition before a large event is generally uncertain.…”

“…This uncertainty greatly affects the “stage–volume” capacity curve of the basin: the total capacity for retention of material behind the constriction without overflow occurring. (As flow material drains through the constriction, this storage capacity can be partially recovered). The extent of filling before an event , which depends on past events and maintenance policy (Carladous et al., 2022; Chahrour, 2021). It is often impractical to regularly assess sites, so the basin condition before a large event is generally uncertain. Initial wood jams.…”

Small-scale study of Debris-Flows Interactions with a Lateral Debris Basin and Crossings: The Manival Torrent case study

“…Deposits were driven by its large width and a very gentle slope (7 % within the basin compared to 12-13 % upstream), in addition to the relatively small openings of the open check dam [11]. As a consequence, the debris basin was modified in 2018 to evolve toward a derivation configuration [1]: a guiding channel with a steeper, regular slope was added in the debris basin; an intermediate interception structure was built at the upstream end of the guiding channel; a lateral weir was also built guiding high flows toward the debris basin which is now located on the left bank and excavated deeply below the guiding channel level. The change of design was motivated by an incision of the channel that could reach up 10 m downstream of the debris basin [1].…”

“…Indeed field observation of such interactions are very rare. As a consequence, structures are designed empirically with simple criteria and often induce side effects as excess in sediment trapping possibly leading to downstream sediment starvation and high maintenance costs [1].…”