Dynamic mechanism of check dams on evolution of river corridors based on UAV telemetry combined with numerical simulations

Abstract

Check dams are a critical soil and water conservation engineering measure in gullies that significantly influence erosion, transportation, and sediment accumulation. Check dams help reduce erosion in the upstream area, ignoring the off-site erosion reduction capacity due to erosion dynamics, and it also alters the morphology of gullies. The morphology of the gully cross-section from the head to the inlet of the gully is mainly “V” shaped, “V, U,” transitional shaped, “U” shaped and trapezoidal shaped. The construction of check dams can force the geomorphologic evolution of the sub-watershed to accelerate the transition to “old age” and reduce the allocation of sediment initiation during field sub-flooding, thus promoting sediment deposition processes. The percentage of downstream scour hours in watersheds where check dams were constructed was 0.65% and 0.80%, respectively, compared to 19.78% and 19.06% in watersheds where there are no check dams. The results reveal the role check dam constructions play in gully morphology evolution from a hydrodynamic perspective and fill the gaps in off-site erosion reduction, providing theoretical support for assessing the role of check dams in soil and water conservation work.