Gully Development on the Foredune of Pehuén Co (Sw Buenos Aires Province, Argentina) and its Relationship with Rainfall and Human Activities

Understanding gully development is necessary to protect beach foredunes efficiently against gully erosion. The evolution of gullies on the foredune of Pehuén Co, Argentina, was explained using a combination of satellite images analysis and UAV models. In 16 years, the area covered by gullies increased 2011.4 m2 (5.6 times in size). The runoff due to precipitation is the major natural erosive agent affecting the active gully field, and its expansion is related to annual rainfall and the recurrence of rainy days. However, man-originated elements changed the drainage network and modified gully development, mainly by the construction of an unpaved road. The influence of the installation of Big Bags at the foredune toe, artificial nourishment, and the use of gullies as descents to the beach are also evaluated. Intervention is needed at gully incisions, mainly at the head of the catchments and early stages, particularly where the mass movement and the generation of cliffs have already begun. There is also a need to evaluate the location of road drainage to both reduce gully expansion and the creation of newer ones.