Effectiveness of Torrential Erosion Control Structures (Check Dams) Under Post-Fire Conditions—The Importance of Immediate Construction

This study examines the effectiveness of torrential erosion control structures (concrete check dams) to mitigate post-fire sediment transport within the Seich Sou Forest in Thessaloniki, Greece. Four years after the fire of 1997, which burned 68% of the forest, check dams were constructed (in 2001) to control erosion and sediment transport in the catchments of Eleonas and Panteleimon. In 2022, our team conducted field surveys, in which the size, effective storage capacity, and siltation of 40 check dams were recorded. The results revealed that the dams stored 14.36% and 18.81% of their total effective capacity in the Eleonas and Panteleimon catchments, respectively, with average annual erosion levels of 0.33 t/ha/year and 0.21 t/ha/year. These low rates of erosion could be attributed to the shallow, rocky soils and rapid post-fire vegetation recovery. However, this study highlights that timely construction of check dams immediately after the fire could have significantly increased their effectiveness. The results showed that if the dams were constructed immediately after the fire, they would retain 6.17 t/ha/year (Eleonas) and 7.08 t/ha/year (Panteleimon), during the first three post-fire years. These values of erosion are in agreement with previously published studies in Mediterranean ecosystems. This study highlighted the importance of the timely construction of post-fire erosion control structures to increase sediment storage and reduce soil transportation.