Evaluation of the post-fire erosion and flood control works in the area of Cassandra (Chalkidiki, North Greece)

We quantified morphological and hydrographical characteristics of two drainage basins (Chanioti and N. Skioni) on Cassandra peninsula of Chalkidiki (North Greece), and evaluated the effectiveness of post-fire flood and erosion control works. The drainage basins were chosen because of their severe damage by fire, post-fire potential for erosion and flood due to the steep relief, and the importance of the area for residential and tourism development. The first measures taken in the area after the fire were salvage cutting of burned trees, a total ban on grazing, and construction of three types of works, log erosion barriers (LEBs), log check dams and contour branch barriers. Almost all necessary post-fire works were completed in both catchments but many construction failures were recorded. Approximately 75 % of the LEBs and 45 % of the contour branch barriers functioned properly, while the remainder failed. Nearly 80 % of the log dams were sedimented to 0-20 % of the dam height, 14.3 % were 20-40 % filled and 5.9 % collapsed. Despite these failures, peak discharge declined by 10.5 % in Chanioti and 20.4 % in N. Skioni catchment. The main reasons for works failures were the rush of construction and the limited supervision of workers, which resulted in floods during the years that followed.