Investigation of the effects of open spur dikes in preventing floods caused by driftwood

A flood is defined as the inundation of adjacent floodplains resulting from the overflow of a river channel when increased discharge exceeds its carrying capacity. Floods typically emerge from the complex interaction between the basin's geomorphological characteristics and human-induced changes, such as land use patterns and anthropogenic channel modifications. These structural factors are compounded by hydrometeorological triggers, including intense and prolonged rainfall, rapid snowmelt leading to soil saturation, increased surface runoff velocity, and the accumulation of floating debris. Driftwood carried by floods can obstruct bridges and dams, triggering water level rises that result in severe erosion and flooding of nearby areas. Measures to trap debris and sediment are taken along the channel bed with common retention structures such as nets, grids, piers and open check dams. Many researchers investigate the potential consequences of blockages in these structures. The Open Spur Dikes (OSD) structures investigated in this thesis are introduced to the literature for the first time. The primary objective of the study is to examine the capability of OSDs to capture woody debris that can obstruct flow in rivers and accumulate at critical cross-sections such as bridge piers. Within the scope of the experimental program, the effects of OSDs on variations in flow depth and bed scour were also investigated. Experimental series involving OSDs with different numbers, angles, and lengths were tested under various channel slopes, discharges, and driftwood transport scenarios. The results demonstrate that OSDs provide effective performance in trapping woody debris and in reducing flow depth and scour at bridge locations.