River training structure, system comprising river training structure, and method for training a river

A river training structure for a river,

• wherein the river has a flow direction, a bank, and a navigation channel with a bottom;
• wherein the river training structure comprises a groyne placed in the river;
• wherein the groyne is a longitudinal groyne extending in flow direction of the river with water of the river along both longitudinal sides of the longitudinal groyne;
• wherein the river training structure comprises concrete blocks, each block being constituted by a central part and four or more legs extending from the central part such that the central part and legs define a three-dimensional configuration allowing a multiple of said blocks to inter-engage with each other three-dimensionally when stacked onto each other;
• wherein the longitudinal groyne is constructed from a multiple of said blocks irregularly stacked onto each other and engaging with each other to form a dam body of inter-engaging blocks, the dam body having a longitudinal slope at the navigation channel side of the dam body.