Computer Modelling of an Aquatic Fauna Complex Concrete Passage at a River Barrage.

The paper presents a 2D computer structure modelling and discharge simulation for an improved aquatic fauna passage consisting on a three compartments stepped concrete channel and considered as a side appurtenant for a small head dam on a river upper course. The foreseen structure aims to reduce the barraging environmental impact by offering optimum flow conditions under given water discharging circumstances, meaning even for ensuring the minimum required sanitary/ecological river discharge as split by the main path through the gate dam and the side passage path. The hydraulic simulation looks to establish the side passage discharge development and in the same time to estimate the extreme values of water velocity, especially at narrowing sections. In case there is necessary, the numerical results would point to further geometrical optimisation by adjusting the existing structural details or by considering additional constructive elements in order to fulfil specific requirements (usually with respect to the maximum water velocities) as indicated by in-force regulations. [ABSTRACT FROM AUTHOR]