Distributed Water Balance Model in Complex Watershed

Most natural rivers, especially in their downstream reaches, consist of a deep and narrow main channel flanked by one or two shallow, complex and vegetated floodplains. Those floodplains provide increased storage for flood waves and protection for towns and cities along the river corridor. Groynes are hydraulic structures that protect against bank erosion, maintain water level by deflecting flow direction, and ensure navigation safety. Groynes constructed on large scale floodplains play important roles in high flood attenuation and protection; however, they add complexity to the system. The first part of this book present modeling the surface and river flow in river network of compound channels flanked by one/two complex floodplains with/without groynes and located in complex watershed using dynamic one- and quasi-two-dimensional river flow routing based on the solution of the full St. Venant Equations with lateral flow. In addition, the effects of the river floodplain impermeable groynes on the flow discharge and water depth have been considered. In the second part,the effects of the floodplain impermeable groynes on the flow structure, velocity and water depth are presented.