Ousmane Sawadogo

Stellenbosch University | SUN · Department of Civil Engineering

This paper investigates local sediment flushing under pressure at dams through a low-level outlet for the control of reservoir sedimentation to protect the hydropower turbines. A state-of-the-art three dimensional fully hydrodynamic computational fluid dynamic (CFD) model was developed with user defined functions which link the sediment mass balanc...

Sediment traps are structures designed to allow the suspended sediment load, which enters river abstraction works or diversion canals, to deposit whilst relatively clean water passes through. The deposited sediment is then removed by making use of gravitational flushing. The sediment traps discussed in this paper are settlers and sand traps. The fo...

Sediment deposition in reservoirs can affect flood levels, drainage from agriculture land, the firm yield of a dam, hydropower operation and navigation. Turbulent suspended sediment transport is the dominant mechanism of sediment transport through most reservoirs. This paper focuses on the simulation of flow and sediment transport patterns utilisin...

The determination of extreme flood levels in an estuary should consider river floods and waves penetrating the estuary. The Breede River estuary in South Africa, 50 km in length, is discussed as case study in this paper. A two-dimensional hydrodynamic model Mike21C of the DHI Group of the 50km estuary (including the estuary mouth) was set up and ca...

For 60-odd years, dredge spoil was artificially dumped in the natural course of the uMfolozi River (near the mouth of the St Lucia estuary), by then conservation managers as it was thought that silt exacerbated from the canalisation of the uMfolozi River was the biggest man-induced risk to the 350km2 estuarine Lake St. Lucia system in South Africa....

The Orange River Re-Planning Study (ORRS, 1997) recommended that the proposed Noordoewer/Vioolsdrift Dam (NVD) site be further investigated as possible dam development downstream of Vanderkloof Dam, in the lower reach of the 2200 km long Orange-Senqu River. The Lower Orange River Management Study (LORMS, 2005) recommended that a re-regulating dam b...

Sediment deposition in reservoirs is an important research topic in engineering practice. Reservoir sedimentation has the potential to affect flood levels, drainage for agricultural land, pump station and hydropower operation as well as navigation. This paper describes the development of a coupled fully three-dimensional (3D) numerical model for th...

This paper discusses the hydraulic design of a proposed new 13 km long flood levee in Malawi. The design addresses an avulsion event which included the wash away of the railway line along the lower Ruo River by the extreme flood of January 2015 and led to the river being diverted permanently in a westerly direction towards the Shire River, away fro...

Hydrological modelling (daily rainfall-runoff-sediment transport) was carried out to predict the sediment yield of the proposed 164 m high Polihali Dam in Lesotho as part of the Phase II detail design of the Lesotho Highlands Water Project (LHWP). Land use scenarios were considered for the years 2009 and 2070. Following model calibration, the long...

ENGLISH ABSTRACT: The scour process of unlined spillways is an important research topic of value in engineering practice. In South Africa numerous unlined spillway dams have experienced severe erosion. This led, in some cases, to the costly concrete lining of spillways for erosion protection. On the other hand, the erosion of unlined spillways can...