Coastal Zones

Biography

Biography: Ahmed Sayed Mohamed

Abstract

Lagos and Lekki lagoons in Nigeria receive seasonal rainy storm water that leads to increased water level of the lagoon due to relatively long residence times and eventually inundation of low-lying and swamp areas. The Nigerian authorities do not permit any breach in the natural barrier to directly release rainy storm waters into the ocean except through the existing Lagos Lagoon outlet. The question of how much water level rise due to rainfall storm water discharges requires an answer since there are ongoing and future development around the Lagos and Lekki Lagoons that may be influenced and inundated. As such the knowledge of design water levels of the lagoons is needed for the design of such coastal development. The water level rise due rainy storm water is considered a dominating component for deriving the design water level of this project. In this regard, this work was carried out to derive the marine design parameters such as design water level. The tool employed for deriving the design parameter is able to model the lagoons with the complex morphological feature. This tool is Delft3D model. In this paper, Delft3D model was utilized to numerically model the lagoons considering tidal driving force, bottom friction, wind stresses as well as mass flux caused by releasing the rainfall storm water. The model was constructed and calibrated. Various scenarios of rainfall storms were simulated and the retained water depth was computed at particular observation points within the lagoons. The design water level was determined at different places within the lagoons.