An Experimental Study on Investigating and Controlling Salt Wedge Propagation

Abstract

This study aims to investigate the variation of profiles and propagation of salt wedge. It also aims to investigate the use of air and water curtains in controlling its propagation. A laboratory flume system was prepared to simulate the propagation of the salt wedge. Relations between the profiles and propagation of salt wedge and the discharge of fresh water, longitudinal slope of bed of flume, the concentration of the salt, and the depth of salt water were obtained and analysed. Seventy-seven experiment runs were carried out to investigate the propagation of salt wedge. Moreover, a set of sixteen experimental runs were conducted to investigate controlling the salt wedge using air or water curtains. It was found that by increasing the discharge of fresh water or the slope of the flume bed leads to a reduction in the length of the salt wedge. This reduction reached a maximum percentage of 95%. The propagation of the salt wedge varies proportionally and linearly with the concentration of salt water and its variation with depth of salt water follows a power function. Furthermore, a maximum reduction of 87% was achieved in the salt wedge propagation when the EC is reduced by about 49%. The salt wedge propagation was reduced by 95.3%% when the salt water depth reduced by 40%. It was found that both of the air and water curtains are efficient methods in controlling the propagation of salt wedge. A minimum discharge of air or water curtains to prevent the propagation of the salt wedge was obtained.