Eur. Phys. J. Plus (2018) 133: 79
https://doi.org/10.1140/epjp/i2018-11890-6

Regular Article

A 2D fluid motion model of the estuarine water circulation: Physical analysis of the salinity stratification in the Sebou estuary

¹ Interdisciplinary Laboratory for Natural Resources and Environment, Faculty of Sciences, Department of Physics, Ibn Tofail University, B.P 242, 14000, Kenitra, Morocco
² Ministry of Energy, Mines, Water and Environment, Water Service of Kenitra City, B.P 203, 14000, Kenitra, Morocco

^* e-mail: haddout.ens@gmail.com
^** e-mail: soufiane.haddout@uit.ac.ma

Received: 19 July 2017
Accepted: 21 January 2018
Published online: 27 February 2018

Abstract

Estuaries, which are coastal bodies of water connecting the riverine and marine environment, are among the most important ecosystems in the world. Saltwater intrusion is the movement of coastal saline water into an estuary, which makes up-estuary water, that becomes salty due to the mixing of freshwater with saltwater. It has become a serious environmental problem in the Sebou estuary (Morocco) during wet and dry seasons, which have a considerable impact on residential water supply, agricultural water supply as well as urban industrial production. The variations of salt intrusion, and the vertical stratification under different river flow conditions in the Sebou estuary were investigated in this paper using a two-dimensional numerical model. The model was calibrated and verified against water level variation, and salinity variation during 2016, respectively. Additionally, the model validation process showed that the model results fit the observed data fairly well (, and m). Model results show that freshwater is a dominant influencing factor to the saltwater intrusion and controlled salinity structure, vertical stratification and length of the saltwater intrusion. Additionally, the extent of salinity intrusion depends on the balance between fresh water discharges and saltwater flow from the sea. This phenomenon can be reasonably predicted recurring to mathematical models supported by monitored data. These tools can be used to quantify how much fresh water is required to counterbalance salinity intrusion at the upstream water intakes.