Al Bardawil Lagoon Hydrological Characteristics

Al Bardawil Lagoon is a very saline lagoon located in North Sinai, Egypt. It is subjected to environmental changes due to the implementation of a mega agricultural project close to its southern border. Accordingly, defining the hydrological characteristics of the lagoon was the objective of the current work to set the hydrological baseline for future changes expected due to ongoing human activities and agricultural developments planned in the lagoon’s vicinity. Historical meteorological data were collected and statistically analyzed to achieve the study objective. In addition, tide action, the lagoon’s bathymetry, and water table fluctuation were studied. Furthermore, groundwater aquifer interaction with the lagoon’s hydrologic system was considered. The study defined the water resources and water losses of the hydrological system of the lagoon. In addition, tide investigations revealed that the tide range is small. Furthermore, the study defined the water budget of the lagoon. Results indicated that the lagoon’s water resources are rainfall with an annual volume of 61.95 million cubic meters (4.4%); the groundwater aquifer contributes about 8.64 million cubic meters (0.6%). Annual evaporation losses are 1155 million cubic meters (82.2%). Salt production requirements represent about 17.8% of the outflow from the lagoon. Results of wind speed and direction data revealed that the dominant regional wind direction is NW and is characterized by magnitudes of about 4.5 m/s Results analysis demonstrated that the inflow of the lagoon is always less than the outflow with an annual volume of 1335 million cubic meter supplemented by the Mediterranean Sea water. This difference maintained water levels in the lagoon below mean sea level throughout the year, with values ranging between 11 and 22 cm. This process maintained a continuous movement of the seawater toward the lagoon. Water table fluctuation results indicated that the average water table in the lagoon is lower than the seawater level, with an average value of 22 cm for the observation period. Furthermore, the difference between the maximum and the minimum water table is in the tide range of the eastern region of the Mediterranean Sea. Similar hydrological studies are recommended for other coastal lagoons in Egypt. In addition, a hydrological observation system is recommended for the Al Bardawil Lagoon.