CLIMATIC CHANGE DETECTION IN THE NORTHWESTERN COASTAL ZONE (EGYPT) AND ITS POSSIBLE IMPACT ON WATER RESOURCE | ||
| Egyptian Journal of Desert Research | ||
| Article 3, Volume 65, Issue 2, December 2015, Pages 233-255 PDF (1.32 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejdr.2015.5952 | ||
| Authors | ||
| Salah M. Abdel Moghith1; Nahla A. Morad* 2; Milad H. Masoud3 | ||
| 1Department of Hydrology, Desert Research Center, El-Matareya, Cairo, Egypt | ||
| 2Department of Hydrology, Desert Research Center, El-Matareya, Cairo, Egypt | ||
| 3Water Research Center, King Abdulaziz University, Saudi Arabia | ||
| Abstract | ||
| In the study area, which extends for about 500 km along the Mediterranean coast of Egypt, the seasonal rainfall is the sole source of water for development activities through either runoff harvesting or shallow aquifer recharge. Rainfall and other meteorological data in the study area were collected from two sources: NASA satellite site and ground stations; namely from west to east Sallum, Barrani, Matruh, Dabaa and Alexandria. Such data have been analyzed to detect and assess any spatial and temporal climatic changes during the period (1900-2014) and the possible impacts upon the shallow groundwater potentials. During the last century, the highest value of annual rainfall was recorded in Alexandria in 1974 (405.1 mm), while the lowest value was recorded in Sallum in 1955 (32.8 mm).This may indicate that extreme climatic conditions were prevailing during the period (1955-1970) from further west to further east. The calculated arithmetic mean of the annual rainfall in the study area is 138.44 mm. The rainfall frequency during the whole period of measurements shows continuous fluctuation either below (Sallum), or above (Alexandria) arithmetic mean. Local climatic changes every 15 years or multiples in the study area are detected through the period 1900-2014. Variations during the whole period of records are well detected, where it ranged from 76.5 mm (Matruh, 1923), 76 mm (Barrani, 1913) and 62 mm (Alexandria, 1938) indicating relative wet condition in the first third of the past century (1910-1940), compared with the whole period. The return period shows that the probability for the occurrence of annual rainfall can be doubled from the mean every about sixty years in all stations except for Sallum, where it be doubled every only 30 years. According to the calculated aridity index, the study area lies between hyper arid in the west to arid climate in the east, without any serious spatial or temporal changes. The temperature analysis indicates that there is a noticeable increase in temperature between the years 1955-1970 and 1995-2010. Worth mentioning the year 2010 is one of the warmest years during this period. In addition, this year (2010) had the lowest amount of rainfall in all the study area (average 50 mm/year). Consequently, the study area was subject to two drought periods (1955-1970 and 1995- 2010) against one relative wet period (1910-1940). The shallow groundwater has been considerably influenced by climatic change in the study area. Water levels have been prominently decreased to about 16.0 m below the mean sea level (zero level) in some localities; e.g. Dabaa - east Matruh. Meanwhile, water salinity increased from about 3000 ppm (1970) to more than 10000 ppm (2010). The water shortage in the drought events, as well as, the over-pumping of wells, cause serious reduction of the thickness of the fresh water lens that floats by specific gravity on the top of the saline water. | ||
| Keywords | ||
| Climate Change; water resources; rainfall analysis; return period; Northwest coast; Egypt | ||
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