Country: Palestinian Territory, Occupied
Size: 365 km²
The Gaza Strip is a part of the Mediterranean coastal plain between Egypt and Israel, where it forms a long and narrow rectangle. Its area is about 365 km2 and its length is approximately 45 km. The population (currently 1.5 millions) characteristics of the Gaza Strip are strongly influenced by political developments which have played a significant role in the growth and population distribution of the Gaza Strip.
The average daily mean temperature ranges from 25 °C in summer to 13 °C in winter. The daily relative humidity fluctuates between 65% in the daytime and 85% at night in the summer, and between 60% and 80% respectively in winter. The mean annual solar radiation is 2200 J/cm2/day. The average annual rainfall varies from 450 mm/yr in the north to 200 mm/yr in the south. Most of the rainfall occurs in the period from October to March, the rest of the year being completely dry. Precipitation patterns include thunderstorms and rain showers, but only a few days of the wet months are rainy days. There is less areal variation in evaporation than in rainfall in the Gaza Strip. Evaporation measurements have clearly shown that the long term average open water evaporation for the Gaza Strip is in the order of 1300 mm/yr. Maximum values in the order of 140 mm/month are quoted for summer, while relatively low pan-evaporation values of around 70 mm/month were measured during the months of December and January.
The hydrogeology of the aquifer consists of one sedimentary basin; the post-Eocene marine clay (Saqiya Group), forms the bottom of the aquifer. Pleistocene sedimentary deposits of alluvial sands, graded gravel, conglomerates, pebbles and mixed soils constitute the regional hydrological system. Intercalated clay deposits of marine origin separate these deposits, and are randomly distributed in the area. The Gaza aquifer can be divided into three sub-aquifers (A, B, C). It is implied that subaquifer A is phreatic, whereas subaquifers B and C become increasingly confined towards the sea. Current rates of aquifer abstraction are unsustainable and deterioration of groundwater quality is documented in many parts of the Gaza Strip. Saltwater intrusion presently poses the greatest threat to the municipal supply and continuous urban and industrial growth is expected to further impact the water quality.