لخّصلي

The main water bearing formation in the Tenth of Ramadan City is the Pleistocene deposits.From the few pumping tests carried out on a number of wells in the area of study, the hydraulic conductivity of the aquifer was found to varies from 30 to 70 m/day and the average specific yield reaches to about 0.2 (The change in groundwater depth of the Pleistocene aquifer towards the south of the area under study is mainly attributed to faults and topography along Cairo-Ismailia Desert Road and south of the Tenth of Ramadan City area (Islam, 1996).The main known inflow resources of water to the aquifer are seepage from Ismailia Canal, the return flow after irrigation in the agricultural lands, the replenishment from the desert wadies and seepage from the main groundwater aquifer of the Nile Delta.The Pleistocene aquifer in the studied area exists under unconfined conditions allover the area and the groundwater is situated in porous material of clastic origin with thickness varies from 75m to 200m.The aquifer is underlain by low permeable sandy limestone of Miocene age and overlain by high permeable Holocene sediments (Abdel-Karim, et al. 1999).The main known outflows of groundwater from aquifer are of abstractions by pumping from the productive wells at the water well field which is

located northwest of the Tenth of Ramadan City.The groundwater depth of the Pleistocene aquifer varies by time from about 70-110 m at 1968 (Khalil, 1968) to about 65-125 m at 1980 (Ministry of Irrigation, 1980) to about 37-85 m at 1993 (Islam, 1996) and about 85-70 m at 2004 (The present work).The relative decrease in groundwater depth by time indicates an increase in the recharge resources to the aquifer from wastewater disposal by time.It is composed of graded sand and gravel intercalated with thin clay and silt lenses and some sabkha deposits.4).

The main water bearing formation in the Tenth of Ramadan City is the Pleistocene deposits. It is composed of graded sand and gravel intercalated with thin clay and silt lenses and some sabkha deposits. The aquifer is underlain by low permeable sandy limestone of Miocene age and overlain by high permeable Holocene sediments (Abdel-Karim, et al. 1999). Accordingly, the pollutant travel times to the saturated zone will generally be short. The Pleistocene aquifer in the studied area exists under unconfined conditions allover the area and the groundwater is situated in porous material of clastic origin with thickness varies from 75m to 200m. Its thickness increases towards Ismailia Canal and decreases due south and southwest directions.

Figure (3) shows the location of the studied water points while table No.1 shows the basic hydrogeological data of the available water wells. The depth to groundwater varies generally between 58m and 70m. The groundwater depth of the Pleistocene aquifer varies by time from about 70-110 m at 1968 (Khalil, 1968) to about 65-125 m at 1980 (Ministry of Irrigation, 1980) to about 37-85 m at 1993 (Islam, 1996) and about 85-70 m at 2004 (The present work). The relative decrease in groundwater depth by time indicates an increase in the recharge resources to the aquifer from wastewater disposal by time. The change in groundwater depth of the Pleistocene aquifer towards the south of the area under study is mainly attributed to faults and topography along Cairo-Ismailia Desert Road and south of the Tenth of Ramadan City area (Islam, 1996).

The average groundwater level in the Pleistocene aquifer ranges from +15m to +19m (Fig. 4). The high water level near Ismailia Canal is attributable to the effect of the canal as a recharging stream for the aquifer. Some anomalies exist due to the local groundwater extraction and infiltration processes.

The available data indicates that the groundwater level of the Pleistocene aquifer in the area of study varies by time from about 8-9 m at 1996 (Islam, 1996) to about 6-9 m at 1997 (El- Araby, 1997) and about 15-19 m at 2004 (The present work). The relative increase in the groundwater level by time indicates an increase in the rate of the recharge to the aquifer from

wastewater disposal by time. The data available for water levels in the Pleistocene aquifer were used to establish the

directions of groundwater flow in the area. Initially, the main direction of groundwater flow is northeast. Due to the activities that have accompanied the settlement (since 1982), some anomalies have developed especially at the water well field and the oxidation ponds. The main known inflow resources of water to the aquifer are seepage from Ismailia Canal, the return flow after irrigation in the agricultural lands, the replenishment from the desert wadies and seepage from the main groundwater aquifer of the Nile Delta. However, another local source of recharge is the seepage from the nearby oxidation ponds. The main known outflows of groundwater from aquifer are of abstractions by pumping from the productive wells at the water well field which is

located northwest of the Tenth of Ramadan City. The well field consists of 24 production wells with a maximum discharge rate of about 60,000m²/day. However, indirect discharge occurred towards Suez Canal.

From the few pumping tests carried out on a number of wells in the area of study, the hydraulic conductivity of the aquifer was found to varies from 30 to 70 m/day and the average specific yield reaches to about 0.2 (