© IDOSI Publications, 2008 Evaluation of Water Quality of Groundwater Recharge in

A study was carried out during winter 2007-2008 at Ghor Feifa Jordan Valley weir to estimate the quantity and quality of artificially recharged water originating from wadi Feifa surface runoff due to construction of diversion weir at its downstream. Results showed that there was a meaningful relationship between the quantity and quality of the stream feeding the diversion weir and groundwater quality exist. The amounts of water recharging local aquifers were estimated to be 0.15m /m/h. The major ionic concentration of 3 the water in the investigated site at different periods indicated that there is an increase in TDS during the first two months of the investigated period due to no rain during November and December 2007; thereafter, during January and February 2008 a decrease in all ionic concentrations in both surface and groundwater was observed. This dilution effect is due to recharge during rainfall periods on the mountainous region of Tafileh area. Stable isotopic composition of water collected from surface and groundwater showed that both sources of water are plotted near the Eastern Mediterranean Water Line (EMWL) indicating same origin of water which is rain water without strong evaporation effect. The tritium concentration of both surface and groundwater were less than 1 TU (tritium unit) indicating that the most probable source of water in the investigation area is from old groundwater in form of base flow in addition to treated wastewater. Results also showed that the recharge rate ranged from 0.05 to 0.21m /m. These results were in agreement with the measurements of static water level 3 recorded in the monitoring wells downstream as the water level raised about 5 cm within three months which is located very close to the diversion weir.


INTRODUCTION
In arid and semi-arid areas, assessment o f Limited water resources in Jordan are a national determining the sustainable yield of aquifers as recharge problem due to limited recharge, population growth and rates are generally low.In the current study, the increasing demand from industry and agricultural sectors.
groundwater recharge was estimated as defined by Lloyd These constraints led to deterioration of water quality and [2] on the basis of average annual rainfall: hyper-arid: 0-50 declining of water level.Therefore conservation of the mm/yr; arid: 50-200 mm/yr and semi-arid: 200-500 mm/yr.existing water resources is essential.
Number of researches was conducted on recharge To face the high water demand, groundwater calculations in Jordan.Recharge to the Rijam (B4) aquifer resources had been exploited at rates much higher than takes place in the mountainous highlands of Shoubak those of the recharge where the difference between lying to the west of the Jafr Basin.Direct recharge by demand and supply exceeds 175 MCM annually [1].In precipitation is negligible, because of the surface area of 1994, Jordan launched a program to explore the use of the playa, where floodwater collects, is covered by very groundwater artificial recharge with the aim to offset some fine sediments, which do not allow for the rapid infiltration of the problems caused by this overexploitation.
of recharge water.The total recharge to the B4 aquifer is groundwater recharge is one of the key challenges in World Appl.Sci.J., 5 (1): 88-93, 2008 around 7 MCM/year [3].In the National Water Master directly to Wadi Feifa at annual discharge of about 0.33 Plan of Jordan [4], the renewable groundwater amount, MCM. which does not appear as base flow is calculated to be Groundwater resources in the study area are 23 MCM/year.The recharge to the aquifer takes place in presented by the pumped wells and the springs the highlands of Irbid and Ajlun and further to the encountered in the catchment area, while surface water northeast beyond Jordan's territories.The deeper lying includes spring flow and flood flow.aquifers of A4 and Kurnub release some water to the B2/A7 in an upward movement, through the overlying METHODOLOGY aquiclude because their piezometric heads are higher than those of the B2/A7 [5].El-Nasser [5]

calculated a recharge
Field Works: Field visits to the investigation area were to this aquifer of 127 MCM/year, with base and spring carried out during winter 2007-2008 to fulfill the aim of this flows of 100 MCM/year.In this figure the groundwater current study.Wadi Feifa Diversion weir, which is the resources extending to Wadi Yabis, Wadi Jurum, Wadi focal point of this investigation and groundwater El-Arab and the Yarmouk River are included.There are downstream were sampled at different periods for 18 desert dams storing about 31 MCM for the purpose of chemical analysis to find the impact of surface runoff animal watering and artificial groundwater recharge.In during winter period on its water quality.The discharge of addition, there are a number of water harvesting projects the base flow of Wadi Feifa was measured using current that utilize the surface water in forms of large ponds and meter and portable weir (16 cm size).The historical data small earth reservoirs [6].
were also compiled from the Ministry of Water and The main objectives of the current study are to Irrigation (MWI) open files.The discharges of the springs examine the recharge efficiency of the Feifa Diversion located in the catchment area were measured as well.Weir for proper management and development of the aquifer systems, investigate the impact of artificial Laboratory Works: The chemical analyses of the recharge on groundwater quality and to determine of the collected water samples were conducted at the quantity of groundwater recharge in the investigated laboratories of the Ministry of Water and Irrigation.The area.
analysis comprises the following cations and anions such Four measuring sites of 350 m long were selected up to form Wadi Feifa with annual surface water discharge of and down of the diversion weir to estimate the recharge about 4.56 MCM.Groundwater resources in the study rates.Results showed that the recharge rate ranged from area consist mainly of springs discharge.Wadi Feifa 0.05 to 0.21m /m (Fig. 2),which was in agreement with the contains 22 springs emerging from different aquifers in the measurements of static water level recorded in the area, there average discharge range from 0.3m /hr for monitoring wells downstream as the water level raised The wet pluvial season during winter 2007/2008 was Conductivity (EC) every year where it was low at the end below average as the precipitation fall during the of winter seasons rising to its maximum value at the end investigated period was around 50% of its annual average of summer season.Generally, there is a slight increase in for this time of the year.Therefore, the water quality of salinity with time which is much lower than expected this season will be higher salinity than its normal under high abstraction amounts that it is attributed to the situation.The water quality of the investigated area is recharge of Feifa stream into the groundwater of the area.affected by the amount of discharge from different Stable isotopic composition of water collected from sources which are springs base flow from Tafileh area, surface and groundwater are shown graphically in Fig. 5. effluent from Tafileh treated wastewater treatment plant The results showed that both sources of water are plotted during summer season in addition to a new source of low near the MMWL indicating same origin of water which is salinity water originates from floods along Tafileh region rain water without strong evaporation effect.during winter seasons.
The tritium concentration of both surface and The major ionic concentration of the water in the groundwater were less than 1 indicating that the most investigated site at different periods during winter probable source of water in the investigation area is from 2007/2008 is shown in Fig. 3. Results indicated that there old groundwater in form of base flow in addition to treated is an increase in TDS during the first two months of the wastewater source.This can be due low amount of rainfall investigated period due to no rain during November and which had no significant impact on groundwater quality December 2007, whereas, during January and February as well as the ratio of rainwater to base flow and effluent 2008 a decrease in all ionic concentrations in both surface from wastewater effluent was too low.and groundwater was observed.This dilution effect of the surface runoff and groundwater during the later two CONCLUSIONS AND RECOMMENDATION months is due to recharge during rainfall periods a s mentioned above where the fresh water component Results of this investigation showed the followings: originated from rainfall of low ionic content [7] on the mountainous region of Tafileh area reached the area.The C The selected site was suitable for artificial recharge effect of dilution is supported by the amount of recharge purposes as shown in Fig. 2 due to the dissolution effect of carbonates.Comparing the investigated area by around 5 cm within three months water salinity of surface water with groundwater during period.different periods it was found that surface water was of lower salinity than groundwater which can be due to It is highly recommended to establish similar sites longer contact period between rocks and water in the along the Jordan valley to improve both quality and aquifers.
quantity of its resources.High pH of the water at the beginning of the experiment ranged from 8.6 to 8.7, high pH raised the ACKNOWLEDGMENT formation of CO which is found at pH above 8. 3 [8].The Sincere thanks for UNESCO for their financial support produced from Tafileh wastewater treatment plant.The of this investigation.We are very thankful to his high pH in both surface and groundwater decreased to Excellency Eng.Khaldoon Kheshman for his support to 7.6-7.7 with occurrence of winter flood as the floods the project team during this investigation.originated from rainfall had almost neutral acidity due to the buffering effect of CaCO .REFERENCES The effect of water recharge on groundwater quality for a long period (1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)