3. HISTORICAL REVIEW OF THE LAND- AND WATER USE IN LOWER JORDAN
3.3 I MPLICATIONS FOR THE GROUNDWATER B UDGET
In this subchapter the impact of the previously described historical review of the development of the Jordan Valley on the groundwater budget will be discussed. For this discussion groundwater level information of all available wells in the study area was collected from various reports (Ionides 1939, Tleel 1963, Hizrallah 1973, BGR/WAJ 1996, MWI open files). In order to compare water table fluctuations from wells drilled in different locations (with different elevations about ground level and water level depths), the individual water levels were normalized. For every considered period the highest water level recorded in each well was set 0. In this way a direct comparison of the different wells is possible.
3.3.1 Prior to the development of the Jordan Valley
In the Jordan Valley, apart from some hand dug and tube wells, no deep wells existed prior to the 1950s. The groundwater system in the alluvial aquifer was only anthropogenic influenced indirectly.
The diversion of surface water at the outlets of the major wadis for small scale irrigation projects reduced infiltration into the alluvial aquifer. The observation wells drilled during the project “The water resources of Transjordan and their development” in 1938 were the first deep wells drilled within the study area (Fig. 3-8; Fig. 3-9).
Fig. 3-8: Location of the wells drilled in 1938. The bold black numbers refer to the numbers given by the Ionides report. The gray ID code refers to the well ID code of the MWI.
The water tables in these wells were monitored on a monthly basis until 1941. Since no other wells were drilled during that time these measurements priovide valuable information about the uninfluenced groundwater system in the area. The water tables were not influenced by pumping neither within these wells nor by adjacent wells. In terms of water table fluctuation the wells AB 1273 (Ionides Well No. 14) and AM 1032 (Ionides Well No. 15) have similar trends. Both show an annual variation, reaching their highest water levels during summer and their lowest in the winter season.
Whereby AB 1273 reacts more closely to precipitation events than AM 1032 (i.e. after the rainy season 1939/40). In general the water table in AB 1273 rises about one month earlier and reaches its highest levels also one month earlier than AM 1032.
Well AB 1046 (Ionides Well No. 11) shows no annual variation, but rather a seasonal one. Its water level rise goes along with two seasons of intensive rainfall (1938/39 and 1939/40). A decline in the water table can be seen after the relatively dry rainy season of 1940/41, which undermines the hypothesis of a direct response to a seasonal trend. An explanation can be found in the location of this well. It is located relatively in the middle of the eastern border of the study area, between the major wadis draining surface water to the Jordan Valley. No influence of surface water percolation takes place. Groundwater inflow from the adjacent consolidated aquifers is also not expected. The well was drilled in the continuation of the Wadi Kafrein Syncline. Groundwater inflow into the alluvial aquifer is believed to happen more along the continuation of the Wadi Kafrein and Wadi Shueib flexures (chapter 2.2.3.3). The flow path to AB 1046 happened consequently via the fan apex of Wadi Kafrein in the alluvial aquifer to the north. High transmissivities together with a low gradient within the alluvial aquifer would lead to a weakening signal and to a more seasonal trend, rather than a monthly one. The major rise of the water table in the both consecutive wetter years (1938/39 and 1939/40) took place in March. In both years the rainy season started intensively in November. So the major rise took place with a delay of about four months and took place around two months later than in the other two wells described before.
Fig. 3-9: Relative water table fluctuation in the observation wells and monthly precipitation recorded at the rainfall station in Madaba for the period 1938-41 (well data taken from Tleel 1963, precipitation data taken from MWI open files).
3.3.2 Beginning of the early development phase in the Jordan Valley, the events of 1968 and their aftermath
In the study area the major well drilling took place at the beginning of the mid fifties. This lead to an ever increasing groundwater abstraction. Fig. 3-10 shows the sharp drop in the water level between the pre-development period and the beginning of the 1960s, a time of heavy groundwater abstraction.
During that period the groundwater level in the area of South Shuneh (AB 1273) dropped by more than twenty meters. Regardless of the intensity of rainfall (for the period from 1963 to 1967) the water level in well AB 1340 (located in the area of South Shuneh) decreased constantly. Intensive groundwater abstraction during this period can be assumed. Well AM 1032 (located in the area to the south of Kafrein) shows a different behaviour. The fluctuation of the groundwater table still follows a seasonal trend, which indicates either less groundwater abstraction or higher recharge to the unconsolidated aquifer in this area compared to the area of South Shuneh.
3 Historical review of land- and water- use in lower Jordan Valley
The sharp rise of the groundwater table during the year of 1967 can be attributed to the intensive rain season of 1966/67 and not, as one might think, to the events of 1967 (Fig. 3-12). The smaller decline of all groundwater tables in Autumn could also be a result of the construction of dams at the outlets of Wadi Shueib and Wadi Kafrein. The consecutive rainy season (1967/68) was rather poor in terms of rainfall quantity. However, in 1968 the sharp depletion that usually occurs after the groundwater table reaches its peak in August to September is missing. The drop is rather small in the area of South Shuneh in particular. This can be explained by minor pumping activities and might be attributed to the effects of the battle of Karameh (March 21, 1968) and its aftermath. As described by Khouri (1981) during this period many farmers abandoned the Jordan Valley for the safer mountain regions and came back only on rare occasions, i.e. to do the necessary irrigation. None or only a few planting activities were reported. This is reflected clearly in the groundwater tables (Fig. 3-12). It should be noted, that for some intervals, where the water table is constant, the recording of AB 1338 must be questioned.Fig. 3-10: Water level changes in study area between 1938 and 1966 (Tleel 1963 and MWI open files). Between 1941 and 63 no measurement records were available.
Fig. 3-11: Location of the wells monitored from 1962 to 1972 and 1980-2002 (MWI open files).
Fig. 3-12: Relative water table fluctuation in the observation wells and monthly and annual precipitation values recorded in Naur for the period 1962 till 1971 (MWI open files).
3.3.3 Period 1980-1989
The wet years of 1980/81 and 1982/83 lead to an increase in water level in all wells (Fig. 3-13). An exception is well AB 1342. It shows an almost constant head for its recorded period. Its location could be a possible explanation. The Sweimeh Observation well (AB 1342) is located near the village of Sweimeh, where recharge to the alluvial aquifer is different from the area of Kafrein and South Shuneh.
The effect of the final extension of the Extended East Ghor Canal on groundwater resources can be clearly seen in the constant rise of water levels in the area of South Shuneh (Fig. 3-13). Although the year 1987/88 can be considered as a year of above average rainfall. Therefore, a major rise in the groundwater table can be expected. The decline of the groundwater table during the winter season is very small. The consecutive rainy season can be regarded as nearly average. But even after this season the rise of the groundwater table is high. Recapitulatory it can be said, that after the final extension of the canal went into service, the stress on groundwater abstraction in its area of influence was reduced.
In the area of Kafrein, an area which is not connected to the canal, a decrease in groundwater levels could be observed (Fig. 3-13). This is very obvioust when the groundwater tables of the wells in the Shuneh area (AB 1340 and AB 1341) are compared to the water levels in the Kafrein Observation well (AM 1032) for the rainy season 1988/89.
3 Historical review of land- and water- use in lower Jordan Valley
Fig. 3-13: Relative water table fluctuation in the observation wells and monthly and annual precipitation values recorded in Naur for the period 1980 – 89 (MWI open files).
3.3.4 Period 1990- 2002
The most eminent feature of this period is the intensive rain season of 1991/92 (Fig. 3-14). As a consequence a sharp rise in groundwater levels can be observed in all well records. The only exception is well AB 1342. Its hydrograph can be understood for reasons discussed above. This well is left out in the following considerations. The rise of the water level in terms of quantity is lowest in AB 1338. The sharp increase of its water table occurs later than in the other wells, indicating a different recharge mechanism and flow path. The increase of the groundwater level in this well happens after a two months delay and it takes place over a wider time span, but with a much smaller increase. While the water level in well AB 1338 increases for six to seven months, the water level in well AM 1032, which is located around three kilometres to the north of AB 1338, increases sharply for a period not longer than 4 months. The rain intensive season of 1991/92 is followed by seasons of very poor rainfall. Consequently the water level show a fluctuating decrease until the wetter season 2001/02.
Unlike in pervious periods well AB 1341 and AB 1340 show only one peak in a period ranging from February till April. The second peak, that usually occurred in August vanished. The seasonal low stays in the period before the rainy season (September to October). A possible explanation for increased pumping activity might be the adding of an additional planting season.
Fig. 3-14: Relative water table fluctuation in the observation wells and monthly and annual precipitation values recorded in Naur for the period 1990 – 2002 (MWI open files).