تقييم الحقل الاصطناعي منطقة حوض (بلاي ؟بليوستوسين) حالة دراسية: العوجا
Date
2015-04-18
Authors
كيان صبري رشاد مناصره
kayan sabri rashad manasra
Journal Title
Journal ISSN
Volume Title
Publisher
AL-Quds University
جامعة القدس
جامعة القدس
Abstract
Al Uja area locates in the Lower Jordan Valley/West Bank, which is a part of shallow
lower eastern aquifer located at an elevation of -220 m in the west to -280 m ( b.s.l). The
availability of ground water, fertile soil, and warm climate during winter months make it
remarkable for its agricultural activities where 600 hectares are under irrigation.
There are two sources of water available at Al Uja area ; these are Al Uja Karstic spring
that drain water from the Mountain carbonate aquifer system with a discharge rate between
0.5 and 8 MCM/a , and nine groundwater boreholes that tape water from the shallow PlioPlistocene
aquifer system, with an annual abstraction of 0.7 MCM/a .
The south-north fault system of the Jordan Rift Valley separates the two aquifer system.
The shallow aquifer system locates to the east of the fault, where the Mountain aquifer
system locates to the west. The Mountain aquifer consists of high fractured and karstified
limestone and dolomite of Upper Cretaceous age, and the shallow aquifer system consists
of gravel, sand, silt, and clay layers of the Dead Sea group.
Groundwater flows from the Mountain aquifer in the west to the Shallow aquifer in the
east through the major fault system. 15% of the Al Uja spring discharge infiltrated into the
Upper Mountain aquifer system and indirect to the shallow system.
The permeability of the Mountain carbonate layers is 2.49*10-1 m/min and decrease to
1.6*10 -2 m/min in the layers of the Shallow aquifer system, this decrease of Kf-value east
wards cause a semi-barrier for groundwater flow regime, also water salinity increase from
1500 µS/cm in Mountain aquifer to 3000 few hundred m to the east of the fault and rise to
6000 µS/cm in the eastern part.
Lowering of water table and increasing salinity in addition to the presence of water
pollution are major obstacles facing the economical development of this region. Due to the
iv
limitation of natural recharge, and over pumping from shallow aquifer system, water
salinity increase and caused a major shift in cropping pattern during the last 30 years,
where more salinity tolerance vegetables and trees are becoming dominant crops.
The main goal of this study is to investigated and estimated different artificial recharge
technique at the area, which are infiltration surface pond, and borehole direct injection.
The surface pond consists of soft material of Lisan formation that consists of 22% sand,
23% clay, and 45 % silt.
The geo-electrical investigations inside the pond show that the wet front reach a depth of
2.5 m depth after 3 days and the infiltrated water velocity is about 9.6 * 10-4
cm/s.
according to this infiltrated water can reach the groundwater table after 50 days of
filtration.
Different volumes of water were injected in the selected borehole, the static water table
raised from 37 m to 34 meter below the ground after five min from the injection. After one
and half hour the static water table fall to the original static level after stop the injection.
The groundwater salinity of the borehole was decreased from 6000µS/cm to less than 550
µS/cm. The decrease of Ec –value through the well after injection test was cause of the
Calcite precipitation.
Our investigation recommended Borehole injection method is the best option for direct
artificial recharge in Al Uja area within the boundary of the Plio-Plistocene shallow aquifer
system and possible to use the available nine boreholes as injection boreholes. And
artificial recharge using surface infiltration pond is not recommended.
Description
Keywords
الدراسات البيئية , Environmental Studies