arb3at hydrology

1Location and aerial extent:
Arbaat valley is basin located at a distance of 35KmNW of Portsudan town confined between longitudes’ 37⁰ and36⁰ 15̒E and latitudes 19⁰ and20⁰N. It’s structurally controlled between the upper and lower gates.
The valley is measured approximately 13Km in Its area (Fadlallah) (2003). It can be possible accessed through and paved tracks,
Arbaat basin represents the main source of Portsudan supply.
1-2 Topography and drainage patterns:-
Generally the catchment area is hilly of elevation ranging from400- 800m a.m.s.l dissected by small creeks pouring through arbaat upper gate controlled by a distance of about 15Km1,e the gradients(182-140/15000)=0.0028
1-3 population and economic activities:-
Most of the people Scattered around and within the hilly area. Most of the in habitants in Arbaat are engaged in grassing sheep; cultivation. Some are paid workers in number of governmental cooperation,
1-4The climate:
The climate of Arbaat is semi-arid to subhumid,the dialy temperature ranges from 18⁰c in winter to 42⁰c in the summer .the manual precipitation average between 70mm/year to100mm/year, there are two periods of rainfalls, one during the summer(Jun-September) and during the winter (October-Jan)in the area between upper and lower gate and the coastal plains.
1-5 Soil and vegetation cover:
The vegetation spread depend on the soil type and the intensity of rainfall .In Arbaat some trees and bushes sparse through the area along the wadi extent, such as acacia.The delta contains clay and silt sediments so that its suitable for cultivation in spite of brackish water tapped at shallow depth.
1-6 the previous studies:-
The studies were carried since the beginning of 20th century after during and after the establishment of Port Sudan harbor (1904).
According to the importance of Arbaat valley as the main water source providing the city with potable water there are mainly studies carried out from different views by governmental sector by researches’ Garb ham (1904) Kennedy (1911) Thomson (1924) white man (1971) .But the first comprehensive hydro geological investigations was done by (hussein1975) and followed by detailed geophysical and hydro geological studies by (Fadlallah2003) .
Sira.Giba and partners (1980) study the availability of surface water exploration at the upper gate of khor Arbaat and the water distribution system of Portsudan town ,the study but the idea of construction of the slow sand filter near the upper ,this idea is not success, because the sand filter was clogged after one year of this construction.
1-7 The present study:-
This study was done during November 2008 in Arbaat area by the 5th year student in faculty of earth science Red Sea University (hydrogeolgical department)
1-8 The objective of study:-
The main objective of the work is to train the fifth year students for how collect explore and evaluated the water in the basin and collect data in the field .Also show to analyze and represent the data in the graphical from manually as well as by using soft ware techniques.
The secondary objectives are:-
i-To study the fluctuation of water level due to the effect of the most at 3.2Km upper stream.
ii-To determine the actual thickness and porosity of the aquifer and to correlate the present valium with already obtained in
iii-To study the hydraulic parameter of the aquifer.
iv-To study the chemistry of water bearing strata along the valley.
1-9 Methodology:-
The flowing proceedings and new techniques are adopted during this investigations
Office work:-
1) Collection of pre-existing data.
2) Review of previous literatures.
3) Prepared broad topographical and satellite image map with scale 1=250.000.
4) Review Hydro geological and chemistry soft ware’s (aquietest & plotchem) which are used for analysis of the collected data .
Field and laboratory work:-
In the field during 19/11/2008,the following hydro geological investigations were carried out .
1) Well inventory along the basin in which the coordinates, Water table, Ec, PH, total depth and type of wells are explored.
2) The location of all civil works , upper dams side damps and main pipe lines are inventoried.
3) The Water samples were chemically analyzed.
1-10 well inventory:
The number of wells drilled in the area estimated of about 100 wells. The first one drilled in (1924) by (the international Water corporation of towns, Red Sea). Most of screens are Johnson type, the installed pumps are submersible pumps, and the tube casing used 8 5/8 inch 10 ¾ inch. The number of working wells during this trip is 14 wells