Assessment of groundwater potential and pollution risk using mathematical modeling case of Gash basin, Kassala Area

مقدم أطروحة جامعية

Muhammad, Sayf al-Din Yusuf

مشرف أطروحة جامعية

Hajaz, Yasin Abd al-Salam

الجامعة

جامعة أم درمان الإسلامية

الكلية

كرسي اليونسكو للمياه

دولة الجامعة

السودان

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2009

الملخص الإنجليزي

This study has been carried out in the Kassala area which is situated between latitudes 15° 31''-15° 20.3'' north and longitudes 36° 14''-36° 32'' east covering an area of 232 Km2 in Eastern Sudan .It is typically a semi arid area with an annual rain fall of 247mm.

the purpose of this study is to predict the behavior of the hydraulic system of the Gash aquifer towards groundwater abstraction by using numerical models.

The study also deals with the general hydrogeology of the Kassala area and the sources and magnitude of pollution .Both field and laboratory methods were carried out to achieve these objectives (several soft ware programs were employed) The main aquifer in the Kassala area is constituted by the alluvial sediments of the Gash River which are composed of fine to coarse grained sandy, gravelly deposits.

This aquifer is mainly under non confined conditions and the groundwater levels vary from 3mto25m below the land surface.

The groundwater movement is parallel to the Gash River toward the North West.

The permeability of the aquifer varies from moderate to high pending on the lithology of the aquifer.

The recharge of groundwater is mainly derived from the infiltration of the surface water of the Gash River during the flood season.

It is equal to 96 million cubic meters per year.

The total annual groundwater abstraction amounts to 108million cubic meters and groundwater storage is equal 384 million cubic meters.

Monitoring of the groundwater levels indicated a long decline trend during the last three decades .However there is state of partial hydrologic equilibrium in the last decade and the groundwater levels remained slightly stable The groundwater of the study area is characterized by a calcium carbonate water type with light to moderate hardness it is dominated by alkaline earth and weak acids.

The salinity is generally low but Wad shereifi, Northern Sawagi areas contain brackish groundwater. The groundwater of Kassala area is under saturated with anhydrite, aragonite, gypsum and fluorite.

It is slightly saturated with calcite and dolomite.

Such minerals occur in the aquifer sediment in the kanker and caliches deposits Groundwater modeling predicts that the designed abstraction rates of the city supply are not sustainable and it is expected that the decline of the water level in the pumped areas will continue and after 20 years of operation the expected drawdown will reach 3 m in the northern and the southern parts of the Kassala area.

It is expected that many wells will become dry with a significant decrease in the yield of the other wells because of the reduction in the saturated thickness. The modeling shows that after 20 years more Nitrate contamination zones will be encountered in the (western, northeastern and southeastern parts).

High concentration of NO3 (500mg / l) contaminants from the south can travel and eventually will reach the north (the north Sawagi area). Based on this study several recommendations are proposed to protect the Gash alluvial aquifer from depletion and pollution hazard

التخصصات الرئيسية

علوم الأرض و المياه و البيئة

الموضوعات

• التلوث
• النماذج الرياضية
• المياه الجوفية
• السودان
• كسلا(ولاية)

عدد الصفحات

161

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-392613