Environmental Isotopic Characterization of Groundwater and Surface Water in Northeast Missan Province,South Iraq

The present work studies the environmental isotopes assess groundwater characteristics of the different parts of the main aquifer in the northeast Missan Province in south of Iraq.Water samples of groundwater and surface water were collected for two dry and wet seasons during the water year of 2011–2012.The study shows that most of the groundwater in the aquifer falls above the global meteoric water line,and all the samples fall below the Mediterranean meteoric water line,indicating that these samples are a mixture of two water types.The tritium content of these samples supports this conclusion.The overall conclusion of this study indicates that there are two sources of groundwater recharge in the studied area:the ephemeral streams(Teeb and Dewerge) and major precipitation sources.According to the tritium levels at or below one tritium unit(TU) obtained from the water,supply wells are highly confined or "not vulnerable".Overall,the 3H results imply that recent recharge has taken place during the last four to five decades.In the recharge area,the high tritium content in the southern part of the Teeb area suggests that the recharge originates from rapid infiltration of surface runoff.Therefore,the groundwater resources in the study area should be protected from contamination,because it will influence the aquifer in a relatively short period of time if any contamination enters the recharge areas of the aquifer.     

Implementation of Rock Typing on Waterflooding Process During Secondary Recovery in Oil Reservoirs: A Case Study,El Morgan Oil Field,Gulf of Suez,Egypt

Waterflooding is one of the most common secondary recovery methods in the oil and gas industry. Globally, this process sometimes suffers a technical failure and inefficiency. Therefore, a better understanding of geology, reservoir characteristics, rock typing and discrimination, hydraulic flow units, and production data is essential to analyze reasons and mechanisms of water injection failure in the injection wells. Water injection failure was reported in the Middle Miocene Hammam Faraun reservoir at El Morgan oil field in the Gulf of Suez, where two wells have been selected as injector’s wells. In the first well (A1), the efficiency of injection was not good, whereas in the other analog A2 well good efficiency was assigned. Therefore, it is required to assess the injection loss in the low efficiency well, where all aspects of the geological, reservoir and production data of the studied wells were integrated to get a complete vision for the reasons of injection failure. The available data include core analysis data (vertical and horizontal permeabilities, helium porosity, bulk density, and water and oil saturations), petrographical studies injection and reservoir water chemistry, reservoir geology, production, and injection history. The quality of the data was examined and a set of reliable X–Y plots between the available data were introduced and the reservoir quality in both wells was estimated using reservoir quality index, normalized porosity index, and flow zone indicator. Integration and processing of the core and reservoir engineering data indicate that heterogeneity of the studied sequence was the main reason for the waterflooding inefficiency at the El Morgan A1 well. The best reservoir quality was assigned to the topmost part of the reservoir, which caused disturbance of the flow regime of reservoir fluids. Therefore, it is clearly indicated that rock typing and inadequate injection perforation strategy that has not been aligned with accurate hydraulic flow units are the key control parameters in the waterflooding efficiency.

     

Impacts of rising water demands in the Juba and Shabelle river basins on water availability in south Somalia

ABSTRACT

Somalia has frequently been affected by droughts, famines and water-related humanitarian crises. Water is scarce and the only perennial streams, the Juba and Shabelle rivers, are trans-boundary with river flows mainly originating from the Ethiopian highlands. In both riparian countries water demands are projected to increase. This paper reveals the impact of rising regional water abstractions on stream flows by illustrating sectoral demands and joining them into scenarios of medium and high population and economic growth. These scenarios are associated to the time horizons of 2035 and 2055, respectively. The scenarios disclose alarming trends especially for the Shabelle River: in the medium and high growth scenarios, water demands surpass the available river flows by 200 and 3500 hm³, respectively. The calculated deficits partly derive from conflicting assumptions about river flows by the two main riparian countries, an obstacle to any integrated planning efforts and sustained regional development.

EDITOR Z.W. Kundzewicz; ASSOCIATE EDITOR F. Hattermann     

Delineation of groundwater zones using lithology and electric tomography in the Khartoum basin, central Sudan

The three towns of Khartoum, Omdurman and Khartoum are located north of the capital of Sudan. This capital has agglomerated to reach more than 7 million inhabitants. The present situation is confronted with a dramatic shortage in freshwater supply. The treatment of surface water from the Nile became costly, particularly in flood season. Thus the authorities turned towards developing groundwater resources. The electric tomography, obtained by the combination of Vertical Electrical Sounding (VES) and well logs, turned out to be very efficient to provide a complete electrical image of the underground from the surface until about 200-m depth. This methodology constitutes a very cheap guide for the evaluation of the quality of groundwater resources in the Khartoum area. To cite this article: M.T. Hussein, H.S. Awad, C. R. Geoscience 338 (2006).     

The surface distortion caused by the tides in galactic binary system

Analytical expression of the equi-potential surface and the distorted potential by tidal effect for binary galactic system has been derived. The comparison between the numerical results and the observed data has been given.     

Use of treated wastewater for managed aquifer recharge in highly populated urban centers: a case study in Addis Ababa,Ethiopia

Fast population growth and rapid industrialization, on one hand, and lack of sewerage network and poor living condition, on the other, have led to the deterioration of surface and ground water quality in the city of Addis Ababa. The urban wastewater is discharged largely into streams that drain the city. Only less than 3% join the wastewater treatment facilities. Due to sporadic rainfall that causes shortage in groundwater recharge, managed aquifer recharge (MAR) experiment was tested on soil column collected from Akaki Well Field which is located in the southern part of the city using water from the Big Akaki River that crosses the same well field and effluent from Kaliti Wastewater Treatment Plant. Water quality analysis for 17 different parameters was done for both the inflow and outflow water samples and soils were tested for electrical conductivity and cation exchange capacity. The results indicate improved water quality as a result of higher attenuation/filtration capacity of the vadose zone in the well field due to the presence of vertisols. The main geochemical processes that have acted in the soil column could be cation exchange, dissolution, precipitation, oxidation, nitrification, die off etc. that are responsible for the effectiveness of vadose zone for MAR.     

Impact of land cover changes and topography on soil quality in the Kasso catchment,Bale Mountains of southeastern Ethiopia

This study assessed land cover change and topographic elevation on selected soil quality parameters in the Kasso catchment, southeastern Ethiopia. Twenty‐seven soil samples collected from 0–30cm depth under four land cover types across three elevation gradients were analysed for selected soil quality parameters. Results indicated that soil particle size distribution is different (p<0.001) in the catchment because of the effect of land cover change and elevation. Most cultivated lands occupy lower elevations where clay accumulates as a result of its movement from higher to lower elevations. Ploughing accentuates weathering, making cultivated lands richer in finer materials. Cation exchange capacity and exchangeable magnesium and potassium negatively correlated with elevation, total nitrogen and available phosphorous. Conversion of natural vegetation to cropland contributed to changes in pH (p<0.05), exchangeable calcium (p<0.01), potassium (p<0.001), available phosphorous (p<0.01) and nitrogen (p<0.01) contents. Parameter soil degradation index results showed that soil organic carbon, nitrogen, available phosphorous and exchangeable potassium contents declined and bulk density increased because of the land cover change. This negative effect on agricultural development and environmental health of the catchment makes an integrated land resource management approach indispensable for sustaining agricultural productivity and the environmental health of the Kasso catchment.