Pollution of water for human consumption is a major environmental challenge in hundreds of towns across Sub-Sahara Africa. The objective of this work was to evaluate the degree of bacterial pollution of ground water sourcesas sources of safe drinking water consumed by local human communities living in urban and peri-urban zones of Bukavu town (eastern DR Congo). Populations living in these zones are generally disfavored in terms of safe watersupply services by the national water corporation (REGIDESO). This study was conducted in 2011 during the dry and rainy seasons from 15 ground water sources used by the population from these peri-urban zones as sources of safe drinking water and as source of safe water for other domestic needs. In total, 150 samples were taken from these water sources. During both rainy and dry seasons, 5 water samples were taken for every source. These samples were analyzed for their physic-chemical and bacteriological properties in comparison to world health organization standards. Results indicated that the degree of bacterial pollution of water was high (T=4.56, P<0.05) during rainy season (20.6 ± 25.3 total coliforms/100 ml of water on average) than during the dry season (3.10 ± 6.023 total
coliforms/100 ml of water on average) across all sources studied. Sources (sites) that were highly polluted included Mulehe I, Kaliba, Kahuranyi, Cemu, Bagira, Funu et Gihamba. Overall, bacterial pollution of drinking water sources was significantly (P<0.05) high during the rainy season than during the dry season. Similarly, cholera epidemic outbreak is high in these zones during the rainy season (September-December). In November-December 2011, more than 400 cases of death were registered in hospital and the victims were from these highly polluted areas where the study was conducted. In fact, the presence of Vibrio cholerae was detected in all rainy season water samples from these areas. The results of this study indicated that Vibrio cholerae is the principal dangerous pollutant agent of these drinking ground water sources used by more than half million people living in peri-urban areas and in over-populated areas in Bukavu town. There is a need to set a system of monitoring water quality for human consumption. Results (findings) of such a monitoring program may be used to inform policy makers and health agents on better strategies to control water pollution in Bukavu and in related Sub-Sahara African towns. There is a need for policy makers to develop new strategies to improve water sanitation and supply everyone safe drinking
groundwater in Bukavu Town. The adoption of water sanitation, rainwater harvesting technologies may help in areas where the national water corporation can’t be able to supply water in short to mid terms.

An investigation was conducted to assess the recharge of an alluvial channel aquifer that is located in Southern Africa. The investigation utilized stable isotopes, groundwater levels response to rainfall and infiltration tests as complimentary tools to identify and understand groundwater recharge processes of the alluvial channel aquifer. The alluvial channel aquifer is characterized by shallow water table conditions (<3 meters below ground level) and quick groundwater level response to rainfall events thereby justifying the application of the water level fluctuation (WLF) method to estimate recharges rates of the aquifer system. The recharging of the alluvial channel aquifers occurs through high preferential infiltration rates as enhanced by pathways created by tree rooting systems. Cavities and holes created by the burrowing animals also contribute to high infiltrations rates along the riparian zone. Saturated infiltrations rates in excess of 1 m/d were determined on the riparian zone of the alluvial channel aquifer. A groundwater recharge rate of 53 mm/year was determined for the alluvial channel aquifer. The groundwater Oxygen-18 (δ18O) and
deuterium (δ2H) compositions plot below the local meteoric water line (LMWL) indicating that the groundwater in the aquifer was exposed to evaporation prior or during the recharging process. The study shows that groundwater levels response to rainfall events can be used as a qualitative tool to distinguish between piston and preferential recharge mechanisms. In general, the study findings suggest that application of complementary tools to assess groundwater recharge can enhance understanding of the process.

Geoelectrical resistivity techniques are based on the response of the earth to the flow of electrical current. With an electrical current passed through the ground and two potential electrodes to record the resultant potential difference between them, we can obtain a direct measure of the electrical impedance of the subsurface material. The resistivity of the subsurface, a material constant, is then a function of the magnitude of the current, the recorded potential difference, and the geometry of the electrode array.

Depending upon the survey geometry, the data are plotted as 1-D sounding or profiling curves or in 2-D crosssection in order to look for anomalous regions. In the shallow subsurface, the presence of water controls much of the conductivity variation. Measurement of resistivity is, in general, a measure of water saturation and connectivity of pore space. Resistivity measurements are associated with varying depths relative to the distance between the current and potential electrodes in the survey, and can be interpreted qualitatively and quantitatively in terms of a lithologic and/or geohydrologic model of the subsurface.

This technique conducted at fifteen vertical electrical sounding (V.E.S) locations; were carried out, employing the expanding Schlumberger configuration, covering a radial distance of 5km from Ain Al-Faras spring area, of Gadames city, Libya, as a part of UNDP sustainable Human Development for Rehabilitation of the Old City of Gadames.

The qualitative and quantitative results of the field curves and space sections together with the available
geological borehole information were used to construct geo-electrical sections for the study area. The most common features characterizing these sections were the appearance of a fault or barrier zone. clearly shows that some of these faults or barrier zones were laterally displaced for a few meters these faults can be divided in two systems oriented in different directions; the first one, trending North-east South- west, whilst, the other one trending nearly in East-west direction. The main obvious feature demonstrated was the intersection between those different systems, in which a horizontal displacement had been occurred, and the trend and delineation of the topographic features of the investigated site strongly reflect the presence of such fault system, and according to the mentioned horizontal displacement (i.e. the intersection) of the fault system, Ain Al Faras spring had been developed, together with Ain
Tala spring few tens of meters to the North-West.

The effectiveness of geo-synthetic clay (GC) material as landfill liners using the system dynamics modeling
approach is the focus of this paper. Study area is the Local Government Area (LGA) in Ogbomoso land of Oyo State, Nigeria. These five LGAs include the urban (Ogbomoso North and Ogbomoso South) and rural (Oriire, Ogo Oluwa and Suurulere). The properties of focus on the material were hydraulic conductivity, porosity, thickness and placement slope. A mathematical model was developed by applying the governing equations coded in Visual Basic Computer programming Language. This model was validated with field data collected on the study area. The interrelationship of the properties and the breakthrough times for GC liner was found through the STELLA 9.1.4 software application. It was discovered from this research that GC liners were more effective in urban than rural LGAs. The GC liner is therefore recommended for use as landfill liner in the urban LGAs of the study area.