The studies on water absorption and density of concrete samples are important because both properties are believed to influence to some extent, the durability of the concrete. Gum Arabic (GA) and sawdust ash (SDA) are both natural and organic. These are used to study their effects on water absorption (WA) and density of concrete samples of the cube, beam, and cylinder, which are always used as test samples in concrete experiments. A concrete mix proportion of 1: 2.24: 2.71, with a cement content of 370 kg-m3, and water to a cementitious ratio of 0.5, were used to which GA dosage of 0.5 ％ wt. ％ of cement, and SDA in proportions of 0 ％, 10 ％, and 30 ％ by wt. ％ of cement was added. The study used four (4) mix levels to study the effects of the additions. Some of the findings showed that gum Arabic increased the water absorption and densities of GA-concrete. The addition of SDA to the GA-concrete mix reduced the water absorption for all the concrete samples. However, the addition of SDA to GA-concrete increased the densities of the cube but decreased those of the beams and cylinders. Statistical relationships between the water absorption and density were established from the study with relative prediction error (RPE) ranging from 0.01 to 0.41.

The article presents the results of mass calculations of local elementary runoff in daily resolution and according to weather stations over thousands of consecutive daily intervals. For computer calculations we used: database meteo.ru and a software package that is a DBMS and a system of equations linking the elements of the water balance with the elements of the heat balance.

In Eurasia, Africa, and both Americas, millions of unexplored hydrometric rivers operate. At the beginning of the XXI century, thanks to the publication of electronic databases, the development of a computer system for mass calculations of current water balances and calculations of evaporation and runoff over thousands of subsequent daily intervals, valuable and reliable hydrological information was discovered in the national meteorological databases. Until now, hydrologists all over the world could construct runoff hydrographs only from hydrometric data of daily measurements of water levels in a river. Now we get multi-year runoff hydrograph chains with daily resolution solely on the basis of weather station data. The World Meteorological Organization could lead the Global Project “Study of the water resources of unexplored rivers of all continents according to weather stations”, the result of which should be the “Atlas of World Water Resources of Local Flow”.

Majority of the population in Malete where research was carried out depend solely on wells as their major source of water supply because of the inexistence of treated pipeborne water. Due to increasing cases of water-borne diseases such as dysentery and cholera in some local Government areas in Kwara State recently, informed this bacteriological surveillance and monitoring of wells. Samples of well water were collected from seven different locations within Malete city in Nigeria and analyzed microbiologically using Membrane Filtration Technique and various isolated colony are tentatively identified based on their biochemical and physiological properties.The organisms were identified as Salmonella sp, Pseudomonas sp, Shigella sp, Escherichia coli, Enterobacter aerogenes, Klebsiella sp, vibrio sp,serattia sp and Proteus sp. The percentage occurrence of the organisms isolated from the well samples showed that Staphylococcus aureus was the most common (22.59％) followed by Escherichia coli (19.45％), and Pseudomonas species with 12.45％ occurrence. Percentage occurrence of Salmonella and Shigella species were 8.95％ and 12.45％ respectively, while, Serratia species was the least with 2.72％ occurrence. Conclusively, proper well location and construction of good wells should be encouraged; control of human activities to prevent sewage from entering water body is the key to the avoiding bacterial contamination of drinking water. Household treatment such as boiling, use of chlorine should be encouraged before water from these wells is used for drinking and all other domestic purposes.

The article presents the draft World Atlas of local water resources, which is based on water-balance calculations on meteorological data.The advantages of maps of isolines of local runoff are described, and the methodology for calculating the initial data is presented. The structure, content, and presentation templates of Atlas information are proposed.The stages of creating the Atlas are analyzed and the work distribution of map production is proposed.

In the face of a growing demand for portable water catalyzed by population and rapid urbanization, there exist a precarious imbalance between water availability and accessibility by the populace. This study seeks to assess residential water demand and distribution as it relates to urban population change in Jalingo, Taraba State Mapping of the existing water supply network was achieved through Geo-referencing and digitization of scanned map obtained from Jalingo Water Agency; Landsat image of 1986, 2001 and 2016 were used for land use land cover classification and change detection analysis adopted to provide insight into spatio-temporal variation in urban extent; population data obtained from National Population Commission was used to analyze population trend and density analysis; using simple regression analysis, the relationship between urban population change and water demand was established; and weighted overlay analysis (WOA) which incorporated elevation and the various land use and cover classes was adopted to identify suitable areas for siting proposed buffer stations and new service areas for water supply facilities within the study area. The results reveal that the population of Jalingo stands 159,950 with a growth rate of 3.2％ coupled with spatial variation in density ranging from 10-80 people per km2 both in the core and peripheral areas. Using built-up area as an indicator of urban change, the associated urban expansion rate from 1986 to 2016 stands at 23％. The increase in population also correlated strongly with water demand (p-value<0.05) and indicates that water demand may outweigh supply at the current coverage of water distribution facilities. Furthermore, demand was projected to be about 7.9 billion cubic meters by 2031. These therefore creates the need for optimization which proposed more buffer stations and facility expansion with a view to enhancing sustainable planning and management of residential water consumption and distribution in the study area.

Networks are an opportunity for more efficient and more effective disposal of water resources. The use of the net in the management of water systems, river and sea-river channels, emphasize the efficiency of integrated water resources decisioning. The conclusions of geomorphogical and paleohydrologic research can provide a more complete picture of hydrological potentials, and adequate hydrological management. The paper recognizes permeations as the basis for designing river channel systems, planning and implementation of rivers, lake-river and sea-river channels in order to better exploit water resources and connect river flows. In this there are prerequisites for water management of the construction of systemic river traffic distances of completely regulated or at least controllable river systems. The analysis of large continental rivers is made by the observation of water systems, comparisons and useful conclusions of the European, African and Asian network systems, as well as the possibilities of their further use and development.

With the development of modern industries, more and more water resources are consumed; Water is a utility, which be one of the most important utilities in industrial scale. Gas scrubbing processes, condensers, separators, cooling towers; Stripping, liquid-liquid extraction and many processes are used in fertilizers and refineries plants. In this paper, the application of the water networks with internal mains introduced. A design methodology for multiple-contaminant water networks with single internal water main is presented.

This study investigated the groundwater regime of the porous medium of Cretaceous sedimentary formation in Shendi sub-basin. The aims of this study are to determine the aquifer characteristics, groundwater flow dynamic, and groundwater balance and storage capacity of the aquifer, using groundwater model techniques. A three dimensional numerical model was developed for two aquifer system to simulate groundwater flow through variably saturated porous medium. Visual MODFLOW, Geographical Information System (GIS) and Aquifer Test techniques were used for model conceptualization, data processing and obtained results manipulation. Model simulation was optimized by using a trial and error method. Acceptable model calibration was obtained with root mean square error (RMS) of 0.313 m and absolute residual mean (ARM) of 0.124 m, normalized root mean square (NRMS％) of 0.6 ％ and mass balance discrepancy of 0.01％ with water reserve of 14.36 m3/d after all prevailing abstraction activities. The general groundwater flow direction, as depicted from model results, is towards east and northeast with a cone of depression at the center of the area, which attributed to heavy abstraction for agricultural activities. The annual groundwater supply from well fields in both aquifers was estimated to be 37×106 m3. Aquifers storage capacities of covering area of 8325 km2 were calculated to be 60×106 m3 and 63×106 m3 for upper and lower aquifer respectively. The sensitivity analyses reflected that the model was more sensitive to hydraulic conductivity and least sensitive to specific storage. The model was validated after sufficient testing had been performed to ensure an acceptable level of predictive accuracy.

The quality of water is of vital concern for mankind since it is directly linked with human welfare. The most common risk to human health associated with water systems is the presence of disease causing microorganisms. This study evaluates Bacteriological Variables in Community Water Bodies in New Juaben Municipality in the Eastern Region of Ghana. Ten (10) drinking water sources sampling sites were purposively sampled and assessed over a period of six months. Bacteriological analysis for the study was done at the Microbiology Laboratory, Council for Scientific and Industrial Research (CSIR) Water Research Institute, Accra. The study revealed that bacterial pollution of the waters was high above the WHO World Health Organisation (WHO) recommended standard for drinking water quality of zero bacteria in 100ml of drinking water. Mean values were between 26.8 and 4850.5 for Total Coliform (TC); 6.3 and 2799.2 for Faecal coliform (FC); 11.3 and 1243.0 for Escherichia coli (E. coli); 33.2 and 6641.0 for Total Heterotrophic Bacteria (THB) in coliform forming units (cfu) respectively. The study recommended that, there should be regular monitoring, treatment and testing of the water quality of the sources of drinking water as well the maintenance of the existing boreholes, pipes and wells in the study communities by GWCL and WATSAN officials to minimize the level of microbial and chemical contamination so that water related diseases could be prevented in this area. Also, source of pipe-borne water is lacking and so should be improved or the coverage should be increased.

The physico-chemical and bacteriological quality of water and sediments and the growth performance of fish following administration of Oreochromis niloticus feeds of two different dietary protein levels were studied in Hapas set in four 200 m2 ponds. Results indicate that water quality parameters monitored were within environmental tolerable limits and for the growth of Oreochromis niloticus. For all the feeds, water temperature was in the range of 27.83°C - 28.67°C, dissolved oxygen 5.01mg/L - 6.11 mg/L and pH 5.4 - 7.01. The levels of biochemical oxygen demand, nitrogen, phosphorus and dissolved organic carbon as well as Salmonella sp, Staphylococcus aureus and Pseudomonas sp were generally beyond acceptable limits with projections of the levels of the physico-chemical parameters indicating further increase. There were no statistical significant differences (P>0.05) in the levels of total nitrogen, phosphorus, biological oxygen demand, dissolved organic carbon and bacteria load before the administration of treatments and at the end of the study.

This study uses Climate Model outputs of HadCM3A2a and HadCM3B2a SRES climate scenarios and downscale the predictors into finer scale resolution using Statistical Downscaling Model (SDSM) to simulate and project the climate at local scale in order to investigate the hydrological impact of possible future climate change in Guder catchment, Upper Blue Nile Basin (Ethiopia). The results, obtained from this climate model, were compared to the observational datasets for precipitation and temperature for the period 1990-2008. To estimate the level of impact of climate change, climate change scenarios of precipitation and temperature were divided into time windows of 30 years each from 2011 to 2100.The downscaled A2a and B2a emission scenarios result indicates a significant increasing trend in mean temperature and precipitation in all future time periods in the study catchment. We applied the Soil and Water Assessment Tool (SWAT) to investigate the response of the water resources of the Guder River catchment to the scenarios of projected climate change. The model output shows that there may be an annual and seasonal increase in inflow volume for both A2a and B2a emission scenarios in three benchmark periods in the future. Potential evapotranspiration in the catchment will also increase up to 25％. Generally, results presented in this study can provide valuable insight to decision makers on the degree of vulnerability of Guder river catchment to climate change, which is important to design appropriate adaptation and mitigation strategies.