by Anika Mahzabin, Md. Jakir Hossain, Siam Alam, Shams E Shifat and Anika Yunus
Original Research
The primary source of drinking water for the approximately 21 million residents of the Dhaka metropolitan area is groundwater. Rapid development and overuse of groundwater resources from the subsurface aquifer are to blame for the alarming rate of groundwater level depletion in the Dhaka metropolitan area. A quick assessment is needed to predict the spatiotemporal distribution of groundwater levels in the future in order to manage this limited resource sustainably. Using the numerical model code MODFLOW, this work makes an attempt to simulate groundwater flow in subsurface aquifer systems. The Dhaka Water Supply and Sewerage Authority's bore log data was used to map the groundwater aquifer networks of the city of Dhaka (DWASA). The data gathered from the Bangladesh Water Development Board was used to assign the model boundary and hydrogeological parameters. All grid cells inside the model recharge boundary are considered to have the same recharge distribution. The model's results show that excessive groundwater extraction from aquifer systems, rather than a decline in recharge rates throughout the corresponding years, is the primary cause of the downward trend in groundwater level inside the city region. If the rate of pumping continues the same as it was in 2020, the depletion of groundwater level may get worse in the following years as a result of the city of Dhaka's growing population and development.
American Journal of Water Resources. 2023, 11(1), 28-40. DOI: 10.12691/ajwr-11-1-4
Pub. Date: May 14, 2023
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by Ndiouga Camara, Mouhamadou Moustapha Mbacké Ndour, Ndèye Khady Tounkara and Séni Tamba
Review Article
This article aims to propose a method of draining rainwater in order to reduce the risk of flooding in the municipality of Taïba Niassène located in the Kaolack region, more precisely in the department of Nioro. To achieve this objective, it was necessary to carry out topographical, geotechnical and hydrological studies to know the nature of the relief, the typology of the soils and the hydrographic network of the area. In addition, the design of the axes to be coated was made taking into account the nature of the terrain to reduce the earthworks. Thus, the coating is designed in such a way that the water will drain along the curbs of the sidewalks to the gully grids positioned near the retention basins. The latter are two in number and are sized with flow rates of 1.318m3/s for basin 1 and 1.1 m3/s for basin 2 for a rainfall duration of five hours.
American Journal of Water Resources. 2023, 11(1), 20-27. DOI: 10.12691/ajwr-11-1-3
Pub. Date: May 07, 2023
1180 Views1 Downloads
by Tatou Rel Dechangue and Kamgang Kabeyene Veronique
Original Research
Linked hydrochemical and isotopic studied were carried out to identify and explain the processes that control the mineralization in miopliocene aquifers in Douala basin. According to the results of the chemical analysis, the water is acidic and poor mineralized. The investigation highlights that groundwater mineralization is mainly influenced by ion exchange process, carbonate dissolution and silicate weathering. Based on isotopic signatures, shallow aquifer groundwater samples were classified into waters with depleted δ18O contents, highlighting the result of a rapid infiltration of local meteoric waters which has undergone a low evaporation process. Deep aquifer and some points of shallow aquifer are more enriched in 18O than the local rains. This reflects a certain level of evaporation which the rainwater would have undergone before reaching the aquifer or the leaching of heavy isotopes accumulated in the unsaturated zone during the dry season. The relatively recent age of the waters that recharge the aquifer explains the weak action of the water-rock interaction hence the weak mineralization of the waters overall.
American Journal of Water Resources. 2023, 11(1), 11-19. DOI: 10.12691/ajwr-11-1-2
Pub. Date: March 01, 2023
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by Sauret Élie Serge Gaëtan, Dende Lushima Zacharie, Compaore Hillary Marie Michelle, Kinglo August M. Abdon, Yabre Sadraki, Koita Mahamadou, Konate Yacouba and Karoui Hela
Original Research
The study focused on the assessment of sources responsible for an urban river’s water quality. To do the analysis, water samples were collected from three sources. The first source was rainfall, the second source was a Wastewater Treatment Plant (WWTP) which releases pre-treated wastewater in the river, and the third source was the river itself at upstream and downstream parts from the WWTP discharge point in the river. The results of the chemical analysis performed on those water samples showed that the water discharged from the WWTP into the river has a poor physico-chemical quality and high microbiological pollution. However as expected, water samples of rainfall were of good quality. Water samples from the river revealed the presence of microbiological flora (total coliforms, fecal coliforms, Escherichia coli and fecal Streptococci) and chemical elements such as ammonium (NH4+), manganese (Mn), nickel (Ni) with high concentrations values than those recommended for irrigation waters as defined by World Health Organization (WHO) and the Food and Agriculture Organization (FAO) of the United Nations. However, parameters like temperature (T°), hydrogen potential (pH), electrical conductivity (EC), total dissolved solids (TDS), suspended solids (SS), chemical oxygen demand (COD), biological oxygen demand (BOD5) ortho-phosphate (PO43-), nitrate (NO3-), nitrite (NO2-), sodium (Na+), bicarbonate (HCO3-), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), zinc (Zn2+) and iron (Fe2+) are in line with the reference values for irrigation. Furthermore, water mixing analysis model "End Members Mixing Analysis (EMMA)" based on principal component analysis (PCA) of physico-chemical parameters of the pre-treated wastewater from the WWTP discharged into the river, the rainfall, and the river collected at upward of WWTP junction discharge point in the river has been developed. The results show that the wastewater pre-treated by the WWTP and discharged into the river contributes to 13.72% of the river water chemistry compared to 33.64% for rainfall and 52.64% for river water before its junction with WWTP. This study revealed that during rainy season, Houet river has high concentrations of NH4+, metallic trace elements (Mn, Ni) and significant microbiological pollution due to (i) the discharge into the river of incomplete treated wastewater coming from the WWTP (ii) but also to the river itself, which minor bed is the depository of urban and domestic wastes. It is true that the river water quality is globally good for market gardening, but to ensure its long-term quality, authorities in charge of water resources and agriculture should (i) monitor and optimize WWTP wastewater treatment efficiency, (ii) and control/limit agricultural and domestic activities with potential pollution risks alongside the river.
American Journal of Water Resources. 2023, 11(1), 1-10. DOI: 10.12691/ajwr-11-1-1
Pub. Date: January 16, 2023
1622 Views9 Downloads