by Ochungo E.A., Ouma G.O., Obiero J.P.O. and Odero N.A.
Original Research
A quality decline trend is suspected to be ensuing in the water originating from boreholes in Langata sub-County; a region located to the south of Nairobi, the capital city of Kenya in East Africa. Despite the existence of this worrisome suspicion, no investigation has been conducted to assuage the fears of the exposed population. This situation however contradicts the great augmenting role of borehole water delivered by vendors to consumers as a coping strategy against the pervasive drought induced water shortage challenge afflicting households in Langata. Hence, a question arose as to whether the identified past drought events have had any chance of influencing the ongoing declining trend of the area’s ground water quality. The purpose of this study was therefore to assess the impact of historical drought events on the ground water quality in Langata Sub County. The profile of drought indices was superimposed over the area’s time series geochemical water quality indices’ profile. Further, the computed area’s groundwater potability grade was used to estimate the probability of water quality deterioration due to drought impact, returning a value of 43.65%. It was found that indeed, ground water quality in the area is on a declining mode. Since water is an elixir of life; the finding from this study is expected to trigger an establishment of a water quality surveillance initiative as a safeguard to public health.
American Journal of Water Resources. 2020, 8(3), 145-154. DOI: 10.12691/ajwr-8-3-5
Pub. Date: July 23, 2020
3243 Views471 Downloads
by M Rafiqul Islam, Munshi Rashid Ahmad, Muhammad Nurul Alam, Mong Sanue Marma and Abdul Gafur
Original Research
The dry-season water scarcity is a problem of crop intensification in many hilly areas of the world. The rainwater or runoff water harvesting (RWH) could be a potential solution for those areas. The methodologies and the criteria for selecting the site for RWH structure are available for macro-watershed but not for micro-watershed. This study aims at selecting a suitable location of RWH structure for micro-watershed through all possible combinations of methodologies and criteria. For this, we developed a conceptual framework where a participatory approach, field and questionnaire surveys with remote sensing and GIS techniques were adopted. After preliminary selection of the watershed site through field surveys, four micro-watersheds were delineated using ArcGIS hydrological tools. Watershed delineation was carried out using SRTM DEM (automatic-delineation) and Google Earth (manual-delineation). Integrated approaches involving both biophysical and socioeconomic factors were followed for identifying the potential site for the RWH structure. In regards to biophysical assessment, various thematic maps, such as stream networks, slope, soil and land use were developed to describe the characteristics of each micro-watershed. The socioeconomic considerations were the number of population to be benefited, possibilities of expanding farming, and accessibility to the watershed reservoir in each micro-watershed. Thus, the results obtained from biophysical and socioeconomic determinants reveal that the micro-watershed (MWS)-2 and MWS-3 are most suitable for the same scores and recommended for constructing the RWH structure. However, various attempts need to consider regarding the choice of crops on hill slopes, conservation of soil, and management of the structure for getting full potential benefits from the watershed reservoir.
American Journal of Water Resources. 2020, 8(3), 134-144. DOI: 10.12691/ajwr-8-3-4
Pub. Date: July 15, 2020
5269 Views702 Downloads
by Dipu Sukumaran and Josna Raj P
Original Research
The present study focus on the water quality analysis of Kuttiyadi River, Kerala, with special reference to saline water intrusion. Salinity intrusion has a serious effect on the water supply in the Kuttiyadi river basin area in the recent years. Kuttiyadi River is the only source of water for supply during summer in Vadakara Municipality and nearby villages. The upstream sampling point which 22.5 km from the river mouth has salinity of 6.83 ‰ showed the rate of intensity of saline intrusion. Through Water quality analysis it is found that salt water intrusion in the river also leads to contamination ground water in the river sides. In some extent salt water intrusion the reason behind deterioration of surface water and ground water in private wells near river side. The results showed significant correlation with salinity and anions like Chloride, and Sulfate. Cations like Magnesium, Sodium, Calcium and Potassium are also significantly correlated with salinity of both surface water and ground water.
American Journal of Water Resources. 2020, 8(3), 128-133. DOI: 10.12691/ajwr-8-3-3
Pub. Date: May 31, 2020
3932 Views568 Downloads
by Ajala Abiodun Ladanu, Semiu Akanmu and Josiah Adeyemo
Original Research
The need for, and the process of, optimizing real time reservoir operations have attracted substantial research attention. Among these is the employment of artificial neural network (ANN), singly or with supporting algorithms, for real time multi-objective reservoir operation optimization. Using Systematic Literature Review (SLR), this paper reviews 66 studies, comprising of studies that employed ANN with or without another training algorithm(s), and those that employed evolutionary algorithm (EA) of any type for real time reservoir operations optimization. From this, it highlights the necessity of using ANN and the suitability of EA as a training algorithm. This paper, from the meta-analysis of the studies reviewed, shows that, though ANN is primarily suitable for real time forecasting, the best network architecture is the real-time recurrent learning (RTRL) neural network algorithm. And, ANN supported with supervised or unsupervised learning algorithm, has better performance potential than those singly used. Also, evolutionary algorithms are presented as viable supporting training algorithms capable of extrapolating data of deeper abstraction, complex uncertainty, with consistent predictive capacities.
American Journal of Water Resources. 2020, 8(3), 118-127. DOI: 10.12691/ajwr-8-3-2
Pub. Date: May 20, 2020
3545 Views644 Downloads
by Diakher Hélène MADIOUNE, Moctar DIAW, Ibrahima MALL, Philippe ORBAN, Serigne FAYE and Alain DASSARGUES
Original Research
Dakar, the Capital city of Senegal concentrates about 23.2% (about 3 millions inhabitants) of the total population [1] and a large proportion of the industrial activities. Water supply is ensured by surface water pumped and piped from the Guiers Lake (250 km distant from the capital) and from groundwater resources. Among these latter, the Diass aquifer system contributes to a substantial proportion (31% in 2019) of the total water supply distribution due to growing demand induced by the rapid demographic growth (about 2.5%). The Diass horst aquifer system located 50 km east of Dakar (Senegal) is exploited with two main aquifers covered by a sandy superficial aquifer: the confined/unconfined Palaeocene karstic limestone and the confined Maastrichtian sandstone aquifer underneath. This system has experienced intensive groundwater abstraction during the last 60 years to meet the increasing water demand. Abstraction for urban drinking water occurs in nine pumping fields with a rate reaching 174,000 m3/d in 2019. This high yield together with the drought conditions since the 1970s is likely to affect groundwater imbalance and change the flow regime. The objective of the study is to improve our understanding of the system dynamic with regards to the high pumping rate in order to build a conceptual scheme for further hydrogeological modeling of the system. In this study, we use monitored pumping rates, piezometric level from 1960s to 2019 and rainfall data from 1931 to December 2016 together with the hydrogeological configuration to infer the dynamics of the aquifer system. The high abstraction rate during the period 1958-2019 which vary from 16,000 to 174,000 m3/d has caused a continuous groundwater level decline (up to 30 m), a modification of the flow patterns and to some extent a quality deterioration through salinization processes as shown in a few boreholes in Sébikotane and Mbour. The piezometric levels which were above the sea level prior 1959 exhibit now negative values and can even reach -40 m in the vicinity of the pumping fields creating therefore piezometric depressions and convergent flow pattern. The hydrodynamic of the system derived from the results show that the reservoir acts as a multilayer aquifer system with interconnected compartments by faults that allow flux exchanges except the confining Ponty and Sébikotane faults. Overexploitation inducing important drawdown has induced an increase of the drainance fluxes between those different compartments [2]. In order to foster more appropriate and sustainable groundwater abstraction in the complex hydrogeological system with regards to demand and water quality conservation, it is important to assess the main system behavior.
American Journal of Water Resources. 2020, 8(3), 104-117. DOI: 10.12691/ajwr-8-3-1
Pub. Date: May 15, 2020
6321 Views894 Downloads