by Yira Yacouba, Bossa Yaovi Aymar, Ngom L. A. L. C. A. Guedji, Hounkpè Jean, Hounkpatin L. Ozias, Mouhamed Idrissou and Sintondji O. Luc
Original Research
This study assesses the impact of future climate change on three water related ecosystem services (WRES) in the Dano catchment. The conceptual rainfall-runoff model HBV light was successfully calibrated (NSE = 0.945, R² = 0.945, and KGE= 0.948) and validated (NSE = 0.648, R² = 0.798, and KGE= 0.551) and demonstrated a good agreement between observed and simulated variables. The projected climate change signal in the catchment was analyzed using the WASCAL high-resolution regional climate simulations (HadGEM2-ES and GFDL-ESM2M under RCP 4.5) between a refence period (1985-2005) and two future periods (2020-2049 & 2070-2099). Compared to the reference period, both climate models show an increase in temperature of +1.9 to +2.8 °C by 2020-2049, and at the end of the century 3.2 to 5.4 °C. Precipitation trends of + 10 to +30 % in the middle of the century and between +37 to +51.4% towards 2100 are projected. The projected annual discharges change signals show an increase of +25 % to +68 % by 2049, while at the end of the century this increase exceeds +80.65. The simulated hydrological changes were translated into changes in WRES provision (hydropower, domestic water consumption, and ecological flow). The projected discharge increase will translate in an increase of hydropower generation potential but this increase in discharge will not be enough to meet future additional domestic water demand. Domestic water supply will decrease because of population growth. Therefore, the projected increase in future discharge will not be sufficient to counterbalance the additional water demand associated to population development.
American Journal of Water Resources. 2023, 11(2), 79-87. DOI: 10.12691/ajwr-11-2-4
Pub. Date: July 11, 2023
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by Siam Alam, Afeefa Rahman and Anika Yunus
Original Research
The drainage congestion problem is getting intensified in Dhaka city of Bangladesh over recent years due to rapid urbanization, inadequate drainage channels, and improper operation of the existing channels. The areas of Shantinagar, Rajarbag, Motijheel, Paltan, and T&T Colony serve as vital economic hubs in South Dhaka, yet they are highly prone to flooding during the rainy season. This study aims to address this problem by employing mathematical modeling to design a robust drainage network capable of effectively managing stormwater for existing and projected rainfall scenarios over 50 and 100 years. To achieve this, we utilize the frequency analysis method to estimate the design storm corresponding to 50 and 100 years return period for the study area. EPA SWMM 5.1 is employed to calculate the parameters of each sub-catchment, conduit network, junction node, and outlet for the drainage model setup. Through model simulation, we analyze the water level of each of the junctions to generate an inundation and hazard map of the study area. The accuracy of our SWMM model is validated in two ways: firstly, by comparing the inundation map produced from the model's water level outputs with the observed flood extent derived from Google Earth imagery, and secondly, by cross-checking the model's simulated runoff coefficient with manually estimated coefficients based on the land use map created from Google Earth. The total runoff volume from the model simulation is used to design the minimum cross-section of each of the conduits. By incrementally adjusting the conduit areas we analyzed the response of the flood hazard scenario of the study area. The findings of this analysis provide insights into the percentage increase in cross-section area required for drainage channels to effectively manage the runoff volume for a 50- and 100-year return period. With the developed model, we are equipped to design and size new components of the drainage system necessary for flood control during extreme scenarios. We anticipate that the outcomes of this study will prove valuable to relevant organizations and experts involved in addressing the drainage congestion issue in Dhaka City. The findings offer insights and recommendations for effectively managing and mitigating flooding through the design and implementation of improved drainage infrastructure.
American Journal of Water Resources. 2023, 11(2), 65-78. DOI: 10.12691/ajwr-11-2-3
Pub. Date: June 28, 2023
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by Faye Moussa Diagne, Biaou Angelbert Chabi, Doulkom Palingba Aimé Marie, Koita Mahamadou and Yacouba Hamma
Original Research
In Burkina Faso, the use of groundwater in a basement environment represents a major asset for rural populations, due to the questionable quality of surface water. It is exploited through boreholes installed with the help of 1D electrical geophysical investigations. Analysis of the database of 206 boreholes reveals that 30% are negative and 40% are unproductive or have a low flow rate of less than 2.5 m3/h in the study area. This has an impact on the access rate, which was set at 80% in 2015, and which is 71.9% in 2015 and 76.4% in 2020. In view of this observation, in order to define the geometry of the aquifer and productivity, we propose to see whether the methodology (1D) presents certain limitations or difficulties in correlating the lineaments with the preferential water circulation corridors in this type of geological context. Does it also allow us to highlight the thickness and nature of the alteration? To achieve this, remote sensing is used followed by validation. Subsequently, possible correlations between the types of geophysical anomalies and the productivity of the boreholes were identified using a statistical analysis of the 206 boreholes. Geophysical prospecting was used to propose new drilling locations based on fracture directions.
American Journal of Water Resources. 2023, 11(2), 49-64. DOI: 10.12691/ajwr-11-2-2
Pub. Date: June 12, 2023
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by Anyizi Bertha Nkemnyi, Lucy Mange Ndip, Benedicta Oshuware Oben, Oben Pius Mbu, Tambekong Talkspeak Arrey and Mbeng Ashu Arrey
Original Research
Pristine or near-pristine freshwater rivers provide numerous ecosystem services to riverine communities. Yet they could be a significant public health threat due to contamination and pollution. This study assessed the disease burden among the population of Akonolinga, on the banks of River Nyong in Cameroon. Semi-structured questionnaires were administered to ten medical facilities within the town. Hospitalization and laboratory diagnosis logs for the year 2020 were reviewed. Results showed that 44.4 ± 1.15% of the respondents had recurrent foodborne diseases between 1 to 10 times a year, and there was strong positive correlation between the rate of foodborne diseases and that of waterborne diseases (rho = 0.881, p = 0.002). Foodborne disease cases were highest during the dry season (66.67 ± 1.73%). Malaria was most prevalent (27.8%) but statistically similar to prevalence of typhoid (22.2%) and diarrhea (22.2%). Bacteria were the major causative agent of diseases, dominated by members of Salmonella (30.3%), Pseudomonas (21.2%) and Escherichia (21.2%). The prevalence of Salmonella was statistically higher than that of Trichomonas, Shigella, Amoeba and Staphylococcus. These results are suggestive of a contaminated environment, poor hygiene etc. which would necessitate behavioural change within the population for better management.
American Journal of Water Resources. 2023, 11(2), 41-48. DOI: 10.12691/ajwr-11-2-1
Pub. Date: May 23, 2023
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