Open Journal of Modern Hydrology

Journal Information
ISSN / EISSN : 2163-0461 / 2163-0496
Current Publisher: Hans Publishers (10.4236)
Total articles ≅ 139
Archived in
SHERPA/ROMEO
Filter:

Latest articles in this journal

Martins Yusuf Otache, John Jiya Musa, Ibrahim Abayomi Kuti, Mustapha Mohammed, Lydia Ezekiel Pam
Open Journal of Modern Hydrology, Volume 11, pp 1-18; doi:10.4236/ojmh.2021.111001

Abstract:
The choice of a particular Artificial Neural Network (ANN) structure is a seemingly difficult task; worthy of relevance is that there is no systematic way for establishing a suitable architecture. In view of this, the study looked at the effects of ANN structural complexity and data pre-processing regime on its forecast performance. To address this aim, two ANN structural configurations: 1) Single-hidden layer, and 2) Double-hidden layer feed-forward back propagation network were employed. Results obtained revealed generally that: a) ANN comprised of double hidden layers tends to be less robust and converges with less accuracy than its single-hidden layer counterpart under identical situations; b) for a univariate time series, phase-space reconstruction using embedding dimension which is based on dynamical systems theory is an effective way for determining the appropriate number of ANN input neurons, and c) data pre-processing via the scaling approach excessively limits the output range of the transfer function. In specific terms considering extreme flow prediction capability on the basis of effective correlation: Percent maximum and minimum correlation coefficient (Rmax% and Rmin%), on the average for one-day ahead forecast during the training and validation phases respectively for the adopted network structures: 8 7 5 (i.e., 8 input nodes, 7 nodes in the hidden layer, and 5 output nodes in the output layer), 8 5 2 5 (8 nodes in the input layer, 5 nodes in the first hidden layer, 2 nodes in the second hidden layer, and 5 nodes in the output layer), and 8 4 3 5 (8 nodes in the input layer, 4 nodes in the first hidden layer, 3 nodes in the second hidden layer, and 5 nodes in the output layer) gave: 101.2, 99.4; 100.2, 218.3; 93.7, 95.0 in all instances irrespective of the training algorithm (i.e., pooled). On the other hand, in terms of percent of correct event prediction, the respective performances of the models for both low and high flows during the training and validation phases, respectively were: 0.78, 0.96: 0.65, 0.87; 0.76, 0.93: 0.61, 0.83; and 0.79, 0.96: 0.65, 0.87. Thus, it suffices to note that on the basis of coherence or regularity of prediction consistency, the ANN model: 8 4 3 5 performed better. This implies that though the adoption of large hidden layers vis-à-vis corresponding large neuronal signatures could be counter-productive because of network over-fitting, however, it may provide additional representational power. Based on the findings, it is imperative to note that ANN model is by no means a substitute for conceptual watershed modelling, therefore, exogenous variables should be incorporated in streamflow modelling and forecasting exercise because of their hydrologic evolutions.
Moussé Landing Sane, Soussou Sambou, Issa Leye, Didier Maria Ndione, Samo Diatta, Ibrahima Ndiaye, Mamadou Lamine Badji, Seïdou Kane
Open Journal of Modern Hydrology, Volume 10, pp 81-104; doi:10.4236/ojmh.2020.104006

Abstract:
Management of reservoir water resources requires the knowledge of flow inputs in this reservoir. Hydrological rainfall-runoff model is used for this purpose. There are several types of hydrological model according the description of the hydrological processes: black-box models, conceptual models, deterministic physical based model. SWAT is a semi-distributed hydrological model designed for water quality and quantity. This versatile tool has been used all around the world to assess and manage water resources. The main objective of the paper is to calibrate and validate the SWAT model on the watershed of Bafing located between 10°30' and 12°30' north latitude and between 12°30' and 9°30' west longitude to assess climate change on this river flows. A DEM with a resolution of 12.5 m × 12.5 m, the daily average flows and the daily observed precipitations on the period 1979-1986 (long period) are used as inputs for the calibration, while precipitations for the period 1988-1994 are used for the validation. The sensitivity analysis was done to detect the most determining coefficients during the calibration step. It shows that 19 parameters are required. Then, the effect of the period on the parameters calibration is checked by considering first the whole period of study and then each year of the period of study. The Nash criterion was used to compare the calculated and the observed hygrographs in each case. The results showed that the longer is the period of calibration, the more accurate is the Nash criterion. The calibration per year gave a best Nash criterion except for a single year. During the validation, the parameters calculated on the long period lead to the best Nash criterion. The values of the Nash criterion calibration and validation are very suitable. These results of calibration can be used to study the long-term evolution of flow at Senegal River on Bafing Makana.
Raymond Diedhiou, Soussou Sambou, Seidou Kane, Issa Leye, , Mousse Landing Sane, Didier Maria Ndione
Open Journal of Modern Hydrology, Volume 10, pp 45-64; doi:10.4236/ojmh.2020.103004

Abstract:
The Sahelian regions have experienced a drought that has made them vulnerable to hydro-climatic conditions. Strategies have been developed to reduce this vulnerability. The governments of Senegal, Mauritania, Mali and Guinea have created the Organization for the development of the Senegal River (OMVS in french) with the aim of realizing large hydraulic installations. This resulted in the construction of the Diama and Manantali dams in the Senegal River Basin. The first aims to stop the saline intrusion, the second to regulate the flow of the river, to allow the irrigation of agricultural perimeters, and to produce electrical energy. The impoundment of the Diama dam has modified the hydraulic behavior of the estuary. The purpose of this study is to carry out the hydraulic modeling of the estuary of Senegal river downstream of the Diama Dam in transient mode by the HEC-RAS software. Two geometric models were constructed on the basis of a digital terrain model (DTM) using the Arc-GIS and HEC GeoRAS soft wares after processing the collected topographic data. The first geometric model, of which the areas of Senegal river downstream Diama Dam have been represented by cross-section, is one-dimensional. The second one is also one dimensional; in this model, the area of the Senegal River estuary downstream Diama Dam is introduced as water storage zones. The components of these models are the stream sections, lateral links, and storage areas. The flood hydrograph downstream Diama Dam is introduced as conditions at the upstream limits of the models while the tidal is introduced as a downstream condition. After the stability and calibration, the results given by HEC-RAS simulations are the variations of the water levels, the temporal variations of the flow rates for each section, the maximum flow velocities and the propagation times of the flood waves. The analysis and comparisons of these results strongly suggest using HEC-RAS issues as a decision-making tool helping to manage floods during times of crisis.
Omar A. Al-Khashman, Hani M. Alnawafleh
Open Journal of Modern Hydrology, Volume 10, pp 1-19; doi:10.4236/ojmh.2020.101001

Abstract:
The study was undertaken to assess the physicochemical and chemical quality of the Tannur dam water in southern Jordan. The water samples were collected in two intervals the first during May 2015 and the second during September 2015. All samples were analyzed for temperature, conductivity, dissolved oxygen, pH, major cations (Ca2+, Mg2+, K+, Na+), and major anions (Cl-, NO3-, HCO3- and SO42-). The hydrogeochemical analyses of thirty-six water samples were used to determine the properties and type of water in the Tannur dam. The ion concentration in the water samples was from dissolution of carbonate rocks and ion exchange processes in clay. The general chemistry of water samples was typical alkaline earth waters with prevailing bicarbonate chloride. The PHREEQC Hydrogeochemical modeling was used to obtain the saturation indices of specific mineral phases, which might be related to interaction with water and aquifer, and to identify the chemical species of the dissolved ions. Calcite and dolomite solubility were assessed in terms of saturation index where they show positive values indication oversaturated SI > 0. The hydrogeochemistry behavior is rather complicated and is affected by anthropogenic and natural sources. The positive correlation values between various parameters indicate that most of ions result from same lithological sources. The abundance of the major ions in water samples is in the following order: HCO3-> Ca2+ > Cl- > NO3- > SO42-) > Na+ > Mg2+ > K+. Water samples of the Tannur dam are generally very hard, high to very high saline and medium alkaline in nature. High total hardness (TH) and total dissolved solids (TDS) in some samples identify the permissible for domestic and irrigation purposes. According to the residual sodium carbonate, SAR and conductivity values, the studied water is suitable for agricultural purposes.
Kassa Issifou Mounou Sambieni, François De Paule Codo
Open Journal of Modern Hydrology, Volume 10, pp 30-43; doi:10.4236/ojmh.2020.102003

Abstract:
Floods and flows data are useful for dimensioning of dikes and dams which often include evacuation devices that regulate flows to ensure the volumes of water. The objective of this study is to estimate the available water resource in the village of Gbédji-Kotovi, located in the watershed of Couffo river in Benin by using sequentially, the HBV (Hydrologiska Byrans Vattenbalansavdelning) and GR4J (Rural Engineering model with 4 daily parameters) climate models. Hydrographs of water levels are simulated according to the calibration period (1994-1999) different from the validation one (1982-1988). Considering the Nash-Sutcliffe model Efficiency coefficient (NSE), the performance of GR4J model during calibration is slightly higher than the performance of the HBV model, while during the validation, the contrary is noticed. The annual rainfall average simulated is 1117.7 mm/year while the average observed is 1104.6 mm/year over the period 1981-2005. By 2050, on one hand, the annual flow rate values will vary from -19.2 to -11.9%, while the actual evapotranspiration will vary between 0.5 and -5.8; on another hand, the potential evapotranspiration and the annual precipitation remain constant. An average flow of 187 millions m3/year for annual average water depth of 1094 mm is obtained at Lanta rain station, which covers an area of 1664.47 km2, while this flow enabled an average flow of 327.5 millons m3/year to be obtained at the virtual station of our study area of 2908.15 km2. The flow rates corresponding to the return periods of 10, 25 and 50 years vary from 5.51 to 12.67 m3/s at the outlet of the virtual station; while those at the outlet of Lanta station vary from 3.6 to 6.6 m3/s. However, the simulated water quantiles cannot be fully mobilized; because of the uses, they undergo upstream and downstream. Thus, Gbédji-Kotovi locality requires the implementation of an integrated water resource management strategy that includes the construction of dikes and dams.
Martins Yusuf Otache, Onemayin David Jimoh, John Jiya Musa, Abdullahi Danmagaji
Open Journal of Modern Hydrology, Volume 10, pp 65-79; doi:10.4236/ojmh.2020.103005

Abstract:
Hydrological drought is usually characterised by water loss over time from both underground and surface supplies. Thus for this study, the assessment of hydrological drought was carried out by employing Cumulative Rainfall/Streamflow Anomaly as preliminary tools for the presence of drought signatures while detailed characterisation was via Streamflow Drought Index (SDI). The results revealed that hydrological drought was observed in all the stations; however, though in general, the stations could be classified as experiencing near normal drought conditions with mild drought signatures. The findings also revealed that the average streamflow deficit volume and durations of the hydrological drought severity were 1.780 Mm3 and 192 months, 1.444 Mm3 and 252 months, 3.148 Mm3 and 252 months, and 0.159 Mm3 and 372 months for Bakolori, Goronyo (pre dam construction era), Goronyo (post dam construction era) and Zobe stations, respectively. The results also revealed the relevance of flow duration curve and analysis of frequency of drought state transition for the development of scenario-based basin water resources management protocol. The coefficient of determination (R2) statistic of the developed regression models indicate that 73.3% and 86.5% variation in streamflow dynamics across the Basin can be explained by climate change variables. However, for sustainable management of water resources in the Basin, it is imperative that characterisation of hydrological drought and monitoring should employ robust indices which use improved monthly precipitation estimates under global warming scenario in addition to ensuring that there is a shift from reactive to proactive approach in order to combat hydrological risk. Hence, a robust framework that finds application both for planning mitigation actions which embody strategic, tactical and emergency components should be designed; to this end, analysis of persistence and recurrence of drought in time and determination of possible recurrent patterns are necessary.
Mohammedreshid A. Aliye, Alemu O. Aga, Teshale Tadesse, Petros Yohannes
Open Journal of Modern Hydrology, Volume 10, pp 105-122; doi:10.4236/ojmh.2020.104007

Abstract:
A number of physically-based and distributed watershed models have been developed to model the hydrology of the watershed. For a specific watershed, selecting the most suitable hydrological model is necessary to obtain good simulated results. In this study, two hydrologic models, Soil and Water Assessment Tool (SWAT) and Hydrological Engineering Centre-The Hydrologic Modeling System (HEC-HMS), were applied to predict streamflow in Katar River basin, Ethiopia. The performances of these two models were compared in order to select the right model for the study basin. Both models were calibrated and validated with stream flow data of 11 years (1990-2000) and 7 years (2001-2007) respectively. Nash-Sutcliffe Error (NSE) and Coefficient of Determination (R2) were used to evaluate efficiency of the models. The results of calibration and validation indicated that, for river basin Katar, both models could simulate fairly well the streamflow. SWAT gave the model performance with the R2 > 0.78 and NSE > 0.67; and the HEC-HMS model provided the model performance with the R2 > 0.87 and NSE > 0.73. Hence, the simulated streamflow given by the HEC-HMS model is more satisfactory than that provided by the SWAT model.
Moshe Gophen
Open Journal of Modern Hydrology, Volume 10, pp 21-29; doi:10.4236/ojmh.2020.102002

Abstract:
Regional Climate Change studied during 1950-2019 aimed at enhancement of aridity was indicated recently in the Lake Kinneret (Israel) watershed. Climate change was indicated by: Higher periodical frequency of negative SPI Values (Standard Precipitation Index), decline of Precipitation regime and River flow inputs that was followed by decline of Lake Kinneret WL and Elevation of ET regime. Nevertheless aridity enhanced the opposite, decline of ET capacities. Underground flows indicated outputs enhancement. The temporal decline of air temperature during 1940-1980 probably due to the change of ALBEDO Factor was twisted later into regional temperature elevation. During the 1950s, old lake Hula and surrounding wetlands were drained and water cover surface was converted to plant cover, which enhanced sunlight energy reflection. Followed eventual climate change, management legislations were a reduction of water allocation for agricultural irrigation. A recent public dispute has indicated contradicted conclusions as causation for WL decline in Lake Kinneret: 1) Enhancement of Agricultural water consumption in the Upper Jordan Watershed and 2) Climate change-aridity enhancement. This paper confirms the second conclusion.
Moshe Gophen
Open Journal of Modern Hydrology, Volume 09, pp 161-177; doi:10.4236/ojmh.2019.94009

Abstract:
The dynamics of N & P nutrient inputs and the consequent epilimnetic concentration during 1969-2018 in Lake Kinneret was studied. The consequences of their availability on algal composition were also studied. Two prominent periods were indicated: 1) Sufficient supply of N accompanied by Peridinium enhancement; 2) N deficiency and P sufficiency-induced Peridinium reduction and Cyanobacterium enhancement. The impact of Anthropocene conditions and dust deposition on N & P availability is evaluated.
Back to Top Top