Water Resources Engineering
M. Nadi; A. Yousefi Kebriya
Abstract
Accurate spatial estimation of temperature is very important in meteorological research. This study investigated the efficiency of temperature products of the Tropical Rainfall Measuring Mission (TRMM) satellite in estimating temperature in Mazandaran Province, and its accuracy were compared with inverse ...
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Accurate spatial estimation of temperature is very important in meteorological research. This study investigated the efficiency of temperature products of the Tropical Rainfall Measuring Mission (TRMM) satellite in estimating temperature in Mazandaran Province, and its accuracy were compared with inverse distance weighting and Co-Kriging interpolation methods. Finally, a new method was proposed to improve the accuracy of temperature estimation by combining the TRMM temperature products and terrains. Data recorded at 25 meteorological stations and 26 monthly and annual TRMM satellite images in 2012 and 2013 were used. The results showed a significant correlation between temperature data and satellite products, latitude, and altitude in significance level of 95%. Analyzing error indices showed that TRMM products have underestimation error that this bias error contributed to about 60% of error in these satellite images. Despite the larger error of TRMM products than interpolation methods, the regression analysis results demonstrated the superiority of satellite temperature products over interpolation methods. Furthermore, higher correlation of observed and estimated data showing that satellite products give a better understanding of cold and hot points of the study area despite its underestimation error. Combining satellite temperature products with influential covariates of altitude and latitude in the regression equation reduced the temperature estimation error of the TRMM products by 80%. The estimation precision increased over 70% compared to other temperature interpolation methods. Analyzing isotherm maps indicate the higher temperature of eastern coasts than western coasts. Moreover, evaluating different temperature estimation methods showed the higher precision of the methods that involved covariates than other methods.
Water Resources Engineering
B. Oghati Bakhshayesh; F. Salmasi; S. Haji Azizi
Abstract
Underground water levels and pore water pressure can be increased as a result of heavy rainfall which can lead failure of earthen slopes. Retaining walls are the most well-known structures in order to increase earthen slope stability. In this study, the stability of earthen slopes is numerically simulated ...
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Underground water levels and pore water pressure can be increased as a result of heavy rainfall which can lead failure of earthen slopes. Retaining walls are the most well-known structures in order to increase earthen slope stability. In this study, the stability of earthen slopes is numerically simulated in critical hydrological situations. The simulations included pore pressure behind the retaining walls which lead to instability. Among the investigated parameters were: precipitation intensity, soil type, position and the diameter of drainage passages. Both horizontal and chimney drainages were simulated for the study. For fine-grained soils with intensive precipitation, using a single horizontal drainage passageway could not maintain sufficient stability for the retaining wall. Precipitation could have severe impact on stability in which increase of 5 to 15 mm/h would increase pore pressure from 7.09 kN to 75.39 kN which is so dramatic change. For coarse-grained soils, a retaining wall provides stability with a single horizontal drainage pipe; the horizontal pipe is able to discharge all the excess water behind the retaining wall. A chimney drainage system provided the best results, and the stability of the retaining wall did not endanger, even under the worst circumstances. Linear and non-linear regression relations were produced in dimensionless form which are providing 0.97 for R2 and 0.11 for RMSE values which implys the accurcy of equations. The accuracy of the regression determine their usage in practical applications.
Water Resources Engineering
S. Mahmood; M. M. Saeed; Z. Kılıç; M. Iqbal; H. A. Rehman
Abstract
With surge irrigation, applying surges to an area is a cheap labor task. In industrialized nations, a variety of electronic valves for discontinuous water application (surges) are available; but their pricing prevents their usage in emerging regions. Additionally, these valves are too advanced for use ...
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With surge irrigation, applying surges to an area is a cheap labor task. In industrialized nations, a variety of electronic valves for discontinuous water application (surges) are available; but their pricing prevents their usage in emerging regions. Additionally, these valves are too advanced for use by growers in underdeveloped nations. As a result, a basic Automatic Surge Gate was developed and tested in the labs to assess its effectiveness in terms of producing on-off surges. The reservoir was built to hold or collect low inflows for barrier functioning, and the gate was positioned on the suction side of the reservoir. Inflow rates, pinions, and poundage placements on the gate lever were the working parameters defined for the gate functioning. In the current investigation, three inflow rates 134, 169, and 187 l/s were employed. By leveraging the low inflows to the reservoir, the automatic surge gate demonstrated the possibility for automating the on-off action. The surge gate produced sizeable outflows even at the lowest inflow rate of 134 l/s into the reservoir. Power-law equations were discovered to be a good representation of the behavior in the statistical models that were also created using quasi statistical method.
Water Resources Engineering
S. N. Motevalian; M. R. Majdzadeh Tabatabai
Abstract
The aim of present study was to investigate the relationship between hydraulic and ecological variables of the studied span and to investigate changes in living conditions of phytoplankton (Amphora ovsalis and Navicula placentula). According to the measurements and analysis of habitat fit curves, it ...
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The aim of present study was to investigate the relationship between hydraulic and ecological variables of the studied span and to investigate changes in living conditions of phytoplankton (Amphora ovsalis and Navicula placentula). According to the measurements and analysis of habitat fit curves, it can be concluded that the highest frequency of Amphora ovsalis and Navicula placentula occurred and specified at flow rate of 15.82 and 14.942 m3/s, respectively. As can be seen, the lowest frequency of Amphora ovsalis and Navicula placentula in this measurement occurred at flow rate of 15.355 and 5.289 m3/s, respectively. The best habitat conditions for Amphora ovsalis and Navicula placentula are in the range of 0.18 -0.31 and 0.18 - 0.265 of Froude number range respectively. The highest density and abundance of Amphora ovsalis and Navicula placentula was observed in the range of 0.017 - 0.055 and 0.017 -0.039 mg/l of phosphate demonstrating that the best growth and living conditions are predisposed in this range for these species had suitable habitat conditions for life in this range. The highest frequency of Amphora ovsalis and Navicula placentula is in the range of 0.019 - 0.071 and 0.047-0.071 mg/l nitrite, respectively. Amphora ovsalis and Navicula placentula had the highest frequency when nitrate ranges 4.48 – 5.16 and 4.48- 5.37 mg/l. The best habitat conditions for Amphora ovsalis and Navicula placentula were between the mean velocity values in the range of 1 -1.2 m/s.
Water Resources Engineering
P. E. Omuku; C. C. Odidika; A. E. Ozukwe; K. O. Iwuozor
Abstract
The objective of this study was to evaluate comparatively the effects of different brands of corrugated roofing sheets on rainwater utilized within Awka metropolis. Different physicochemical parameters were assessed in the rain water harvested using established standard laboratory procedures. The rain ...
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The objective of this study was to evaluate comparatively the effects of different brands of corrugated roofing sheets on rainwater utilized within Awka metropolis. Different physicochemical parameters were assessed in the rain water harvested using established standard laboratory procedures. The rain water was harvested directly (control) and also collected after passing through the different brands of corrugated roofing sheets (samples). The results showed no appreciable effects on the physical appearance, observable odour, or taste of the water samples compared to the control sample. However, at 30 °C, there were minor changes in the pH. The amount of suspended solids (SS) in mg/100ml, total solids (TS), and total dissolved solids (TDS) found in each of the samples, including the control sample, did not vary. This showed that the corrugated roofing sheet has no significant effect on the SS, TS, and TDS of the rain water harvested within the study area. Iron, zinc, and chloride ions followed a similar trend as SS, with Fe and Zn occurring at non-detectable limits of the instrumentation, while the levels of Cl- ion (3mg/100ml) did not vary in all the samples, including the control sample. The results revealed that corrugated roofing sheets affect the total alkalinity and methyl orange alkalinity of the harvested rain water in the study area greatly but had no impact on their physical appearance.
Water Resources Engineering
O. O. Ajani; G. O. Olutona; A. A. Adeniji
Abstract
Groundwater plays a very important and fundamental part in human existence because of its essential role in living systems. The study aimed at carrying out an empirical study into groundwater protective potential and water quality around Obafemi Awolowo University solid waste facility and AbaGboro Community. ...
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Groundwater plays a very important and fundamental part in human existence because of its essential role in living systems. The study aimed at carrying out an empirical study into groundwater protective potential and water quality around Obafemi Awolowo University solid waste facility and AbaGboro Community. This was achieved by using the electrical resistivity method to delineate the subsurface inhomogeneity around the dumpsite facility and also using the PG990 Atomic Absorption Spectrometer for metal analysis of water quality. The Schlumberger electrode array arrangement was engaged in the survey. A total of twelve vertical electrical soundings (VES) data was collected within the Obafemi Awolowo University dumpsite. The water samples were collected at two locations within the AbaGboro community which was 4.5 Km from the dumpsite to determine its quality. The results of the VES revealed the depth, resistivity, and thickness. The observed resistivity and the thickness values were further used in determining the groundwater protective potential, by calculating the Dar-Zarrouk parameters which showed that 91.7% of the study area is within poor/weak protective potential. The result from the water analysis of the hand-dug bore holes of the two different locations in the AbaGboro Community showed the presence of heavy metal concentrations as Pb, As, Mn, Cd, Zn, Cr and Co. Therefore, periodic assessment of water quality should always be carried out because we cannot anticipate when the groundwater will be contaminated due to relatively poor/weak groundwater protective potential.
