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71.
Today, the world's population is rising dramatically, and in line with this increase in the population of food and agricultural products, there must be an increasing in the number of problems associated with this process of agricultural land. Then it is necessary to use the maximum potential of this lands that product maximum yield without any damage. To reach this objective, land suitability evaluation is the most important way that can reach human to this objective. The main objective of this research was to compare different irrigation methods based on a parametric evaluation system in an area of 221402 ha in the Khosouyeh Subbasin of the Fars province, in the south of Iran. After preparing land unit map, 37 points were selected for sampling. Soil properties were evaluated and analyzed. Suitability maps for drop and gravity irrigation were generated using GIS technique. The results revealed land suitability of 98.42% of the case study was classified as permanently not suitable (N2) and 1.52% currently not suitable (N1) for gravity irrigation. On the other hand, land suitability of 77.73% of the case study was classified as permanently not suitability (N2), 6.05% currently not suitable (N1), 12.43% marginally suitable (S3) and 3.79% moderately suitable (S2) for drop irrigation. The limiting factors for both kinds of drop and gravity irrigation are soil depth and slope of land. 相似文献
72.
The special feature of bend flow leads to scouring of the bed and bank. Various parameters like flow depth, flow velocity or discharge, geometry of bend and characteristics of bed material may affect the scour process. Experiments were carried out to study the effect of some important parameters on bend scour under clear water condition. Experiments were conducted in a 0.6m wide and 0.7m high flume with 90 degree bend. The lateral variations of bed slope were studied. The maximum depth of scour was correlated to densimetric Froude number, relative bend radius and relative depth of flow. 相似文献
73.
Sina Maghami Nick Nadim K. Copty Selen Deviren Saygın Hasan Sabri Öztürk Burak Demirel S. Mehdi Emadian Günay Erpul Majid Sedighi Masoud Babaei 《水文研究》2024,38(3):e15135
Soil salt accumulation is a widespread problem leading to diminished crop yield and threatening food security in many regions of the world. The soil salinization problem is particularly acute in areas that lack adequate soil water drainage and where a saline shallow water table (WT) is present. In this study, we present laboratory-scale column experiments, extending over a period of more than 400 days that focus on the processes contributing to soil salinization. We specifically examine the combined impact of soil compaction, surface water application model and water quality on salt dynamics in the presence of a saline shallow WT. The soil columns (60 cm height and 16 cm diameter) were packed with an agricultural soil with bulk densities of 1.15 and 1.34 g/cm−3 for uncompacted and compacted layers, respectively, and automatically monitored for water content, salinity and pressure. Two surface water compositions are considered: fresh (deionized, DI) and saline water (~3.4 mS/cm). To assess the sensitivity of compaction on salt dynamics, the experiments were numerically modelled with the HYDRUS-1D computer program. The results show that the saline WT led to rapid salinization of the soil column due to capillarity, with the salinity reaching levels much higher than that at the WT. However, compaction layer provided a barrier that limited the downwards moisture percolation and solute transport. Furthermore, the numerical simulations showed that the application of freshwater can temporarily reverse the accumulation of salts in agricultural soils. This irrigation strategy can help, in the short-term, alleviate soil salinization problem. The soil hydraulic properties, WT depth, water quality, evaporation demand and the availability of freshwater all play a role in the practicability of such short-term solutions. The presence of a saline shallow WT would, however, rapidly reverse these temporary measures, leading to the recurrence of topsoil salinization. 相似文献
74.
Spatio-temporal characterization of the Pliocene aquifer conditions in Wadi El-Natrun area,Egypt 总被引:2,自引:1,他引:2
Wadi El-Natrun area has recently undergone extensive urban and agricultural expansion. Due to the absence of natural surface
irrigation supplies, the only source of water in the area is the Pliocene groundwater aquifer. As a result, secondary salinization
from increased abstractions is the major threat to the groundwater aquifer. There is a dire need for efficient strategies
to ensure long-term sustainability of the area’s productive agriculture. These strategies should be based on scientific spatio-temporal
monitoring and analysis of the groundwater conditions that is also lacking. To capture the spatio-temporal variability in
groundwater conditions, field measurements of total dissolved solids, electrical conductivity, pH, temperature, and water
level as well as lab-based ionic composition were performed on 47 groundwater samples collected during 2006 and 2007. Determinations
of the hydrochemical characteristics, water types, salt assemblages, and the sodium adsorption ratio were carried out on the
samples. Reference data sets recorded in 1973 and 1997 were available for the area and were used to monitor the changes occurred
in these periods. Geographic information system (GIS) was appraised for mapping and for integrated analysis of the different
layers. Remotely sensed change detection techniques were applied to the Landsat TM and the ETM + imageries and used to highlight
the extensive reclamation and urbanization and to find key trends for the alterations in the groundwater conditions and their
spatial association with land covers. Results revealed a topographic depression-induced flow pattern, predominance of leaching
and dissolution processes, the presence of saline lakes, over-pumping from the Pliocene aquifer, and temporal changes in land
uses are the main factors combined to control the spatio-temporal variability in the groundwater. Results also clarified the
presence of two: northwestern and southeastern zones that varied distinctively in their hydrodynamic and hydrochemical characteristics.
The northwestern zone showed an average water level decline of 15 m, the water of which is brackish (av. 2,037 mg/l) with dominant Na+, Cl− and SO4
2− ions. The groundwater of this zone is characterized by high to very high salinity hazard and high to very high alkali hazard
and is not recommended for irrigation on soils with poor drainage and without proper management for salinity control. The
southeastern zone showed water level decline less than 2 m, the water of which is fresh (av. 424 mg/l) with major Na+, HCO3
−, Cl−, and SO4
2− ions, and quality suitable for irrigation with medium to high salinity and low to medium alkali hazards. The article represents
the first step towards an integrated management of Wadi El-Natrun groundwater resources within a GIS framework. 相似文献
75.
Masoud Rabeti Moghadam Alireza Sadeghi Abdollahi 《Marine Georesources & Geotechnology》2017,35(3):376-396
Breakwaters provide a calm sea basin for ships and protect harbor facilities by reflecting wave energy toward the open sea area. Their performance under environmental loadings is the main concern for coastal engineers. Liquefaction susceptibility of loose sediments of seabed threatens performance of these structures. The article investigates soil liquefaction effects on the seismic performance of Iran liquefied natural gas (LNG) composite breakwater. Performance-based design method, considering both grade of the breakwater and acceptable level of damages, was selected as design philosophy. Liquefaction-induced damages to the breakwater were determined by numerical analysis. Since the obtained level of deformations did not meet allowable damages, soil improvement against liquefaction was considered. Different improvement patterns were proposed based on distribution of pore pressure ratio (ru) beneath the breakwater to control its seismic performance. This investigation revealed that the most important area for soil improvement is located near the toes of breakwater to control the slope instability and performance of the breakwater. 相似文献
76.
The ultimate goal of reservoir simulation in reservoir surveillance technology is to estimate long-term production forecasting and to plan development and management of petroleum fields. However, maintaining reliable reservoir models which honour available static and dynamic data, involve inherent risks due to the uncertainties in space and time of the distribution of hydrocarbons inside reservoirs. Recent applications have shown that these uncertainties can be reduced by quantitative integration of seismic data into the reservoir modelling workflows to identify which areas and reservoir attributes of the model should be updated. This work aims using seismic data to reduce ambiguity in calibrating reservoir flow simulation model with an uncertain petro-elastic model, proposing a circular workflow of inverted seismic impedance (3D and 4D) and engineering studies, with emphasis on the interface between static and dynamic models. The main contribution is to develop an updating procedure for adjusting reservoir simulation response before using it in the production forecasting and enhance the interpretive capability of reservoir properties. Accordingly, the workflow evaluates consistency of reservoir simulation model and inverted seismic impedance, assisted by production history data, to close the loop between reservoir engineering and seismic domains. The methodology is evaluated in a complex, faulted, sandstone reservoir, the Norne benchmark field, where a significant reservoir behaviour understanding (about the static and dynamic reservoir properties) is obtained towards the quantitative integration of seismic impedance data. This leads to diagnosis of the reservoir flow simulation reliability and generation of an updated simulation model consistent with observed seismic and well production history data, as well as a calibrated petro-elastic model. Furthermore, as Norne Field is a benchmark case, this study can be considered to enrich the discussions over deterministic or probabilistic history matching studies. 相似文献
77.
Kiyosi Kawanisi Masoud Bahrainimotlagh Mohamad Basel Al Sawaf Mahdi Razaz 《水文研究》2016,30(13):2247-2254
The acquisition of reliable discharge estimates is crucial in hydrological studies. This study demonstrates a promising acoustic method for measuring streamflow at high sampling rate for a long period using the fluvial acoustic tomography system (FATS). The FATS recently emerged as an innovative technique for continuous measurements of streamflow. In contrast to the traditional point/transect measurements of discharge, the FATS enables the depth‐averaged and range‐averaged flow velocity along the ray path to be measured in a fraction of a second. The field test was conducted in a shallow gravel‐bed river (0.9 m deep under low‐flow conditions, 115 m wide) for 1 month. The parameters (stream direction and bottom elevation) required for calculating the streamflow were deduced by a nonlinear regression to the discharge data from the well‐established rating curve. The cross‐sectional average velocities were automatically calculated from the acoustic data, which were collected on both riverbanks every 30 s. The FATS was connected to the internet so that the real‐time flow data could be obtained. The FATS captured discharge variations at a cut‐off frequency of approximately 70 day?1. The stream exhibited temporal discharge changes at multiple time scales ranging from a few tens of minutes to days. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
78.
Masoud Goharrokhi Hoda Pahlavan David A. Lobb Philip N. Owens Shawn P. Clark 《水文研究》2019,33(15):2048-2056
Collecting a representative time‐integrated sample of fluvial fine‐grained suspended sediment (<63 μm) is an important requirement for the understanding of environmental, geomorphological, and hydrological processes operating within watersheds. This study (a) characterized the hydrodynamic behaviour of a commonly used time‐integrated fine sediment sampler (TIFSS) using an acoustic Doppler velocimeter (ADV) in controlled laboratory conditions and (b) measured the mass collection efficiency (MCE) of the sampler by an acoustic Doppler current profiler under field conditions. The laboratory results indicated that the hydrodynamic evaluations associated with the original development of the TIFSS involved an underestimation of the inlet flow velocity of the sampler that results in a significant overestimation of the theoretical MCE. The ADV data illustrated that the ratio of the inlet flow velocity of the sampler to the ambient velocity was 87% and consequently, it can be assumed that a representative sample of the ambient fine suspended particles entered into the sampler. The field results showed that the particle size distribution of the sediment collected by the TIFSS was statistically similar to that for the ambient sediment in the Red River, Manitoba, Canada. The MCE of the TIFSS in the field trials appeared to be as low as 10%. Collecting a representative sample in the field was consistent with the previous findings that the TIFSS is a suitable sampler for the collection of a representative sample of sufficient mass (e.g., >1 g) for the investigation of the properties of fluvial fine‐grained suspended sediment. Hydrodynamic evaluation of the TIFSS under a wider range of hydraulic conditions is suggested to assess the performance of the sampler during high run‐off events. 相似文献
79.
Masoud Moghaddasi Misko Cubrinovski J. Geoff Chase Stefano Pampanin Athol Carr 《地震工程与结构动力学》2011,40(2):135-154
Complex seismic behaviour of soil–foundation–structure (SFS) systems together with uncertainties in system parameters and variability in earthquake ground motions result in a significant debate over the effects of soil–foundation–structure interaction (SFSI) on structural response. The aim of this study is to evaluate the influence of foundation flexibility on the structural seismic response by considering the variability in the system and uncertainties in the ground motion characteristics through comprehensive numerical simulations. An established rheological soil‐shallow foundation–structure model with equivalent linear soil behaviour and nonlinear behaviour of the superstructure has been used. A large number of models incorporating wide range of soil, foundation and structural parameters were generated using a robust Monte‐Carlo simulation. In total, 4.08 million time‐history analyses were performed over the adopted models using an ensemble of 40 earthquake ground motions as seismic input. The results of the analyses are used to rigorously quantify the effects of foundation flexibility on the structural distortion and total displacement of the superstructure through comparisons between the responses of SFS models and corresponding fixed‐base (FB) models. The effects of predominant period of the FB system, linear vs nonlinear modelling of the superstructure, type of nonlinear model used and key system parameters are quantified in terms of different probability levels for SFSI effects to cause an increase in the structural response and the level of amplification of the response in such cases. The results clearly illustrate the risk of underestimating the structural response associated with simplified approaches in which SFSI and nonlinear effects are ignored. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
80.
Sadeghi Farhang Monjezi Masoud Jahed Armaghani Danial 《Natural Resources Research》2020,29(2):887-903
Natural Resources Research - Drilling and blasting operations are one of the most effective techniques for rock removal in mines. However, these operations are associated with some environmental... 相似文献