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1.
Hatem A. Ewea Amro M. M. Elfeki Jarbou A. Bahrawi Nassir S. Al-Amri 《Arabian Journal of Geosciences》2016,9(5):424
Runoff peak and volume in flood studies are estimated relying on temporal rainfall distribution from various storm patterns. Usually, SCS distributions types (I, II, III, IA) are commonly used. Using these distributions in runoff calculations assume that the in situ temporal rainfall pattern typically behaves as the one described by the SCS-type distribution, which is due to cyclonic frontal storms and actually developed in temperate environment. To what extent such assumption is valid in the arid environment? How much the impacts of rainfall temporal patterns are reflected in runoff volumes and peaks? The aim objectives of the current study are to answer the above two questions and clarify the validity of aforementioned assumption and exemplify such effect. Real rainfall data collected from rain gauges of Makkah Al-Mukkramah region over a period of more than 20 years are utilized. Temporal rainfall patterns and their parameters are deduced. Many hydrological simulations are performed and comparisons, in terms of runoff volume and peak flows, are made to show the effects of the common rainfall storm patterns and the developed rainfall storm patterns in the region based on the current study. Results indicate that major bursts of the design rainfall storm pattern are located in the first time of the storm period in the two quartiles which is mainly due to convective rainfall type in thunderstorms unlike the commonly used by SCS types relying on frontal cyclonic storms. Makkah Al-Mukkramah temporal rainfall pattern does not behave as the “typical pattern” assumed by SCS distributions that are deduced from different environments. The impacts of the temporal pattern reflected as an overestimate in the runoff peak reached to 68 %. The developed hyetographs and tables presented in the current study are recommended to enhance economical and rational design practice in watersheds of Makkah Al-Mukkramah region. 相似文献
2.
Hatem A. Ewea Nassir S. Al-Amri Mohamed A. Dawoud Amro M. Elfeki 《Natural Hazards》2018,94(2):801-817
Forecasting and monitoring extreme floods in arid regions like Saudi Arabia (SA) are a big challenge for engineers and hydrologists. It is difficult to derive reliable flood estimates at any site without adequate flood measurements. Therefore, envelope curves were developed for reliable estimates of flood peaks. Relaying on recorded flood events in SA, Francou–Rodier approach is used to develop the Regional Maximum Flood (RMF) for some wadis and for SA as a whole. A total of 3121 flood events in 32 arid basins of sizes varying from 99 to more than 4500 km2 are collected and analyzed. Results show that established regional coefficients (K) range between 2.76 and 5.5. The RMF formula for the Saudi regions is Q?=?251 A0.45. The flood-frequency analysis showed that the Log-Pearson Type III is best. The extreme observed floods for the envelope curve for K?=?5.5 accommodate floods of recurrence interval ranging between 1000 and 100,000 years. The study results provide more realistic runoff peaks for a design of flood protection works for SA watersheds and for the similar environment. Consequently, it is recommended to use the developed envelope curves and models for efficient, safe and precise hydraulic structures design in SA. 相似文献
3.
Development of storm hyetographs for flood forecasting in the Kingdom of Saudi Arabia 总被引：1，自引：0，他引：1
This paper presents the derivation of the design storm hyetograph patterns for the Kingdom of Saudi Arabia based on real rainfall events from meteorological stations distributed throughout the Kingdom. Two thousand twenty-seven rainfall storms for a 20–28-year period were collected and analyzed covering 13 regions of the Kingdom. Four distinct dimensionless rainfall hyetograph patterns have been obtained over the Kingdom, while two patterns have been obtained for each individual region because of the lack of data for long-duration storms in individual regions. The resulting dimensionless rainfall patterns for each region can be used to develop storm hyetographs for any design duration, total rainfall depth and return period. It has been shown that the developed storm hyetographs have different features from other storm patterns that are commonly used in arid zones. The study recommends using these curves for the design of hydraulic structures in Kingdom of Saudi Arabia and regions alike. 相似文献
4.
Abderraouf El Ouazzani Taibi Amro Elfeki Guoping Zhang 《Arabian Journal of Geosciences》2011,4(5-6):1005-1018
The research presented in this paper focuses on the application of a newly developed physically based watershed modeling approach, which is called representative elementary watershed approach. The study stressed the effects of uncertainty of input parameters on the watershed responses (i.e., simulated discharges). The approach was applied to the Zwalm catchment, which is an agriculture-dominated watershed with a drainage area of 114 km2 located in East Flanders, Belgium. Uncertainty analysis of the model parameters is limited to the saturated hydraulic conductivity because of its high influence on the watershed hydrologic behavior and availability of the data. The assessment of output uncertainty is performed using the Monte Carlo method. The ensemble statistical watershed responses and their uncertainties are calculated and compared with measurements. The results show that the measured discharges fall within the 95% confidence interval of the modeled discharge. This provides the uncertainty bounds of the discharges that account for the uncertainty in saturated hydraulic conductivity. The methodology can be extended to address other uncertain parameters as far as the probability density function of the parameter is defined. 相似文献
5.
6.
This paper proposes an extension of a single coupled Markov chain model to characterize heterogeneity of geological formations, and to make conditioning on any number of well data possible. The methodology is based on the concept of conditioning a Markov chain on the future states. Because the conditioning is performed in an explicit way, the methodology is efficient in terms of computer time and storage. Applications to synthetic and field data show good results. 相似文献
7.
The CMC (coupled Markov chain) model, which is based on the extension of Markov chains in two-dimensions, is used in the reduction
of uncertainty in geological structures when conditioned (i.e., honours the data and their location) on a number of boreholes.
The model has been applied to an unconsolidated aquifer deposit located in the central Rhine-Meuse delta (the Gorkum study
area) in the Netherlands. A comparison is also made between the CMC and the SIS (sequential indicator simulation) model, which
is based on Kriging and co-Kriging theories on the same deposit. The results show the potential applicability of the CMC model
in reducing the uncertainty in geological configurations when a sufficient number of boreholes is available. Reproduction
of the global geological features requires relatively few boreholes (in this case study, nine boreholes with 30-m spacing
over a distance of 240 m). However, reproduction of the proportion of each state requires a relatively large number of boreholes
(in this case study 31 boreholes with 8-m spacing over a distance of 240 m). It has been shown that variograms can be deceptive
in modeling the spatial pattern and that they reflect only part of the complete spatial structure in the field. The use of
transition probabilities via the CMC model provides a better alternative approach, because it uses multiple point information.
Amro M. M. Elfeki on leave from Department of Irrigation and Hydraulics, Faculty of Engineering, Mansoura University, Mansoura,
Egypt 相似文献
8.
Arabian Journal of Geosciences - In this paper, a spreadsheet modeling is introduced as a tool for studying fully distributed real-world engineering problems. The merits of using the spreadsheet... 相似文献
9.
Detection of contaminant plumes released from landfills: numerical versus analytical solutions 总被引：4，自引：3，他引：1
N. Buket Yenigül André T. Hensbergen Amro M. M. Elfeki F. Michel Dekking 《Environmental Earth Sciences》2011,64(8):2127-2140
Contaminant leaks released from landfills are a threat to groundwater quality. The groundwater monitoring systems installed
in the vicinity of such facilities are vital. In this study the detection probability of a contaminant plume released from
a landfill has been investigated by means of both a simulation and an analytical model for both homogeneous and heterogeneous
aquifer conditions. Since the detection probability is a sensitive quantity, we first compare the two methods for homogeneous
aquifer conditions to assess the errors that are encountered by performing simulations. The analysis shows that the simulation
model yields the detection probabilities of a contaminant plume at a given monitoring well quite well in the homogeneous case.
For heterogeneous aquifers we apply the approximated analytical model based on macro-dispersivities. Here we find that this
model is insufficient in monitoring system design, since the obtained analytical values of the detection probabilities at
a given monitoring well differ significantly from those computed by simulation. 相似文献
10.
Natural Hazards - This study used a simulation methodology for dam break analysis and flood simulation in an urbanized arid region, namely Um Al-Khair dam in Jeddah, Saudi Arabia. The analysis was... 相似文献