Abdullah Wagdani - Academia.edu (original) (raw)

Papers by Abdullah Wagdani

Earth systems and environment, Mar 5, 2024

Arab Gulf Journal of Scientific Research, 2008

Namman Basin is an arid mountainous basin located in the western region of Saudi Arabia and has a... more Namman Basin is an arid mountainous basin located in the western region of Saudi Arabia and has a drainage area of about 650 km 2 . Namman unconfined groundwater aquifer is the source of water to the historic underground galleries known as Ain Zubaidah. The galleries became dry due to the fall of groundwater levels dramatically in the last few decades. The galleries can be restored only if a proper water resources management is utilized in the basin. The aim of this research is to investigate two major hydrological components, namely rainfall and runoff, which are essential for a proper management of the water resources of the basin. Rainfall and runoff records for ten rain gauge stations and one runoff gauge station are used to investigate major characteristics of rainfall and runoff in Namman basin. Rainfall records are analyzed to derive conclusion about rainfall occurrence, depth, duration, temporal distribution and extreme values. The relation between rainfall depth and elevation is also investigated. Runoff records are utilized to investigate seasonal variation of runoff. Values of runoff coefficient for all runoff events are computed and the relation between rainfall and runoff for the basin are discussed. The results show that there are more than 30 rainstorms per year and only about two runoff events are usually observed. The temporal analysis of rainfall and runoff indicates that there are two rainy seasons, one is during fall and winter season and the other is during spring seasons while runoff is mainly observed in the winter season. Values of runoff coefficient were very low with mean value of 0.013, which indicate that most rainfall infiltrate through the alluvial channels of the basin.

Arabian Journal of Geosciences, 2021

Construction of intensity-duration-frequency (IDF) curves is crucially important for the design a... more Construction of intensity-duration-frequency (IDF) curves is crucially important for the design and management of hydro-systems and hydraulic structures. The existence of long-term records of short-duration rainfall is essential for the development of IDF curves. In arid regions, short-duration rainfall records are usually scarce and daily rainfall data are the most commonly available. However, synthetic rainfall hyetographs can afford a simple and suitable tool for extracting short-duration rainfall from daily rainfall data. This study aims to evaluate the ability of the four standard NRCS synthetic rainfall distributions to generate short-duration rainfall data from daily data that might be used to construct IDF curves for an arid region in western Saudi Arabia. The historical intensity and daily rainfall records are collected from 10 recording rainfall stations in Jeddah-Makkah-Taif (JMT) hydrologic region located in western Saudi Arabia. In this study, 2-, 3-, 6-, 12-, and 24-h types I, IA, II, and III NRCS dimensionless rainfall time distributions are used to convert the observed daily rainfall data into shorter duration data. The generated data are used to develop IDF curves and they were compared with those constructed from the available observed rainfall intensity data. Values of the mean absolute percentage error (MAPE) for the used gauge stations range between 5 and 11%. The comparison shows that the NRCS synthetic rainfall distributions are capable to generate short-duration rainfall data that can be used to construct IDF curves for the JMT region. The results also suggest that the 6-h type II NRCS distribution produced IDF curves that are very comparable with those extracted from the observed data. The results also indicate that the 3-h types I and III NRCS distributions have relatively low overall mean values of MAPE (10 to 12%). They can be considered the second-best choice after the 6-h NRCS distribution for developing IDF curves for the study region. This may highlight the applicability of the proposed technique in the JMT region.

Water resources engineering, 1995

Ten basins in Indiana were selected to study their geomorphologic properties, fractal characteris... more Ten basins in Indiana were selected to study their geomorphologic properties, fractal characteristics and geomorphologic instantaneous unit hydrographs (GIUHs). Horton\u27s laws of stream network were found to be valid for these basins. Drainage maps of these basins were delineated manually and by using two digital elevation models (DEMs). Except for regions where elevation data are unreliable, geomorphologic properties of automatically derived and manually delineated drainage basins are similar. Feder (1988) and Rosso et al. (1991) formulas were used to compute fractal dimensions of the main stream length of the basins. The computed fractal dimensions were found to be comparable to the measured fractal dimensions. The method of Mesa and Gupta (1987) to compute main stream length was modified to be applicable to basins with more than one major channel. Discharge and energy fluxes in the study watersheds were found to follow power law distributions. Exponents of the resulting power laws do not show the universality suggested by Rodriguez-Iturbe et al. (1992). The performance of three GIUH models was evaluated by using them to simulate runoff hydrographs from the study basins. For all of these models, peak flow and time to peak were found to be sensitive to the value of the streamflow velocity. The streamflow velocities of the three models were found to be correlated. A new method of estimating the non-measurable parameters of these models was developed. In this method, parameters were estimated as a function of rainfall and geomorphologic properties of the basin

Two hydrologic aspects of droughts are investigated in this study as a part of the work conducted... more Two hydrologic aspects of droughts are investigated in this study as a part of the work conducted for the task committee on water management during droughts. In the first part a monthly water balance model was used to investigate the response of watersheds to climatic change. In the second part, a method of drought identification is investigated. The results from these models are presented and discussed.

One of the major issues in the arid region is the availability of hydrological data for hydrologi... more One of the major issues in the arid region is the availability of hydrological data for hydrological studies of the basins for water resources projects. Since the Kingdom of Saudi Arabia (KSA) is a huge country and contains many arid basins it is awfully expensive and time-consuming to make hydrological networks for studying all these basins. Therefore, the Affinity Propagation (AP) clustering technique is proposed to cluster basins into groups that are similar in morphological, hydrological, and landcover characteristics and defining an exemplar (a representative basin) to each group. This basin is utilized for the installation of a detailed hydrological network. The hydrological response of that basin can be transferred and scaled appropriately to other basins in the cluster since they are hydrologically and morphologically similar. A pilot study is performed on 18 sub-basins in the southwestern part of KSA. GIS software is used to extract basin attributes and the clustering proce...

Misr Journal of Agricultural Engineering, 2009

Misr Journal of Agricultural Engineering, 2009

Journal of King Saud University - Science, 2020

Development of Intensity-Duration-Frequency (IDF) Curves is important for the design of various h... more Development of Intensity-Duration-Frequency (IDF) Curves is important for the design of various hydraulic structures such as culverts, dams, and stormwater drainage systems. In this paper, rainfall analyses are conducted to evaluate the effect of using rainfall records from different rain gauge types on IDF Curves construction. Rainfall data are collected from two recording rain gauges at Namman catchment in western Saudi Arabia. Using the available 13 years rainfall data of the two gauges, annual maxima rainfall series values are extracted and used for IDF curves computations. The rainfall gauge which is equipped with a siphon produced IDF curves with higher precipitation intensities in comparison with the other gauge. This indicates that the siphon mechanism plays an important role in decreasing the under-catchment amount of the tipping bucket gauges during heavy rainfall storms. The current study shows that the under-catchment amount of tipping-bucket rain gauges can have a significant impact on the IDF curves and the characteristics of the design storm. A correction relationship to adjust rain intensity data sets of recording rain gauges that are not furnished with siphons is proposed in this paper. The adjusted rainfall intensity values are utilized to construct reliable IDF curves.

Arabian Journal of Geosciences, 2020

Background: Graves disease (GD) is an organ-specific autoimmune disease characterized by hyperthy... more Background: Graves disease (GD) is an organ-specific autoimmune disease characterized by hyperthyroidism, diffuse goiter, autoantibodies against thyroid-specific antigens, and dermopathy. Studies of GD have demonstrated the importance of the Th2 and Th17 immune responses in mediating disease progression. In the present study, we investigated the role of a Th2 cytokine, thymic stromal lymphopoietin (TSLP), in GD and Th17 differentiation. Methods: In this study, we genotyped 470 patients with GD at 3 single nucleotide polymorphisms (SNPs) in TSLP. In addition, the serum concentrations of TSLP were determined in 432 patients and 272 controls. Ten patients and controls each were further screened using in vitro Th17 differentiation assays. The SNPs were genotyped using ABI TaqMan W SNP genotyping assays. For the Th17 differentiation assays, peripheral blood mononuclear cells (PBMCs) isolated from the patients and controls were placed into Th17 differentiation media, and interleukin 17 expression levels were determined. Results: Haplotype analysis indicated that patients with the Ht3 (TCC) haplotype have a 3.28-fold higher risk of developing GD (p = 0.007), whereas those with the Ht5 (TCG) haplotype had a 0.03-fold, reduced risk of developing GD (p = 1 × 10 −14). SNP rs3806933 (p = 0.007) was associated with female Graves ophthalmopathy (GO). TSLP expression levels were higher in GD patients than in control subjects, and TLSP was also shown to promote the differentiation of Th17 cells in GD patients. Conclusions: These results suggest that polymorphisms in TSLP may be used as genetic markers for the diagnosis and prognosis of GD. Furthermore, TLSP may be a target for treating GD.

Geomatics, Natural Hazards and Risk, 2020

The Horton-Strahler ratios are important to describe the stream network and to identify the hydro... more The Horton-Strahler ratios are important to describe the stream network and to identify the hydrologic response of a basin using the GIUH concept. These ratios are often sensitive to the selected threshold area for the extraction of the stream network form digital elevation models (DEM). Researches are seeking to find out the appropriate threshold with no success. Self-similarity approach of the properties of the stream network can provide an estimation of equivalent Horton-Strahler ratios using parameters independent of the threshold area. This approach is applied on four arid basins in Saudi Arabia. The equivalent Horton-Strahler ratios are used to derive GIUH based on Nash and Fr echet hydrograph models. The results indicate that the Horton-Strahler ratios and the length of the highest order stream depend strongly on the threshold and consequently, the GIUH characteristics show discrepancies due to the threshold. This study recommends to use threshold area that is equal to 0.02% of the basin area for basins less than 280 km 2 and 0.002% of the basin area for basins large than 2700 km 2 .The comparison between the measured and the equivalent hydrographs of Nash and Fr echet models for each event shows that there are obvious discrepancies in terms of peak discharge, Q p , time to peak,T p , time lag, T lag , and the runoff volume. The results of Nash model are relatively better to represent the measured hydrographs. The minimum relative error (RE) of some events are: RE of Q p ranges between 12.5% for Nash to 61% for Fr echet, RE of T p is À53.8% for both Nash and Fr echet, while RE of T lag is 0.0% for both Nash and Fr echet and RE of runoff volume ranges between À37.5% for Nash to À34.5% for Fr echet. The study recommends investigating other GIUH models to improve the RE in arid regions.

Journal of African Earth Sciences, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Arabian Journal of Geosciences, 2016

The goal of this work is to assess the effect of utilizing different types of tipping bucket rain... more The goal of this work is to assess the effect of utilizing different types of tipping bucket rain gauges in investigating rainfall characteristics. A dual tipping bucket (TB) rain gauge station is installed in the upper catchment of Numan basin in Saudi Arabia. The main difference between the two gauges is that the Hydrological Services (HS) gauge is equipped with a siphon tube which reduces undercatchment particularly during heavy rainfall. Records of both gauges for the period 2006 to 2013 are collected, analyzed, and compared, focusing on the characteristics of rainfall events as well as rainfall temporal variability. The HS gauge recorded higher values of total rainfall depth compared to the Texas Electronics (TEMM) gauge. For the individual storms as well as the 5-min rainfall, HS gauge also reported higher mean rainfall depths. Regarding temporal characteristics of reported rainfall, no significant variations are observed between the values of storm duration of the two gauges. The TEMM gauge has the advantage of recoding more storms with depth less than 1 mm. The current study suggests the use of a corrective factor for rainfall record of the TEMM gauge.

Arabian Journal for Science and Engineering, 2014

In this study, a dual tipping-bucket (TB) rain gauge station is installed in an arid region in we... more In this study, a dual tipping-bucket (TB) rain gauge station is installed in an arid region in western Saudi Arabia. The size of the gauge collector was the only difference between the two installed rain gauges. Records of both gauges for the period 2006-2013 are collected, analyzed and compared, focusing on characteristics of rainfall events as well as rainfall temporal variability. The two gages recorded almost the same total rainfall depth but significantly different mean storm depth values. For the large storms, both gauges recorded the same mean storm depth. However, significantly variable values throughout the storm duration are observed. The TB gauge with the larger funnel size (TEMM) has the advantage of recoding more storms with depth less than 1 mm though it underestimates the depth for storms of high intensities. This study also shows the importance of using dual rain gauges in arid regions where large storms are rare and hence can be missed if only one gauge is used due to gauge failure, which is not a surprise in such harsh environment.

Arabian Journal of Geosciences, 2015

In this study, rainfall analysis is carried out to investigate the areal rainfall characteristics... more In this study, rainfall analysis is carried out to investigate the areal rainfall characteristics of three major basins in western Saudi Arabia. The drainage area of study basins ranges from 395 to 3500 km 2. Records of rainfall intensity and durations were collected from nine recording rain gauge located in these basins. The mean areal rainfall depth is determined and used to compute the mean areal rainfall intensity for all the recoded rainfall events. The data were also utilized to compute frequency distributions of areal rainfall intensity and duration. Exponential distributions are fitted for the areal rainfall intensity and durations. The fitted distributions are found in a good agreement with the observed frequencies.

Arabian Journal for Science and Engineering, 2014

In this study, ten Indiana basins were selected to investigate their geomorphologic characteristi... more In this study, ten Indiana basins were selected to investigate their geomorphologic characteristics. The drainage area of these basins covers a wide range. Stream networks of these basins are classified according to both Strahler’s and Shreve’s ordering systems. Based on these ordering systems, more than twenty primary and secondary geomorphologic parameters were determined for each study basin. Horton’s laws of stream numbers, stream length and stream area were checked and found valid for these Indiana basins. Values of cumulative drainage area were used to investigate the exceedance probability distribution of mean annual discharge and energy fluxes in the study watersheds. The results of the study show that discharge and energy fluxes were found to follow power law distributions. Exponent of the resulting power laws does not show the universality suggested by previous investigations.

Journal of King Abdulaziz University-Meteorology, Environment and Arid Land Agriculture Sciences, 2010

Journal of King Abdulaziz University-Meteorology, Environment and Arid Land Agriculture Sciences, 2010

... Majareesh sub-basin has the largest contribution to groundwater rechage of Namman basin, whil... more ... Majareesh sub-basin has the largest contribution to groundwater rechage of Namman basin, while Arar and Yarij sub-basins have the smallest contributions. ... محمد الشربيني كيوان, Kiwan,Mohammed S. Researcher, kiwanahmed@hotmail.com. Files. File Name, Type, Description. ...

Arabian Journal of Geosciences

Earth systems and environment, Mar 5, 2024

Arab Gulf Journal of Scientific Research, 2008

Namman Basin is an arid mountainous basin located in the western region of Saudi Arabia and has a... more Namman Basin is an arid mountainous basin located in the western region of Saudi Arabia and has a drainage area of about 650 km 2 . Namman unconfined groundwater aquifer is the source of water to the historic underground galleries known as Ain Zubaidah. The galleries became dry due to the fall of groundwater levels dramatically in the last few decades. The galleries can be restored only if a proper water resources management is utilized in the basin. The aim of this research is to investigate two major hydrological components, namely rainfall and runoff, which are essential for a proper management of the water resources of the basin. Rainfall and runoff records for ten rain gauge stations and one runoff gauge station are used to investigate major characteristics of rainfall and runoff in Namman basin. Rainfall records are analyzed to derive conclusion about rainfall occurrence, depth, duration, temporal distribution and extreme values. The relation between rainfall depth and elevation is also investigated. Runoff records are utilized to investigate seasonal variation of runoff. Values of runoff coefficient for all runoff events are computed and the relation between rainfall and runoff for the basin are discussed. The results show that there are more than 30 rainstorms per year and only about two runoff events are usually observed. The temporal analysis of rainfall and runoff indicates that there are two rainy seasons, one is during fall and winter season and the other is during spring seasons while runoff is mainly observed in the winter season. Values of runoff coefficient were very low with mean value of 0.013, which indicate that most rainfall infiltrate through the alluvial channels of the basin.

Arabian Journal of Geosciences, 2021

Construction of intensity-duration-frequency (IDF) curves is crucially important for the design a... more Construction of intensity-duration-frequency (IDF) curves is crucially important for the design and management of hydro-systems and hydraulic structures. The existence of long-term records of short-duration rainfall is essential for the development of IDF curves. In arid regions, short-duration rainfall records are usually scarce and daily rainfall data are the most commonly available. However, synthetic rainfall hyetographs can afford a simple and suitable tool for extracting short-duration rainfall from daily rainfall data. This study aims to evaluate the ability of the four standard NRCS synthetic rainfall distributions to generate short-duration rainfall data from daily data that might be used to construct IDF curves for an arid region in western Saudi Arabia. The historical intensity and daily rainfall records are collected from 10 recording rainfall stations in Jeddah-Makkah-Taif (JMT) hydrologic region located in western Saudi Arabia. In this study, 2-, 3-, 6-, 12-, and 24-h types I, IA, II, and III NRCS dimensionless rainfall time distributions are used to convert the observed daily rainfall data into shorter duration data. The generated data are used to develop IDF curves and they were compared with those constructed from the available observed rainfall intensity data. Values of the mean absolute percentage error (MAPE) for the used gauge stations range between 5 and 11%. The comparison shows that the NRCS synthetic rainfall distributions are capable to generate short-duration rainfall data that can be used to construct IDF curves for the JMT region. The results also suggest that the 6-h type II NRCS distribution produced IDF curves that are very comparable with those extracted from the observed data. The results also indicate that the 3-h types I and III NRCS distributions have relatively low overall mean values of MAPE (10 to 12%). They can be considered the second-best choice after the 6-h NRCS distribution for developing IDF curves for the study region. This may highlight the applicability of the proposed technique in the JMT region.

Water resources engineering, 1995

Ten basins in Indiana were selected to study their geomorphologic properties, fractal characteris... more Ten basins in Indiana were selected to study their geomorphologic properties, fractal characteristics and geomorphologic instantaneous unit hydrographs (GIUHs). Horton\u27s laws of stream network were found to be valid for these basins. Drainage maps of these basins were delineated manually and by using two digital elevation models (DEMs). Except for regions where elevation data are unreliable, geomorphologic properties of automatically derived and manually delineated drainage basins are similar. Feder (1988) and Rosso et al. (1991) formulas were used to compute fractal dimensions of the main stream length of the basins. The computed fractal dimensions were found to be comparable to the measured fractal dimensions. The method of Mesa and Gupta (1987) to compute main stream length was modified to be applicable to basins with more than one major channel. Discharge and energy fluxes in the study watersheds were found to follow power law distributions. Exponents of the resulting power laws do not show the universality suggested by Rodriguez-Iturbe et al. (1992). The performance of three GIUH models was evaluated by using them to simulate runoff hydrographs from the study basins. For all of these models, peak flow and time to peak were found to be sensitive to the value of the streamflow velocity. The streamflow velocities of the three models were found to be correlated. A new method of estimating the non-measurable parameters of these models was developed. In this method, parameters were estimated as a function of rainfall and geomorphologic properties of the basin

Two hydrologic aspects of droughts are investigated in this study as a part of the work conducted... more Two hydrologic aspects of droughts are investigated in this study as a part of the work conducted for the task committee on water management during droughts. In the first part a monthly water balance model was used to investigate the response of watersheds to climatic change. In the second part, a method of drought identification is investigated. The results from these models are presented and discussed.

One of the major issues in the arid region is the availability of hydrological data for hydrologi... more One of the major issues in the arid region is the availability of hydrological data for hydrological studies of the basins for water resources projects. Since the Kingdom of Saudi Arabia (KSA) is a huge country and contains many arid basins it is awfully expensive and time-consuming to make hydrological networks for studying all these basins. Therefore, the Affinity Propagation (AP) clustering technique is proposed to cluster basins into groups that are similar in morphological, hydrological, and landcover characteristics and defining an exemplar (a representative basin) to each group. This basin is utilized for the installation of a detailed hydrological network. The hydrological response of that basin can be transferred and scaled appropriately to other basins in the cluster since they are hydrologically and morphologically similar. A pilot study is performed on 18 sub-basins in the southwestern part of KSA. GIS software is used to extract basin attributes and the clustering proce...

Misr Journal of Agricultural Engineering, 2009

Misr Journal of Agricultural Engineering, 2009

Journal of King Saud University - Science, 2020

Development of Intensity-Duration-Frequency (IDF) Curves is important for the design of various h... more Development of Intensity-Duration-Frequency (IDF) Curves is important for the design of various hydraulic structures such as culverts, dams, and stormwater drainage systems. In this paper, rainfall analyses are conducted to evaluate the effect of using rainfall records from different rain gauge types on IDF Curves construction. Rainfall data are collected from two recording rain gauges at Namman catchment in western Saudi Arabia. Using the available 13 years rainfall data of the two gauges, annual maxima rainfall series values are extracted and used for IDF curves computations. The rainfall gauge which is equipped with a siphon produced IDF curves with higher precipitation intensities in comparison with the other gauge. This indicates that the siphon mechanism plays an important role in decreasing the under-catchment amount of the tipping bucket gauges during heavy rainfall storms. The current study shows that the under-catchment amount of tipping-bucket rain gauges can have a significant impact on the IDF curves and the characteristics of the design storm. A correction relationship to adjust rain intensity data sets of recording rain gauges that are not furnished with siphons is proposed in this paper. The adjusted rainfall intensity values are utilized to construct reliable IDF curves.

Arabian Journal of Geosciences, 2020

Background: Graves disease (GD) is an organ-specific autoimmune disease characterized by hyperthy... more Background: Graves disease (GD) is an organ-specific autoimmune disease characterized by hyperthyroidism, diffuse goiter, autoantibodies against thyroid-specific antigens, and dermopathy. Studies of GD have demonstrated the importance of the Th2 and Th17 immune responses in mediating disease progression. In the present study, we investigated the role of a Th2 cytokine, thymic stromal lymphopoietin (TSLP), in GD and Th17 differentiation. Methods: In this study, we genotyped 470 patients with GD at 3 single nucleotide polymorphisms (SNPs) in TSLP. In addition, the serum concentrations of TSLP were determined in 432 patients and 272 controls. Ten patients and controls each were further screened using in vitro Th17 differentiation assays. The SNPs were genotyped using ABI TaqMan W SNP genotyping assays. For the Th17 differentiation assays, peripheral blood mononuclear cells (PBMCs) isolated from the patients and controls were placed into Th17 differentiation media, and interleukin 17 expression levels were determined. Results: Haplotype analysis indicated that patients with the Ht3 (TCC) haplotype have a 3.28-fold higher risk of developing GD (p = 0.007), whereas those with the Ht5 (TCG) haplotype had a 0.03-fold, reduced risk of developing GD (p = 1 × 10 −14). SNP rs3806933 (p = 0.007) was associated with female Graves ophthalmopathy (GO). TSLP expression levels were higher in GD patients than in control subjects, and TLSP was also shown to promote the differentiation of Th17 cells in GD patients. Conclusions: These results suggest that polymorphisms in TSLP may be used as genetic markers for the diagnosis and prognosis of GD. Furthermore, TLSP may be a target for treating GD.

Geomatics, Natural Hazards and Risk, 2020

The Horton-Strahler ratios are important to describe the stream network and to identify the hydro... more The Horton-Strahler ratios are important to describe the stream network and to identify the hydrologic response of a basin using the GIUH concept. These ratios are often sensitive to the selected threshold area for the extraction of the stream network form digital elevation models (DEM). Researches are seeking to find out the appropriate threshold with no success. Self-similarity approach of the properties of the stream network can provide an estimation of equivalent Horton-Strahler ratios using parameters independent of the threshold area. This approach is applied on four arid basins in Saudi Arabia. The equivalent Horton-Strahler ratios are used to derive GIUH based on Nash and Fr echet hydrograph models. The results indicate that the Horton-Strahler ratios and the length of the highest order stream depend strongly on the threshold and consequently, the GIUH characteristics show discrepancies due to the threshold. This study recommends to use threshold area that is equal to 0.02% of the basin area for basins less than 280 km 2 and 0.002% of the basin area for basins large than 2700 km 2 .The comparison between the measured and the equivalent hydrographs of Nash and Fr echet models for each event shows that there are obvious discrepancies in terms of peak discharge, Q p , time to peak,T p , time lag, T lag , and the runoff volume. The results of Nash model are relatively better to represent the measured hydrographs. The minimum relative error (RE) of some events are: RE of Q p ranges between 12.5% for Nash to 61% for Fr echet, RE of T p is À53.8% for both Nash and Fr echet, while RE of T lag is 0.0% for both Nash and Fr echet and RE of runoff volume ranges between À37.5% for Nash to À34.5% for Fr echet. The study recommends investigating other GIUH models to improve the RE in arid regions.

Journal of African Earth Sciences, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Arabian Journal of Geosciences, 2016

The goal of this work is to assess the effect of utilizing different types of tipping bucket rain... more The goal of this work is to assess the effect of utilizing different types of tipping bucket rain gauges in investigating rainfall characteristics. A dual tipping bucket (TB) rain gauge station is installed in the upper catchment of Numan basin in Saudi Arabia. The main difference between the two gauges is that the Hydrological Services (HS) gauge is equipped with a siphon tube which reduces undercatchment particularly during heavy rainfall. Records of both gauges for the period 2006 to 2013 are collected, analyzed, and compared, focusing on the characteristics of rainfall events as well as rainfall temporal variability. The HS gauge recorded higher values of total rainfall depth compared to the Texas Electronics (TEMM) gauge. For the individual storms as well as the 5-min rainfall, HS gauge also reported higher mean rainfall depths. Regarding temporal characteristics of reported rainfall, no significant variations are observed between the values of storm duration of the two gauges. The TEMM gauge has the advantage of recoding more storms with depth less than 1 mm. The current study suggests the use of a corrective factor for rainfall record of the TEMM gauge.

Arabian Journal for Science and Engineering, 2014

In this study, a dual tipping-bucket (TB) rain gauge station is installed in an arid region in we... more In this study, a dual tipping-bucket (TB) rain gauge station is installed in an arid region in western Saudi Arabia. The size of the gauge collector was the only difference between the two installed rain gauges. Records of both gauges for the period 2006-2013 are collected, analyzed and compared, focusing on characteristics of rainfall events as well as rainfall temporal variability. The two gages recorded almost the same total rainfall depth but significantly different mean storm depth values. For the large storms, both gauges recorded the same mean storm depth. However, significantly variable values throughout the storm duration are observed. The TB gauge with the larger funnel size (TEMM) has the advantage of recoding more storms with depth less than 1 mm though it underestimates the depth for storms of high intensities. This study also shows the importance of using dual rain gauges in arid regions where large storms are rare and hence can be missed if only one gauge is used due to gauge failure, which is not a surprise in such harsh environment.

Arabian Journal of Geosciences, 2015

In this study, rainfall analysis is carried out to investigate the areal rainfall characteristics... more In this study, rainfall analysis is carried out to investigate the areal rainfall characteristics of three major basins in western Saudi Arabia. The drainage area of study basins ranges from 395 to 3500 km 2. Records of rainfall intensity and durations were collected from nine recording rain gauge located in these basins. The mean areal rainfall depth is determined and used to compute the mean areal rainfall intensity for all the recoded rainfall events. The data were also utilized to compute frequency distributions of areal rainfall intensity and duration. Exponential distributions are fitted for the areal rainfall intensity and durations. The fitted distributions are found in a good agreement with the observed frequencies.

Arabian Journal for Science and Engineering, 2014

In this study, ten Indiana basins were selected to investigate their geomorphologic characteristi... more In this study, ten Indiana basins were selected to investigate their geomorphologic characteristics. The drainage area of these basins covers a wide range. Stream networks of these basins are classified according to both Strahler’s and Shreve’s ordering systems. Based on these ordering systems, more than twenty primary and secondary geomorphologic parameters were determined for each study basin. Horton’s laws of stream numbers, stream length and stream area were checked and found valid for these Indiana basins. Values of cumulative drainage area were used to investigate the exceedance probability distribution of mean annual discharge and energy fluxes in the study watersheds. The results of the study show that discharge and energy fluxes were found to follow power law distributions. Exponent of the resulting power laws does not show the universality suggested by previous investigations.

Journal of King Abdulaziz University-Meteorology, Environment and Arid Land Agriculture Sciences, 2010

Journal of King Abdulaziz University-Meteorology, Environment and Arid Land Agriculture Sciences, 2010

... Majareesh sub-basin has the largest contribution to groundwater rechage of Namman basin, whil... more ... Majareesh sub-basin has the largest contribution to groundwater rechage of Namman basin, while Arar and Yarij sub-basins have the smallest contributions. ... محمد الشربيني كيوان, Kiwan,Mohammed S. Researcher, kiwanahmed@hotmail.com. Files. File Name, Type, Description. ...

Arabian Journal of Geosciences