Hydraulics

Drainage network detection and assessment of network storage capacity in agrarian landscape

by Paolo Tarolli

Published in Hydrological Processes, 2012. Co-authored with Federico Cazorzi, Giancarlo Dalla Fontana, Alberto De Luca, Giulia Sofia

Drainage networks in agrarian landscape within floodplains constitute surface's discontinuities that are expected to... more Drainage networks in agrarian landscape within floodplains constitute surface's discontinuities that are expected to affect hydrological response during floods. Drainage network recognition and quantification of water storage capacity within channels are, therefore, crucial for watershed planning and management. These evaluations require accurate spatial information for the area of interest and in most cases, when studying large catchments, broad datasets of ditches locations and descriptions are not available. In order to characterize drainage networks for large areas, the availability of high resolution topography derived by airborne laser scanner (LiDAR) represents a new and effective tool. Nowadays LiDAR DTMs covering large areas are readily available for public authorities, and there is a greater and more widespread interest in the application of such information for the development of automated methods aimed at solving geomorphological and hydrological problems. While LiDAR DTMs reliability in steep landscape has been proven by several recent studies, only few researches have been conducted to take into account the effectiveness of these data in agrarian low relief landscapes. The goal of this research is to propose a semi-automatic approach based on a LiDAR DTM to (1) detect drainage networks in agrarian/floodplain contexts, and (2) to estimate some of the network summary statistics (network length, width, drainage density and storage capacity). The procedure is applied in two typical alluvial-plain areas in the North East of Italy, and tested comparing automatically derived network with surveyed ones. The results underline the capability of high resolution DTMs for drainage network detection and characterization in the context of agrarian landscapes within floodplains, opening at the same time new challenges to evaluate some hydrological processes in these areas

Natural Stable River Section Design Using Fluvial-12

by Aminuddin Ab Ghani

Darus, A., Ab. Ghani, A., Zakaria, N.A. & Abdullah, R.(2005). Natural Stable River Section Design using FLUVIAL-12, Bulletin Institution of Engineers Malaysia (May 2005), pp 24-27

Sediment transporting capacity, curvature effects as well as composition of channel bed and bank materials needmore Sediment transporting capacity, curvature effects as well as composition of channel bed and bank materials need
to be considered by the engineer during the design process of natural channels. Neglecting these effects would
normally result in instability problems because channel morphology usually changes with time.

Mathematical model (FLUVIAL-12) has gradually become popular in designing stable sections because it is more
economical compared to physical model. The model is capable of predicting instability effects such as riverbed
changes due to erosion and sedimentation during flood, thereby providing the necessary information for the
design or bank protection work.

In this paper, the application of FLUVIAL-12 for Raia River shows that the study reach can be preserved to its natural characteristics provided that the river bank should be covered with natural protection which produce the flow resistance to the value of Manning’s n = 0.045.

Sediment transport modeling and flood risk mapping in Geographic Information System (GIS)

by Aminuddin Ab Ghani

Sinnakaudan, S.K., Ab. Ghani, A., Ahamad, S.A. & Zakaria, N.A. (2004). Sediment Transport Modeling and Flood Risk Mapping in Geographic Information System (GIS), 4th Annual Seminar of National Science Fellowship 2004, 20th - 22nd December Penang, Malaysia

The requirement for risk based analysis and risk mapping become more prominent since the Urban Stormwater Management... more The requirement for risk based analysis and risk mapping become more prominent since the Urban Stormwater Management Manual for Malaysia (MASMA), which was introduced by Department of Irrigation and Drainage Malaysia (DID) in year 2000. The manual requires all drainage designs to
consider risk factors. Non-structural measures such as setting of minimum floor levels and/or platform levels may also be used to mitigate the effects of floods larger than the design event (DID, 2000). They should be considered within the design process as possible alternative or complementary components of the overall design (DID, 2000).

As a result, the current research presents the development of a new total bed material load equation using multiple linear regression analyses that is applicable for flood risk analysis in Malaysian rivers. It was developed and embedded as a modified version of HEC-6 model (USACE, 1991) and named SEDFlood model (Sinnakaudan, 2003).

Pari River, which is one of the main tributary of Kinta River located in Ipoh,Perak, Malaysia (Figure 2) has been chosen to
quantify the flooding scenarios to meet the tasks specified in this study.

A study of hydraulic characteristics for flow in equatorial rivers

by Aminuddin Ab Ghani

Lai S.H., Bessaih N., Law P.L., Ab. Ghani, A., Zakaria, N.A & Mah Y.S. (2008). A Study of Overbank Flow Hydraulic Characteristics in Equatorial Natural Rivers, International
Journal of River Basin Management, IAHR. Vol. 6, No.3, pp. 213-223. ISSN 1571-5124

This paper presents the results obtained from field measurements taken in several frequently flooded equitorial... more This paper presents the results obtained from field measurements taken in several frequently flooded equitorial rivers, including velocity distributions,
stage discharge relationships, roughness behaviours and discharge estimation. These have illustrated the large difference in velocity between the main channel and floodplain under flood conditions, and the effects of momentum transfer between deep and shallow flow, which include reduction in main channel velocity and discharge capacity, leading to a reduction in compound section capacity at depth above bankfull.

Another significant characteristic that has been found is that the floodplain regions behave as storage reservoirs (V = 0 m/s) in most cases due to high resistance of long and thick grasses along the flood plains (n = 0.07−0.1). Flow resistance relationships have been presented in terms of Manning’s coefficient and Darcy-Weisbach friction factor, showing the complex nature of flow resistance in the rivers and further explaining the danger inherent in the conventional practices of extrapolating inbank data for the analysis of overbank flows. Results for discharge estimation have been shown for comparison with actual data, the errors incurred by applying empirical methods to compound channel flows have been quantified and found to depend on the particular method used.

Discharge estimation for equatorial natural rivers with overbank flow

by Aminuddin Ab Ghani

Lai S.H., Bessaih N., Law P.L., Ab. Ghani, A., Zakaria, N.A.& Mah, Y.S. (2008). Discharge Estimation for quatorial Natural Rivers with Overbank Flow. International Journal of River Basin Management, IAHR. Vol. 6, No.1, pp. 13-21. ISSN 1571-5124

The estimation of discharge capacity in river channels is complicated by variations in geometry and boundary... more The estimation of discharge capacity in river channels is complicated by variations in geometry and boundary roughness. Estimating flood flows is particularly difficult because of compound cross-sectional geometries and because of the difficulties of flow gauging. Results are presented of a field study including the stage-discharge relationships and surface roughness in term of the Darcy-Weisbach friction factor, fa for several frequently
flooded equatorial natural rivers. Equations are presented giving the apparent shear force acting on the vertical interface between the main channel and floodplain.

The resulted apparent friction factor, fa is shown to increase rapidly for low relative depth. A method for predicting the discharge of overbank flow of natural rivers is then presented, by means of a composite friction, fc, which represents the actual resistance to flow due to the
averaged boundary shear force and the apparent shear force. Equations are also presented giving the composite friction factor from easily calculated parameters for overbank flow of natural rivers. The results obtained using the methods proposed show that a significant improvement has been achieved compare to the discharge obtained using traditional methods, with an averaged error of 2.7%.

Determination of apparent and composite friction factors for flooded equatorial natural rivers

by Aminuddin Ab Ghani

Lai S.H., Bessaih N., Law P.L., Ab. Ghani, A., & Mah, Y.S. (2008). Determination of Apparent and Composite Friction Factor for Flooded Equatorial Natural Rivers, International Journal of River Basin Management, IAHR. Vol. 6, No.1, pp. 3-12, ISSN 1571-5124

This paper presents results, calculated from field measurements taken in several frequently flooded natural rivers,... more This paper presents results, calculated from field measurements taken in several frequently flooded natural rivers, which include D and R relationships, variation of flow resistance with depth of flow, the apparent friction factor, and the composite friction factor for flooded natural rivers. The results obtained have shown the complexity of flow resistance in natural rivers due to the interaction between the main channel and floodplain flow. The
interaction has given rise to a pair of apparent shear stresses at the interface region, which can significantly reduce the discharge capacity of the rivers.

The apparent shear was quantified in terms of an apparent friction factor, fa, and it was found that the apparent shear stress is many times greater than the averaged boundary shear stress of the rivers. Based on the averaged boundary shear stress and apparent shear stress, the composite (actual) friction factor for the rivers can be estimated accurately (R2 = 0.99) using a statistical method that had been derived.

Evaluation of equations on total bed material load

by Aminuddin Ab Ghani

Ariffin, J., Ab. Ghani, A., Zakaria, N.A., & Yahaya, A.S. (2002). Evaluation of Equations on Total Bed Material Load, International Conference on Urban Hydrology for the 21st Century, Kuala Lumpur, 14 – 16 October, pp. 321-327.

Predictions of total bed material load for Malaysian rivers using selected empirical equations were made based on 56... more Predictions of total bed material load for Malaysian rivers using selected empirical equations were made based on 56 sets of field data. Data were obtained through observations made from three rivers namely Sungai Lui, Sungai Semenyih and Sungai Langat in Malaysia. The rivers are categorised under wide rivers with width to depth ratio greater than 10. Data covers flow discharges from 2.7 m3/s to 54.078 m3/s, flow velocities from 0.411 m/s to 1.422 m/s, flow depths from 0.3664 m to 2.4425 m and median sediment sizes between 0.582 mm to 2.415 mm. The equations used in the evaluation are Ackers and White, Engelund and Hansen, Yang and the equation proposed by Wu et al. The selection was based on the performance of these equations by past investigators who showed good agreement between observed and calculated transport rates. The range of data used by these investigators are tabulated. Graphical comparisons of the calculated and measured transport rates are shown. The accuracy and the reliability of these formulas are verified.

Inlet and Sewer Traps for Sediment Control in Stormwater Drainage ‐ A Malaysian Case Study

by Aminuddin Ab Ghani

Fraser, A.G., Ashley, R.M., & Ab. Ghani, A. (2000). Inlet and Sewer Traps for Sediment Control in Stormwater Drainage: A Malaysian Case Study, Joint Conference on Water Resources Engineering & Water Resources Planning and Management, ASCE, Minneapolis,
USA, 30 July - 2 August, Section 39, Chapter 2. ISBN: 0784405174

The city of Alor Setar in Kedah, is an important developing centre of business and communications for the Northwest of... more The city of Alor Setar in Kedah, is an important developing centre of business and communications for the Northwest of Malaysia. However, the capacities of the existing storm drains in Alor Setar are severely restricted as a result of sediment deposits washed‐in during high intensity rainfall events. These deposits result in stagnant, polluted areas of water within the catchment and a loss of hydraulic capacity needed to deal with large storms. Methods of sediment deposition prediction have been applied to UK catchments with limited degrees of success. The application of these methods has been used to propose an improved sediment management strategy for Alor Setar. The methods involve the development of a simplified hydraulic model of the test catchment and the prediction of areas within the system where deposits are most likely to occur. Using this formation options for invert trap placement can be developed in order to determine their most effective locations. Further analyses are also proposed in order to determine the fill rates of these traps throughout an average year. A proactive maintenance plan can therefore be developed in preference to the reactive maintenance methods currently employed This planned programme of maintenance should ensure that best use of traps is made at all times in order to protect the system from flooding and pollution problems.

Incipient Motion Of Sediment Particles Over Deposited Loose Beds In A Rectangular Channel

by Aminuddin Ab Ghani

Ab. Ghani, A., Salem, A.M., Abdullah, R., Yahaya, A. S., & Zakaria, N.A. (1999). Incipient Motion Of Sediment Particles Over Deposited Loose Beds In A Rectangular Channel, 8th International Conference on Urban Storm Drainage, IAHR, Sydney, Australia, Vol. 1, pp. 157-
163, 30 Aug.– 3 September. ISBN: 0858257181

New experimentals work were conducted to study the effects of sediment deposits’ thickness on the incipient motion of... more New experimentals work were conducted to study the effects of sediment deposits’ thickness on the incipient motion of particles in a rigid rectangular channel. The results show that the deposits’ thickness significantly affects the channel’s ability to erode the sediment deposits.
New equations were derived taking into account the effects of deposits’ thickness.

Evaluation of Alluvial River Stability for River Restoration: Case Study of Raia River and Pari River

by Aminuddin Ab Ghani

Darus, A., Ab. Ghani, A., Zakaria, N.A & Abdullah, R. (2003). Evaluation of Alluvial River Stability for River Restoration: Case Study of Raia River and Pari River. East-Asia Regional Seminar on River Restoration, Kuala Lumpur, 13 – 15 January.

As a result of increasing economic growth of the country, areas within river catchments are being developed intomore As a result of increasing economic growth of the country, areas within river catchments are being developed into
new commercial, industrialization and housing purposes. Effect of this rapid urbanization has accelerated its impact
on the hydrology and geomorphology. These evelopments have caused dramatically increase in the surface runoff
and the behaviour of their sediment output hence resulting higher sediment yield.

Since any flood mitigation works would likely affect channel modification, knowledge of predicting the geometry
changes involving the sediment transport movement to maintain the channel stability and design capacity are
significant and necessary. Comparisons on several empirical design methods including regime theory and mathematical model (FLUVIAL-12) were carried out for Raia River that is considered as a natural river and Pari River, which has been canalized. Such evaluations were used to find out the appropriate method that will minimize the morphological changes in river channel.

The results indicate that mathematical model (FLUVIAL-12) comprising component of water and sediment routing
is capable of predicting instability effects such as significant erosion and sedimentation along river channel.
The simulation results from FLUVIAL-12 also indicate that this model is capable of producing stable design section
based on maintaining the maximum section capacity and high bank stability.

L'état, la terre et l'eau enter Nil et Syr-Darya: Remarques introductives

by Pierre Briant

Annales. Histoire, Sciences Sociales, 2002/3 57e année, p. 517-529

Retour sur Alexandre et les katarraktai du Tigre (Première partie)

by Pierre Briant

Studi Ellenistici 2006

Appraisal of soft computing techniques in prediction of total bed material load in tropical rivers

by Aminuddin Ab Ghani

Chang, C.K., Azamathulla, H.Md., Zakaria, N. A. & Ab. Ghani, A. (2012). Appraisal of Soft Computing Techniques in Prediction of Total Bed Material Load in Tropical Rivers,
Journal of Earth System Science, Vol. 121, No. 1, pp. 125-133, ISSN 0253-4126

This paper evaluates the performance of three soft computing techniques, namely Gene-Expression Programming (GEP)... more This paper evaluates the performance of three soft computing techniques, namely Gene-Expression Programming (GEP) (Zakaria et al 2010), Feed Forward Neural Networks (FFNN) (Ab Ghani et al 2011), and Adaptive Neuro-Fuzzy Inference System (ANFIS) in the prediction of total bed material load for three Malaysian rivers namely Kurau, Langat and Muda. The results of present study are very promising: FFNN (R 2 = 0.958, RMSE = 0.0698), ANFIS (R 2 = 0.648, RMSE = 6.654), and GEP (R 2 = 0.97, RMSE = 0.057), which support the use of these intelligent techniques in the prediction of sediment loads in tropical rivers.

Numerical modelling of 3-D tidal currents and water quality indicators in the Bristol Channel

by Roger Falconer - Cardiff University

Paper 60:  Lin, B. and Falconer, R. A. 2001. Numerical modelling of 3-D tidal currents and water quality indicators in the Bristol Channel”, Proceedings of the Institution of Civil Engineers, Water and Maritime Engineering. 148(3), 155-166.

Abstract
Details are given of the principle processes of flow and contaminant transport in coastal, estuarine... more Abstract
Details are given of the principle processes of flow and contaminant transport in coastal, estuarine and inland waters and the application of computer models to predict these processes. A typical computer modelling approach is outlined, involving a finite difference solution of the three-dimensional equations of mass and momentum conservation and the advective-diffusion (or solute transport) equation. Examples are given of the application of the model to predict the spatial and temporal distributions of velocity components and water quality indicators in the Bristol Channel.

2010: F. BRAEMER, B. GEYER, C. CASTEL et M. ABDULKARIM, “ Conquest of new lands and water systems in the western Fertile Crescent (Central and Southern Syria”, Water History Volume 2, Number 2, p. 91-114

by Castel Corinne

co-authored with F. BRAEMER, B. GEYER and M. ABDULKARIM,in Water History Volume 2, Number 2, p. 91-114

Sustainable River Management: from the sediment transport and river equilibrium perspectives (In Malay)

by Aminuddin Ab Ghani

Ab. Ghani, A. (2008). Sustainable River Management: from the sediment transport and river equilibrium perspectives, USM Professorial Talk Series, ISBN: 9789838613828 (In Malay)

Sediment transport modeling for Kulim River-A case study

by Aminuddin Ab Ghani

Chang, C. K., Ab. Ghani, A., Abdullah, R. & Zakaria, N.A.(2008). Sediment Transport Modeling for Kulim River: A Case Study. Journal of Hydro-Environment Research, IAHR, Vol. 2, No.1, pp. 47-59, ISSN: 1570-6443.

Rapid urbanization has accelerated impact on the catchment hydrology and geomorphology. This rapid development which... more Rapid urbanization has accelerated impact on the catchment hydrology and geomorphology. This rapid development which takes place in river catchment will result in higher sediment yield and affect river morphology and river channel stability; it also becomes the main cause for serious flooding in urban areas. Therefore, it is necessary to predict and evaluate the river channel stability due to the existing and future developments. This study proceeds at Kulim River in Kedah state, a natural stream in Kedah, Malaysia. The FLUVIAL-12 model, an erodible-
boundary model which simulates inter-related changes in channel-bed profile, width variation and changes in bed topography was selected for this study. Engelund-Hansen formula and roughness coefficient n ¼ 0.030 were found to be the best combination to represent the sediment
transport activity in the study reach, where good agreements were obtained for both water level and bed profiles between the measured data and predicted results by FLUVIAL-12 model. The model simulation results for existing conditions, future conditions and long-term modeling show that the sediment size and channel geometry in Kulim River changed significantly. However, modeled results show that future changes in cross
sectional geometry will be limited and erosion along the reach will slow down from 2006 to 2016, thus Kulim River was predicted to be stable at most locations.

Sediment deposition in a rigid monsoon drain

by Aminuddin Ab Ghani

Ab. Ghani, A., Zakaria, N.A. & Kassim, M. (2008). Sediment Deposition in a Rigid Monsoon Drain, International Journal of River Basin Management, IAHR, Vol. 6, No.1, pp. 23-30, ISSN 1571-5124

Field data collections to study the physical sediment characteristics and trends of sediment deposition were carried... more Field data collections to study the physical sediment characteristics and trends of sediment deposition were carried out at Raja River monsoon drain made up of concrete channels for the period of 2000 and 2001. Assessments of the existing incipient motion equations developed from experimental works were made using the measured field data. The results show that equations by Novak & Nalluri (1975), El‐Zaemey (1991) and Ab. Ghani et al. (1999) are able to predict satisfactorily the sediment deposition in rigid channel

Machine Learning Approach to Predict Sediment Load: A Case Study

by Aminuddin Ab Ghani

Azamathullah, H.Md., Ab. Ghani, A., Chang, C.K., Abu Hasan, Z., & Zakaria, N. A. (2010). Machine Learning Approach to Predict Sediment Load – A Case Study, CLEAN – Soil, Air, Water. Vol. 38, No. 10, pp. 969-976, ISSN: 1863-0650

In this study, a novel machine learning technique called the support vector machine (SVM) method is proposed as a new... more In this study, a novel machine learning technique called the support vector machine (SVM) method is proposed as a new predictive model to predict sediment loads in three Malaysian rivers. The SVM is employed without any restriction to an extensive database compiled from measurements in the Muda, Langat, and Kurau rivers. The SVM technique demonstrated a superior performance compared to other traditional sediment-load methods. The coefficient of determination, 0.958, and the mean square error, 0.0698, of the SVM method are higher than those of the traditional method. The performance of the SVM method demonstrates its predictive capability and the possibility of the generalization of the model to nonlinear problems for river engineering applications.

Gene-Expression Programming for the Development of A Stage-Discharge Curve of the Pahang River

by Aminuddin Ab Ghani

Azamathulla, H.Md., Ab. Ghani, A., Leow, C.S., Chang, C.K., & Zakaria, N. A.(2011).Gene-Expression Programming for the Development of A Stage-Discharge Curve of the Pahang River, Water Resources Management, Vol. 25, No. 11, pp. 2901 –2916, ISSN 0920-4741

This study presents Gene-Expression Programming (GEP), an extension of Genetic Programming (GP), as an alternative... more This study presents Gene-Expression Programming (GEP), an extension of Genetic Programming (GP), as an alternative approach to modeling the stage-discharge relationship for the Pahang River. The results are compared to those obtained by more conventional methods, i.e., the stage rating curve (SRC) and regression techniques. Additionally, the explicit formulations of the developed GEP models are presented. The performance of the GEP model was found to be substantially superior to both GP and the conventional models.