A Water Quality Study of the Selangor River, Malaysia Suriyani Awang March 2015 Thesis submitted for the Degree of Doctor of Philosophy School of Environmental Sciences University of East Anglia Norwich England "This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognize that its copyright rests with the author and that use of any information derived there from must be in accordance with current UK Copyright Law. In addition, any quotation or extract must include full attribution.” i ABSTRACT Malaysia’s rapid economic and demographic development has put pressures on its water supplies and consequently on the quality of its river water. The Selangor River, close to the nation’s capital, is now a major source of water and there are fears that its water quality will deteriorate. The Malaysian Government in its Vision for Water 2025 states that rivers should achieve Class II as measured by Malaysia’s Water Quality Index (WQI) (Class I is cleanest). The objectives of this thesis are to investigate the effects of flow through the 10 major tidal control gates (TCGs) which regulate run-off from the oil-palm plantations into the river, and to predict the water quality for the river in 2015, 2020 and 2030. In order to achieve these objectives it was necessary to set-up, calibrate and validate a commercial one-dimensional numerical model, InfoWorks, which includes both the hydrodynamics and water quality of the river-estuary network. It was concluded that there was insufficient hydrodynamic (stage and current) and water quality data to fully calibrate and validate the InfoWorks model but it performed well when compared with measured salinity transects. The model was found to be relatively insensitive to the choice of diffusion parameters but needed a high value for the oxygen transfer velocity, 0.3 m h-1, to get reasonable values for the dissolved oxygen (DO) along the river. The effect of run-off through the TCGs was less than expected and attributed to the high oxygen transfer velocity and needs to be addressed before the model can properly represent run-off through the TCGs. The model shows the WQI of the lower reaches of the river to be Class III in both wet and dry seasons except close to the estuary where it is Class II due to tidal flushing. The dissertation identifies several deficiencies in the model; the lack of an operational ramp function at the estuary boundary, the use of a single value of the oxygen transfer velocity throughout, and the exclusion of water extraction. Land-use changes above Rantau Panjang, the upper boundary of the InfoWorks model, and water quality data were used to estimate the water quality and its uncertainties at Rantau Panjang in 2015, 2020 and 2030 due to predicted development in the upper catchment for both wet and dry seasons. InfoWorks models of water quality along the river in 2015, 2020 and 2030, which included extraction at the Batang Berjuntai barrage, predict little change in the WQ (Class II/III boundary) below the barrage during the dry season but a rapid deterioration in the wet season (down to Class III/IV by 2030) showing the importance of water extraction to the water quality of the river. Overall, because of its relative simplicity and ease of operation, InfoWorks is considered to be a useful tool for river management in Malaysia. i ACKNOWLEDGEMENT First of all, my praises and thanks to Almighty Allah, the Most Gracious the Most Merciful, who gave me the knowledge, encouragement and patience to accomplish this research study. May the peace and blessings of Allah be upon our Prophet Mohammad pbuh. I wish to express my sincere appreciation and millions thanks to my supervisor, Prof. C.E Vincent, for his patience, guidance and kind help. Without his continued support and interest, this thesis would not be completed. His good deeds will always be remembered. Also to another two supervisory team members, Dr. Rosalind Boar and Dr Tony Dolphin for fruitful discussion, ideas and advices. I am also indebted to the National Hydraulics Research Institute of Malaysia (NAHRIM), Department of Irrigation and Drainage (DID) and the Ministry of Natural Resources and Environment (NRE) especially the officers and staffs (Ir. Hj Juhaimi Jusoh, En Azizi Seman, En. Sadiq Kasmani, En Syaiful Bahren and the technicians) who gave their support when I did the field work and getting the data and related information. I also need to take this opportunity to say many thanks to Haji Abdul Jalil Hassan and HR Asia Wallingford software team for their guidance, advice and knowledge in software technical supports. Last but not least to my beloved husband, M. Idrus Said and my gorgeous sons, M. Amir Irfan and M. Azim Imtiaz for continual support and unconditional love. Also to my family members and friends who have directly or indirectly helped and contributed to the success of this study. ii TABLE OF CONTENTS ABSTRACT i ACKNOWLEDGEMENT ii TABLE OF CONTENTS iii LIST OF TABLES vii LIST OF FIGURES x LIST OF SYMBOLS/TERMINOLOGY xvi CHAPTER 1 INTRODUCTION 1 1.0The demand for water in Malaysia 1 1.1 Malaysian vision for Water 2025 6 1.2 River water quality management in Malaysia 6 1.2.1 Organisation and legislation 6 1.2.2 National water quality standards 9 1.3 The importance of this study 10 1.4 Research objectives 11 1.5 Thesis structures 12 CHAPTER 2 WATER QUALITY MANAGEMENT AND 14 MODELLING 2.0 Introduction 14 2.1 Water quality management and modelling in 14 Europe 2.2 Water quality management and modelling in the US 16 2.3 Water quality management and modelling in the 17 Southeast Asia 2.4 Water quality management and modelling in 19 Malaysia 2.5 The integrated River Basin Management (IRBM) 20 concept 2.6 Water quality and management in the Selangor 21 River basin 2.7 Summary 24 CHAPTER 3 MODEL DESCRIPTION 25 3.0 Introduction 25 3.1 The Hydrodynamic Model 26 3.1.1 Hydrodynamic Equations 27 3.2 Water Quality 28 3.2.1 Advection-Diffusion Equation 29 3.2.2 Dissolved Oxygen Module 30 iii 3.2.2.1 Dissolved Oxygen 31 3.2.2.2 Re-aeration 31 3.2.2.3 Biochemical Oxygen Demand 32 3.2.2.4 Chemical Oxygen Demand 34 3.2.2.5 COD or BOD? 34 3.2.2.6 Ammoniacal Nitrogen 35 3.2.2.7 Denitrification 35 3.3 The Malaysian Water Quality Index (WQI) 37 3.4 Setting up the river model 39 3.4.1 River cross sections 39 3.4.2 Manning’s Roughness Coefficient, n 42 3.4.3 Tidal Control Gates 42 3.5 Summary 49 CHAPTER 4 DATA COLLECTION AND PREPARATION FOR 50 MODELLING OF THE SELANGOR RIVER 4.0 Introduction 50 4.1 Description of study area 50 4.1.1 Location 50 4.1.2 Climate 51 4.1.3 The Selangor river system and its 51 characteristics 4.1.4 Soil 52 4.1.5 Land-use 54 4.1.6 Human activities by the coast and 57 their impact 4.1.7 River pollution 57 4.2 River hydraulic Data 59 4.2.1 Bathymetric (river cross section) data 59 4.2.2 Tidal data 59 4.3 River Flow Data at Rantau Panjang 62 4.3.1 Discharge Measurement 64 4.3.2 Stage-Discharge Relationship 66 4.4 Tidal control gates 68 4.4.1 Water levels behind the TCGs 73 4.4.2 Canal dimensions and lengths 74 4.5 Water Quality Data 75 4.5.1 DOE sampling stations 75 4.5.2 NAHRIM sampling campaigns 76 4.5.3 Quality assurance analysis 79 4.6 Run-off through the tidal control gates 80 4.6.1 Estimating net flow using a Simple 80 Water Balance Model 4.6.2 Run-off from sub-catchments 80 4.6.3 Run-off coefficient 81 4.7 Rainfall data 82 4.8 Summary 85 iv CHAPTER 5 MODEL BOUNDARY CONDITIONS AND 87 CALIBRATION 5.0 Introduction 87 5.1 Boundary conditions 87 5.1.1 Hydrodynamic boundary conditions 87 5.1.2 Water quality boundary conditions 88 5.2 Hydrodynamic model set-up and calibration 92 5.2.1 How good is the hydrodynamic 92 model? – Model evaluation 5.2.2 Initial tidal stage set-up 93 5.2.3 Manning’s Roughness coefficient, n 95 5.3 Calibration of the mixing processes 96 5.4 Ramp function 97 5.5 Wet and dry seasons 103 5.6 Summary 104 CHAPTER 6 PRESENT WATER QUALITY: ANALYSIS AND 105 DISCUSSION 6.0 Introduction 105 6.1 Calibrating and validating re-aeration in the 106 InfoWorks Water Quality model against measurements 6.2 Variation in WQI along the Selangor River 110 6.2.1 Dry season (May-July) water quality 112 6.2.2 Wet season (Oct-Dec) water quality 116 6.3 Impact of run-off from TCGs on the Selangor 119 River water quality 6.4 7Q10 – Low flow analysis 122 6.5 Summary 125 CHAPTER 7 PREDICTION OF FUTURE WATER QUALITY: 2015, 127 2020 and 2030 7.0 Introduction 127 7.1 Land-use and land-use changes 128 7.2 Estimation of water quality parameters 136 7.2.1 Estimating water quality at Rantau Panjang 137 in 2015, 2020 and 2030 7.3 Uncertainties in the water quality calculations 140 7.4 WQI of the Selangor River in 2015, 2020 and 141 2030 7.4.1 Water abstraction 141 7.4.2 Water quality along the Selangor 141 River 7.4.2.1 Predicted WQI for 2015 145 7.4.2.2 Predicted WQI for 2020 145 7.4.2.3 Predicted WQI for 2030 145 7.5 Summary 146 v CHAPTER 8 DISCUSSION OF RESULTS 148 8.0 Introduction 148 8.1 Limitation of the InfoWorks hydrodynamic 148 model for the Selangor River 8.2 Prediction of present water quality 150 8.3 Effects of run-off through the TCGs 151 8.4 Prediction of water quality in 2015, 2020 and 154 2030 8.5 Impacts on the Selangor River fire fly colonies 156 8.6 The need for further work 157 CHAPTER 9 CONCLUSIONS 159 9.0 Introduction 159 9.1 The InfoWorks Hydrodynamic Model 160 9.2 The InfoWorks Water Quality Model 160 9.3 Prediction of Present water quality 160 9.4 Prediction of future water quality 161 9.5 Effects on the fire flies 162 9.6 Overall conclusions of