PAPER IX: WATER USE MANAGEMENT FINAL REPORT MARCH 2004 WUP-JICA TEAM Vol. II: Supporting Report, Paper IX: Water Use Management WUP-JICA, March 2004 TABLE OF CONTENTS SUMMARY................................................................................................................. IX-1 CHAPTER 1: INTRODUCTION.............................................................................. IX-10 CHAPTER 2: RIVER WATER USE MANAGEMENT IN JAPAN ..................... IX-11 1. EXISTING WATER USE AND RIVER FLOW REGIME....................... IX-11 1.1 Land Area and Population ..................................................................... IX-11 1.2 Existing Water Use................................................................................ IX-11 1.3 River Flow Regime................................................................................ IX-12 1.4 Storage Dam .......................................................................................... IX-12 2. WATER USE MANAGEMENT BY WATER RIGHT.............................. IX-12 2.1 Principles of Water Use Management ................................................... IX-12 2.1.1 River Water............................................................................... IX-12 2.1.2 Groundwater ............................................................................. IX-13 2.2 Water Rights.......................................................................................... IX-13 2.2.1 Principles of Granting Water Right .......................................... IX-13 2.2.2 Necessary Consultation and Coordination prior to Granting Water Right............................................................................... IX-14 2.2.3 Priority Order............................................................................ IX-15 2.2.4 Term of Validity ....................................................................... IX-15 2.2.5 Existing Water Rights............................................................... IX-15 3. DESIGN RIVER FLOW FOR WATER USE MANAGEMENT.............. IX-16 3.1 General .................................................................................................. IX-16 3.2 Natural Flow.......................................................................................... IX-16 3.3 Design Low Flow .................................................................................. IX-16 3.3.1 Probability of Design Low Flow .............................................. IX-17 3.3.2 Preparation of Design Flow Regime (Hydrograph).................. IX-17 3.3.3 Estimation ofr Future Design Low Flow .................................. IX-18 3.4 Required Minimum Flow ...................................................................... IX-19 3.4.1 Objectives and Functions of the Flow ...................................... IX-19 3.4.2 Seasonal Variation of Flow....................................................... IX-19 3.4.3 Reliability of Flow.................................................................... IX-19 4. WATER RESOURCES DEVELOPMENT................................................. IX-21 4.1 Water Conflicts...................................................................................... IX-21 IX-S1 Vol. II: Supporting Report, Paper IX: Water Use Management WUP-JICA, March 2004 4.1.1 General...................................................................................... IX-21 4.1.2 Inter-basin Water Diversion...................................................... IX-21 4.2 Principles and Policy of Water Resources Development....................... IX-21 4.2.1 Maintenance of Required Minimum Flow................................ IX-21 4.2.2 New Water Development.......................................................... IX-22 4.2.3 Long-Term Water Resources Development Plan ..................... IX-22 4.2.4 Optimum and Equitable Water Resources Development.......... IX-23 4.3 Inter-basin Water Diversion of Yoshino River (Example) .................... IX-23 4.3.1 General Description of the Basin .............................................. IX-23 4.3.2 Old Inter-basin Diversion.......................................................... IX-24 4.3.3 New Inter-basin Diversion........................................................ IX-24 5. WATER USE COORDINATION AND MONITORING .......................... IX-27 5.1 Water Use Restriction in Drought Time ................................................ IX-27 5.1.1 General...................................................................................... IX-27 5.1.2 Processes of Water Use Restriction .......................................... IX-27 5.2 Water Use Monitoring ........................................................................... IX-28 5.2.1 Necessity of Water Use Monitoring.......................................... IX-28 5.2.2 Water Use Monitoring System.................................................. IX-28 5.3 Water Use Coordination and Monitoring in Tone River (Example) ..... IX-29 5.3.1 Main Features of the River Basin ............................................. IX-29 5.3.2 Water Use Monitoring .............................................................. IX-30 5.3.3 Low Flow Control..................................................................... IX-31 5.3.4 Reasons for Good Performance of Water Use Monitoring....... IX-33 6. HOW TO ESTABLISH THE REQUIRED MINIMUM FLOW............... IX-35 6.1 General................................................................................................... IX-35 6.2 Procedure to Establish the Required Minimum Flow............................ IX-35 6.2.1 Basic Assumption ..................................................................... IX-35 6.2.2 Methodology............................................................................. IX-36 6.2.3 Estimation Method of Environmental Flow.............................. IX-37 6.3 Establishment of Required Minimum Flow in Shinano River (Example)..................................................................................... IX-41 6.3.1 General...................................................................................... IX-41 6.3.2 Water Balance along the Mainstream ....................................... IX-42 6.3.3 Estimation of Required Environmental Flow ........................... IX-43 6.3.4 Establishment of Required Minimum Flow.............................. IX-45 6.3.5 Further Study ............................................................................ IX-45 6.4 Retrieval of River Valley Environments................................................ IX-45 IX-ii Vol. II: Supporting Report, Paper IX: Water Use Management WUP-JICA, March 2004 6.4.1 General...................................................................................... IX-45 6.4.2 Environmental Water Release of Saga Hydropower Dam (Example)......................................................................... IX-46 6.5 Control of Salinity Intrusion.................................................................. IX-49 6.5.1 General...................................................................................... IX-49 6.5.2 Control of Salinity Intrusion in the Tone River (Example) ...... IX-49 CHAPTER 2: WATER USE MANAGEMENT IN LOWER MEKONG ............. IX-55 1. DISCUSSIONS ON ACCEPTABLE MINIMUM MONTHLY NATURAL FLOW ........................................................................................ IX-55 1.1 General .................................................................................................. IX-55 1.2 Purpose of Establishment of the AMMNF ............................................ IX-55 1.3 Protection of the Existing Water Uses................................................... IX-57 1.3.1 General...................................................................................... IX-57 1.3.2 Water Right System in the Riparian States............................... IX-57 1.3.3 Water Management Rules for International Rivers .................. IX-60 1.3.4 Preliminary Conclusions........................................................... IX-60 1.4 Design Probability of AMMNF............................................................. IX-61 1.5 Definition of Natural Flow .................................................................... IX-62 1.6 Quantity of Existing Water Use on the Mainstream.............................. IX-66 1.6.1 General...................................................................................... IX-66 1.6.2 Water Use in the Upstream and Middle Reaches ..................... IX-66 1.6.3 Water Use in the Mekong Delta ............................................... IX-67 1.6.4 Comments on Surplus Water on the Mainstream ..................... IX-67 1.7 How to Increase Water Utilization Rate................................................ IX-69 2. DISCUSSIONS ON WATER USE MONITORING................................... IX-70 2.1 General .................................................................................................. IX-70 2.2 Necessity of Water Use Monitoring ...................................................... IX-70 2.2.1 Monitoring Necessity at National Level................................... IX-70 2.2.2 Monitoring Necessity at Regional Level .................................. IX-71 2.2.3 Necessity of Integrated Monitoring of River Flow and Water Use ................................................................................. IX-72 2.3 Discussions on Water