The Project of Landslide Management in the Republic of Mauritius
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THE REPUBLIC OF MAURITIUS MINISTRY OF PUBLIC INFRASTRUCTURE AND LAND TRANSPORT (MPI) THE PROJECT OF LANDSLIDE MANAGEMENT IN THE REPUBLIC OF MAURITIUS FINAL REPORT MAIN REPORT March 2015 JAPAN INTERNATIONAL COOPERATION AGENCY KOKUSAI KOGYO CO., LTD. NIPPON KOEI CO., LTD. GE CENTRAL CONSULTANT INC. JR FUTABA INC. 15-044 THE REPUBLIC OF MAURITIUS MINISTRY OF PUBLIC INFRASTRUCTURE AND LAND TRANSPORT (MPI) THE PROJECT OF LANDSLIDE MANAGEMENT IN THE REPUBLIC OF MAURITIUS FINAL REPORT MAIN REPORT March 2015 JAPAN INTERNATIONAL COOPERATION AGENCY KOKUSAI KOGYO CO., LTD. NIPPON KOEI CO., LTD. CENTRAL CONSULTANT INC. FUTABA INC. Location of Study Area 20°0'0"E 30°0'0"E 40°0'0"E 50°0'0"E 60°0'0"E 70°0'0"E 80°0'0"E 20°0'0"N 20°0'0"N 10°0'0"N 10°0'0"N 0°0'0" 0°0'0" Republic of Mauritius 10°0'0"S 10°0'0"S 20°0'0"S 20°0'0"S 0500 1,000 2,000 km 20°0'0"E 30°0'0"E 40°0'0"E 50°0'0"E 60°0'0"E 70°0'0"E 80°0'0"E Detai l Map Vallee Pitot La Butte Chitrakoot Quatre Soeurs Location Map Rate of Currency Translation 1 USD = 34.959 Rs = 119.68 JPY 100 Rs = 3.098 USD = 370.75 JPY Rs: Mauritius Rupee As of March 1st, 2015 Photos of the Project (1) Courtesy visit to the Deputy Prime Minister and Conclusion on commencement of the Project, 30th Minister of MPI, 28th May 2012 May 2012 1st Steering Committee, 29th May 2012 2nd Steering Committee, 1st Nov. 2012 3rd Steering Committee, 21st Nov. 2013 4th Steering Committee, 19th Jan. 2015 Photos of the Project (2) 1st Stakeholder Meeting (Chitrakoot), 22nd Sep. 2nd Stakeholder Meeting (Quatre Soeurs), 12th Apr. 2012 2013 5th Stakeholder Meeting (Vallee Pitot), 12th Dec. 1st Technical Transfer Seminar, 10th Oct. 2012 2014 2nd Technical Transfer Seminar, 20th Nov. 2013 3rd Technical Transfer Seminar, 20th Jan. 2015 Photos of the Project (3) Site visit by IOC, 13th Jun. 2012 4th Technical Workshop 【Landuse Policy】, 30th Jul. 2012 5th Technical Workshop 【Aerial Photo 10th Technical Workshop 【Stability Analysis and Interpretation】, 6th Sep. 2012 Countermeasures】, 5th Mar. 2013 1st Training in Japan, 2nd Training in Japan, 24th Nov. ~ 15th Dec. 2012 17th Aug. ~ 8th Sep. 2013 Photos of the Project (4) Boring Survey (Quatre Soeurs), 2nd Oct. 2012 Technical Guidance on Horizontal Drilling for Landslide Countermeasure Works (Chitrakoot), 30th Oct. 2014 2nd Site Meeting for the Construction of Landslide Completed Countermeasure Work 【River Countermeasure Works (Chitrakoot), 1st Sep. 2014 Type-3】, 12th Dec. 2014 Completed Countermeasure Work 【Bridge Completed Countermeasure Work 【Horizontal Type-3】, 12th Dec. 2014 Drainage】, 12th Dec. 2014 CONTENTS Location Map Photos Contents List of Figures List of Tables List of Photos Abbreviations Digest Page 1 Introduction .................................................................................. 1-1 1.1 General ..................................................................................................... 1-1 1.2 Background of the Project ......................................................................... 1-1 1.3 Objectives of the Project ........................................................................... 1-2 1.3.1 Objective ......................................................................................................... 1-2 1.3.2 Desired Outcome ............................................................................................ 1-2 1.3.3 Outcome of the Project ................................................................................... 1-2 1.4 Scope of the Project .................................................................................. 1-3 1.4.1 Project Areas ................................................................................................... 1-3 1.4.2 List of JICA Expert Team and Counterparts ................................................... 1-4 1.5 Major Activities .......................................................................................... 1-5 2 Basic Survey ................................................................................. 2-1 2.1 Topography ............................................................................................... 2-1 2.2 Geology and Rainfall ................................................................................. 2-2 2.3 Landslide Inventory Survey ....................................................................... 2-5 2.3.1 Classification of Hazard Area ......................................................................... 2-7 2.3.2 Site Reconnaissance ........................................................................................ 2-9 2.3.3 Inventory and Location Map ......................................................................... 2-17 2.3.4 GIS Database ................................................................................................ 2-21 2.4 Existing Countermeasures ...................................................................... 2-25 2.4.1 Structural Countermeasures .......................................................................... 2-25 2.4.2 Non-Structural Countermeasures .................................................................. 2-26 2.5 Social Survey .......................................................................................... 2-28 2.5.1 Basic Information Survey ............................................................................. 2-28 2.5.2 Attitude Survey about Landslide Disasters ............................................. 2-34 2.6 Organizations and Systems .................................................................... 2-38 2.6.1 Organizational and Institutional Formation .................................................. 2-38 2.7 Economic Survey .................................................................................... 2-43 2.7.1 National Economic Indicators ....................................................................... 2-43 2.7.2 National Economic Policies in Mauritius ..................................................... 2-44 2.7.3 Fiscal Policy for 2014 ................................................................................... 2-46 i 2.7.4 Fiscal Policy of the Ministry of Public Infrastructure (MPI) 2014-2016 ...... 2-47 2.7.5 Budget for LMU ........................................................................................... 2-49 3 Landslide Management Plan 1 (Survey and Results) ................ 3-1 3.1 Landslide Hazard Area .............................................................................. 3-1 3.2 Topographic Survey .................................................................................. 3-3 3.2.1 Specifications .................................................................................................. 3-3 3.2.2 Deliverables .................................................................................................... 3-3 3.3 Geological Survey ..................................................................................... 3-7 3.3.1 Geology of the Landslide Area ....................................................................... 3-7 3.3.2 Laboratory Test ............................................................................................. 3-11 3.3.3 Water Quality Analysis ................................................................................. 3-31 3.4 Monitoring ............................................................................................... 3-35 3.4.1 Installation of Monitoring Devices ............................................................... 3-35 3.4.2 Monitoring Results ........................................................................................ 3-38 3.5 Geophysical Exploration ......................................................................... 3-50 3.5.1 Elastic Wave Exploration.............................................................................. 3-50 3.5.2 Two-Dimensional Resistivity Exploration .................................................... 3-59 3.6 Drilling Survey ......................................................................................... 3-68 3.6.1 Drilling Plan .................................................................................................. 3-68 3.6.2 Core Drilling ................................................................................................. 3-70 3.6.3 Installation of Observation Equipment ......................................................... 3-73 3.6.4 Drilling Results ............................................................................................. 3-78 3.6.5 Standard Penetration Test ............................................................................. 3-79 3.7 Field Reconnaissance ............................................................................. 3-82 3.7.1 Damage to Houses ........................................................................................ 3-82 3.7.2 Results of Field Reconnaissance ................................................................... 3-89 3.8 Disaster Inspection ................................................................................ 3-120 3.8.1 Significance and Objectives of Disaster Inspection .................................... 3-121 3.8.2 Method of Disaster Inspection .................................................................... 3-122 3.8.3 Results of Disaster Inspection ..................................................................... 3-122 3.8.4 Recommendation on Disaster Inspection ...................................................