Topography and Geology the STUDY on SABO and FLOOD CONTROL for WESTERN RIVER BASINS of MOUNT PINATUBO in the REPUBLIC of the PHILIPPINES
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The Study on Sabo and Flood Control for Western River Basins of Mount Pinatubo in the Republic of the Philippines Final Report Supporting Report APPENDIX-II Topography and Geology THE STUDY ON SABO AND FLOOD CONTROL FOR WESTERN RIVER BASINS OF MOUNT PINATUBO IN THE REPUBLIC OF THE PHILIPPINES FINAL REPORT SUPPORTING REPORT APPENDIX II TOPOGRAPHY AND GEOLOGY Table of Contents Page CHAPTER 1 TOPOGRAPHY..........................................................................................II-1 1.1 Topographic Condition in the Study Area .........................................................II-1 1.1.1 Topography ..........................................................................................II-1 1.1.2 Volcanic Activities ...............................................................................II-1 1.1.3 Pyroclastic Fall and Flow Deposits .....................................................II-2 1.1.4 Lahar....................................................................................................II-2 1.1.5 River System........................................................................................II-3 1.1.6 River Channel ......................................................................................II-4 1.2 Aerial Photography............................................................................................II-5 1.2.1 Scope of Work......................................................................................II-5 1.2.2 Work Execution ...................................................................................II-5 1.2.3 Output ..................................................................................................II-6 1.3 Photogrammetric/Ortho-photo Mapping ...........................................................II-6 1.3.1 Scope of Work......................................................................................II-6 1.3.2 Work Specification...............................................................................II-7 1.3.3 Final Results ......................................................................................II-10 1.4 River Profile and Cross Section Survey ..........................................................II-11 1.4.1 Scope of Work and Specification.......................................................II-11 1.4.2 Sounding Survey at Mapanuepe Lake ...............................................II-12 1.4.3 Establishment of Riverbed Movement Monitoring Sections.............II-12 1.4.4 Survey Result.....................................................................................II-12 CHAPTER 2 GEOLOGY ...............................................................................................II-14 2.1 Geological Condition in the Study Area ..........................................................II-14 2.2 Geological Investigation by Core Drilling.......................................................II-14 2.2.1 Objective and Scope of Work ............................................................II-14 2.2.2 Result of Core Drillings.....................................................................II-15 2.3 Additional Core Drilling and Laboratory Test.................................................II-20 i 2.3.1 Objective and Scope of Work ............................................................II-20 2.3.2 Core Drilling......................................................................................II-20 2.3.3 Laboratory Test ..................................................................................II-20 2.3.4 Result of Core Drilling ......................................................................II-20 2.3.5 Field Permeability Tests.....................................................................II-24 2.3.6 Field Density Tests and Relative-density Tests..................................II-24 2.3.7 Grain Size Analysis............................................................................II-24 2.3.8 Subsoil Condition of the Sto. Tomas River Dike (Figure 2.3.13)......II-25 2.4 Maraunot Notch Survey...................................................................................II-25 2.4.1 Field Survey.......................................................................................II-25 2.4.2 Breach of Maraunot Notch ................................................................II-26 2.4.3 Geo-resistivity Survey .......................................................................II-26 2.4.4 Schmidt Hammer Test........................................................................II-27 2.4.5 Probability of Future Breach..............................................................II-27 2.4.6 Proposed Countermeasures................................................................II-28 ii List of Tables Page Table 1.1.1 Changes in River Channel before and after Eruption of Mount Pinatubo...................................................................................................II-T1 Table 1.2.1 Photo Course and Quantity .....................................................................II-T2 Table 1.3.1 GPS Coordinates.....................................................................................II-T3 Table 1.3.2 Elevation of GPS, BM, Pricking Points (1/3) .........................................II-T4 Table 1.3.2 Elevation of GPS, BM, Pricking Points (2/3) .........................................II-T5 Table 1.3.2 Elevation of GPS, BM, Pricking Points (3/3) .........................................II-T6 Table 2.2.1 Details of Core Drillings .........................................................................II-T7 Table 2.2.2 Tests Conducted for Core Drillings.........................................................II-T7 Table 2.3.1 Additional Core Drillings........................................................................II-T8 Table 2.3.2 Tests Conducted for Additional Core Drilling ........................................II-T8 Table 2.3.3 Results of Permeability Tests ..................................................................II-T9 Table 2.3.4 Results of Field Density and Relative Density Test................................II-T9 Table 2.4.1 Classification of Rock for Schmidt Hammer Test ................................II-T10 iii List of Figures Page Figure 1.1.1 Topographic Map in the Study Area .......................................................II-F1 Figure 1.1.2 View of Mount Pinatubo before and after Eruption................................II-F2 Figure 1.1.3 Pinatubo Volcano Disaster Map ..............................................................II-F3 Figure 1.1.4 Pyroclastic Flow Deposits in the Marella River .....................................II-F4 Figure 1.1.5 Grain Size Distribution of Riverbed Materials in Eastern and Western Pinatubo Area............................................................................II-F5 Figure 1.1.6 Basin Boundary Map...............................................................................II-F6 Figure 1.1.7 Change in Catchment Area in the Bucao River System..........................II-F7 Figure 1.1.8 Location of Dammed-up Lakes...............................................................II-F8 Figure 1.2.1 Photo Index Map.....................................................................................II-F9 Figure 1.3.1 GPS Network Plan in the Study Area ...................................................II-F10 Figure 1.3.2 Map Index Sheet ...................................................................................II-F11 Figure 1.4.1 Location Map of Cross Section Survey in the Lower Bucao River......II-F12 Figure 1.4.2 Location Map of Cross Section Survey in the Balin Baquero River ....II-F13 Figure 1.4.3 Location Map of Cross Section Survey in the Maloma River ..............II-F14 Figure 1.4.4 Location Map of Cross Section Survey in the Sto. Tomas River..........II-F15 Figure 1.4.5 Location Map of Cross Section Survey in the Mapanuepe Lake..........II-F16 Figure 2.1.1 Geological Map of Mount Pinatubo and Environs ...............................II-F17 Figure 2.2.1 Borehole Location in the Maculcol Bridge...........................................II-F18 Figure 2.2.2 Borehole Location in the Maloma River...............................................II-F19 Figure 2.2.3 Borehole Location in the Bucao River..................................................II-F20 Figure 2.2.4 Borehole Location in the Aglao River ..................................................II-F21 Figure 2.2.5 Category in Unified Soil Classification System....................................II-F22 Figure 2.2.6 Soil Profile at the Maculcol Bridge.......................................................II-F23 Figure 2.2.7 Soil Profile at the Maloma Bridge ........................................................II-F24 Figure 2.2.8 Soil Profile at the Bucao Bridge............................................................II-F25 Figure 2.2.9 Soil Profile in Upstream of the Marella River ......................................II-F26 Figure 2.2.10 Soil Profile at the Mt. Bagang...............................................................II-F27 Figure 2.3.1 Borehole Location Plan in the Bucao River..........................................II-F28 Figure 2.3.2 Borehole Location Plan in the Lower Sto. Tomas River.......................II-F29 Figure 2.3.3 Borehole Location Plan in the Middle Sto. Tomas River......................II-F30 Figure 2.3.4 Borehole Location Plan in the Upper Sto. Tomas River .......................II-F31