Executive Summary Karama No.1 Hydropower Project Feasibility Study Report EXECUTIVE SUMMARY PT.PLN(PERSERO) (Indonesia） China Gezhouba Group Company Limited （China） November 2011 Executive Summary Table of Contents 1 Introduction ................................................................................................................................ - 1 - 1.1 Background of the project ............................................................................................... - 4 - 1.2 Basic conditions of Karama No.1 Hydropower project ................................................ - 5 - 1.3 Reference Standard .......................................................................................................... - 7 - 2. Project Survey ........................................................................................................................... - 9 - 2.1 The mapping data available ............................................................................................ - 9 - 2.2 Mapping work arrangement ......................................................................................... - 10 - 2.2.1 Finished work at stage 1 ...................................................................................... - 10 - 2.2.2 Finished work at stage 2 ...................................................................................... - 10 - 2.3 Finished surveys ..............................................................................................................- 11 - 2.3.1 Achievements at stage 1 ....................................................................................... - 11 - 2.3.2 Achievements at stage 2 ....................................................................................... - 11 - 2.4 Residual survey work .................................................................................................... - 12 - 3. Study on hydrology and sediment .......................................................................................... - 13 - 3.1 Overview of drainage basin ........................................................................................... - 13 - 3.2 Basic data ........................................................................................................................ - 13 - 3.3 Meteorology .................................................................................................................... - 14 - 3.4 Runoff .............................................................................................................................. - 15 - 3.4.1 Runoff of reference stations ................................................................................ - 15 - 3.4.2 Damsite runoff ...................................................................................................... - 16 - 3.5 Flood ................................................................................................................................ - 17 - 3.5.1 Probable maximum flood .................................................................................... - 17 - 3.5.2 Frequency flood .................................................................................................... - 17 - 3.6 Sedimentation ................................................................................................................. - 20 - 3.7 Stage-discharge relation ................................................................................................ - 20 - 3.8 Specialized hydrologic station planning ....................................................................... - 20 - 4 Engineering geology ................................................................................................................. - 20 - 4.1 Investigation Brief .......................................................................................................... - 20 - 4.2 Regional Geology ........................................................................................................... - 21 - 4.2.1 Topography ........................................................................................................... - 21 - 4.2.2 Stratigraphic Lithology ....................................................................................... - 21 - 4.2.3 Geological Structure & Earthquake ................................................................... - 21 - 4.2.4 Volcanic Activity ................................................................................................... - 22 - 4.2.5 Hydrogeology ........................................................................................................ - 22 - 4.3 Geology in Reservoir Area ............................................................................................ - 22 - 4.3.1 General Geology ................................................................................................... - 22 - 4.3.2 Engineering Aspects ............................................................................................. - 23 - 4.4 Geology at Upstream Dam Site ..................................................................................... - 25 - 4.4.1 Dam Site ................................................................................................................ - 25 - 4.4.2 Waterway System ................................................................................................. - 26 - 4.5 Downstream Dam Site ................................................................................................... - 27 - 4.5.1 Power System ........................................................................................................ - 29 - 4.5.2 Sluice Tunnel ......................................................................................................... - 30 - 4.5.3 Spillway ................................................................................................................. - 30 - Executive Summary 4.6 Construction Material ................................................................................................... - 30 - 5 Seismicity .................................................................................................................................. - 31 - 5.1 Tectonic Features............................................................................................................ - 31 - 5.2 Seismic Activity .............................................................................................................. - 31 - 6 Study on power market ............................................................................................................ - 32 - 6.1 Design target year .......................................................................................................... - 32 - 6.2 Power supply scope ........................................................................................................ - 32 - 6.3 Existing problems for power grid ................................................................................. - 32 - 6.4 Load forecasting ............................................................................................................. - 32 - 6.5 Load curve ...................................................................................................................... - 33 - 6.6 Development and planning of power supply ............................................................... - 33 - 6.7 Preliminary power balance of power system ............................................................... - 34 - 7 Project Layout Selection .......................................................................................................... - 34 - 8 Project scale .............................................................................................................................. - 35 - 8.1 Selection of normal pool level ....................................................................................... - 35 - 8.2 Selection of level of dead water ..................................................................................... - 36 - 8.3 Selection of installed capacity ....................................................................................... - 36 - 9 Recommended project arrangement ...................................................................................... - 37 - 9.1 Project ranking and flood control standards .............................................................. - 37 - 9.2 Water retaining structure .............................................................................................. - 38 - 9.3 Water release structures ................................................................................................ - 38 - 9.4 Diversion power generation system .............................................................................. - 39 - 9.5 Powerhouse and switching station ................................................................................ - 39 - 9.6 Treatment of foundation and side slope ....................................................................... - 40 - 9.6.1 Foundation treatment .......................................................................................... - 40 - 9.6.2 Side slope treatment and protection ................................................................... - 41 - 9.7 Safety monitoring design ............................................................................................... - 42 - 10 Permanent and temporary