Assessment of Hydropower Potential of Nepal Final Report Abbreviation and Acronyms AHEP : Available Gross Hydroelectricity Potential ASTER : Advance Spaceborne Thermal Emission and Reflection Radiometer AMF : Average Monthly Flow APHRODITE : Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation B : Breadth BCDP : Building Code Development Project B/C : Benefit-Cost Ratio BoQ : Bill of Quantities CAR : Catchment Area Ratio CCT : Central Churia Thrust CFRD : Concrete Faced Rock Fill Dam COD : Commercial Operation Date DCF : Discounted Cash Flow DEM : Digital Elevation Model DHM : Department of Hydrology & Meteorology DMG : Department of Mines & Geology DoED : Department of Electricity Development d/s : Downstream E : East EIA : Environmental Impact Assessment EMI : Equal Monthly Installment ESA : European Space Agency ESRI : Environmental System Research Institute EU-DEM : European Union Digital Elevation Model FDC : Flow Duration Curve WECS i Assessment of Hydropower Potential of Nepal Final Report GHEP : Gross Hydroelectricity Potential GIS : Geographic Information System GLOF : Glacial Lake Outburst Flood GoN : Government of Nepal GPS : Global Positioning System GWh : Giga Watt-Hour H : Height ha : Hectares HEC-HMS : Hydrologic Engineering Center-Hydrologic Modeling System HFL : High Flood Level HFT : Himalayan Frontal Thrust HPP : Hydropower Project HRU : Hydrological Response Unit ICOLD : International Commission on Large Dams ICIMOD : International Center for Integrated Mountain Development IDC : Interest During Construction IDW : Inverse Distance Weighting IEE : Initial Environmental Examination IHA : International Hydropower Association INPS : Integrated Nepal Power System IPPs : Independent Power Producers IRR : Internal Rate of Return IS : Indian Standards IVF : Index of Volumetric Fit JICA : Japan International Cooperation Agency J/V : Joint Venture km : Kilometer kV : Kilo Volt WECS ii Assessment of Hydropower Potential of Nepal Final Report kW : Kilo Watt kWh : Kilo Watt-Hour L : Length m : Meter MAE : Mean Absolute Error masl : Meters above Sea Level MATLAB : Matrix Labooratory MBT : Main Boundary Thrust MCT : Main Central Thrust MDT : Main Dun Thrust MFT : Main Frontal Thrust MHEP : Maximum Hydroelectricity Potential mm : Millimeter MSE : Mean Square Error MT : Mahabharta Thrust MTF : Monthly Turbine Flow MW : Mega Watt N : North NEA : Nepal Electricity Authority NEIC : National Earthquake Information Center NGDC : National Geological Data Center NPV : Net Present Value NPR. : Nepalese Rupees NRMSE : Normalized Root Mean Square Error NSE : Nash-Sutcliffe Coefficient of Efficiency O&M : Operation and Maintainance PBIAS : Percentage BIAS PERT : Program Evaluation and Review Technique WECS iii Assessment of Hydropower Potential of Nepal Final Report PGA : Peak Ground Acceleration PSO : Particle Swarm Optimization Q : River Discharge QCBS : Quality and Cost-Based Selection RoR : Run-of-the-River rpm : Revolutions per Minute RMSE : Root Mean Square Error s : Second S : South SAE : Standard Deviation Absolute Error SNRTP : Strengthening National Rural Transport Programme SOTER : Soil and Terrain Database Programme SRTM : Shuttle Radar Topography Mission STDS : South Tibetean Detachment System TL : Transmission Line ToR : Terms of Reference u/s : Upstream USDA : United States Department of Agriculture USGS : United Stated Geological Survey US$ : United States Dollars UTM : Universal Transverse Mercator VB : Volume Bias VDC : Village Development Committee W : West WECS : Water and Energy Commission Secretariat yr : Year WECS iv Assessment of Hydropower Potential of Nepal Final Report Table of Contents Abbreviation and Acronyms ............................................................................................................i Table of Contents ............................................................................................................................ v List of Figures ................................................................................................................................xi List of Tables .............................................................................................................................. xiii 1. INTRODUCTION ................................................................................................................... 1 Background .......................................................................................................................... 1 Objectives ............................................................................................................................ 2 Scope of Work ..................................................................................................................... 2 Structure of the report: ......................................................................................................... 4 2. DATA COLLECTION ............................................................................................................ 5 2.1. Hydrological & Meteorological data ............................................................................ 5 2.1.1 Collection of Average Monthly Rainfall Data .......................................................... 5 2.1.2 Collection of Average Monthly Discharge Data ...................................................... 5 2.2. Data on Geographical Information Systems (GIS)....................................................... 6 2.3. Data on Hydropower Project Studies ........................................................................... 6 2.3.1 Koshi Basin Master Plan Study ................................................................................ 7 2.3.2 Gandaki River Basin Power Study ........................................................................... 7 2.3.3 Mahakali & Karnali Basin Master Plan Study .......................................................... 7 2.3.4 Storage Project Master Plan Study ........................................................................... 8 2.3.5 Projects Identified by Independent Power Producers (IPPs) .................................... 8 3. GIS Analysis .......................................................................................................................... 10 3.1 Preparation of Topographic Terrain Data ................................................................... 10 3.2 Delineation of Sub-Catchments .................................................................................. 11 3.3 Analysis of Physiographic Variables for Sub-Catchments......................................... 12 3.4 Analysis of Gross Heads............................................................................................. 12 3.5 Validation of gross heads ........................................................................................... 12 v Assessment of Hydropower Potential of Nepal Final Report 3.6 Thematic map preparation .......................................................................................... 14 4. Hydrological Analysis ........................................................................................................... 15 4.1 Empirical Assessment................................................................................................. 16 4.1.1 Methodology ........................................................................................................... 16 4.1.2 Flood Flow .............................................................................................................. 19 4.2 Hydrological modelling using HEC-HMS ................................................................. 20 4.2.1 Modelling approach ................................................................................................ 20 4.2.2 Model parameters .................................................................................................... 22 4.2.3 Model application and results ................................................................................. 22 4.2.4 Calibration and validation ....................................................................................... 32 4.2.5 Flow computation ................................................................................................... 33 5. Geology and Geomorphology ............................................................................................... 34 5.1 General........................................................................................................................ 34 5.2 Geology of Nepal Himalaya ....................................................................................... 34 5.2.1 Indo-Gangetic Plain (Terai) .................................................................................... 34 5.2.2 Sub-Himalaya (Siwaliks or Churia Group) ............................................................. 35 5.2.3 Lesser Himalaya ...................................................................................................... 35 5.2.4 Higher Himalaya ..................................................................................................... 36 5.2.5 Tibetan-Tethys Himalaya ........................................................................................ 36 5.3 Regional Geology ....................................................................................................... 36 5.3.1 Eastern Nepal Himalaya ........................................................................................