Supporting Report C HYDROGEOLOGY AND
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Supporting Report C HYDROGEOLOGY AND GROUNDWATER MANAGEMENT Abbreviations Indonesia English BBWS Balai Besar Wilayah Sengai Large River Basin Organization DEM - Digital Elevation Model Kementerian Energi dan Sumber Daya ESDM Mineral Ministry of Energy and Mineral Resources GCM - Global Climate Model GCMs - General Circulation Models Indonesian Regional Water Utility PDAM Perusahaan Daerah Air Minum Company PP Peraturan Pemerintah Government regulation The Republic of Indonesia THE PROJECT FOR ASSESSING AND INTEGRATING CLIMATE CHANGE IMPACTS INTO THE WATER RESOURCES MANAGEMENT PLANS FOR BRANTAS AND MUSI RIVER BASINS (WATER RESOURCES MANAGEMENT PLAN) FINAL REPORT Supporting Report C : HYDROGEOLOGY AND GROUNDWATER MANAGEMENT Table of Contents Abbreviations Page PART 1 GENERAL CHAPTER C1 PROJECT OBJECTIVE, ANALYSIS METHOD AND CONCEPT OF GROUNDWATER POTENTIAL ........................................................ C1-1 C1.1 Objective and Analysis Method .................................................................................. C1-1 C1.1.1 Objective ....................................................................................................... C1-1 C1.1.2 Analysis Method............................................................................................ C1-1 C1.2 Concept of Groundwater Potential .............................................................................. C1-1 C1.2.1 Basic Concept ................................................................................................ C1-1 C1.2.2 Definition of Groundwater Potential in Indonesia ........................................ C1-2 C1.2.3 Definition of Groundwater Potential in This Project ..................................... C1-3 C1.2.4 Constraints in Groundwater Potential Evaluation ......................................... C1-4 PART 2 BRANTAS RIVER BASIN CHAPTER C2 GROUNDWATER CONDITION IN BRANTAS RIVER BASIN ........ C2-1 C2.1 Geology ....................................................................................................................... C2-1 C2.2 Hydrogeology.............................................................................................................. C2-2 C2.3 Wells and Springs Distribution ................................................................................... C2-3 C-i C2.3.1 Wells and Springs Distribution from Existing Reports and Maps ................. C2-3 C2.3.2 ESDM Registered Wells ................................................................................ C2-4 C2.4 Groundwater Level Observation ................................................................................. C2-6 C2.5 Present Total Groundwater Demand by Regency/City ............................................... C2-7 CHAPTER C3 GROUNDWATER MODELING IN BRANTAS RIVER BASIN ........... C3-1 C3.1 Groundwater Flow Model ........................................................................................... C3-1 C3.1.1 Basic Information .......................................................................................... C3-1 C3.1.2 Model Input ................................................................................................... C3-2 C3.2 Groundwater Flow Simulation for Present Groundwater Condition .......................... C3-5 C3.2.1 Calibration Target .......................................................................................... C3-5 C3.2.2 Result of Simulation ...................................................................................... C3-6 CHAPTER C4 GROUNDWATER POTENTIAL EVALUATION IN BRANTAS RIVER BASIN ............................................................................................. C4-1 C4.1 Groundwater development plan and Presidential Decree ........................................... C4-1 C4.1.1 Groundwater development plan up to 2030 .................................................. C4-1 C4.1.2 Presidential Decree No. 26 of 2011 ............................................................... C4-2 C4.2 Groundwater Potential under the Present Conditions ................................................. C4-2 C4.2.1 Groundwater Potential in Previous Project ................................................... C4-2 C4.2.2 Groundwater Potential in This Project .......................................................... C4-3 C4.3 Groundwater Potential under the Near Future Condition in 2030 .............................. C4-5 C4.3.1 Analytical Condition for 2030 ....................................................................... C4-5 C4.3.2 Groundwater Demand in 2030 ...................................................................... C4-5 C4.3.3 Groundwater Potential in 2030 ...................................................................... C4-6 C4.4 Groundwater Potential under the Future Condition in 2050 ....................................... C4-7 C4.4.1 Analytical Condition for 2050 ....................................................................... C4-7 C4.4.2 Future Groundwater Recharge ...................................................................... C4-8 C4.4.3 Groundwater Potential in 2050 ...................................................................... C4-9 C4.5 Evaluation and Additional Groundwater Development Potential for Each Scenarios ................................................................................................................... C4-11 C4.5.1 Evaluation Method ...................................................................................... C4-11 C4.5.2 Result of Evaluation .................................................................................... C4-14 C4.6 Groundwater Potential under the Additional Groundwater Demand ........................ C4-18 C4.6.1 Additional Groundwater Demand ............................................................... C4-18 C4.6.2 Evaluation and Groundwater Potential under the Additional Groundwater Demand ................................................................................. C4-19 C-ii CHAPTER C5 GROUNDWATER MANAGEMENT FOR DROUGHT IN BRANTAS RIVER BASIN ......................................................................... C5-1 C5.1 Sustainable Groundwater Cycle .................................................................................. C5-1 C5.2 Impacts of Climate Change on Groundwater Resources ............................................ C5-2 C5.3 Measures for Groundwater Resources ........................................................................ C5-3 C5.4 Approximate Well Construction Cost for Additional Groundwater Demand ............. C5-4 C4.1.1 Basic Specifications and Unit Prices ............................................................. C5-4 C4.1.2 Approximate Well Construction Cost ............................................................ C5-4 PART 3 MUSI RIVER BASIN CHAPTER C6 GROUNDWATER CONDITION IN MUSI RIVER BASIN ................ C6-1 C6.1 Geology ....................................................................................................................... C6-1 C6.2 Groundwater Basin and Hydrogeology ....................................................................... C6-1 C6.3 Coastal Peatland Areas ................................................................................................ C6-3 C6.4 Groundwater Level Observation ................................................................................. C6-3 C6.4.1 Construction of Observation Wells ................................................................ C6-3 C6.4.2 Observation Result ........................................................................................ C6-5 C6.5 Groundwater Use ........................................................................................................ C6-6 CHAPTER C7 CHANGES IN REGIONAL GROUNDWATER POTENTIAL IN MUSI RIVER BASIN ................................................................................. C7-1 C7.1 Effective Rainfall ........................................................................................................ C7-1 C7.2 Present Groundwater Potential .................................................................................... C7-1 C7.3 Estimation Method of Future Groundwater Potential ................................................. C7-2 C7.4 Changes in Groundwater Potential Under Climate Change ........................................ C7-3 C7.4.1 Selection of Climate Change Scenarios ........................................................ C7-3 C7.4.2 Forecast of Groundwater Potential Change ................................................... C7-3 C7.4.3 Estimation of Groundwater Potential Change from Groundwater Level Data ............................................................................................................... C7-5 CHAPTER C8 CHANGED IN GROUNDWATER ENVIRONMENT IN COASTAL PEATLAND AREAS ............................................................... C8-1 C8.1 Analysis Condition ...................................................................................................... C8-1 C8.2 Changes in Groundwater Level ................................................................................... C8-3 C8.3 Evaluation of the Result .............................................................................................. C8-3 C-iii List of Tables Page Table C2.1.1 Topographical Zone in Brantas River Basin ........................................................ C2-1 Table C1.1.2 Hydrogeological