Supporting Report (2) (Feasibility Study)
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JAPAN INTERNATIONAL COOPERATION AGENCY MINISTRY OF HOUSING & PLANTATION INFRASTRUCTURE SRI LANKA LAND RECLAMATION & DEVELOPMENT CORPORATION THE STUDY ON STORM WATER DRAINAGE PLAN FOR THE COLOMBO METROPOLITAN REGION IN THE DEMOCRATIC SOCIALIST REPUBLIC OF SRI LANKA FINAL REPORT VOLUME IV : SUPPORTING REPORT (2) (FEASIBILITY STUDY) MARCH 2003 NIPPON KOEI CO., LTD. LIST OF VOLUMES VOLUME I : EXECUTIVE SUMMARY VOLUME II : MAIN REPORT VOLUME III : SUPPORTING REPORT (1) VOLUME IV : SUPPORTING REPORT (2) VOLUME V : DATA BOOK Exchange Rate Applied US$1.00 = Sri Lanka Rupee 96.26 = ¥ 118.94 (as of August 2002) N 79 50' E 80 E IN ° ° OF GAL Negombo G M SRI LANKA AREA COLOMBO 7°10' N OF MAP INDIAN OCEAN Key Map 80°10' E Ja Ela Basin Kalu Oya Basin 7°N Colombo Greater Colombo Basin Weras Ganga Basin 6°50' N Bolgoda Basin Panadura 6°40' N Legend Basin Boundary Scale Study Area Boundar 0 5 10 km Kalutara The Study on Storm Water Drainage Plan for the Colombo Metropolitan Region in the Democratic Socialist Republic of Sri Lanka Location Map JAPAN INTERNATIONAL COOPERATION AGENCY THE STUDY ON STORM WATER DRAINAGE PLAN FOR THE COLOMBO METROPOLITAN REGION IN THE DEMOCRATIC SOCIALIST REPUBLIC OF SRI LANKA FINAL REPORT VOLUME IV : SUPPORTING REPORT (2) (FEASIBILITY STUDY) LIST OF ANNEXES ANNEX 1 SOCIO-ECONOMY AND ECONOMIC EVALUATION ANNEX 2 INSTITUTION AND LEGISLATION ANNEX 3 HYDROLOGY ANNEX 4 LAND USE ANNEX 5 ENVIRONMENT ANNEX 6 SOCIAL DIMENSIONS ANNEX 7 STORM WATER DRAINAGE ANNEX 8 PRELIMINARY DESIGN ANNEX 9 CONSTRUCTION PLAN AND COST ESTIMATE ANNEX 10 OPERATION AND MAINTENANCE SUPPORTING REPORT (2) ANNEX 1 : SOCIO-ECONOMY AND ECONOMIC EVALUATION THE STUDY ON STORM WATER DRAINAGE PLAN FOR THE COLOMBO METROPOLITAN REGION IN THE DEMOCRATIC SOCIALIST REPUBLIC OF SRI LANKA FINAL REPORT VOLUME IV : SUPPORTING REPORT (2) ANNEX 1 : SOCIO-ECONOMY AND ECONOMIC EVALUATION TABLE OF CONTENTS Page CHAPTER 1 PRESENT CONDITIONS OF WERAS GANGA BASIN 1.1 General Characteristics of Weras Ganga Basin ..............................................A1-1 1.2 Administrative Division...................................................................................A1-1 1.2.1 Administrative Unit Coverage for Weras Ganga Basin.....................A1-1 1.2.2 Administrative Unit in Weras Ganga Basin.......................................A1-2 1.3 Population........................................................................................................A1-2 1.4 Economic Conditions ......................................................................................A1-3 1.4.1 General Characteristics of Economic Activities................................A1-3 1.4.2 Regional Production (GRDP)............................................................A1-4 1.5 Household Income in Weras Ganga Basin......................................................A1-5 CHAPTER 2 SOCIO-ECONOMIC FRAMEWORK IN WERAS GANGA BASIN 2.1 Prospect of Sri Lanka and Importance of Weras Ganga Basin for the Development of CMR ...............................................................................A1-7 2.1.1 Upward Trend of Sri Lanka ...............................................................A1-7 2.1.2 Importance of Weras Ganga Basin for the Development of CMR....A1-7 2.2 Population Framework ....................................................................................A1-8 2.2.1 Basic Assumption (Basic condition)..................................................A1-8 2.2.2 Projected Population Density ............................................................A1-8 2.2.3 Population Framework.......................................................................A1-9 2.3 Economic Framework .....................................................................................A1-9 2.3.1 Economic Framework of Sri Lanka...................................................A1-9 2.3.2 Economic Framework of Weras Ganga Basin................................... A1-10 2.4 Future Properties............................................................................................. A1-11 2.4.1 Land Value......................................................................................... A1-12 2.4.2 Building Value ................................................................................... A1-13 i CHAPTER 3 ECONOMIC EVALUATION FOR WERAS GANGA STORM WATER DRAINGE PROJECT 3.1 Methodology.................................................................................................... A1-14 3.2 Economic Cost ................................................................................................ A1-14 3.3 Economic Benefit............................................................................................ A1-14 3.3.1 Types of Project Benefits .................................................................. A1-14 3.3.2 Flood Damage Reduction Benefit...................................................... A1-15 3.3.3 Land Enhancement Benefit ...............................................................A1-19 3.3.4 Economic Activity Acceleration Benefit........................................... A1-21 3.4 Intangible Benefit ............................................................................................ A1-22 3.5 Economic Evaluation for Proposed Weras Ganga Storm Water Drainage Project.............................................................................................. A1-24 ii LIST OF TABLES Page Table 1.3.1 Population of Weras Ganga Basin by GN Divisions in 2001 (1/4 - 4/4).................................................... A1-T1 Table 3.3.1 Flood Damage per ha in Weras Ganga Basin (1/2 - 2/2)................ A1-T5 Table 3.3.2 Direct Flood Damage per ha with Inundation Depth without Project (1/8 - 8/8).............................................................. A1-T7 Table 3.3.3 Probable Flood Damage in Weras Ganga Basin............................. A1-T15 Table 3.3.4 Annual Average Flood Damage in Weras Ganga Basin without Project ............................................................................... A1-T16 Table 3.3.5 Flood Damage Reduction Benefit .................................................. A1-T17 Table 3.5.1 Cost Benefit Stream of F/S Project ................................................ A1-T18 iii Final Report, Volume IV Feasibility Study Supporting Report (2) Annex 1, Chapter 1 CHAPTER 1 PRESENT CONDITIONS OF WERAS GANGA BASIN 1.1 General Characteristics of Weras Ganga Basin Weras Ganga Basin (feasibility study area), with the area of 55.5 km2, is located in the southeast part of Colombo District which borders on Kalutara District on south, Galle Road on west, High Level Road on north, and covering northwest half of Kesbewa PS. It is characterized as one of fast growing areas in CMR (Colombo Metropolitan Region) and strategically important for the development of CMR. A northwest part of Weras Ganga Basin is designated as a Core Area in the CMRSP (Colombo Metropolitan Regional Structure Plan) prepared by UDA (Urban Development Authority) where population is highly concentrated and a large scale urban development is expected. Weras Ganga Basin plays an important role as a center of the economic and social activity and provision of housing for the people of CMR. Dehiwala - Mount Lavinia, Ratmalana, and Moratuwa are centers of industrial and commercial activities where sawmill and garment factories are operating. Service activities are concentrated mainly along Galle Road. Maharagama and Kesbewa are characterized mainly as a residential area, and the potential for residential development is high due to urban sprawl phenomena from Colombo and migration from the other areas of Sri Lanka. The area surrounding Weras Ganga provides a waterfront environment and is a popular area for recreational activities as well as residential development. 1.2 Administrative Division 1.2.1 Administrative Unit Coverage for Weras Ganga Basin Weras Ganga Basin is composed of parts of six DS Divisions, Dehiwala - Mount Lavinia DS Division, Ratmalana DS Division, Moratuwa DS Division, Sri Jayawardenapura Kotte DS Division, Maharagama DS Division, and Kesbewa DS Division. Six Local Authorities are in the Weras Ganga Basin, Dehiwala - Mount Lavinia MC, Moratuwa MC, Sri Jayawardenapura Kotte MC, Maharagama UC, Homagama PS, and Kesbewa PS. Administrative units of DS Divisions and Local Authorities are shown in table below. Nippon Koei Co., Ltd. A1 - 1 The Study on Storm Water Drainage Plan for the Colombo Metropolitan Region Final Report, Volume IV Feasibility Study Supporting Report (2) Annex 1, Chapter 1 DS Division and Local Authorities DS Divisions Local Authorities Dehiwala - Mount Lavinia Dehiwala - Mount Lavinia MC Ratmalana Dehiwala - Mount Lavinia MC Moratuwa Moratuwa MC Sri Jayawardenapura Kotte Sri Jayawardenapura Kotte MC Maharagama Maharagama UC Homagama PS (a part of Kottawa South GN) Kesbewa Kesbewa PS 1.2.2 Administrative Unit in Weras Ganga Basin Since the Weras Ganga Basin boundary and administrative boundaries do not always match, the administrative units that have area both within and outside Weras Ganga Basin need to be separated based on GN Division boundary. There are 85 GN Divisions in Weras Ganga Basin. The coverage within Weras Ganga Basin is estimated as shown in the table below. Number of GN Divisions (Unit: Number) Administrative Units Total Number of Number of GN Division in (DS Divisions) GN Division Weras Ganga Basin Dehiwala - Mount Lavinia 14 6 Ratmalana 13 8 Moratuwa 42 9 Sri Jayawardenapura Kotte 20 5 Maharagama 41 12