Water Adaptation Strategies and Agricultural Productivity Under Changing Climate
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Working Paper No. 2015-12 Water Adaptation Strategies and Agricultural Productivity Under Changing Climate Manolo G. Villano, Dulce D. Elazegui, Precious R. Zara, Raem Dominic S. Brion and Agnes C. Rola. Center for Strategic Planning and Policy Studies (formerly Center for Policy and Development Studies) College of Public Affairs and Development University of the Philippines Los Baños College, Laguna 4031 Philippines Telephone: (63-049) 536-3455 Fax: (63-049) 536-3637 Homepage: www.uplb.edu.ph The CSPPS Working Paper series reports the results of studies by the Institute faculty and staff which have not been reviewed. These are circulated for the purpose of soliciting comments and suggestions. This paper was published as FSE/CIDS Working Paper 2014-10 by the University of the Philippines Center for Integrative and Development Studies (UP CIDS). The views expressed in the paper are those of the authors and do not necessarily reflect those of CSPPS, the agency with which the authors are affiliated, and the funding agencies, if applicable. Please send your comments to: The Director Center for Strategic Planning & Policy Studies (formerly CPDS) College of Public Affairs University of the Philippines Los Baños College, Laguna 4031 Philippines Email: [email protected] LIST OF ACRONYMS BAS Bureau of Agricultural Statistics BRIS Balanac River Irrigation System CIS Communal Irrigation Systems CLUP Comprehensive Land Use Plan CI Cropping Intensity DA-RFU Department of Agriculture - Regional Field Unit DENR Department of Environment and Natural Resources DRRM Department of Public Works and Highways DPWH Disaster Risk Reduction and Management ENSO El Niño Southern Oscillation FUSA Firmed-up Service Area FGD Focused Group Discussion GOCC Government-Owned and/or Controlled Corporations KII Key Informant Interview LLDA Laguna Lake Development Authority LGU Local Government Unit MBRLC Mindanao Baptist Rural Life Center MBSCPL Mount Banahaw - San Cristobal Protected Landscape NCCAP National Climate Change Action Plan NIA National Irrigation Administration NIS National Irrigation System NWRC National Water Research Centre NGO Non-Government Organization OSA Original Service Area PAGASA Philippine Atmospheric, Geophysical and Astronomical Service Administration PAMB Protected Area Management Bureau STW Shallow Tube Well SALT Sloping Agricultural Land Technology SFR Small Farm Reservoir SWIP Small Water Impoundment SCRIS Sta. Cruz River Irrigation System CGMCM3 Third Generation Coupled Global Climate Model UPLB University of the Philippines Los Baños i TABLE OF CONTENTS Page List of Acronyms i Table of Contents ii List of Tables iv List of Figures v ABSTRACT vi INTRODUCTION 1 Background of the Study 1 1.1. Objectives of the Study 3 Location and territorial coverage of the Study Area 3 METHODOLOGY 5 RESULTS AND DISCUSSION 5 The hydrology and water resources of the Sta. Cruz Watershed 5 Topography and land use features 5 Climate and rainfall 7 River systems and Springs 8 Groundwater 9 Utilization of water supply from the watershed 10 Manifestations of climate change in the study area 12 Potential impacts of climate change to water resources and crop production 14 Flooding and sedimentation 14 Water scarcity 16 Landslide 18 Water quality degradation 18 Threats to ensuring food security 19 Water adaptation strategies and technologies 22 Protect and enhance the watershed’s capacity to nurture its water 22 resources Improve the performance of existing irrigation systems 24 Avert the occurrence of landslide 25 Control water quality degradation 25 Factor climate change in the planning, design and rehabilitation of water 26 resources project Improve the generation and sharing of climate and hydrological 26 information Policy issues and governance 27 SUMMARY AND CONCLUSION 28 POLICY RECOMMENDATIONS 30 REFERENCES 32 iii LIST OF TABLES No. Title Page 1 Municipalities covered by the Sta. Cruz Sub-Watershed 4 2 Elevation-Area relationship of the Sta. Cruz Sub-Watershed 6 3 Area per slope range of the Sta. Cruz Sub-Watershed 6 4 Land Use Change within the Sta. Cruz Watershed from 1993 to 2014 6 5 Average monthly rainfall and number of rainy days in Sta. Cruz and Nagcarlan, 7 Laguna 6 Major rivers passing each municipality within the Sta. Cruz Watershed 9 7 Groundwater data of some municipalities within or near the Sta. Cruz Sub- 9 Watershed 8 National Irrigation systems (NIS) serving farms within the Sta. Cruz Sub 11 Watershed 9 Communal Irrigation Systems (CIS) abstracting water from the Sta. Cruz Sub- 11 Watershed 10 Destructive typhoons that affected Laguna area from 2004 – 2006 12 11 Percent deviation of the 2004 – 2012 monthly rainfall from the 1994 – 2003 period 13 12 Percent deviation of the 2004 – 2012 maximum daily rainfall per month from the 13 1994 – 2003 period LIST OF FIGURES No. Title Page 1 Spring water storage tank in Barangay Bukal, Nagcarlan 16 2 The present SCRIS Diversion Dam 17 3 A garbage-filled irrigation canal in San Pablo Sur, Sta. Cruz 19 v ABSTRACT This study aimed to explain the water and food security-environment interactions in a dynamic setting brought about by climate change focusing on the Sta.Cruz wateshed with the end goal of identifying water adaptation measures and policy recommendations to minimize the adverse effects of climate change and improve the welfare of communities. Based on available secondary information, focused group discussions, key-person intereviews and field ocular inspections, an indicative assessment was made on the watershed’s water resources conditions and water supply utilization, manifestation of climate change and potential impacts of climate change on water resources and crop production. Findings indicate that while the level of rice self-sufficiency of communities within the watershed are below 50 %, and that there are manifestations of pronounced rainfall variability as well as apparent reductions in the output of water supply sources, it appears in general, that the impacts of previous strong typhoons to their means of livelihood are not so serious or permanent to deny them the capacity to restore agricultural productivity within resonable period or acquire food from other sources. There are indications, however, that if the present rate of deforestation and non-sustainable agricultural production pracitices are not effectively controled in the near future, frequent occurrences of more extremely strong typhoons and habagats will cause more serious and probably permanent damages to their agricultural production systems through more intense and persistent flooding, sedimentation and significant decrease in the output of water supply sources. Averting such grim scenario includes the following “no-regrets” adaptation measures: protection and enhancement of the watershed’s capacity to nurture its water resources through protection and reforestation of declared forest reservation or protected areas and promotion of sustainable agriculture mainly through enforcement of conservation farming tchnologies in sloping agricultural lands; improvement in the performance of existing irrigation systems; foctoring climate change in the planning, design, and rehablitation of water resources projects; and improvement in the generation and sharing of climate and hydrologic information. For the effective and timely implementation of the above measures, the LGUs, being mandated as fronline agencies for addressing issues on climate change, should undergo more intensive “education” on climate change for them to be able to pass needed relevant reoulutions and executive orders. Policy and institutional concerns would include the following: strengthening the river councils; promote and support the implementation of the existing Mout Banahaw-San Cristobal Protected Landscape; policies to encourage adoption of soil and water conservation technologies; economic/finacial schems for farmers to cope with impacts of climate change- related events; olicies and programs on livelihood to improve household resilience. Key words: climate change, wateshed, water resources, rice self-sufficiency, typhoons, habagats, protected areas, conservation farming, hydrologic information WATER ADAPTATION STRATEGIES AND AGRICULTURAL PRODUCTIVITY UNDER CHANGING CLIMATE Manolo G. Villano, Dulce D. Elazegui, Precious R. Zara, Raem Dominic S. Brion and Agnes C. Rola I. INTRODUCTION 1.1. Background of the Study Agriculture remains the country’s backbone for the sustainable attainment of food security. This sector is greatly vulnerable to climate change especially due to the increase occurrences of El Nino Southern Oscillation (ENSO) and La Nina events, bringing drought and extreme rainfalls, respectively. Agriculture, being strongly dependent on water resources and climatic conditions, and crop production, being extremely sensitive to large year-to-year weather fluctuations, will greatly affect the country’s production and have a domino effect on our food self- sufficiency (NCCAP, 2011). With a nationwide average annual rainfall of about 2,400 mm, water is not supposed to be a problem in the Philippines. Unfortunately, such rainfall is not uniformly distributed with respect to time and space throughout the country; thus, limiting its direct availability for agriculture. As such, some farms in the country can plant rice and other crops at least two times a year just depending on rainfall but others can only plant once unless waters from springs, rivers, lakes, and underground could be tapped through irrigation systems. In the hydrologic cycle,