A New Course: Managing Drought and Downpours in the Santiago Metropolitan Region
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JULY 2019 R: 19-07-A REPORT A NEW COURSE: MANAGING DROUGHT AND DOWNPOURS IN THE SANTIAGO METROPOLITAN REGION LEAD AUTHOR ANDREA E. BECERRA COAUTHORS JORDAN HARRIS, CAROLINA HERRERA, PÍA HEVIA, AMANDA MAXWELL ACKNOWLEDGMENTS The authors would like to acknowledge the valuable contributions of NRDC’s staff in the Water program, including Larry Levine, Kate Poole, and Tracy Quinn. This report also benefited greatly from the thorough scrutiny and feedback of Dr. Gonzalo Bacigalupe (CIGIDEN), Sebastián Bonelli (The Nature Conservancy in Chile), Dr. Avery Cohn (The Fletcher School at Tufts University), Daniela Duhart (lawyer, Chile), Dr. John Durant (Tufts University School of Engineering), Dr. Jesse Keenan (Harvard Graduate School of Design), and Bernardo Reyes (Ética en los Bosques in Chile). About NRDC The Natural Resources Defense Council is an international nonprofit environmental organization with more than 3 million members and online activists. Since 1970, our lawyers, scientists, and other environmental specialists have worked to protect the world’s natural resources, public health, and the environment. NRDC has offices in New York City, Washington, D.C., Los Angeles, San Francisco, Chicago, Montana, and Beijing. NRDC works in Latin America to promote robust policies and innovative solutions to help Latin American countries grow towards a low-carbon, climate-resilient future while protecting important natural resources. Visit us at nrdc.org. About Adapt Chile and the Chilean Network of Municipalities for Climate Action Adapt Chile is a Chilean NGO with the mission of promoting the transversal integration of climate change into planning, development and decision-making processes on a subnational scale, in order to strengthen local responses to climate change. Coordination of the Chilean Network of Municipalities for Climate Action represents the core of Adapt Chile’s activities. The Network is an active community of practice and technical collaboration, made up of over 60 municipalities that voluntarily commit to integrating climate change into local planning, management and work programs. Visit us at adapt-chile.org and www.redmunicc.cl. NRDC Chief Communications Officer:Michelle Egan NRDC Managing Directors of Communications: Lisa Goffredi and Jenny Powers NRDC Publications Director: Mary Annaïse Heglar NRDC Policy Publications Editor: Leah Stecher Cover image: © Cristián Plos Lira Design and Production: www.suerossi.com © Natural Resources Defense Council 2019 Table of Contents Introduction ............................................................................................................................................................4 Water Management Challenges in the Santiago Metropolitan Region ....................................................................7 Rising Flood Hazards ....................................................................................................................................................................7 Inefficient Water Use in Urban and Rural Sectors .......................................................................................................................7 Leaks and Unauthorized Consumption ........................................................................................................................................9 Insufficient Data ...........................................................................................................................................................................9 Conflicts Over Groundwater .........................................................................................................................................................9 One Basin Treated as Multiple Basins .........................................................................................................................................10 Water Management Solutions ................................................................................................................................12 Greening the City .........................................................................................................................................................................12 Increasing Efficiency ...................................................................................................................................................................14 Reducing Water Losses ................................................................................................................................................................16 Acquiring Data .............................................................................................................................................................................16 Organizing Groundwater Users ...................................................................................................................................................17 Moving Toward a More Integrated Basin ....................................................................................................................................17 Conclusion ..............................................................................................................................................................19 Introduction In the past decade, climate change has brought record-breaking heat, flooding, drought, and forest fires to central Chile.1 These events have negatively impacted livelihoods, cut hydroelectric power generation, discouraged tourism, decreased agriculture yields, and limited the availability of potable water in some communities.2 And the problem is only getting worse. Chile is expected to see an increase in floods and face the greatest water stress—a measure of how much more demand there is for water relative to available supply—in the Western Hemisphere over the next 40 years.3 In fact, the impacts of climate change, including drought and flooding, are predicted to cost the country’s gross domestic product (GDP) 1 percent every year for the next eight decades. To put this in perspective, 1 percent of Chile’s GDP in 2018 was equivalent to 1.9 trillion Chilean pesos ($2.8 billion).*,4 The Metropolitan Region (MR) is an economic powerhouse coincide with an existing allocation problem—an estimated and the seat of Chile’s capital city, Santiago. It is home 20 aquifers in the MR are over-allocated, meaning the to 7.1 million people (40.5 percent of the country’s rights to pump groundwater exceed the available water population) and produces 46 percent of the country’s GDP.5 supply.7 All of this exacerbates the problem of diminishing Climate change and the accompanying water stress pose groundwater supplies, a major source of water for Chile’s unique challenges for both urban and rural populations in rural sector. Diminishing water sources are leaving the the MR. Extreme heat coupled with precipitation rates that country’s agricultural economy and rural communities have declined by 20 to 30 percent in the past two decades increasingly vulnerable to drought. have resulted in a chronic water deficit.6 These factors FIGURE 1: MAXIMUM TEMPERATURE MAXIMUM TEMPERATURE Maximum temperature recorded annually at the Quinta Normal meteorological station in Santiago, Chile. The red dotted line is a linear trend line indicating an increase in temperatures at a steady rate. In 2016 and again in 2017, the highest temperature in recorded history was measured in the capital. 38 37 36 35 34 33 Annual Max Temperature (Celsius) Annual Max Temperature 32 31 1977 1980 1983 1986 1990 1993 1996 1999 2002 2002 2005 2008 2011 2014 2017 Year Source: Developed by the authors using data from the Annual Climatology ReportAnnual by Max the Temperature Meteorological (Celsius) Directorate of Chile (DGAC) for the years 1977–2017.8 * All $ in this report are in USD. Page 4 A NEW COURSE: MANAGING DROUGHT AND DOWNPOURS IN THE SANTIAGO METROPOLITAN REGION NRDC FIGURE 2: ANNUAL PRECIPITATION IN SANTIAGO (MM) While precipitation rates typically vary from year to year, precipitationANNUAL inPRECIPITATION the past 10 years, IN fromSANTIAGO 2008 to (MM) 2017, falls well below Santiago’s historical average. 800 700 600 Historical Average (1931-1960) 500 Historical Average (1961-1990) Historical Average (1991-2017) 400 Annual Precipitation (mm) 300 New 10-year Average (2008-2017) 200 100 0 1990 1993 1996 1999 2002 2005 2008 2011 2014 2017 Source: Developed by the authors using data from the Annual Climatology Report by the Meteorological Directorate of Chile (DGAC) for the years 1990–2017. Even as the region grapples with a water-scarce future, snowfall are predicted to receive greater rainfall instead, Santiago is expected to see more floods every year, increasing the volume of water and the chances of an which can compromise water quality and supply, damage extreme flooding event.13 In addition to disrupting the infrastructure, and increase health risks.9 When compared water supply, floods can cause electricity outages, spread with averages from 1912 to 1999, the MR experienced a waterborne illnesses, take lives, and cause major damage 22 percent increase in the number of floods and nearly to infrastructure including roads, bridges, and electricity six times more landslides per year between 2000 and grids. 2017.10 In less than a decade, the MR has experienced Already exacerbated by climate change, these pressing three major flooding events that cut off water supplies to water issues will likely become more complex