Adapting to climate variability and change in Chile’s Maipo basin
The Maipo river basin plays a vital role in Chile's economy. With government and community input, researchers are exploring adaptation options to sustain water resources—and the economic activities they support—in the face of growing demand and a changing climate.
In early January 2014, a smoky haze hung over Chile's capital, Santiago. Wildfires raged across the country's central-southern region, as Chile entered its fourth consecutive year of drought. The fires stoked mounting fears about how this already vulnerable region would withstand the impacts of climate change.
Much is at stake for Chile: sustained by the Maipo river basin, the city of Santiago and its surroundings are home to nearly 40% of the country's population. As well as providing water for domestic use, the basin is a hub for agriculture, mining, and power generation. Despite recurring droughts and occasional floods, the semi-arid Mediterranean climate is ideal for grape production. Just south of the capital, the Maipo Valley is one of the country's most important wine-producing regions.
The competition for water resources is already intense. But pressure on the Maipo basin is rising as Santiago's population and industries grow, and as the country looks to tap hydro-electrical power from the basin's tributaries upstream. Meanwhile, climate change projections show temperatures rising as rainfall declines. Given the region's role in Chile's national economy, a strategy for adapting to climate change is an urgent priority.
Wine production is an important contributor to Chile's economy, and may be threatened by future water stress. Pinpointing vulnerabilities
To support the development of such a strategy, a research team led by the Center for Global Change at the Pontificia Universidad Católica de Chile is mapping the Maipo basin's vulnerabilities to climate change. Linking with a diverse range of stakeholders, the team is assessing water availability and quality, supply and demand pressures, as well as how different users and economic sectors depend on the resource.
Availability and use of water within the region varies greatly. Urbanization has increased density in the Santiago Metropolitan Region and as a result, water demand for human consumption continues to grow. However, users who are far from the headwaters tend to have the least secure access to water, which is often of poorer quality. The agricultural sector is responsible for most of the water demand in the basin, and at the country level as well.
On the supply side, researchers are looking upstream, to what is happening in the Andean glaciers. They are measuring changes in glacier mass, and conducting soil and water analysis to understand how climate and land use changes will affect the basin below. To gauge demand, the team is drawing on historical data from water utilities, complemented by household surveys.
After consolidating evidence, the team will use Water and Evaluation Planning (WEAP) simulation software to develop a hydrological model that shows the possible effects of various water supply and demand scenarios. These scenarios will provide a base for proposing adaptation choices that respond to the changes underway.
Exploring regional climate trends
To ensure future plans take climate change into account, the team is downscaling widely accepted global circulation models using local weather station data to pinpoint more precisely how global temperature and rainfall projections will translate at the basin level. Their analysis so far suggests a decline in precipitation ranging from 10% in the near term (2010–2040) with a drop of up to 30% under worst case scenarios by the end of the century. Temperatures will progressively warm by 1 °C over the historical average in the near term, rising by 2.5 to 3.5 °C by 2100.
The project's Scenario Building Team exchange ideas at a workshop. Building expertise, awareness
Beyond research, the project aims to build a regional base of expertise and a multi-stakeholder forum for managing the basin over the long term. Given the increasing competition over a dwindling resource, involving a range of water users and those responsible for its protection is vital to ensure lasting solutions. A Scenario Building Team has been created for the project, with the goal of bringing together government, business, and civil society representatives, including from Santiago's municipal government; water utility companies; conservation groups; and a range of national ministries concerned with the environment and climate change, agriculture, housing and urban issues, and public security.
“The project must raise consciousness among the actors involved,” says project leader Sebastian Vicuña. “We need to build the necessary capacity and institutional structure to continue this work.”
Looking ahead: framing adaptation options
The next step for researchers will be to frame adaptation choices to reduce vulnerability. For example, with projections suggesting higher temperatures and less rainfall, what steps will encourage households, farms, and industries to change or reduce their water use?
According to Sebastian Vicuña, there may also be room for improvement in Santiago's public parks, where irrigation is currently ad hoc: “These and other municipal green spaces are not being watered as they should be, and adaptation measures can be applied to improve their water management.”
The benefits of research may extend beyond the Maipo basin. The team is involving students from other Latin American countries and will share findings widely, including through peer-reviewed journals and at international conferences. As a result, the university's Center for Global Change stands to become a regional centre of excellence, able to help other regions facing similar threats to their river basins.
Mary O'Neill is an Ottawa-based writer.
The project “Vulnerability and Adaptation to Climate Variability and Change in the Maipo Basin, Central Chile” is funded through the IDRC Research Initiative on Water Resources and Adaptation to Climate Change in Asia, Latin America and the Caribbean with funds from the Government of Canada's fast-start financing.
Watch a video interview with Sebastian Vicuña: