California-Chile Water Nexus 1: Urban Drought Solutions

Though the two places are separated by thousands of miles, a quick glance at California and central Chile reveals striking similarities. Both share a long Pacific coastline, large agriculture economies, and similar Mediterranean climates perfect for wine growing, leading to iconic vineyard landscapes that line their hills and valleys. Chile and California also share similar water challenges -- and, ultimately, they can share the solutions to those challenges, to plan for and adapt to current and future droughts.

Credit: Carl Bauer and Luis Catalán, University of Arizona (pg.3)

This blog was co-written with Andrea Becerra (NRDC) and Cristina Huidobro (the Resilient Cities Unit of the Metropolitan Regional Government of Santiago in Chile).

Experts are predicting another serious drought for California and the western United States this summer, going as far to portend a rare “megadrought.” Diminishing snow cover and an extremely dry winter in the north are stoking fears and leaving policymakers, farmers, businesses and residents looking for urgent solutions. On the other side of the globe, Chile is in the midst of its own 11-year megadrought. A recent study of tree rings reveals that a drought of this scale has not impacted the central region of Chile for over 1,000 years.  Although June was the wettest month in the last 15 years for central Chile, the annual accumulated rainfall remains below normal and 2020 is still the second driest year in the last 20 years. The central part of the country, as in previous years, is expected to be the most impacted in the coming decades.

Though the two places are separated by thousands of miles, a quick glance at California and central Chile reveals striking similarities. Both share a long Pacific coastline, large agriculture economies, and similar Mediterranean climates perfect for wine growing, leading to iconic vineyard landscapes that line their hills and valleys. Chile and California also share similar water challenges—and, ultimately, they can share the solutions to those challenges, to plan for and adapt to current and future droughts.


In this context, NRDC and the Resilient Cities Office of the Metropolitan Regional Government of Santiago are holding a series of bilingual webinars designed to create the space where experts and stakeholders in Chile and California can share their challenges and experiences, and learn from each other. Our first webinar focused on urban solutions California has created to build resilience against water scarcity, based on the most intense part of its recent drought, from 2014-2017. We presented both the lessons the state learned from that experience, and the strategies California is employing to prepare for future droughts.

Building Resilience Against Drought: Urban Solutions in California

Amid a worsening multi-year drought, California Governor Brown in January 2014 called for Californians to voluntarily reduce urban water use by 20 percent. Several months later, only an eight percent reduction was achieved. So in April 2014, he mandated that Californians reduce water use by 25 percent. That decree also prohibited wasteful water practices, such as allowing irrigation to run off from your landscape, and required the state to start collecting monthly water use data from each of the 400+ urban water suppliers. The targets worked in complement with fines for non-compliance, an education campaign, and intense media coverage. Thanks to these efforts, Californians were able to reduce their water consumption by 24 percent.

When the governor declared the drought emergency over in 2017, the state began distilling lessons from the experience:

  • Residents demonstrated an enormous potential for water savings with temporary efforts (e.g., stop watering lawns) as well as permanent ones (install water-efficient appliances).
  • Regular and monthly collection of water use data is important for analyzing trends and maintaining accountability. The new monthly water use data was critical for making savings. It also showed co-benefits: the reductions in water use required less pumping of water, which translated to a lot of energy savings—more than all of the state’s energy efficiency measures combined. UPDATE: California recently adopted permanent mandatory monthly data reporting.
  • The state needs better metrics for water efficiency. Per capita water use, which was used to determine compliance with mandatory reduction targets, is helpful for tracking progress for a particular community over time but is less helpful for determining how efficiently water is being used in communities with different landscapes and climates.
  • Water suppliers’ water shortage contingency plans must be consistent to improve accountability and, so that the state has a clear understanding of how they will be used as a tool during future droughts.
  • The state needs to plan for longer droughts, in the 10-12-year range (not 3-5 years), particularly for rural areas that depend entirely on over-drafted groundwater supplies.
  • Rate structures can and should be designed to allow water suppliers to recover sufficient revenues even while they are encouraging their customers to be more water efficient.  And water suppliers must educate customers that while rates may increase to cover fixed costs during periods of water shortage, water conservation and efficiency efforts will minimize increases in customer bills.
  • Climate change means that droughts may be followed by intense wet years and flooding, and we need to be prepared to capture that water and mitigate risks of floods.


The images show an area northeast of Madera, in the Sierra Nevada Mountains’ foothills. The image on the right was taken April 5, 2011, when winter rainfall was at a normal level. The image on the left was taken on May 15, 2014, amid the drought's peak.

Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

Policymakers, experts, and stakeholders also began developing a “Portfolio Approach” to improve local reliability and resilience, protect the environment, and save money. This approach includes: 1) improving water efficiency, 2) investing in stormwater capture, 3) expanding recycled water, and 4) advancing groundwater management through the Sustainable Groundwater Management Act (SGMA).

1. Water conservation & efficiency

Water conservation and efficiency can include things such as replacing thirsty turf landscapes with climate appropriate plants, changing out old plumbing fixtures and appliances with new, more efficient ones, or reducing water losses from leaks or water main breaks. Enhancing water efficiency brings multiple environmental benefits by reducing unnecessary water use from the source and reducing the carbon footprint associated with water withdrawals, treatment, transportation and end-use. Improved water efficiency through reduced water losses can also create socioeconomic benefits by decreasing the loss of non-revenue water, reducing extraction and treatment costs while still meeting water demands. Reducing water losses can also help mitigate water damages to infrastructure and property from leakages, in turn reducing risks of water pollution from seeping pipes. And finally, reducing water losses help improve revenue streams for water utilities, increasing revenue share and protecting affordability.

2. Stormwater capture

Droughts will likely be followed by intense precipitation and flooding. Strategies that slow and capture storm flows can provide new water supplies and improve water quality, while also protecting people’s lives and property. These strategies can be on a small scale, such as transforming landscapes around our homes and businesses so that they capture water instead of letting it run off into the street. This can also reduce the heat island effect and simultaneously improve soil quality. Solutions can also be large scale, such as infrastructure that diverts stormwater from flowing into the ocean to infiltration basins where it can recharge aquifers.

3. Recycled water

Both small- and large-scale water recycling projects have the potential to increase water supply and improve water security, but these solutions have been largely untapped. Decentralized recycled water or on-site reuse systems like installing in-home “gray water” systems can capture wastewater from our homes for outdoor use and even toilet flushing. Large commercial buildings, particularly in San Francisco, are creating new systems at a bigger scale, and even district-scale solutions are being developed. In addition to reducing potable water consumption, on-site reuse saves water treatment costs given that water is treated as it is needed for its end-use application (right treatment for the right use). Decentralized recycled water systems also increase the capacity of sewer systems by reducing wastewater flows, increasing savings to communities who have to pay for this infrastructure. Finally, on-site reuse reduces the likelihood of wastewater overflow to streets, which is a benefit for public health as well.

These decentralized solutions sometimes get less attention than the large scale centralized recycled water systems where municipal wastewater goes through additional treatment processes which allow it to be reused. Initially this recycled water was pumped into a separate distribution system made up of purple pipes (to help distinguish it from drinking water) and was used solely for irrigation, mostly large landscapes like parks and golf courses. More recently, advancements in treatment technology and water quality monitoring have allowed wastewater to be treated to drinking water standards and used to supplement drinking water supplies. In Orange County, California, treated wastewater is put into a large groundwater basin and then pumped back out and used to supply homes and business. In San Diego, a project was recently approved that will allow treated wastewater to be added to a reservoir to supplement the existing drinking water supply. And finally, California is in the process of adopting standards that will allow purified wastewater to be placed directly into the drinking water system. While more energy intensive and costly than water efficiency and most stormwater capture projects, recycling wastewater, especially from treatment plants that discharge to the ocean where it serves no beneficial purpose, can be a smart strategy for meeting future water needs.

4. Groundwater management

Under the Sustainable Groundwater Management Act (SGMA) of 2014, local and regional authorities in medium and high-priority groundwater basins have formed groundwater sustainability agencies that oversee the preparation and implementation of a local groundwater sustainability plan. SGMA is California’s first attempt to regulate this resource--the state has relied heavily on groundwater for decades and a lack of regulation has led to over pumping its supply, which not only diminishes the resource but also causes land subsidence, or the land to drop. For this reason, we’ve seen as much as 12 to 14 feet drop in land levels. This is important because when land subsides over a groundwater aquifer, the aquifer permanently loses its full capacity to contain water in the future. We need to make sure we are sustainably managing our groundwater to avoid losing this critical capacity in the future.


Photo taken near the San Joaquin River, Merced County, California, showing a marker of 7.3 feet (2.2 meters) of subsidence.

Credit: USGS/Justin Brandt.

California and Chile share urgent water scarcity problems, yet they are not alone. Drought is a growing concern for many places right now, and a future of dwindling water resources should scare us. But it should also frighten us into action and jumpstart policymakers, civil society, and the private sector to push for fast, smart, economic and efficient solutions that, as much as possible, benefit everyone. There are many water supply options available and local conditions will dictate how to prioritize the various solutions to achieve safe, reliable, and affordable water for each community. If we don’t make the right choices today about how we manage our water, we face a daunting future. In this context, it is as important as ever to advance solutions and seek answers in every corner of the world, so we can plan for current and future droughts that scientists predict will undoubtedly be exacerbated by climate change.

To watch the first episode in the webinar series titled “The U.S.–Chile Water Exchange: Shared Water Management Experiences and Solutions,” and to learn more about this initiative visit here.

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