By Natasha Krell

In December 2017, Patricia Gonzalez and her colleagues published a paper on a novel water demand system dynamics model that integrates social and structural drivers of water conservation in WRR. We asked her a couple of questions.

1. Where are you from, where are you based, and what are you currently working on?
I was born and raised in Lima, Peru. I live in the San Francisco Bay Area now, where I am finishing up my PhD at Stanford University. My research looks at the dynamics of urban water supply and demand, emerging challenges for water management, and how utilities can work together in innovative ways to help secure more resilient water supplies. I’m currently investigating the use of market incentives to design more collaborative water management policies. For example, setting regional conservation targets and allowing utilities to trade conservation credits amongst themselves, like a cap-and-trade system.

2. What is the take home message of your paper?
This paper was focused on uncovering shifting water use behaviors in response to public awareness of water scarcity. We found that public behavior does indeed follow some significant and predictable patterns, which correlate to how prominent water issues are in the public agenda. Essentially, the more exposure the public has to drought messaging, the more responsive they are to conservation incentives. However, this behavior reverses once the memories of drought start to fade. This means that policies, public outreach, and media coverage of water issues can play an important role in managing water demand, and can potentially be used to encourage a more long-lasting change in public perceptions and social norms.

3. The concept of “social memory” is an interesting take on why water users rebound in demand after a period of drought. What led you to this hypothesis or inspired you to work on this research question?
I was inspired by recent socio-hydrologic literature introducing the concept of social memory to help explain feedback dynamics between environmental conditions and societal decisions, particularly papers by DiBaldassarre, Sivapalan, and others. Back in 2015 we were in the height of a historic drought, and my research group was working closely with water utilities who told us they were seeing their customers conserve water beyond what they were expecting and they weren’t sure why. The drought really highlighted the role of public behaviors in achieving conservation goals, as well as the fact that there is still a big gap in our understanding of those behaviors. If you look at the water use projections that utilities use for planning, most of these follow a linear trend, generally assuming that water demand per capita will remain relatively steady. Yet, if you look at water use over the past few decades, it doesn’t look like this. In many places, water demand is flattening down despite growing populations, and in places like California where you have periodic droughts you see the pattern of water use going down during drought and then slowly come back up. It seems like an obvious pattern from a conceptual point of view, but it made me question whether there was a better way to model water demand and to quantify the role of behavioral conservation. I thought this looked a lot like the recent papers I was reading about social memory, and I was excited to be able to test this concept on real observations.

4. In the article, you suggest that models generally assume static conditions and do not account for changing systems dynamics of resource use such as behavioral changes. Do you see the field of socio-hydrological modeling moving in this direction to incorporate more real-time dynamics of human behavior? What do you think are important aspects for future work?
I definitely think we are moving towards more holistic models that help us understand the complexities and shifting dynamics of real systems, including the uncertainties of public behaviors. Water resources issues are interdisciplinary by nature. You have to be able to account for changing climatic and hydrologic conditions, the effect of technologies and engineered systems, as well the social aspects of water management. It only makes sense to try to approach water systems from a dynamic and interdisciplinary lens. Of course that is easier said than done. On the one hand, we have more tools available than ever, including access to big data and direct lines of engagement with the public through information technology platforms. On the other hand, I think there is still a lot of room to improve when it comes to crossing disciplinary boundaries, not only within academia but also in establishing partnerships with industry and practitioners.

5. Since there no current metrics to study the relationship between drought severity and public awareness, you developed a novel index of hydrologic drought saliency. Can you explain this index in layman’s terms and why it is useful?
We developed this index of hydrologic drought saliency as a way to represent both the severity and duration of drought conditions. It is adapted from an existing metric, the palmer drought severity index (PDSI), which measures dryness based on precipitation and temperature. PDSI is an indicator of recent conditions, whereas we were trying to measure how bad a drought is based on cumulative conditions over time. For example, PDSI may go up and down from one month to the next, but a single dry month doesn’t mean we are in a drought and a single wet month doesn’t mean a drought is over. That distinction is important when you’re looking at long-term conditions and trying to correlate that to policies and public awareness. Typically, droughts become salient only once conditions become consistently bad. In our study, the new index was useful because it allowed us to compare different drought experiences and acknowledge that a short and severe drought can a have similar saliency (and lead to similar political attention) than a tamer but longer drought, and California has seen both types of situations.

Reference paper: Gonzales, P., & Ajami, N. (2017). Social and structural patterns of drought-related water conservation and rebound. Water Resources Research, 53, 10,619–10,634. https://doi.org/10.1002/2017WR021852