Río Seco (Dry River) in El Alto, Bolivia, where water scarcity is a major concern even before future climate change is considered.
Río Seco (Dry River) in El Alto, Bolivia, where water scarcity is a major concern even before future climate change is considered.

The Bolivian capital, La Paz, and its fast-growing neighbour, El Alto, are prime examples of the water resource management challenges that are arising in the Andes, where demand is growing rapidly and multiple players – urban dwellers, farmers, the power sector, etc. – compete over limited supplies. At the same time, climate change is raising significant concerns: snow and glacier melt is a crucial part of the water supply, but glaciers are visibly shrinking; changing precipitation patterns, meanwhile, are increasing the need for agricultural irrigation.

The water supply systems are already stretched to capacity, and officials are looking for ways to avoid a crisis. But water infrastructure is costly and long-lasting: the choices they make today will affect the cities’ water supplies – and those of surrounding rural areas – for decades. And given how fast conditions are changing, it is difficult to know whether a solution that works today will keep the water flowing in the 2020s, 2030s or beyond.

As part of the Climate Investment Funds Pilot Program for Climate Resilience (PPCR), SEI researchers have been working with local officials in La Paz and El Alto to identify the most “robust” policy and investment options for both the short and long terms. The project, which is funded by the Inter-American Development Bank with additional support from the Challenge Program for Water and Food (CPWF), combines extensive stakeholder engagement, sophisticated water supply and demand modelling, scenario analysis, and visualization tools that turn complex data into easy-to-understand, interactive graphics.

Making sense of all the moving parts

The first step in the analysis was a participatory process based on the XLRM framework developed by the RAND Corp., which starts by identifying external factors that could affect the outcome (in this case, climate change, population growth, increased demand for water linked to rising incomes, increased demand for irrigation water, and potential policy changes that could alter the relative priority given to urban and rural water uses). Next, they identified policy levers – the management strategies and investment choices they could make – and the relationships between those levers. Finally, they identified ways to measure the performance of each strategy, such as the reliability of the water supply system and its ability to recover after a failure.

The analysis was done in stakeholder workshops led by the Ministry of Water and Environment (MMAyA). Then the data were fed into a model of water supply and demand built with SEI’s Water Evaluation and Planning (WEAP ) software. The model was run hundreds of times to examine the performance of six strategies, including new reservoirs, measures to reduce water waste in rural and urban settings, and wetlands conservation, individually and combined, under different combinations of scenarios, up to 2030 and up to 2050.

Communicating the science

Such testing and evaluation generates an enormous amount of data. The researchers’ next challenge was therefore to distil these results into something understandable and useful for policy-makers. To do this, the project used Tableau , a proprietary interactive data visualization application that SEI has also used to model a range of infrastructure investment options in Afghanistan .

“With Tableau we could show, clearly and simply, how the different proposed strategies performed, based on the huge mass of complex data we had generated in the process,” says SEI Staff Scientist Laura Forni, an economist at SEI’s Davis, Calif., office who did the visualizations. “Tableau’s interactive dashboard also allowed the policy-makers could explore the different options, and combinations of options.”

“One of our most striking findings so far is that, while some of the proposed strategies look good until 2025-30­ – improving the water supply to El Alto and other areas – all of them fail after that, once uncertainties like climate change, population growth, changes in agriculture are factored in,” says SEI Senior Scientist Marisa Escobar, the project leader. “That let the stakeholders know that they need to find integrated strategies that can work past 2050, with multiple strategies on both the supply and demand sides, and involving both urban and agricultural uses. With the toolkit we have developed, they can keep testing new combinations of approaches.”

Escobar gave an overview of the project and its methodology at a World Water Week session on dealing with uncertainty, while Forni presented the project’s use of Tableau as part of a session on the “science and art” of water cooperation. In addition, Nilo Lima, who has shepherded the project at the Ministry of Environment and Water, offered a policy-maker’s perspective on the project as part of the Malin Falkenmark Seminar.

Along with helping decision-makers in La Paz and El Alto, the project was meant to develop and test a methodology that could be applied across the Andes region, and that is already happening, Escobar notes. “We are using this robust decision support approach in a project in Colombia and in another project in Bolivia , and our collaborators in Chile are also applying it.”

A visualization shows whether each option meets a given performance standard (blue) or fails (orange). Click to see a larger image.