Launch: CUBHIC tools support rapid assessment of water quantity and quality benefits of nature-based solutions

Water Feb 13, 2020
Sydney Moss

Five years ago, the water utility serving Lima, SEDAPAL, made a bet on nature. The utility approved the largest financial commitment for natural infrastructure investment of any country in Latin America, to be funded by the monthly tariffs paid by the mega-city’s water users. Today, Forest Trends and our partners on the USAID- and Canadian-funded Natural Infrastructure for Water Security project in Peru are working closely with SEDAPAL to bring the first tranche of investable projects using this tariff to the field. The projects focus on the upper catchments of the Chillon, Rimac, and Alto Mantaro rivers that feed the city, with interventions ranging from the restoration of wetlands and grasslands to the rehabilitation and replication of pre-Incan infiltration channels called amunas.

But how will SEDAPAL – and, more to the point, Lima’s water users – know what they are getting for these investments in nature? How do we compare the contribution of a pre-Inca canal to a restored wetland? What is a fair price for these investments, that considers not only what they cost to implement but also the value of their contributions to securing Lima’s water supply?

This week, Forest Trends and our partners are launching the first series of tools that will allow practitioners and decision-makers in Lima, and throughout Peru, to begin to answer those questions in a practical way. The CUBHIC tools, named for their Spanish acronym, support quantified estimates of the impacts of the most common nature-based solutions for water in Peru, in terms of water quantity (increases in dry season flow) and quality (reductions in sediments and nutrient pollution).

The CUBHIC Tools were developed by US-based engineering firm Kieser & Associates, working closely with Forest Trends and CONDESAN. Each methodology allows the quantification of water benefits of nature-based solutions at the level of a project site, offering a practical alternative to costly, time-intensive, and data-intensive hydrological models like SWAT to quantify the water benefit of ecosystem services.

Each downloadable CUBHIC tool set includes a Benefits Calculator (Excel) and a Technical Primer which describes each natural infrastructure intervention, the full methodology and equations used in the calculator, the technical justification and scientific references supporting the methodological approach, and the data inputs needed to apply the methodology. Users enter site specific data such as soil and vegetation characteristics, precipitation and temperature data (highs and lows or mean).  They are encouraged to use data from official sources, such as Peru’s national weather service SENAMHI, as well as field data, and are provided with default values for inputs like curve number, based on observable site characteristics. The CUBHIC tool then immediately estimates hydrological benefits, comparing between potential project scenarios provided by the user, and even offering preliminary estimates of cost-effectiveness of alternative options.

“CUBHIC fills a critical gap in Peru by offering simple, site-level methods for generating quantified estimates of benefits of nature-based solutions,” said Gena Gammie, Deputy Chief of Party of the Natural Infrastructure Water Security project. “Before these methods, practitioners and decision-makers were in the dark on one of the most important aspects of project design. We hope CUBHIC will be used widely in Peru – and even in other countries with similar contexts – and look forward to working with local stakeholders to evolving and expanding the tools in response to local needs.”

CUBHIC tools have been developed for seven types of nature-based solutions. Click on the links below to access the Technical Primers and Benefits Calculator for each solution, each available in Spanish and English. You can also access our webinar introducing the CUBHIC tools to Peruvian practitioners here.

For more information or to provide feedback on the CUBHIC tools, please contact Gabriel Rojas,  


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