Huasco Basin

LEAD ORGANIZATION

UNESCO-IHP

ORGANIZATIONS INVOLVED

Water Board of the Huasco River Basin (JVRH); CAZALAC; Drección General de Aguas

Problem Statement

There is uncertainty on the sustainability of multipurpose water reservoir management in the Huasco basin (Chile) under climate change scenarios, requiring a stress test for the currently installed water allocation rules to the different sectors.

Case Study

The watershed hosts a wide range of economic activities in the catchment that depend strongly on water usage (commercial grape, citric fruit and olive production, small scale and traditional agriculture, mining industry and hydro power), creating competing water uses.

In dry years, this water scarcity is further enhanced, creating additional stress on the economic sectors and society. Over the last decade, a clear reduction in precipitation was observed, generating a multiannual drought that lasted up to seven years, resulting in a strong reduction of the water level in the main Santa Juana reservoir. In this case study, a stress test is performed to identify the most likely scenarios of precipitation reduction and temperature increase, which is evaluated with the calibrated water model of the watershed, identifying potential threats to the water security of the watershed.

Key Concepts

The case study focusses on the decision making problem at hand (water allocation rules are under stress due to a current multi-annual drought) and a stress test performed to identify if climate models are able to identify a clear signal regarding the watershed. By feeding this information into the operational water allocation model (the Water Evaluation And Planning System) of the Water Board, this case study identifies how climate projections can identify (un-)sustainable decision making in a watershed with multiple competing water uses.

Outcomes & Lessons Learned

Climate change is expected to affect the region severely, projecting further precipitation decreases in a watershed already vulnerable to water stress, combined with higher expected temperatures. To become actionable, these projected climate change impacts need to be translated to the watershed level, to identify if the current water allocation rules remain operational under the expected water deficit scenarios.

KEY WORDS

Climate change projects, multipurpose water reservoir management, irrigation, overexploitation, drylands, arid climate zone

COUNTRIES OR REGIONS INVOLVED

Chile, Peru, Bolivia, Colombia, Costa Rica, Argentina and Honduras.

KEY STAKEHOLDERS

Water users (agriculture, industry and mining, hydro power), Huasco Water Board (Junta de Vigilancia Rio Huasco), Research centers (CAZALAC), funding agencies (EU-DEVO and Spanish Development Cooperation-AECID) and UNESCO-IHP

About the Knowledge Platform

The Knowledge Platform is designed to promote and showcase an emerging set of approaches to water resources management that address climate change and other uncertainties -- increasing the use of "bottom-up approaches" through building capacity towards implementation, informing relevant parties, engaging in discussion, and creating new networks. This is an ongoing project of the Alliance for Global Water Adaptation (AGWA) funded by the World Bank Group.

Contact AGWA

Alliance for Global Water Adaptation
7640 NW Hoodview Cir.
Corvallis, Oregon 97330
USA
http://alliance4water.org