Achieving water security and guaranteeing the sustainable use of water resources require series of investments at the catchment scale. Yet, competing water uses pose an initial layer of complexity about the type of intervention a catchment requires. Additionally, the nature of climatic and no-climatic uncertainties, threatening possible investments, leave decision makers with insufficient knowledge about the performance of chosen intervention options in a changing world. So, decision makers require novel tools which would facilitate the description and communication of key metrics in an uncertain future.

This project studies the sensitivity of the multipurpose Chancay-Lambayeque Basin water resources hydraulic system (Peru) to changes in climatic and no-climatic forces. A series of proposed interventions to enhance the current hydraulic system look to satisfy water supply to ~400,000 people, guarantee water for increasing irrigation activities, and maintain ecological flows, while providing protection for El Niño-driven floods.

The assessment was carried out using the DMDU deiven Decision Tree Framework (DTF, Ray and Brown,2015). This is a bottom-up and two-step approach which, in this project, examined the performance of economic, resilience, robustness, and reliability metrics of selected interventions such as the construction of new reservoirs, the expansion of groundwater development, and the conservation and generation of green-infrastructure, subjected to various climate realizations. Also, the effects of changes in urban water supply and irrigation demands, siltation in existing reservoirs, and other non-climatic parameters and trade-offs were analyzed. The results of this study highlight the potential (while acknowledging limitations) of DMDU tools to prioritize investments in river catchment planning while engaging local stakeholders in decision making.