ASSESSING THE INFLUENCE OF AGRICULTURAL AND MINING DEMANDS IN THE HYDROLOGIC CYCLE OF TWO CONNECTED WATERSHEDS IN SOUTHERN PERU

The water cycle has been always affected by the needs of economic activities. In Peru, the main two economic activities are mining and agriculture, from which agriculture tends to have a bigger impact on land use. Both economic activities are interested in water availability for their operations, mining is also interested in energy production. To satisfy these needs, the government in Peru is building more reservoirs to assure water supply and hydroelectric power. Most efforts to manage long-term water supply are applied to watersheds with larger urban populations, while rural watersheds are left behind without long-term planning, and with a poor understanding of the future water supply potential.

This study aims to elucidate the impacts of mining and agricultural needs inside two connected watersheds (Quilca and Camana) draining into the Pacific Ocean in southern Peru, focusing mainly on reservoirs and their resilience against climate change. The Quilca watershed hosts the Arequipa city (the second largest city in Peru) and has features of an urban basin, on the other hand, Camana has features of a rural watershed. Both watersheds have 4 reservoirs, and Camana has two diversions into Quilca to satisfy the multiple water needs.

The modeling approach developed integrates the topics by carrying out a distributed-parameter simulation with PRMS. The simulation implements the aforementioned features and we use a highly discretized model with a fine resolution of input data for climate, land use, and water features. The analysis includes future man-made infrastructure, climate-change scenarios, and land use (i.e., more conversion to agriculture and mining, or increased urban footprint). Our study represents a novel water resources analysis focused on evaluating future sustainability and integrated solutions to identified problems for two adjacent Peruvian watersheds, each with different current and future uses, but both having a similar need to ensure a sustainable future water supply.