eng Science and Education Publishing American Journal of Water Resources 2333-4819 2025-06-10 13 2 51 62 10.12691/ajwr-13-2-3 AJWR20251323 article Mengye Chen mchen15@ou.edu 1 Yongjie Huang 2 Xiao-Ming Hu 2 Ming Xue 2 3 Yang Hong 3 Hector Mayol Novoa 4 Elinor R. Martin 4 Renee A. McPherson 4 Siyu Zhu 4 Andres Vitaliano Peraz 4 Jos¨¦ Luis Ticona Jara 5 Isaac Yanqui Morales 5 School of Civil Engineering and Environmental Engineering, University of Oklahoma, Norman, Oklahoma, USA Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, Oklahoma, USA Universidad Nacional de San Agust¨ªn de Arequipa, Arequipa, Peru Servicio Nacional de Meteorolog¨ªa e Hidrolog¨ªa del Per¨² (SENAMHI), Arequipa, Peru Climate change is anticipated to drastically impact South America differently in different regions. As a climate-vulnerable area, the Peruvian Andes region is projected to have hydrological changes that can potentially devastate the region. Leveraging the output of an existing hyperresolution Regional Climate Model (RCM) and a state-of-art hydrological model (Coupled Routing of Excessive STorage, CREST), this study examines changes in hydrological conditions in 2075-2079 compared to its semi-current state in 2015-2019 in Arequipa region under the Shared Socioeconomic Pathways 5-8.5 (SSP5-8.5) scenarios. The region would face a 19.8% runoff reduction, 83%-86% averaged streamflow reduction, and 37.8 days of wet season duration reduction. The Rio Chili would experience complete ¡°no water¡± events in 2078 and 2079, and all the 1st order stream reaches would be dry more than 50% of the time between 2075 and 2079 compared to less than 40% of the time in 2015-2019. However, the flood risk would not decrease in the future, with the City of Arequipa expected to face at least one flood event that is more severe than its 2017 and 2019 floods, and Rio Colca would have many more flood events in the future. https://pubs.sciepub.com/ajwr/13/2/3/ajwr-13-2-3.pdf Regional Climate Model Hydrologic model Peruvian Andes future streamflow