Hydrologic Analysis of an Intensively Irrigated Area in Southern Peru Using a Crop-Field Scale Framework

Majes is one of the largest agricultural areas in Arequipa region (southern Peru). Low seasonal precipitation and increasing water demands for irrigation, industry, human consumption have made supply projections a major concern. Agricultural development becoming more extensive this dry, sunny climate where crops can be grown year-round. However, because type project usually involves significant perturbations to regional cycle, understanding effects irrigation on local hydrology crucial. Based watershed-scale Soil Water Assessment Tool (SWAT), investigation focuses impacts intensive hydrological responses region. This study unique we allow crop-field scale input within our regional-scale model provide information at smaller scale, which important inform stakeholders decision makers. Each hydrologic response unit (HRU) was generated represent an individual crop field, so that management practices could applied according real-world scenarios. The file each HRU modified include different operation schedules rotation, harvest, tillage. calibrated validated against monthly observed stream discharge during 2009–2020 period. Additionally, evapotranspiration, volume, daily downstream river (Siguas) were used verify performance. A total 49 sub-basins 4222 HRUs created, with 3000 designated fields. simulation results revealed infiltration from activities represents majority annual groundwater return flow, makes substantial contribution streamflow Siguas River. Simulations also suggested flow processes interactions between surface impact balance area. variability had higher runoff than illustrating component area future resources resiliency under expected change Finally, there need perform follow-up implementation guideline decision-makers assess sustainable varying climatic conditions arid irrigated system.