Abstract
This paper evaluates the long-term impact of rehabilitated irrigation canals under Argentinas PROSAP III program on vineyard productivity in San Juan province. We combine 20 years of Landsat-derived NDVI data with survey data from 299 grape producers and apply a synthetic difference-in-differences (SDID) framework to estimate causal effects. Additional robustness checks include propensity score matching and inverse probability weighting. Results indicate that canal rehabilitation increased NDVI by 0.91%, equivalent to yield gains of approximately 144 kilograms per hectare, with peak impacts of 2.5% (386 kg per ha) five years post-intervention. The study highlights the productivity benefits of irrigation investments and demonstrates the value of remote sensing for large-scale agricultural impact evaluations. Findings offer policy-relevant insights for designing and monitoring rural infrastructure programs in water-scarce regions.