Mehdi Guelmamen

Abstract

Recent drought episodes have underscored growing tensions in water resource management. These supply pressures coincide with mounting concerns over water quality, as both climate change and land use practices contribute to the degradation of surface and groundwater. Agriculture, in particular, has been singled out for its role in nitrate and pesticide contamination. This article investigates the economic and institutional determinants of raw water quality in France, with a specific focus on agricultural land use. Using spatial econometric models and a panel dataset covering the Rhin-Meuse basin from 2008 to 2023, we assess the extent to which agricultural activity influences nitrate and pesticide concentrations in water catchments. We also examine how social, geographic, and governance factors interact with land use patterns to shape pollution outcomes, explicitly accounting for spatial spillover effects. Our findings show that agricultural land use is a strong and robust determinant of nitrate pollution, while pesticide contamination reflects more heterogeneous pressures. Significant spatial spillovers confirm that pollution processes extend beyond administrative boundaries. However, we do not find evidence of a direct cost pass-through from predicted chemical pollution to drinking water prices. Instead, pricing outcomes are more strongly associated with land-use composition and institutional arrangements, suggesting a partial decoupling between environmental degradation and tariff formation.