Potential ecological impact of climate change on the water quality of an intensively managed agricultural watershed in Quebec, Canada

This study investigated the effects of climate change (CC) on water redistribution in a micro-watershed of a lowland agricultural area of the Bras d'Henri River in the temperate cold climate of Quebec, Canada. A Water Flow and Balance Simulation Model (WaSiM-ETH) was used to simulate the hydrology using current climatic conditions and land use characteristics, applying Richards' equation. A one-day temporal resolution was used with a spatial resolution of 2 x 2 m. The CC scenarios Coupled Global Climate Model, version 1 (CGCM1) and Hadley Centre Coupled Model, version 3.1 (HadCM3.1) were downscaled to the regional level and integrated into WaSiM-ETH and evaluated for both current and modified climatic conditions. Mean annual precipitation values (P) increased from 15-33%, evapotranspiration from 7-26%, and discharge (Q) from 16-45%. The identification of the significant water quality problem represented by average value of total suspended solids (TSS) 265.29 (kg ha(-1)), nutrients: nitrogen (NO3-N) 16.83 (kg ha(-1)) and total phosphorus (TP) 0.59 (kg ha(-1)) for the whole evaluated period; and (TSS) 148.09 (kg ha(-1)), (NO3-N) 5.65 (kg ha(-1)) and (TP) 0.31 (kg ha(-1)) during the days with surface runoff, in relation to water quantity and CC creates the basis for erosion risk assessment.