Assessing the Effects of Bioenergy Cropping Scenarios on Surface and Groundwater of an Intensively Agricultural Basin in Central Greece

Pinios river basin constitutes the most important agricultural production area in Greece, contributing to the degradation of the quality and quantity of surface and groundwater bodies. Bioenergy crops, implemented as part of the existing cropping systems, could be a novel and efficient mitigation strategy against water degradation contributing to the production of energy through renewable sources. This study uses the Soil and Water Assessment Tool (SWAT) to first develop a representative model of Pinios river basin and evaluate its current state with respect to water availability and nitrate water pollution. A low input perennial bioenergy crop, switchgrass, is then simulated closely to the Greek conditions, to investigate its potential effects on water through three implementation scenarios: installation and growth of switchgrass in the entire irrigated cropland, exclusively in irrigated sloping (slopes > 1.5%) cropland and exclusively in irrigated non-sloping cropland. The simulated results demonstrate that under all scenarios, water quality improvements with respect to nitrate loads entering surface and groundwater bodies were significant, with their reduction being directly affected by the extent that switchgrass replaced the resource-demanding conventional crops. However, the potential of improving water status with growing switchgrass only in sloping areas was considerable, at the same time with significant biomass production. The study also highlights the contribution of the bioenergy crop to the increase of groundwater levels across the basin, implying that its adoption could be a promising means against water scarcity.