Hydrological responses to forest cover change in mountains under projected climate conditions

This study quantified the hydrological responses to the forest cover change in the upper part of Sola River basin, Forest Creek catchment, southern Poland, under projected climatic conditions. The Soil Water Assessment Tool (SWAT) will be applied to investigate the response of the hydrology regime to deforestation and reforestation processes. Under two emission scenarios (A1B and B1, IPCC) of the general circulation model GISS_E (NASA Goddard Institute) were employed to generate future possible climatic conditions. A key point is to assess both the rate of change in hydrological conditions after the collapse of the spruce stands (occupied 80% area in 2003) and the time necessary to stabilize the water management after the afforestation. Such elements as rainfall, evapotranspi-ration, streamflow, retention and water runoff were taken for examination and analysis. During 10 years (2003-2012) 56% of the catchment area was completely without trees, as a result water retention decreased by 43%, the rate of runoff water from the catchment increased by 48%. It was found that the time required to stabilize the hydrological regime on the catchment is approximately 50-55 years. The acceleration of this process is possible by increasing the share of broadleaved species in the composition of the target stands in this area. Changing the relationship between deciduous and coniferous species from 0.17 in 2003 to 0.70 in 2020 will be a great benefit to adaptation process and reclaim water balance stability.