Modeling the impact of climate change and agricultural management practices on soil erosion in the agricultural basin of Lakes Prespa

Abstract

Erosion and sediment delivery are currently problems of interest for the Lakes Prespa basin. The potential for global climate changes to increase the risk of soil erosion is clear, but the actual damage is not. A model analysis of climate change impacts on runoff and erosion in this basin was not performed previously. The objective of this study was to investigate the effects of climate change and agricultural land management on channel and soil surface erosion, as well as sediment yield in streams in this basin. For this reason, in this study, the DHSVM (Distributed Hydrology Soil Vegetation Model) model was used. The model was first calibrated using data for the period of (2010 - 2016), and then was used to predict results for the year 2045 using statistically downscaled global climate data. Three tillage scenarios were incorporated into DHSVM: conventional till, reduced till, and no till. Results have shown that climate change and agricultural practices, particularly surface treatments to the land, can impact surface runoff and suspended sediment generation. Runoff and sediment generation are strongly related, and runoff flows in rills and gullies typically carry suspended sediment loads downstream. Another factor that can affect formation of these channels and overland flow is land use. The results also showed that as the projected climate–driven intensity of storms increase, more runoff is predicted in the Lakes Prespa basin. Sensitivity of the model to surface erosion and changes in channel sediment bed depth were both evaluated for several parameters that relate to erosion. Observations have shown that suspended sediment concentrations can drastically increase, but model results do not yet display large fluctuations in suspended sediment concentrations which are typically observed in nature as a result of storm and erosion events. In the long term, continued improvements to this preliminary model of the Lakes Prespa basin can provide better insight into the effects of climate change on the riparian habitat of fish in the basin and the sediment budget of the surrounding area.