Landscape pattern and climate dynamics effects on ecohydrology and implications for runoff management: case of a dry Afromontane forest in northern Ethiopia

Abstract

In this study, we assessed the land use land cover dynamics, rainfall trends, spatio-temporal runoff potentials, and proposed runoff management options in a dry Afromontane forest in northern Ethiopia. Satellite images (1986, 2001 and 2018) were classified using the maximum likelihood method, and responses to runoff were determined using a hydrologic model. A trend-free pre-whitening Mann–Kendall (TFPW-MK) test was used to analyze the areal weighted rainfall trends. The forest and shrubland coverage expanded (451 and 421 ha/year) between 1986 and 2001; however, the forest land showed lower rate of increment (248 ha/year) during 2001–2018 due to anthropogenic influences. The shift of bimodal rainy seasons to a monomodal with high runoff volume was experienced in 2001–2018. The TFPW-MK test revealed that the rainfall trend was statistically insignificant, but showed a decreasing pattern. In general, ecological restoration can be achieved via implementing the proposed conservation measures like percolation pond, storage tank, check dams, contour bunds, terraces, trenches, area closure and combination of these measures.