Review, impact of land use/cover change on soil erosion in the Lake Tana Basin, Upper Blue Nile, Ethiopia

Alemsha Bogale

doi:10.1007/s13201-020-01325-w

Abstract

Lake Tana Basin is located in upper Blue Nile Basin which is comprises a total area of 15,096 km2 of which 3063 km2 is covered by the Lake which is the source of Blue Nile river. Lake Tana Basin and Blue Nile River provide various benefits also for downstream countries. The basin is highly degraded by different natural and manmade problems and it influence both Ethiopia and downstream countries. The main cause of basin degradation is inappropriate LULC. Huge area of cultivated land using without suitable management is the major basin problem. It is due to insure food security coming from unprecedented population growth rate. Forested land has encouraged the infiltration capacity and permeability of the land. It helps to increase the recharge capacity contribute to base flow whereas it is vice versa for cultivated land which is quick overland flow and significant soil erosion have observed. Besides, the soil erosion from agricultural land is the main source of nutrient enters to the lake which is the cause for eutrophication. To combat such problems both up and downstream countries should discuss together and design and implement appropriate basin management strategies to sustain the biodiversity and hydrological system of the basin.

Highlights

Mostly dominated by mountainoustopography is the source of water for east Africa which is from rainfallrunoff process (Derib et al 2009)
Soil erosion is the major threat in Lake Tana Basin
Cultivated land is the major kind of land use which is the main factor contributed to soil erosion

Summary

Introduction

Mostly dominated by mountainoustopography is the source of water for east Africa which is from rainfallrunoff process (Derib et al 2009). Forested land has potential to conserve rainfall and increase infiltration capacity of the surface to encourage subsurface water availability whereas deforestation and land degradation process are susceptible to overland flow and reduce infiltration and recharge flux This results in quicker runoff responses were flow rates increase and we presume that this partly causes the increase in the high flow index and aggravate soil erosion. The study by Estifanos (2014) was proved within the findings of FAO When we compare this result with the predicted annual soil loss rate in Lake Tana Basin which is >60 ton ha−1 yr−1 in rugged topographies and it decreases up to 15 ton ha−1 yr−1 on the area with better catchments characteristics (Yitaferu 2007). Intensive researches about root cause of soil erosion and to design appropriate control method are not clearly known

Conclusion

Findings

Compliance with ethical standards