loading page

Event-based runoff and sediment yield dynamics and controls in the sub-humid headwaters of the Blue Nile, Ethiopia
  • +6
  • Habtamu Assaye Deffersha,
  • Jan Nyssen,
  • Jean Poesen,
  • Hanibal Lemma,
  • Derege Meshesha,
  • Alemayehu Wassie,
  • Enyew Tsegaye,
  • Deribew Fentie,
  • Amaury Frankl
Habtamu Assaye Deffersha
Bahir Dar University College of Agriculture and Environmental Sciences
Author Profile
Jan Nyssen
Ghent University Faculty of Sciences
Author Profile
Jean Poesen
KU Leuven
Author Profile
Hanibal Lemma
Bahir Dar University Institute of Technology
Author Profile
Derege Meshesha
Bahir Dar University College of Agriculture and Environmental Sciences
Author Profile
Alemayehu Wassie
Bahir Dar University College of Agriculture and Environmental Sciences
Author Profile
Enyew Tsegaye
Bahir Dar University College of Agriculture and Environmental Sciences
Author Profile
Deribew Fentie
Bahir Dar University College of Agriculture and Environmental Sciences
Author Profile
Amaury Frankl
Ghent University Faculty of Sciences
Author Profile

Abstract

Land degradation due to soil erosion presents a challenge for sustainable development. We investigated the impact of land use type and land management practices on runoff and sediment yield dynamics in the northwestern highlands of Ethiopia. The study area included 14 zero-order catchments with a surface area ranging from 324 m2 to 1715 m2. V-notch weirs produced from plastic jars were introduced as measuring alternatives that met local constraints. Runoff depth at the weir was registered at 5-min intervals during two rainy seasons in 2018 and 2019. Rainfall was measured using tipping-bucket rain gauges. Runoff samples were collected in 1-L bottles and suspended sediment concentration (SSC) was determined. The mean event runoff coefficient ranged from 3% for forests to 56% for badlands. Similarly, the mean annual sediment yield (SY) was lowest for forests (0.8 Mg ha-1 yr-1) and highest for badlands (43.4 Mg ha-1 yr-1), with significant differences among land use types (14.8 Mg ha-1 yr-1 in cropland, 5.7 Mg ha-1 yr-1 in grazing land, and 2.9 Mg ha-1 yr-1 in plantations). Soil organic matter (SOM) reduced runoff and SY, necessitating the consideration of agronomic and land management practices that enhance SOM. Annual SY decreased exponentially with the rock fragment cover (RFC). In fields where RFC was less than 20%, collecting rock fragments for installing stone bunds resulted in a net increase in SY. Rehabilitating badlands and enhancing SOM content in croplands can substantially reduce catchment SY and, hence considerably contribute to the sustainability of this type of environment.

Peer review status:IN REVISION

17 Mar 2021Submitted to Land Degradation & Development
18 Mar 2021Assigned to Editor
18 Mar 2021Submission Checks Completed
07 Apr 2021Reviewer(s) Assigned
11 May 2021Review(s) Completed, Editorial Evaluation Pending
25 May 2021Editorial Decision: Revise Major