Evaluating in Situ Water and Soil Conservation Practices with a Fully Coupled, Surface/Subsurface Process‐Based Hydrological Model in Tigray, Ethiopia
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Date
2016
Journal Title
Journal ISSN
Volume Title
Publisher
Land Degradation & Development
Abstract
In situ water and soil conservation (WSC) practices are a promising intervention to improve rainwater management particularly in the semiarid
to dry sub-humid tropics. This study applies a fully coupled surface–subsurface process-based model (HydroGeoSphere) to simulate in
detail rainwater partitioning as affected by two in situ WSC practices [terwah+ (TER+) and derdero+ (DER+)] currently under study on
Vertisols in Tigray, Ethiopia and to evaluate the treatments in terms of rainwater partitioning. In the TER+ practice, contour furrows of
0·2m wide and 0·1m deep are created at 1·5m intervals between permanent broad beds, whereas in DER+, permanent raised beds 0·6m wide
with furrows 0·2m wide and 0·1m deep are created, to minimize runoff and water logging. The model accurately reproduced measured
surface runoff (e.g. in DER+: Nash–Sutcliffe model efficiency E = 0·6 for calibration and 0·7 for verification) and soil moisture content
(DER+: E = 0·6 for calibration and 0·8 for verification). Runoff depth was lowest under DER+ (50 mm) followed by TER+ (67 mm) and
significantly higher in conventional tillage (CT) (160 mm). Simulated transpiration, evaporation and drainage out of the root zone were all
higher under DER+ and TER+ compared with CT. The effects of DER+ and TER+ practices on rainwater partitioning were more pronounced
in wet years than in dry years. The model proved to be a promising and versatile tool to assess the impact of WSC practices on rainwater
partitioning at the field scale.
Description
Keywords
Surface-subsurface flow model, Water and soil conservation
Citation
Opolot, E., Araya, T., Nyssen, J., Al‐Barri, B., Verbist, K., & Cornelis, W. M. (2016). Evaluating in situ water and soil conservation practices with a fully coupled, surface/subsurface process‐based hydrological model in Tigray, Ethiopia. Land Degradation & Development, 27(8), 1840-1852. DOI: 10.1002/ldr.2335