Adimassu, Zenebe

Gebreyohanes, Solomon

Mekonnen, Kindu

Seyoum, Solomon

Tamene, Lulseged

Woldearegay, Kifle

Yaekob, Tesfaye

Tamene, Lulseged D.

CGSpace

Impacts of SWC interventions and land use on discharge and sediment yield in the cool sub-moist Highlands of EthiopiaIntroductionSoil erosion is a serious problem for agricultural production in Ethiopia. To tackle it, communities are engaged in various soil and water conservation (SWC) and water harvesting practices. Our study aimed to evaluate the impacts of activities to manage the watershed – specifically by measuring discharge and sediment yield at plot and watershed levels. To measure runoff and sediment yield (Fig. 3) hydrological stations wereinstalled at two sub-watersheds: one treated with SWC measures and theother without.0.020.040.060.080.0100.0120.0140.0160.01 2 3 4 5 6 7 8 9 10 11 12 13Weekly total Discharge and Rainfall (mm)Weeks (first week is from August 17 to 23, 2014)Watershed With SWC (33.83 ha) Without (22.08 ha) RainfallParameters WatershedsWith SWC Without SWCArea (Ha) 33.83 22.08Rainfall (mm) 737.60 737.60Discharge (m3/watershed) 134682.40 105933.00Discharge (m3/ha) 3981.15 4797.69Sediment Yield (ton/watershed) 31.03 102.05Sediment Yield (ton/ha) 0.92 4.62ResultsOur results from three-month’s discharge show that the total suspendedsediment yield of the unmanaged sub-watershed was about three-fold comparedwith the managed one. Sediment yield also reduced by about 70 % due toimplementation of SWC and water harvesting measures at the watershed scale.ConclusionOur results show that the soil and water conservation mobilization program achieved theintended target to reduce soil erosion and increase retention capacity of the watersheds.Integrating physical measures with biological options and supplementing these with waterharvesting structures can promote their adoption. Further analysis is being done to estimatethe impacts of the various interventions of soil nutrient loss and crop productivity.Figure 1. Location of the study area in the Basona Woreda of Gudoberet and Adisghe Kebeles, north Shewa, central Ethiopia Table 1. Sediment and discharge summary dataFigure 6. Water yield of the study sub-watershedsTesfaye Yaekob, Lulseged Tamene, Solomon Gebreyohanes, Solomon Seyoum, Kindu Mekonnen, Zenebe Adimassu, Kifle Woldearegay0100200300400Faba Beanwithout SWCFaba Beanwith SWCEucalyptuswoodlot withSWCGrazing land Mean231130 123345207Mean runoff (mm)4.722.280.212.68 2.470.000.501.001.502.002.500.001.002.003.004.005.00Faba Beanwithout SWCFaba Bean withSWCEucalyptuswoodlot withSWCGrazing land MeanAverage Sediment Conc.(SSC)(g lt-1)Mean Soil Loss (ton/ha)Soil Loss Average SSC (g lt-1)From 15 runoff events, the highest average runoff (345 mm) was observed on grazing land (Figure 4). Terrace with trench on cropland has reduced runoff and soil loss by 44 %  and 52%, respectively (Figure 4 & 5). Figure 5. Effects of land use and management on soil loss at Gudoberet Kebele, central Ethiopia Figure 4. Runoff estimated for different land use and management at GudoberetKebele, central EthiopiaBoth watersheds have similar characteristics and land use/cover types. Each measurement consisted of flow depth, determining instantaneous runoff discharge (Q, m3 s−1) and sampling suspended sediments. Figure 3. Two small watersheds with hydrological stationsFigure 2. Setup of the experimental plot at the GudoBeret Kebele, central EthiopiaMethodologyIn 2014, we set up runoff plots to evaluate the effect of different land usesand SWC practices on runoff and soil loss.We evaluated three major land use/cover types(cultivated, grazing and eucalyptus woodlots)and different SWC practices (soil bunds,trenches, grass strips). Hydrologically boundedrunoff plots of 22m length and 4m width wereinstalled for each treatment (Figure 2). Tankerswere fitted mid-slope to receive runoff anderoded soil collected from each plot. Wemeasured the depth of water in both tanksevery day in the morning to determine thevolume of runoff. We took 500ml suspendedsediment samples, oven dried at 105 0C for 24hours, to determine sediment concentration.AcknowledgementThis research was undertaken with support from Africa RISING, a program financed by the United States Agency for International Development (USAID) as part of the United States Government’s Feed the Future Initiative.

Impacts of SWC interventions and land use on discharge and sediment yield in the cool sub-moist Highlands of Ethiopia

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Impacts of SWC interventions and land use on discharge and sediment yield in the cool sub-moist Highlands of Ethiopia

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