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Assessing the Impacts of Land Use and Land Cover Changes on Hydrology of the Mbarali River sub-catchment. The Case of Upper Great Ruaha sub-Basin, Tanzania

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Engineering（科研） 2018年第9期10卷 616-635页

作者： Edmund Mutayoba Japhet J. Kashaigili Frederick C. Kahimba Winfred Mbungu Nyemo A. Chilagane Department of Built Environmental Engineering Mbeya University of Science and Technology Mbeya Tanzania Department of Engineering Science and Technology Sokoine University of Agriculture Morogoro Tanzania Department of Forest Resource Assessment and Management Sokoine University of Agriculture Morogoro Tanzania

Intensification of agricultural land use and population growth from 1990-2017 has caused changes in land cover and land use of the Mbarali River sub-catchment which is located in the Upper Great Ruaha sub basin, Tanzania. This has affected the magnitude of the surface runoff, total water yield and the groundwater flow. This study assesses the impacts of the land cover and land use changes on the stream flows and hydrological water balance components (surface runoff, water yield, percolation and actual evapotranspiration). The land use and land cover (LULC) maps for three window period snapshots, 1990, 2006 and 2017 were created from Landsat TM and OLI_TIRS with the help of QGIS version 2.6. Supervised classification was used to generate LULC maps using the Maximum Likelihood Algorithm and Kappa statistics for assessment of accuracy. SWAT was set up and run to simulate stream flows and hydrological water balance components. The assessment of the impacts of land use and land cover changes on stream flows and hydrological water balance component was performed by comparing hydrological parameters simulated by SWAT using land use scenarios of 2006 and 2017 against the baseline land use scenario of 1990. Accuracy of LULC classification was good with Kappa statistics ranging between 0.9 and 0.99. There was a drastic increase in areal coverage of cultivated land, for periods 1990-2006 (5.84%) and 2006-2017 (12.05%) compared to other LULC. During 2006 and 2017 surface runoff increased by 4% and 9% respectively;however, water yield increased by only 0.5% compared to 1990 baseline period. This was attributed to increased proportion of cultivated land in the sub-catchment which has a high curve number (59.60) that indicates a higher runoff response and low infiltration rate.

关键词： Geographic Information System (GIS) Mbarali River sub-catchment Land Use and Cover Change Soil and Water Assessment Tool (SWAT) Water Balance Stream Flow

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Farmers’ Perception of Soil Erosion and Adoption of Soil Conservation Technologies at Geshy sub-catchment, Gojeb River catchment, Ethiopia

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Agricultural Sciences 2019年第1期10卷 46-65页

作者： Melku Dagnachew Alemu Asfaw Kebede Awdenegest Moges Natural Resources Management Wolaita Soddo University Wolaita Sodo Ethiopia Haramaya Institute of Technology Haramaya University Dire Dawa Ethiopia Hawassa Institute of Technology Hawassa University Hawassa Ethiopia

The study was conducted to investigate farmers’ perception of soil erosion, participation and adoption of soil conservation technologies (SWC) in Geshy sub-catchment of Gojeb river catchment, Omo-Gibe basin, Ethiopia during 2016. The study is based on a detailed survey of 77 households using structured interviews, field observation and focus group discussion. Descriptive and chi-square statistics were applied to analyze factors that affected farmers’ perceived soil erosion severity, participation and adoption options. The results revealed that about 79% of farmers perceived soil erosion problem and its consequences and 97.4% of them believed that it can be controlled. Almost all (97.4%) farmers acknowledged the presence of SWC technologies and about 92.2% of them were participated in conservation activities voluntarily. Thus, 93.5% of them realized decreasing rate of soil erosion and 79.9% of them observed an increasing trend in soil fertility status. Consequently, 94.8% of them confirmed the potential of SWC technologies to halt land degradation and improve land productivity. Furthermore, 98.7% of them were willing to adopt with very good adoption judgment and 94.8% of them were willing to continue maintaining constructed technologies in the future. Principally, farmers’ perception of soil erosion, their genuine participation derived from their conviction, and adoption of induced SWC technologies are the decisive elements for the success of watershed management interventions.

关键词： Adoption Perception Soil and Water Conservation Soil Erosion Geshy sub-catchment Ethiopia

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Lithological and tectonic response on catchment characteristics of Rishi Khola, Sikkim, India

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Journal of Mountain Science 2021年第11期18卷 3003-3024页

作者： Ujwal Deep SAHA Sohini NEOGY Jhikmik KAR Uttam MUKHOPADHYAY Vivekananda College for Women University of CalcuttaKolkata 700008India Banwarilal Bhalotia College Asansol 713303India Vidyasagar College Kolkata 700006India

Rishi Khola,a sub-watershed of Teesta river,traverses along the Main Central Thrust(MCT)with a multitude of litho units and structural *** study examines the impact of tectonic and lithologic controls in configuring the catchment characteristics of Rishi Khola,Sikkim,*** SRTM 30m DEM and Landsat 8 satellite image have been used for extracting the river network,preparing the sub-catchments,the longitudinal profile and thereby calculating the morphotectonic *** aggregated tectonic index(ATI)has been prepared to map the intensity of tectonic perturbations in the fluvial environment using the entropy weightage method(EWM)and Weighted Linear Combination(WLC).The undulating nature of the longitudinal profile with prominent knick points confirms the presence of tectonic disturbances and lithological *** all the computed morphotectonic indices and the ATI,it has been evident that the region has experienced surface *** viewed at the entire catchment,the morphotectonic indices suggest ample responses to the tectonic perturbations due to the dominance of lithology-controlled hill slope processes and fluvial *** spatiality of the tectonic sensitiveness is rather concentrated into certain pockets of differential stress field formed due to fault thrusting of the *** study chiefly focuses on the peculiarity of the watershed which displays a complex response of tectonic and rock structure;wherein the proposed methodology has been successful in excavating such complex responses around the Himalayan thrusts.

关键词： Himalayas Lithology Main Central Thrust(MCT) Morphotectonics Rishi Khola sub-catchment

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Modelling surface runoff using the soil conservation service-curve number method in a drought prone agro-ecological zone in Rwanda

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International Soil and Water Conservation Research 2019年第1期7卷 9-17页

作者： Dieudonne Uwizeyimana Stephen M.Mureithi Simon M.Mvuyekure George Karuku Geoffrey Kironchi Department of Land Resource Management and Agricultural Technology University of NairobiP.O Box 2905300625 NairobiKenya Ministry of Agriculture and Animal Resources of Rwanda P.O.Box 6961KigaliRwanda Rwanda Agriculture and Animal Resources Development Board P.O.Box 5016KigaliRwanda

Runoff farming is reported to improve land productivity and crop yields in hot and dry *** study was conducted to assess the available rainwater that can be harvested in a conserved catchment in a drought prone agro-ecological *** study was carried out in the Cyili sub-catchment,southern province of Rwanda,which has an irregular rainfall pattern and unexploited runoff *** Conservation Service-Curve Number method (SCS-CN),CROPWAT model version 8 and Hazen model with an average daily rainfall data recorded from 1971 to 2016 were applied to estimate the runoff and water requirements in the study *** of the study revealed that more than half rainfall water received in the catchment was lost through runoff (229.8 mm) and effective rainfall was lower (246.9 mm) than the actual crop water requirement for maize (330 mm).The expected seasonal surface runoff volume to be harvested by the farmers was 3008 m3 ha-1 per season and 1.29 × 106 m3 per season for the entire whole sub-catchment (430 ha).Based on Hazen model,the return period of low rainfall (dry spell) event would be expected every 2 years with a 98% probability of *** sub-catchment has higher potential runoff volume to stabilize the deficit of water demand in the period of short rainy *** suggests that rainwater harvesting through supplementary irrigation is an option to improve the crop yield in the dry period as well as in the annual dry season.

关键词： Available rainwater Cyili sub-catchment Curve number Runoff Rwanda

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