Land use/Land cover Changes and Associated Impacts on Water Yield Availability and Variation, Mereb-Gash River Basin in Horn of Africa

2020 ◽  
Author(s):  
Simon Measho ◽  
Baozhang Chen ◽  
Petri Pellikka ◽  
Lifeng Guo ◽  
Huifang Zhang
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Climate Variability ◽  
River Basin ◽  
Water Yield ◽  
Land Use Land Cover ◽  
Horn Of Africa ◽  
Lulc Changes ◽  
Forested Areas ◽  
Annual Water

<p>Climate variability, drought, and deforestation are increasing in the Horn of Africa (HOA). Evaluating land use/land cover (LULC) changes and their impacts on water availability and variation are vital actions for regional land-use planning and water resources management. LULC changes during 2000-2015 were estimated using high resolution Landsat images and Google Earth Engine cloud platform, and land-use dynamics index (K). The impact of LULC change on water yield was evaluated using the InVEST model. The results at regional scale show that there were rapid decreases in the area of forests and barren lands (-K) while there was a drastic increase in built-up area (+K values). The transition was found to decrease from forested land to low biomass with highest and lowest values of 51.13% and 16.7%, respectively. There were similar LULC changes in the Mereb-Gash river basin. The total annual water yield increased for all the catchments during 2000-2015, and reached the peak in 2010. The highest annual water yield decreased in the forested lands from 43.18 million m<sup>3</sup> in 2000 to 4.1 million m<sup>3</sup> in 2015. There was a strong positive correlation between areal changes (%) and the annual water yield variations (%) in all the LULC types except for the water body, and the correlation was significantly positive for the forested areas (p<0.01). The study demonstrates that the decrease in forested areas and expansion in the built-up areas had large impact on water yield. The impacts may further increase pressure on the ecosystem services, exacerbate water scarcity, and food insecurity unless basic measures are planned and implemented.</p><p>Key words: LULC; climate variability; InVEST; annual water yield; K-index</p><p> </p>

scholarly journals Effects of Climate and Land Use/Land Cover Changes on Water Yield Services in the Dongjiang Lake Basin

2021 ◽  
Vol 10 (7) ◽  
pp. 466
Author(s):  
Wenbo Mo ◽  
Yunlin Zhao ◽  
Nan Yang ◽  
Zhenggang Xu ◽  
Weiping Zhao ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Water Resource Management ◽  
Water Source ◽  
Water Yield ◽  
Lake Basin ◽  
Lake Area ◽  
Land Use Land Cover ◽  
Lulc Changes ◽  
Regional Water

Spatial and quantitative assessments of water yield services in watershed ecosystems are necessary for water resource management and improved water ecological protection. In this study, we used the InVEST model to estimate regional water yield in the Dongjiang Lake Basin in China. Moreover, we designed six scenarios to explore the impacts of climate and land use/land cover (LULC) changes on regional water yield and quantitatively determined the dominant mechanisms of water yield services. The results are expected to provide an important theoretical reference for future spatial planning and improvements of ecological service functions at the water source site. We found that (1) under the time series analysis, the water yield changes of the Dongjiang Lake Basin showed an initial decrease followed by an increase. Spatially, water yield also decreased from the lake area to the surrounding region. (2) Climate change exerted a more significant impact on water yield changes, contributing more than 98.26% to the water yield variability in the basin. In contrast, LULC had a much smaller influence, contributing only 1.74 %. (3) The spatial distribution pattern of water yield services in the watershed was more vulnerable to LULC changes. In particular, the expansion of built-up land is expected to increase the depth of regional water yield and alter its distribution, but it also increases the risk of waterlogging. Therefore, future development in the basin must consider the protection of ecological spaces and maintain the stability of the regional water yield function.

scholarly journals Spatiotemporal impacts of land use land cover changes on hydrology from the mechanism perspective using SWAT model with time-varying parameters

2018 ◽  
Vol 50 (1) ◽  
pp. 244-261 ◽  
Author(s):  
Yunyun Li ◽  
Jianxia Chang ◽  
Lifeng Luo ◽  
Yimin Wang ◽  
Aijun Guo ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
River Basin ◽  
Hydrological Process ◽  
Time Varying ◽  
Land Use Land Cover ◽  
Varying Parameters ◽  
Lulc Changes ◽  
Time Varying Parameters ◽  
Land Surfaces

Abstract It is critically important to quantify the impact of land use land cover (LULC) changes on hydrology, and to understand the mechanism by which LULC changes affect the hydrological process in a river basin. To accurately simulate the hydrological process for a watershed like the Wei River Basin, where the surface characteristics are highly modified by human activities, we present an alternative approach of time-varying parameters in a hydrological model to reflect the changes in underlying land surfaces. The spatiotemporal impacts of LULC changes on watershed streamflow are quantified, and the mechanism that connects the changes in runoff generation and streamflow with LULC is explored. Results indicate the following: (1) time-varying parameters’ calibration is effective to ensure model validity when dealing with significant changes in underlying land surfaces; (2) LULC changes have significant impacts on the watershed streamflow, especially on the streamflow during the dry season; (3) the expansion of cropland is the major contributor to the reduction of surface water, causing decline in annual and dry seasonal streamflow. However, the shrinkage of woodland is the main driving force that decreases the soil water, thus contributing to a small increase in streamflow during the dry season.

scholarly journals Hydrologic responses to climate and land-use/land-cover changes in the Bilate catchment, Southern Ethiopia

2021 ◽  
Author(s):  
Hailu Gisha Kuma ◽  
Fekadu Fufa Feyessa ◽  
Tmane Adugna Demissie
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Climate Model ◽  
Actual Evapotranspiration ◽  
Water Yield ◽  
Southern Ethiopia ◽  
Land Use Land Cover ◽  
Lulc Change ◽  
Lulc Changes ◽  
Hydrologic Responses

Abstract The likely effects of climate and land-use/land-cover (LULC) changes on hydrologic processes in Bilate catchment, Ethiopia were evaluated. The study emphasizes the evaluation of individual and combined impacts on hydrologic responses of climate and LULC changes. Climatic scenarios included a downscaled regional climate model from CORDEX-Africa. The CA–Markov model was used to project LULC. The results revealed that distinct changes on hydrologic responses occurred which follow the direction of climate and LULC changes. A 30.87% decline in rainfall resulted in about 4.09, 1.43 and 3.57% decline in runoff, groundwater and water yield, respectively. A rise in mean temperature by 1.3 °C resulted in 7 and 0.8% increase in potential and actual evapotranspiration, respectively. Runoff, groundwater and water yield are projected to decrease by 11.24, 12.54 and 11.54%; however, potential and actual evapotranspiration are projected to increase by 19 and 14.7%, respectively, under combined climate and LULC changes. The joint effects of climate and LULC changes on hydrologic responses in the forthcoming were higher than the variation trend of climate or LULC change alone. Climate change compared with LULC change has a higher impact on hydrologic responses. The results obtained provide further insight into future water balance, assistance in water resources planning and management.

scholarly journals Geospatial analysis of wetlands based on land use/land cover dynamics using remote sensing and GIS in Sindh, Pakistan

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110261
Author(s):  
Hamza Islam ◽  
Habibuulah Abbasi ◽  
Ahmed Karam ◽  
Ali Hassan Chughtai ◽  
Mansoor Ahmed Jiskani
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Vegetation Cover ◽  
Vegetation Index ◽  
Kappa Statistics ◽  
Natural Ecosystem ◽  
Land Use Land Cover ◽  
Dry Land ◽  
Lulc Changes ◽  
Manchar Lake

In this study, the Land Use/Land Cover (LULC) change has been observed in wetlands comprises of Manchar Lake, Keenjhar Lake, and Chotiari Reservoir in Pakistan over the last four decades from 1972 to 2020. Each wetland has been categorized into four LULC classes; water, natural vegetation, agriculture land, and dry land. Multitemporal Landsat satellite data including; Multi-Spectral Scanner (MSS), Thematic Mapper (TM), and Operational Land Imager (OLI) images were used for LULC changes evaluation. The Supervised Maximum-likelihood classifier method is used to acquire satellite imagery for detecting the LULC changes during the whole study period. Soil adjusted vegetation index technique (SAVI) was also used to reduce the effects of soil brightness values for estimating the actual vegetation cover of each study site. Results have shown the significant impact of human activities on freshwater resources by changing the natural ecosystem of wetlands. Change detection analysis showed that the impacts on the land cover affect the landscape of the study area by about 40% from 1972 to 2020. The vegetation cover of Manchar Lake and Keenjhar Lake has been decreased by 6,337.17 and 558.18 ha, respectively. SAVI analysis showed that soil profile is continuously degrading which vigorously affects vegetation cover within the study area. The overall classification accuracy and Kappa statistics showed an accuracy of >90% for all LULC mapping studies. This work demonstrates the LULC changes as a critical monitoring basis for ongoing analyses of changes in land management to enable decision-makers to establish strategies for effectively using land resources.

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