scholarly journals Impact of Land Management on Water Resources, a South African Context

2021 ◽  
Vol 13 (2) ◽  
pp. 701
Author(s):  
Mary Nkosi ◽  
Fhumulani I. Mathivha ◽  
John O. Odiyo
Keyword(s):  
Water Resources ◽  
Land Cover ◽  
South African ◽  
Land Management ◽  
Sustainable Use ◽  
Land Use Land Cover ◽  
Domestic Water ◽  
African Context ◽  
Water Scarce ◽  
South African Water

Globally, the changes exerted on the land cover have shown greater impacts on the quality and quantity of water resources and thus affecting catchment’s hydrological response (i.e., runoff, evapotranspiration, infiltration, amongst others). South Africa is a water-scarce country faced with domestic water supply challenges. A systematic review was conducted on the overview impacts of land use/land cover changes on water resources. Despite the country’s best efforts in ensuring the protection and sustainable use of water resources, the review indicated that water quality has been compromised in most parts of the country thus affecting water availability. The increase in water demand with development presents the need for better integrated strategic approaches and a change in behaviour towards water resource and land management. Thus, the review suggested a few possible solutions that will promote sustainable development, while protecting and preserving the integrity of South African water resources.

scholarly journals Impact of Climate and Land Use/Land Cover Change on the Water Resources of a Tropical Inland Valley Catchment in Uganda, East Africa

Climate ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 83
Author(s):  
Geofrey Gabiri ◽  
Bernd Diekkrüger ◽  
Kristian Näschen ◽  
Constanze Leemhuis ◽  
Roderick van der Linden ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Land Cover ◽  
Rainy Season ◽  
Hydrological Processes ◽  
Land Use Land Cover ◽  
Lulc Change ◽  
Inland Valley ◽  
Headwater Catchment

The impact of climate and land use/land cover (LULC) change continues to threaten water resources availability for the agriculturally used inland valley wetlands and their catchments in East Africa. This study assessed climate and LULC change impacts on the hydrological processes of a tropical headwater inland valley catchment in Uganda. The hydrological model Soil and Water Assessment Tool (SWAT) was applied to analyze climate and LULC change impacts on the hydrological processes. An ensemble of six regional climate models (RCMs) from the Coordinated Regional Downscaling Experiment for two Representative Concentration Pathways (RCPs), RCP4.5 and RCP8.5, were used for climate change assessment for historical (1976–2005) and future climate (2021–2050). Four LULC scenarios defined as exploitation, total conservation, slope conservation, and protection of headwater catchment were considered. The results indicate an increase in precipitation by 7.4% and 21.8% of the annual averages in the future under RCP4.5 and RCP8.5, respectively. Future wet conditions are more pronounced in the short rainy season than in the long rainy season. Flooding intensity is likely to increase during the rainy season with low flows more pronounced in the dry season. Increases in future annual averages of water yield (29.0% and 42.7% under RCP4.5 and RCP8.5, respectively) and surface runoff (37.6% and 51.8% under RCP4.5 and RCP8.5, respectively) relative to the historical simulations are projected. LULC and climate change individually will cause changes in the inland valley hydrological processes, but more pronounced changes are expected if the drivers are combined, although LULC changes will have a dominant influence. Adoption of total conservation, slope conservation and protection of headwater catchment LULC scenarios will significantly reduce climate change impacts on water resources in the inland valley. Thus, if sustainable climate-smart management practices are adopted, the availability of water resources for human consumption and agricultural production will increase.

scholarly journals The Impact of Land Use/Land Cover Change (LULCC) on Water Resources in a Tropical Catchment in Tanzania under Different Climate Change Scenarios

2019 ◽  
Vol 11 (24) ◽  
pp. 7083 ◽  
Author(s):  
Kristian Näschen ◽  
Bernd Diekkrüger ◽  
Mariele Evers ◽  
Britta Höllermann ◽  
Stefanie Steinbach ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Land Cover ◽  
Water Balance ◽  
Land Cover Change ◽  
Sub Saharan Africa ◽  
Climate Change Scenarios ◽  
Land Use Land Cover ◽  
The Impact

Many parts of sub-Saharan Africa (SSA) are prone to land use and land cover change (LULCC). In many cases, natural systems are converted into agricultural land to feed the growing population. However, despite climate change being a major focus nowadays, the impacts of these conversions on water resources, which are essential for agricultural production, is still often neglected, jeopardizing the sustainability of the socio-ecological system. This study investigates historic land use/land cover (LULC) patterns as well as potential future LULCC and its effect on water quantities in a complex tropical catchment in Tanzania. It then compares the results using two climate change scenarios. The Land Change Modeler (LCM) is used to analyze and to project LULC patterns until 2030 and the Soil and Water Assessment Tool (SWAT) is utilized to simulate the water balance under various LULC conditions. Results show decreasing low flows by 6–8% for the LULC scenarios, whereas high flows increase by up to 84% for the combined LULC and climate change scenarios. The effect of climate change is stronger compared to the effect of LULCC, but also contains higher uncertainties. The effects of LULCC are more distinct, although crop specific effects show diverging effects on water balance components. This study develops a methodology for quantifying the impact of land use and climate change and therefore contributes to the sustainable management of the investigated catchment, as it shows the impact of environmental change on hydrological extremes (low flow and floods) and determines hot spots, which are critical for environmental development.

scholarly journals Watershed Hydrological Response to Combined Land Use/Land Cover and Climate Change in Highland Ethiopia: Finchaa Catchment

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1801 ◽  
Author(s):  
Wakjira Takala Dibaba ◽  
Tamene Adugna Demissie ◽  
Konrad Miegel
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Land Cover ◽  
Surface Runoff ◽  
Regional Climate ◽  
Water Yield ◽  
Land Use Land Cover ◽  
Ensemble Mean ◽  
The Future

Land use/land cover (LULC) and climate change affect the availability of water resources by altering the magnitude of surface runoff, aquifer recharge, and river flows. The evaluation helps to identify the level of water resources exposure to the changes that could help to plan for potential adaptive capacity. In this research, Cellular Automata (CA)-Markov in IDRISI software was used to predict the future LULC scenarios and the ensemble mean of four regional climate models (RCMs) in the coordinated regional climate downscaling experiment (CORDEX)-Africa was used for the future climate scenarios. Distribution mapping was used to bias correct the RCMs outputs, with respect to the observed precipitation and temperature. Then, the Soil and Water Assessment Tool (SWAT) model was used to evaluate the watershed hydrological responses of the catchment under separate, and combined, LULC and climate change. The result shows the ensemble mean of the four RCMs reported precipitation decline and increase in future temperature under both representative concentration pathways (RCP4.5 and RCP8.5). The increases in both maximum and minimum temperatures are higher for higher emission scenarios showing that RCP8.5 projection is warmer than RCP4.5. The changes in LULC brings an increase in surface runoff and water yield and a decline in groundwater, while the projected climate change shows a decrease in surface runoff, groundwater and water yield. The combined study of LULC and climate change shows that the effect of the combined scenario is similar to that of climate change only scenario. The overall decline of annual flow is due to the decline in the seasonal flows under combined scenarios. This could bring the reduced availability of water for crop production, which will be a chronic issue of subsistence agriculture. The possibility of surface water and groundwater reduction could also affect the availability of water resources in the catchment and further aggravate water stress in the downstream. The highly rising demands of water, owing to socio-economic progress, population growth and high demand for irrigation water downstream, in addition to the variability temperature and evaporation demands, amplify prolonged water scarcity. Consequently, strong land-use planning and climate-resilient water management policies will be indispensable to manage the risks.

Effects of dynamic land use/land cover change on water resources and sediment yield in the Anzali wetland catchment, Gilan, Iran

2020 ◽  
Vol 712 ◽  
pp. 136449 ◽  
Author(s):  
Helen Aghsaei ◽  
Naghmeh Mobarghaee Dinan ◽  
Ali Moridi ◽  
Zahra Asadolahi ◽  
Majid Delavar ◽  
...  
Keyword(s):  
Land Use ◽  
Water Resources ◽  
Land Cover ◽  
Land Cover Change ◽  
Sediment Yield ◽  
Land Use Land Cover ◽  
Anzali Wetland

scholarly journals Future Impact of Land Use/Land Cover Changes on Ecosystem Services in the Lower Meghna River Estuary, Bangladesh

2020 ◽  
Vol 12 (5) ◽  
pp. 2112 ◽  
Author(s):  
Muhammad Ziaul Hoque ◽  
Shenghui Cui ◽  
Imranul Islam ◽  
Lilai Xu ◽  
Jianxiong Tang
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Management ◽  
Ecosystem Service ◽  
River Estuary ◽  
Management Policy ◽  
Land Use Land Cover ◽  
Trade Offs ◽  
Rural And Urban ◽  
Land Use Scenarios

Assessing the effects of different land use scenarios on subsequent changes in ecosystem service has great implications for sustainable land management. Here, we designed four land use/land cover (LULC) scenarios, such as business-as-usual development (BAUD), economic development priority (EDP), ecological protection priority (EPP), and afforestation development priority (ADP), through a Cellular Automata-Markov (CA-Markov) model, and their effects on ecosystem service values (ESVs) were predicted, using historical LULC maps and ESV coefficients of the Lower Meghna River Estuary, Bangladesh. Findings revealed that agricultural and mangrove forest lands experienced the greatest decreases, while rural and urban settlement land had the greatest increases, leading to a total ESV decrease of US$105.34 million during 1988-2018. The scenario analysis indicated that ESV in 2038 would also decrease by US$41.37 million and US$16.38 million under the BAUD and EDP scenarios, respectively, while ESV will increase by US$60.61 million and US$130.95 million under the EPP and ADP scenarios, respectively. However, all the future land use scenarios will lead to 1.65%, 10.21%, 7.58%, and 6.75% gaps in total food requirements, respectively. Hence, from the perspective of maximizing ESVs and minimizing the trade-offs in food gaps, the ADP scenario could be the optimal land management policy for the studied landscape.

Land use, land cover, and climate change across the Mississippi Basin: Impacts on selected land and water resources

2004 ◽  
pp. 249-261 ◽  
Author(s):  
Jonathan A. Foley ◽  
Christopher J. Kucharik ◽  
Tracy E. Twine ◽  
Michael T. Coe ◽  
Simon D. Donner
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Land Cover ◽  
Land Use Land Cover

Management of water resources in South Africa with respect to the textile industry

1997 ◽  
Vol 36 (2-3) ◽  
pp. 303-310 ◽  
Author(s):  
L. R. Gravelet-Blondin ◽  
S. J. Barclay ◽  
C. M. Carliell ◽  
C. A. Buckley
Keyword(s):  
South Africa ◽  
Water Resources ◽  
South African ◽  
Textile Industry ◽  
Oxygen Demand ◽  
Industrial Effluents ◽  
Annual Rainfall ◽  
Acceptable Quality ◽  
Kwazulu Natal ◽  
Water Scarce

South Africa is a water scarce country with an average annual rainfall of less than 60% of the world average. It is therefore important to encourage industries to minimise water consumption, and recycle and re-use water and effluent where possible. The South African Department of Water Affairs and Forestry is responsible for the management of water resources in South Africa, thereby ensuring the provision of adequate water supplies of acceptable quality for all recognised users. Of the industrial effluents produced in South Africa, textile effluents are considered to be one of the most problematic in the KwaZulu-Natal coastal area, especially in terms of colour, chemical oxygen demand (COD) and salinity (total dissolved solids, TDS). Of these, colour is perceived to be the most problematic as it is visual pollution and gives rise to public complaints. The Department has been actively involved, through negotiations with management and local authorities, in encouraging the textile industries to reduce the colour load discharged from the factories. Four case studies will be presented describing the approach taken by the Department to solve the problem of textile effluent discharge.

Hydrological modelling of Sahelian hydrological paradox: accounting for explicit land use/land cover change in the simulation of hydrological processes

2021 ◽  
Author(s):  
Roland Yonaba ◽  
Angelbert Chabi Biaou ◽  
Mahamadou Koita ◽  
Tazen Fowé ◽  
Adjadi Lawani Mounirou ◽  
...  
Keyword(s):  
Land Use ◽  
Water Resources ◽  
Land Cover ◽  
Burkina Faso ◽  
Surface Runoff ◽  
Hydrological Modelling ◽  
Integrated Modelling ◽  
Annual Rainfall ◽  
Land Use Land Cover ◽  
Lulc Changes

<p>Land use/land cover (LULC) change is a major factor affecting the hydrological response at the watershed scale. However, hydrological modelling, in its current practice, is usually carried using a single and static LULC layer for simulation runs over long periods. Eventually, this approach leads to failure in accounting for LULC spatial and temporal changes as well as non-linear impacts on simulated outputs. Besides, in the typical case of Sahelian hydrosystems, previous modelling attempts based on this approach failed at reproducing the well-known Sahelian hydrological paradox which occurred in the area during the period 1970-1990. This study aims at assessing the added value of dynamical integration of LULC changes in hydrological modelling of surface runoff in Sahelian hydrosystems. The Tougou watershed (37 km²), located in Northern Burkina Faso is selected as a case study. LULC maps of the watershed are produced from 1952 to 2017 from the processing of Landsat satellite images. The SWAT (Soil & Water Assessment Tool) model, using the SCS-CN method (for surface runoff estimation), is calibrated and validated using observed runoff data collected over the period 2004-2018. The calibration/validation is carried using LULC maps of the watershed in 1999, 2009 and 2017, dynamically integrated into the model using a specific land use update module. Further, the calibrated model parameters helped in the reconstitution of surface runoff over the historical period 1952-2005 and integrating dynamically LULC maps in 1952, 1973, 1986 and 1999. The results showed that between the periods 1952-1968 (P1) and 1986-2005 (P3), the average annual rainfall decreased by 87.9 mm while paradoxically, average annual runoff increased by 1 mm. Further analysis revealed that the increase in runoff is mainly attributed to LULC changes (+647%) which offsets the effect of the decrease in rainfall (-547%). From the analysis of LULC maps, it was found that from P1 to P3 periods, the decrease in natural vegetation (CN = 67.3 ± 5.7) by 40%, replaced by bare and degraded soils (CN = 83.8 ± 2.5) explained the observed increase in surface runoff potential of the watershed, as shown by their calibrated CN values. These findings are reminiscent of the Sahelian hydrological paradox reported in the literature and provide evidence of the sensitivity of surface runoff to LULC changes. Overall, the results call to hydrologists, water resources planners and managers, regarding the advantages of coupling LULC changes in hydrological modelling. Also, the study advocates for the development of integrated modelling platforms integrating both LULC changes and hydrological modelling to allow a better understanding and the more accurate long-term forecasting of water resources, in particular in the case of Sahelian hydrosystems.</p><p><strong>Keywords:</strong> Dynamic LULC input, Hydrological modelling, Surface runoff, SWAT model, Burkina Faso, Sahelian paradox.</p>

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