Modeling the changing sediment yield of the Amazon under climate change and deforestation scenarios and the possible impacts on the Guiana coast

2020 ◽  
Author(s):  
Safaa Naffaa ◽  
L.P.H. (Rens) van Beek ◽  
Frances E.Dunn ◽  
Steven de Jong
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Land Cover ◽  
Sediment Yield ◽  
Coastal Erosion ◽  
Sediment Supply ◽  
Trapping Efficiency ◽  
Amazon River ◽  
Land Cover Changes

<p>The Amazon River is an important source of the sediment that is transported and accumulated along the coast of Suriname. As such it is an important factor in maintaining the coastline as this sediment is deposited in mud banks that move towards the shore and coalesce with it, thus preventing coastal erosion. Accordingly, a steady and adequate supply of sediment from the Amazon river is required especially considering increased coastal erosion rates that may occur as a result of rising sea levels due to climate change. Yet at the same time, climate change may alter the hydrological regime of the Amazon and influence its transport capacity, affecting sediment transport to the mouth and coast. Furthermore, the sediment supply to the river may be altered as a result of land cover changes and other anthropogenic activities, including deforestation and sediment trapping in existing and future planned reservoirs.<br>Studying the transport of sediment from source to sink and quantifying how future changes affect the mean rate of sediment supply to the Surinam coast and its variability will lead to a better understanding of the intricacies involved. We use a spatial-temporal process-based model together with a set of plausible scenarios of future change based on combinations of the Shared Socioeconomic Pathways (SSP) and the Representative Concentration Pathways (RCP). In this study, we used two models: PCRGLOB-Set and PCRGLOB-WB. PCRGLOB-SET is based on the RUSLE equation and is used to assess the local sediment supply including the effects of land cover changes. PCRGLOB-WB simulates hydrological responses and changes under climate and land-use change. Moreover, PCRGLOB-WB is used to determine the trapping efficiency of reservoirs. The PCRGLOB-WB model was applied to a business-as-usual scenario for the 21st century (SSP 2 with RCP 6.0) and we considered uncertainty in the projected climate by using 5 Global Climate Models (GCMs). We apply the model to different future scenarios considering climate, socioeconomic and land-use change. For validation, the observations of six stations along the Amazon river were compared to the estimations of the models for the historical period (1971-2010), which also serves as a reference run to evaluate changes in sediment production and sediment yield. </p>

Impacts of land use and land cover changes on hydrological processes and sediment yield determined using the SWAT model

2021 ◽  
Author(s):  
Edivaldo Afonso de Oliveira Serrão ◽  
Madson Tavares Silva ◽  
Thomás Rocha Ferreira ◽  
Lorena Conceição Paiva de Ataide ◽  
Cleber Assis dos Santos ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Sediment Yield ◽  
Swat Model ◽  
Hydrological Processes ◽  
Land Cover Changes

scholarly journals Effect of Land Use Land Cover and Climate Change on River Flow and Soil Loss in Didessa River Basin, South West Blue Nile, Ethiopia

Hydrology ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 2 ◽  
Author(s):  
Kinati Chimdessa ◽  
Shoeb Quraishi ◽  
Asfaw Kebede ◽  
Tena Alamirew
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Cover ◽  
River Basin ◽  
Sediment Yield ◽  
Soil Loss ◽  
River Flow ◽  
Land Use Land Cover ◽  
The Impact ◽  
Soil Losses

In the Didessa river basin, which is found in Ethiopia, the human population number is increasing at an alarming rate. The conversion of forests, shrub and grasslands into cropland has increased in parallel with the population increase. The land use/land cover change (LULCC) that has been undertaken in the river basin combined with climate change may have affected the Didessa river flow and soil loss. Therefore, this study was designed to assess the impact of LULCC on the Didessa river flow and soil loss under historical and future climates. Land use/land cover (LULC) of the years 1986, 2001 and 2015 were independently combined with the historical climate to assess their individual impacts on river flow and soil loss. Further, the impact of future climates under Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5) scenarios on river flow and soil loss was assessed by combining the pathways with the 2015 LULC. A physically based Soil and Water Assessment Tool (SWAT2012) model in the ArcGIS 10.4.1 interface was used to realize the purpose. Results of the study revealed that LULCC that occurred between 1986 and 2015 resulted in increased average sediment yield by 20.9 t ha−1 yr−1. Climate change under RCP2.6, RCP4.5 and RCP8.5 combined with 2015 LULC increased annual average soil losses by 31.3, 50.9 and 83.5 t ha−1 yr−1 compared with the 2015 LULC under historical climate data. It was also found that 13.4%, 47.1% and 87.0% of the total area may experience high soil loss under RCP2.6, RCP4.5 and RCP8.5, respectively. Annual soil losses of five top-priority sub catchments range from 62.8 to 57.7 per hectare. Nash Stuncliffe Simulation efficiency (NSE) and R2 values during model calibration and validation indicated good agreement between observed and simulated values both for flow and sediment yield.

scholarly journals Effects of Climate and Land-Cover Changes on Soil Erosion in Brazilian Pantanal

2019 ◽  
Vol 11 (24) ◽  
pp. 7053 ◽  
Author(s):  
Carina Colman ◽  
Paulo Oliveira ◽  
André Almagro ◽  
Britaldo Soares-Filho ◽  
Dulce Rodrigues
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Soil Erosion ◽  
Land Cover ◽  
Ecosystem Service ◽  
Soil Loss ◽  
Land Cover Changes ◽  
Rainfall Erosivity ◽  
Comprehensive Planning ◽  
Brazilian Pantanal

The Pantanal biome integrates the lowlands of the Upper Paraguay Basin (UPB), which is hydrologically connected to the biomes of the Cerrado and Amazon (the highlands of the UPB). The effects of recent land-cover and land-use (LCLU) changes in the highlands, combined with climate change, are still poorly understood in this region. Here, we investigate the effects of soil erosion in the Brazilian Pantanal under climate and LCLU changes by combining different scenarios of projected rainfall erosivity and land-cover management. We compute the average annual soil erosion for the baseline (2012) and projected scenarios for 2020, 2035, and 2050. For the worst scenario, we noted an increase in soil loss of up to 100% from 2012 to 2050, associated with cropland expansion in some parts of the highlands. Furthermore, for the same period, our results indicated an increase of 20 to 40% in soil loss in parts of the Pantanal biome, which was associated with farmland increase (mainly for livestock) in the lowlands. Therefore, to ensure water, food, energy, and ecosystem service security over the next decades in the whole UPB, robust and comprehensive planning measures need to be developed, especially for the most impacted areas found in our study.

CLIMATE- AND LAND USE-INDUCED RISKS TO WATERSHED SERVICES IN THE NYANDO RIVER BASIN, KENYA

2011 ◽  
Vol 47 (2) ◽  
pp. 339-356 ◽  
Author(s):  
MWANGI GATHENYA ◽  
HOSEA MWANGI ◽  
RICHARD COE ◽  
JOSEPH SANG
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Sediment Yield ◽  
Land Surface ◽  
Assessment Tool ◽  
Surface Condition ◽  
Water Yield ◽  
Minor Effect ◽  
Watershed Services

SUMMARYClimate change and land use change are two forces influencing the hydrology of watersheds and their ability to provide ecosystem services, such as clean and well-regulated streamflow and control of soil erosion and sediment yield. The Soil Water Assessment Tool, SWAT, a distributed, watershed-scale hydrological model was used with 18 scenarios of rainfall, temperature and infiltration capacity of land surface to investigate the spatial distribution of watershed services over the 3587 km2 Nyando basin in Western Kenya and how it is affected by these two forces. The total annual water yield varied over the 50 sub-basins from 35 to 600 mm while the annual sediment yield ranged from 0 to 104 tons ha−1. Temperature change had a relatively minor effect on streamflow and sediment yield compared to change in rainfall and land surface condition. Improvements in land surface condition that result in higher infiltration are an effective adaptation strategy to moderate the effects of climate change on supply of watershed services. Spatial heterogeneity in response to climate and land use change is large, and hence it is necessary to understand it if interventions to modify hydrology or adapt to climate change are to be effective.

Temporal Evaluation of Climate Change on Land Use and Land Cover Changes in the Southeastern Region of Bangladesh from 2001 to 2016

2021 ◽  
pp. 509-525
Author(s):  
Shahidul Islam ◽  
Mingguo Ma ◽  
Md. Nuralam Hossain ◽  
Sumon Ganguli ◽  
Md Nazirul Islam Sarker
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Cover ◽  
Land Cover Changes ◽  
Southeastern Region

Impact of Climate and Land Use Changes on the Flood Hazard of the Middle Brahmaputra Reach, India

2012 ◽  
Vol 7 (5) ◽  
pp. 573-581 ◽  
Author(s):  
Subashisa Dutta ◽  
◽  
Shyamal Ghosh
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Land Cover ◽  
Climate Change Scenario ◽  
Hydrological Model ◽  
Flood Hazard ◽  
Baseline Period ◽  
Change Scenario ◽  
Flood Characteristics

Being the highest specific discharge river in the world, the Brahmaputra has a large floodplain area of 700 km in length in its middle reaches falling in the high flood vulnerability category. Floods generated in upland Himalayan catchments are mainly controlled by land use and land cover, storm characteristics, and vegetation dynamics. Floods propagate through a floodplain region consisting of wetlands, paddy agriculture, and wide braided river reaches with natural constraint points (nodals) that make the reaches more vulnerable to flood hazards. In this study, a macroscale distributed hydrological model was used to obtain the flood characteristics of the reaches. A hydrological model with spatially distributed input parameters and meteorological data was simulated at (1 km × 1 km) spatial grids to estimate flood hydrographs at the main river and itsmajor tributaries. Aftermodel validation, “best guess” land use change scenarios were used to estimate potential changes in flood characteristics. Results show that at the middle reaches of the Brahmaputra, peak discharge increases by a maximum of 9% for land use change scenarios. The same model with bias-corrected climatological data from a regional climate model (RCM) simulation (PRECIS) was used to obtain future changes in flood generation and its propagation through the basin in the projected climatological scenario. Changes in flood characteristics with reference to the baseline period show that the average duration of flood waves will increase from 15.2 days in the baseline period (1961-1990) to 19.3 days in the future (2071-2100). Peak discharge will increase by an average of 21% in the future in the projected climate change scenario. After statistics on changes of flood characteristics in the projected climate change scenario (2071-2100) were obtained, a 2-dimensional hydrodynamic model was used to obtain flood inundation and velocity distribution on the floodplain. Distribution of velocity and inundation depth was spatially analyzed to obtain flood hazard zones in the projected climate change scenario. Results show that spatial variation in flood hazard zones will be significantly altered in the projected climate change scenario compared to land use/land cover changes.

scholarly journals Impacts of long-term disturbance on soil health with relation to vegetation distribution in a tropical ecosystem

2020 ◽  
Vol 2 (4) ◽  
pp. 149-156
Author(s):  
C. N. Basweti ◽  
◽  
S. Otor ◽  
S. Manohar ◽  
◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Land Cover ◽  
Soil Health ◽  
Integrated Approach ◽  
Soil Productivity ◽  
Land Cover Changes ◽  
Vegetation Distribution ◽  
Grassland Soil

Land-use and land-cover changes are the main cause of soil degradation and associated human and environmental problems. The study was conducted in Mai Mahiu ecosystem, Kenya whose aim was to assess long-term (1985 to 2015) impacts of land-use and land-cover changes on soil health with disturbance-induced vegetation distribution. Landsat archive was utilized to detect land-use change for 30 years at an interval of 15 years and analysed based on supervised image classification. Four land-use practices (undisturbed forest, disturbed forest, cropland and grassland) were selected and soil sampled to 15 cm depth for soil analyses. In this period, cropland increased by 135% at the expense of natural forest while built-up areas increased by three times. Soil bulk density increased significantly (p<0.001) from 0.93±0.02 g cm-3 in forest soil to 1.27±0.02 g cm-3 in disturbed grassland. Soil pH had significant change (p=0.002) that ranged between 6.19±0.14 and 7.18±0.12. Soil organic carbon declined significantly (p=0.008) with land-use change with losses of up to 63% recorded in disturbed grassland. Total nitrogen levels declined from 0.34% in the forest to 0.15% in disturbed grassland soil. The pronounced changes in land-use and land-cover in Mai Mahiu have negatively affected the soil health with a potential drop in soil productivity and ecosystem provisioning. An integrated approach, enforcement of relevant laws and policy implementation are recommended to restoring and maintaining soil quality of this ecosystem.

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