scholarly journals Climate or land cover variations: what is driving observed changes in river peak flows? A data-based attribution study

2018 ◽  
Author(s):  
Jan De Niel ◽  
Patrick Willems
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Climate Variability ◽  
Hydrological Cycle ◽  
Hydrological Regime ◽  
Interaction Effects ◽  
Land Cover Changes ◽  
Peak Flows ◽  
Catchment Characteristics ◽  
Interaction Terms

Abstract. Climate change and land cover changes are influencing the hydrological regime of our rivers. The intensification of the hydrological cycle caused by climate change is projected to cause more flooding in winters and an increased urbanization could amplify these effects by a quicker runoff on paved surfaces. The relative importance of both drivers, however, is still uncertain and interaction effects between both drivers are not yet well understood. In order to better understand the hydrological impact of climate variability and land cover changes, including their interaction effects, we fitted a statistical model to historical data over 3 decades for 29 catchments in Flanders, covering various catchment characteristics. It was found that the catchment characteristics explain up to 18 % of changes in river peak flows, climate variability 6 % and land cover changes 8 %. Interaction terms explain up to 32 %. An increase in urban area of +1 % might cause increases in river peak flows up to +5 %.

scholarly journals Climate or land cover variations: what is driving observed changes in river peak flows? A data-based attribution study

2019 ◽  
Vol 23 (2) ◽  
pp. 871-882 ◽  
Author(s):  
Jan De Niel ◽  
Patrick Willems
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Peak Flow ◽  
Hydrological Cycle ◽  
Interaction Effects ◽  
Land Cover Changes ◽  
Climate Variations ◽  
Peak Flows ◽  
Catchment Characteristics ◽  
Flows Over Time

Abstract. Climate change and land cover changes are influencing the hydrological regime of rivers worldwide. In Flanders (Belgium), the intensification of the hydrological cycle caused by climate change is projected to cause more flooding in winters, and land use and land cover changes could amplify these effects by, for example, making runoff on paved surfaces faster. The relative importance of both drivers, however, is still uncertain, and interaction effects between both drivers are not yet well understood. In order to better understand the hydrological impact of climate variations and land cover changes, including their interaction effects, we fitted a statistical model for historical data over 3 decades for 29 catchments in Flanders. The model is able to explain 60 % of the changes in river peak flows over time. It was found that catchment characteristics explain up to 18 % of changes in river peak flows, 6 % of changes in climate variability and 8 % of land cover changes. Steep catchments and catchments with a high proportion of loamic soils are subject to higher peak flows, and an increase in urban area of 1 % might cause increases in river peak flows up to 5 %. Interactions between catchment characteristics, climate variations and land cover changes explain up to 32 % of the peak-flow changes, where flat catchments with a low loamic soil content are more sensitive to land cover changes with respect to peak-flow anomalies. This shows the importance of including such interaction terms in data-based attribution studies.

scholarly journals Quantitative analysis of the impacts of climate and land-cover changes on urban flood runoffs: a case of Dar es Salaam, Tanzania

2021 ◽  
Author(s):  
Philip Mzava ◽  
Patrick Valimba ◽  
Joel Nobert
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Land Cover Change ◽  
Dar Es Salaam ◽  
Land Cover Changes ◽  
Urban Flooding ◽  
Combined Effects ◽  
Peak Flows ◽  
The Past ◽  
The Future

Abstract Over the past half-century, the risk of urban flooding in Dar es Salaam has increased due to changes in land cover coupled with climatic changes. This paper aimed to quantify the impacts of climate and land-cover changes on the magnitudes and frequencies of flood runoffs in urban Dar es Salaam, Tanzania. A calibrated and validated SWAT rainfall-runoff model was used to generate flood hydrographs for the period 1969–2050 using historical rainfall data and projected rainfall based on the CORDEX-Africa regional climate model. Results showed that climate change has a greater impact on change in peak flows than land-cover change when the two are treated separately in theory. It was observed that, in the past, the probability of occurrence of urban flooding in the study area was likely to be increased up to 1.5-fold by climate change relative to land-cover change. In the future, this figure is estimated to decrease to 1.1-fold. The coupled effects of climate and land-cover changes cause a much bigger impact on change in peak flows than any separate scenario; this scenario represents the actual scenario on the ground. From the combined effects of climate and land-cover changes, the magnitudes of mean peak flows were determined to increase between 34.4 and 58.6% in the future relative to the past. However, the change in peak flows from combined effects of climate and land-cover changes will decrease by 36.3% in the future relative to the past; owing to the lesser variations in climate and land-cover changes in the future compared with those of the past.

Moisture recycling in five different regions with Mediterranean climates around the world

2021 ◽  
Author(s):  
Jolanda Theeuwen ◽  
Obbe Tuinenburg ◽  
Arie Staal ◽  
Bert Hamelers ◽  
Stefan Dekker
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Cover ◽  
Temporal Variability ◽  
Hydrological Cycle ◽  
Land Cover Changes ◽  
Atmospheric Moisture ◽  
Moisture Recycling ◽  
The World ◽  
Mediterranean Regions

<p>Weather extremes are predicted to be more intense and recurrent in the future because of climate change. Previous studies show that Mediterranean regions around the world are especially vulnerable to extreme events that depend on the hydrological cycle, such as droughts and floods. Land use and land cover changes may enhance these events, as they influence the exchange of moisture and energy between the land surface and atmosphere. To better understand the role of extremes in a future climate, we need to improve our understanding of the impact of climate change on the terrestrial hydrological cycle. Atmospheric transport of moisture is an important element of this cycle as it determines the allocation of evaporated moisture. We are especially interested in the sink-source relations. So, how land contributes to the moisture recycling over land further away, and the origin of the precipitation over, the so-called precipitation-shed. Tuinenburg et al. (2020) recently published a dataset with high-resolution global atmospheric moisture connections from evaporation to precipitation, allowing novel detailed insight. We used this dataset to study temporal variability in atmospheric moisture connections for five different regions with Mediterranean climates. We investigated the dependency of different Mediterranean regions on local and remote moisture sources, and how this dependency varies throughout the year. Large differences in the spatial pattern of moisture recycling over land showed to exist between the Mediterranean regions on the Northern and Southern Hemisphere. Additionally, of all regions, the Mediterranean Basin shows the largest temporal variability. This information is essential to study how local changes in land use and land cover have and will further affect the hydrological cycle in local and remote regions. This helps us to understand how climate extremes could change in the future as a result of land use and land cover changes.  </p><p> </p><p>Tuinenburg, O. A., Theeuwen, J. J. E., and Staal, A. Global evaporation to precipitation flows obtained with Lagrangian atmospheric moisture tracking, PANGAEA, https://doi.org/10.1594/PANGAEA.912710, 2020.</p>

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.

Assessment of future climate change impacts on the hydrological regime of selected Greek areas with different climate conditions

2016 ◽  
Vol 48 (5) ◽  
pp. 1327-1342 ◽  
Author(s):  
Spyridon Paparrizos ◽  
Andreas Matzarakis
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Hydrological Cycle ◽  
Meteorological Data ◽  
Hydrological Regime ◽  
Future Climate ◽  
Future Climate Change ◽  
Water Losses ◽  
Climate Conditions ◽  
The Future

Assessment of future variations of streamflow is essential for research regarding climate and climate change. This study is focused on three agricultural areas widespread in Greece and aims to assess the future response of annual and seasonal streamflow and its impacts on the hydrological regime, in combination with other fundamental aspects of the hydrological cycle in areas with different climate classification. ArcSWAT ArcGIS extension was used to simulate the future responses of streamflow. Future meteorological data were obtained from various regional climate models, and analysed for the periods 2021–2050 and 2071–2100. In all the examined areas, streamflow is expected to be reduced. Areas characterized by continental climate will face minor reductions by the mid-century that will become very intense by the end and thus these areas will become more resistant to future changes. Autumn season will face the strongest reductions. Areas characterized by Mediterranean conditions will be very vulnerable in terms of future climate change and winter runoff will face the most significant decreases. Reduced precipitation is the main reason for decreased streamflow. High values of actual evapotranspiration by the end of the century will act as an inhibitor towards reduced runoff and partly counterbalance the water losses.

Assessing the effects of the climate change on land cover changes in different time periods

2017 ◽  
Vol 10 (4) ◽  
Author(s):  
Hassan Khosravi ◽  
Ali Azareh ◽  
Hadi Eskandari Dameneh ◽  
Elham Rafiei Sardoii ◽  
Hamed Eskandari Dameneh
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Land Cover Changes ◽  
Time Periods

scholarly journals Ephemeral stream dynamics, land cover changes and climate variability in the marginal grabens of the northern Ethiopian Rift Valley

Afrika Focus ◽  
2016 ◽  
Vol 29 (2) ◽  
Author(s):  
Biadgilgn Demissie
Keyword(s):  
Land Cover ◽  
Climate Variability ◽  
Rift Valley ◽  
Rainfall Variability ◽  
Bank Erosion ◽  
Ethiopian Rift ◽  
Land Cover Changes ◽  
Northern Ethiopia ◽  
Ephemeral Streams ◽  
Alluvial Deposits

This study focused on ephemeral streams morphodynamics and their relation with hydro-climatic and bio-physical characteristics in their headwater and graben floors in the marginal grabens along the northern Ethiopian Rift Valley. The Raya graben was taken as a case study area, which is the largest marginal graben in northern Ethiopia. The link between rainfall variability and land cover changes shows that there was a negative correlation between precipitation and deforestation which implies that an increase in precipitation decreases deforestation deterring the peasants from tree cutting. Regarding the relationship between upper catchment characteristics and river morphology, results show that upper catchment area is the most important controlling factor of the length of and the area occupied by the rivers in the graben bottom. A simple hydraulic analysis based on the change of specific discharge as the river ow approaches the bridges demonstrates that the abrupt change in channel width as the river approaches the bridge is the main cause of the thick deposition and, consequently, of the increased frequency of overbank oods upstream of the road bridges in the study area. The results related to channel bank erosion capacity of ash oods show that all the peak discharges were equally important in triggering channel bank erosion. Concomitantly, vegetated channels are much more resist- ant to channel bank erosion than non-vegetated banks. Land changes in graben bottoms dictate that the changes are not simply related to a distributary river system but that human interven- tion (e.g., the conversion of bushland and forests into cropland, settlement on alluvium, and avoidance of losing farmland to other land units) and natural vegetation regeneration (e.g., alluvial deposits into shrubland) are also important. Overall, the study suggests that to control the morphodynamics of the ephemeral rivers and their impact on farming activities in the gra- ben bottom, catchment rehabilitation activities need to focus both on the upper catchment and the river channels in the graben bottom. Key words: ephemeral streams, land change, graben, Rift Valley, land cover, climate variability 

scholarly journals Effects of Land Cover Changes on Sediment and Nutrient Balance in the Catchment with Cascade-Dammed Waters

2020 ◽  
Vol 12 (20) ◽  
pp. 3414
Author(s):  
Dawid Szatten ◽  
Michał Habel
Keyword(s):  
Water Quality ◽  
Land Cover ◽  
Catchment Area ◽  
Nutrient Balance ◽  
Water Environment ◽  
Hydrological Regime ◽  
Trapping Efficiency ◽  
Land Cover Changes ◽  
Matter Transport

It is commonly believed that changes in the use of the catchment area have a direct impact on the quality of the water environment. Rivers with dams and reservoirs are characterized by a disturbed outflow of sediments and nutrients from the catchment area. The research was based on indicating the variation in time and space of loads of selected parameters of the water quality of the Brda River (Northern Poland) against the land cover changes based on the CORINE Land Cover (CLC) data for the 1990–2018 period. In the lower part of the Brda catchment area, there are three hydropower dams with reservoirs in the form of a cascade, whose work clearly affects the hydrological regime of the river. The analysis of the dependence of the dynamics of water quality changes on the usage of CLC was based on indicators such as sediments (suspended sediment load) and nutrients (total phosphorus load and total nitrogen load). The use of hydrological data on the Brda discharge above and below the reservoirs made it possible to calculate sediment and nutrient trapping efficiency. Linking the CLC data with the indices responsible for the mechanical denudation of the catchment area made it possible to show the strength of changes taking place in the catchment area. The results of the research do not indicate any direct correlation between land cover changes and the dynamics of the denudation process and matter transport in the Brda catchment area. As our research shows, the strong influence on the hydrological regime of the catchment points out the necessity to search for still other research methods supporting the decision-making cycle in the field of water management in the face of climate change.

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
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