scholarly journals Chemical weathering and long-term CO2consumption in the Ayeyarwady and Mekong river basins in the Himalayas

2015 ◽  
Vol 120 (6) ◽  
pp. 1165-1175 ◽  
Author(s):  
Takuya Manaka ◽  
Souya Otani ◽  
Akihiko Inamura ◽  
Atsushi Suzuki ◽  
Thura Aung ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
River Basins ◽  
Mekong River

scholarly journals Enhancing capacities of riparian professionals to address and resolve transboundary issues in international river basins: experiences from the Lower Mekong River Basin

2012 ◽  
Vol 16 (9) ◽  
pp. 3183-3197 ◽  
Author(s):  
W. Douven ◽  
M. L. Mul ◽  
B. Fernández-Álvarez ◽  
S. Lam Hung ◽  
N. Bakker ◽  
...  
Keyword(s):  
Capacity Building ◽  
Training Evaluation ◽  
River Basins ◽  
Mekong River ◽  
Training Methods ◽  
Training And Education ◽  
International River Basins ◽  
Wide Range ◽  
International River ◽  
Capacity Building Programme

Abstract. This paper analyses the design and impact of capacity building programmes aimed at enhancing capacities of riparian professionals to address and resolve transboundary issues in international river basins. The case study is a programme developed by the Mekong River Commission (MRC). A post-training evaluation was applied to assess its impact in terms of individual capacity enhancement and change (use and application of knowledge, factors hampering application, and change in function and opportunities within the organisation). The design of the Capacity Building Programme of the MRC Flood Management and Mitigation Programme required a well balanced range of subjects (such as IWRM (integrated water resources management), model and decision support systems, and international water law). The post-training evaluation, 6 months after the last training workshop, showed an increase in familiarity with the topics for all 37 respondents, with the highest increase for the respondents with few years of working experience and from training and education institutions. The relevance of the subjects taught was highlighted by 95% of the respondents, and 78% of the participants had already used some of the acquired knowledge in their job. The respondents indicated that they did not have sufficient opportunities to apply all knowledge. The phased implementation and training of lecturers during the training workshops had a good impact, directly through increasing involvement in facilitation and delivery of the capacity building programme and through the use of the knowledge gained in short courses and development of curricula at their institute. For these types of capacity building programmes, a few recommendations can be made. The selection of participants is crucial for the application of the learned knowledge in their work. The integrative nature of transboundary water issues calls for a capacity building programme addressing a wide range of subjects, which can be understood by a wide range of professionals from different sectors. Training methods should also address this integrative nature through, e.g. roleplays and case studies. A successful capacity building programme needs to address the three levels of capacity building (enabling environment, organisations, and individual staff) and involve national and regional training and education institutes.

scholarly journals Distributed model of hydrological and sediment transport processes in large river basins in Southeast Asia

2015 ◽  
Vol 12 (7) ◽  
pp. 6755-6797 ◽  
Author(s):  
S. Zuliziana ◽  
K. Tanuma ◽  
C. Yoshimura ◽  
O. C. Saavedra
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
River Basin ◽  
River Basins ◽  
Large River ◽  
Mekong River ◽  
Distributed Model ◽  
Mekong River Basin ◽  
Chao Phraya River ◽  
Large River Basins

Abstract. Soil erosion and sediment transport have been modeled at several spatial and temporal scales, yet few models have been reported for large river basins (e.g., drainage areas > 100 000 km2). In this study, we propose a process-based distributed model for assessment of sediment transport at a large basin scale. A distributed hydrological model was coupled with a process-based distributed sediment transport model describing soil erosion and sedimentary processes at hillslope units and channels. The model was tested on two large river basins: the Chao Phraya River Basin (drainage area: 160 000 km2) and the Mekong River Basin (795 000 km2). The simulation over 10 years showed good agreement with the observed suspended sediment load in both basins. The average Nash–Sutcliffe efficiency (NSE) and average correlation coefficient (r) between the simulated and observed suspended sediment loads were 0.62 and 0.61, respectively, in the Chao Phraya River Basin except the lowland section. In the Mekong River Basin, the overall average NSE and r were 0.60 and 0.78, respectively. Sensitivity analysis indicated that suspended sediment load is sensitive to detachability by raindrop (k) in the Chao Phraya River Basin and to soil detachability over land (Kf) in the Mekong River Basin. Overall, the results suggest that the present model can be used to understand and simulate erosion and sediment transport in large river basins.

scholarly journals Climatic effects on rapid chemical and physical denudation rates measured with cosmogenic nuclides in the Ōhau catchment, New Zealand

2021 ◽  
Author(s):  
◽  
Maia Bellingham
Keyword(s):  
Carbon Dioxide ◽  
New Zealand ◽  
Chemical Weathering ◽  
Southern Alps ◽  
Grain Sizes ◽  
Denudation Rates ◽  
Climate Stability ◽  
Mountain Landscapes ◽  
Carbon Dioxide Cycling

<p>Understanding how active mountain landscapes contribute to carbon dioxide cycling and influences on long-term climate stability requires measurement of weathering fluxes from these landscapes. The few measured chemical weathering rates in the Southern Alps are an order of magnitude greater than in the rest of the world. Rapid tectonic uplift coupled with extreme orographic precipitation is driving exceptionally fast chemical and physical denudation. These rates suggest that weathering in landscapes such as the Southern Alps could play a significant role in carbon dioxide cycling. However, the relative importance of climate and tectonics driving these fast rates remains poorly understood.   To address this gap, in situ ¹⁰Be derived catchment-averaged denudation rates were measured in the Ōhau catchment, Canterbury, New Zealand. Denudation rates in the Dobson Valley within the Ōhau catchment, varied from 474 – 7,570 m Myr⁻¹, aside from one sub-catchment in the upper Dobson Valley that had a denudation rate of 12,142 m Myr⁻¹. The Dobson and Hopkins Rivers had denudation rates of 1,660 and 4,400 m Myr⁻¹ respectively, in these catchments. Dobson Valley denudation rates show a moderate correlation with mean annual precipitation (R²=0.459). This correlation supports a similar trend identified at local and regional scales, and at high rates of precipitation this may be an important driver of erosion and weathering.   Sampling of four grain sizes (0.125 to > 8 mm) at one site in the Dobson Valley resulted in variability in ¹⁰Be concentrations up to a factor of 2.5, which may be a result of each grain size recording different erosional processes. These observations demonstrate the importance of assessing potential variability and the need to sample consistent grain sizes across catchments.   Chemical depletion fractions measured within soil pits in the upper Dobson Valley indicate chemical weathering contributes 30% of total denudation, and that physical erosion is driving rapid total denudation. Chemical weathering appears to surpass any proposed weathering speed limit and suggests total weathering may not be limited by weathering kinetics. This research adds to the paucity of research in New Zealand, and for the first time presents ¹⁰Be derived denudation rates from the eastern Southern Alps, with estimates of the long-term weathering flux. High weathering fluxes in the Southern Alps uphold the hypothesis that mountain landscapes play an important role in carbon dioxide cycling and long-term climate stability.</p>

scholarly journals Assessment of Three Long-Term Gridded Climate Products for Hydro-Climatic Simulations in Tropical River Basins

Water ◽  
2017 ◽  
Vol 9 (3) ◽  
pp. 229 ◽  
Author(s):  
Mou Leong Tan ◽  
Philip W. Gassman ◽  
Arthur P. Cracknell
Keyword(s):  
River Basins ◽  
Tropical River

Long-term water balance partitioning explained by physical and ecological characteristics in world river basins

Ecohydrology ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. e2072 ◽  
Author(s):  
Daniel Mercado-Bettín ◽  
Juan F. Salazar ◽  
Juan Camilo Villegas
Keyword(s):  
Water Balance ◽  
River Basins ◽  
Ecological Characteristics

Land Use and Land Cover in Irrigated Drylands: a Long-Term Analysis of Changes in the Mendoza and Tunuyán River Basins, Argentina (1986–2018)

2020 ◽  
Vol 13 (4) ◽  
pp. 875-899
Author(s):  
Facundo Rojas ◽  
Cecilia Rubio ◽  
Martín Rizzo ◽  
Marta Bernabeu ◽  
Nur Akil ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
River Basins ◽  
Term Analysis

Understanding and overcoming risks to cooperation along transboundary rivers

Water Policy ◽  
2014 ◽  
Vol 16 (5) ◽  
pp. 824-843 ◽  
Author(s):  
Ashok Subramanian ◽  
Bridget Brown ◽  
Aaron T. Wolf
Keyword(s):  
Risk Reduction ◽  
River Basins ◽  
Third Parties ◽  
Decision Makers ◽  
Transboundary Rivers ◽  
Equity And Access ◽  
Decision Making Processes ◽  
International River ◽  
Made In

This study reviews the experience of cooperation in five international river basins, focusing on the perceptions of risks and opportunities by country decision makers responding to a specific prospect of cooperation, and the effects of risk reduction and opportunity enhancement on the cooperation process. We explore the following five categories of risk: Capacity and Knowledge; Accountability and Voice; Sovereignty and Autonomy; Equity and Access; and Stability and Support. We surmise that risk perception plays a key and less understood role in decision-making processes over shared rivers cooperation, and conclude that countries and third parties can best achieve sustainable cooperation when long-term investments are made in risk reduction. We also point to areas for further study to better understand the motivations for cooperation.

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