Lancang-Mekong Basin Research Articles

Extreme Precipitation Events Variation and Projection in the Lancang-Mekong River Basin Based on CMIP6 Simulations

In recent years, global climate change causes more extreme precipitation events in Lancang-Mekong River Basin (Lancang-Mekong Basin). It leads to the increase of rainstorm and flood risk, which poses a threat to the flood control safety of Lancang-Mekong Basin. Based on the precipitation data of four global climate models of CMIP6, this paper selected six indexes, including PRCPTOT and R10, to study the change characteristics of the extreme precipitation indexes in the Lancang-Mekong Basin during 1980–2020 and predicted the development trend of the extreme precipitation indexes in the Lancang-Mekong Basin during 2021–2050. The results show that from 1980 to 2020, the extreme precipitation events in regions I and IV showed an increasing trend, while those in regions II and III showed a decreasing trend. From 2021 to 2050, the extreme precipitation events in all regions of the Lancang-Mekong River show an upward trend, and most indexes increased compared with the historical period. The extreme precipitation indexes in most regions increases the most under the scenario of SSP5-8.5, while the increase is small under the scenario of SSP2-4.5; The six extreme precipitation indexes selected in the paper can better reflect the trend of extreme precipitation events and floods. The trend of extreme precipitation indexes in the Lancang-Mekong River basin in the future is more significant, which indicates that it may be affected more frequently by extreme precipitation events and floods.

High-resolution and Multitemporal Impervious Surface Mapping in the Lancang-Mekong Basin with Google Earth Engine

High-resolution and Multitemporal Impervious Surface Mapping in the Lancang-Mekong Basin with Google Earth Engine

High-resolution and Multitemporal Impervious Surface Mapping in the Lancang-Mekong Basin with Google Earth Engine

High-resolution and Multitemporal Impervious Surface Mapping in the Lancang-Mekong Basin with Google Earth Engine

Politicization of the Hydropower Dams in the Lancang-Mekong Basin: A Review of Contemporary Environmental Challenges

To date, hydropower dams raise numerous interpretations about their impact on the Lancang-Mekong River. While most research studies analyze the negative aspects of hydropower development on people’s livelihoods and local environments, the hydropower sector was historically one of the most iconic economic segments facilitating transboundary water cooperation for decades. By using the constructive discourse analysis and critical political ecology approach, the presented text (1) outlines the current environmental narratives over the Lancang-Mekong hydropower development and (2) explores the politicization of the Chinese mainstream dams. The data were collected upon the multi-level content analysis of relevant sources and double-checked with the Lancang-Mekong Cooperation and Conflict Database (LMCCD) monitoring over 4000 water-related events among six riparian countries between 1990 and 2021. Our data show that (i) there is a stark contrast in positive and negative narratives over the rapid hydropower development, (ii) the impact of mainstream dams on the river is more often discussed than that of tributary dams, (iii) implications of the hydropower dams are often interpreted upon the non-traditional research inputs rather than widely accepted studies, and (iv) developing the contradictory arguments through social and public media contributes to greater polarization of the multi-stakeholders’ viewpoints in the accountable research dialogue.

Politicization of science in the Lancang–Mekong Basin: the Eyes on Earth Study

ABSTRACT In April 2020, the Eyes on Earth published a comprehensive research study presenting new evidence about the changing dynamics of the Lancang–Mekong River water flow. The Eyes on Earth Study (EoE Study) received significant media attention and raised concerns about hydrological changes that negatively affect the downstream countries. By drawing on the politicization of science theories and using the Lancang–Mekong Cooperation and Conflict Database, we (1) provide an overview the EoE Study’s findings; (2) outline the scientific and non-scientific responses to the EoE Study’s conclusions; and (3) study various implications of the politicization of the EoE Study.

Reciprocity in practice: the hydropolitics of equitable and reasonable utilization in the Lancang-Mekong basin

Equitable and reasonable utilization (ERU), the cornerstone of international water law, recognizes the rights of states to utilize shared water resources. However, there is ambiguity in ERU’s application, and upstream states often perceive it as against their interests. Recent research highlights the important role reciprocity plays in international water law, yet how reciprocity is practiced in transboundary water governance remains poorly understood. Combining literature on international law, hydropolitics and international relations, this article conceptualizes ‘reciprocity in practice’ for international watercourses as interconnected legal, social and political processes by which state and non-state actors negotiate ERU and distribute benefits and harms. We pay particular attention to power relations and perceptions of fairness that influence the form and (dis)continuity of reciprocity. We demonstrate our approach through an analysis of evolving legal regimes and issues of navigation, hydropower, flood and drought management, and economic regionalization in the Lancang-Mekong basin, focusing on relations between China and downstream states. We demonstrate how multiple forms of reciprocity occur simultaneously across issues that are often analyzed individually, complicating common narratives of China’s unilateralism. We show, however, that practiced positive reciprocity is weak and exclusive, generating distrust and resistance from those excluded or who experience harms. Overall, we suggest that processes of ‘reciprocity in practice’ are at the heart of meaningful negotiation, institutionalization and practice of ERU, and that, as a model of water allocation, ERU should be contextualized to wider process of allocation of benefits and harms that include but go beyond water, and in which power relations fundamentally matter.

Variations in terrestrial water storage in the Lancang-Mekong river basin from GRACE solutions and land surface model

Measurement of regional water resource variations is significant for understanding water cycle and water management. This is especially true for transboundary river basins. This study investigated the terrestrial water storage dynamics of the Lancang-Mekong River basin, which has a total area of 795,000 km2 and distributed between six countries in Southeast Asia, based on the terrestrial water storage anomalies (TWSA) from the Gravity Recovery and Climate Experiment (GRACE) satellites and the Global Land Data Assimilation System (GLDAS) model. A spatial weighted centroid analysis concept from geographical information science was introduced to track the movement of terrestrial water storage centroid of the basin. And the response of terrestrial water storage dynamics to climate variations throughout the basin was examined by quantifying the correlations of TWSA with a multi-scalar drought index. Results show that during 2003 to 2016, the upstream basin (Lancang River basin) experienced slight decreasing trends (ranging from −2.45 to 0 km3/yr revealed by five different GRACE solutions), and the downstream basin (Mekong River basin) generally did not express statistically significant trends; five GRACE solutions are more consistent in the downstream basin than the upstream basin, and the mascons-based TWSA processed at Jet Propulsion Laboratory (JPL) produced quite different results with the other four solutions. Generally, there are good correlations between GRACE observations and GLDAS model. The TWSA is 1–2 month lagged correlated with precipitation, evapotranspiration, and runoff anomalies, because water from precipitation may take a long period to loss from evapotranspiration and infiltrate into the soil. In general, water storage dynamics are closely correlated with climatic dry and wet conditions at middle-long periods (6–12 months) in the basin, and the correlation coefficients in wet season are generally higher than those in dry season. However, a different pattern was found since 2010: in the 2010–2016 period, correlations between TWSA and the multi-scalar drought index in Lancang River basin reduced relative to the 2003–2009 period but became stronger in Mekong River basin after 2009. The results of this study highlight the differentiation of water storage dynamics’ response to the climate variation between upstream and downstream of Lancang-Mekong basin in the period 2010–2016 and the possibility of examining basin storage disturbed by human activities in the basin.