Studying Onset and Evolution of Agricultural Drought in Mekong River Basin through Hydrologic Modeling

Departures in precipitation from the normal are the cause of the onset of agricultural drought. In this study, we aim to identify extreme precipitation deficits using an index called Percent Normal (PN). We applied the proposed PN index to the agriculturally productive Mekong River Basin (MRB) to evaluate the propagation of precipitation deficits into agricultural drought based on the change in slope and mean of the precipitation, soil moisture and evapotranspiration anomalies. The results of the study showed the proposed PN index identified historical droughts in the years 1992, 1997–1998 and 2000–2006 in MRB; of these, 1992 was shown to be the longest drought, which lasted from the 43rd week (October) of 1991 to the 49th week (December) of 1994. The short-term but extreme drought was identified to occur in 2005 with below-normal precipitation that lasted for more than a year. An immediate effect of precipitation deficit was observed in evapotranspiration (ET) and soil water for agricultural (Thailand) and forested regions (Parts of Cambodia) of the basin with <5 weeks lag. We conclude that the drought indices adopted in this study are suitable to identify the small and long-term drought events, which will facilitate the development of a drought-resilient agricultural production system.

Random Forest-Based Reconstruction and Application of the GRACE Terrestrial Water Storage Estimates for the Lancang-Mekong River Basin

Terrestrial water storage (TWS) is a critical variable in the global hydrological cycle. The TWS estimates derived from the Gravity Recovery and Climate Experiment (GRACE) allow us to better understand water exchanges between the atmosphere, land surface, sea, and glaciers. However, missing historical (pre-2002) GRACE data limit their further application. In this study, we developed a random forest (RF) model to reconstruct the monthly terrestrial water storage anomaly (TWSA) time series using Global Land Data Assimilation System (GLDAS) and Climatic Research Unit (CRU) data for the Lancang-Mekong River basin. The results show that the RF-built TWSA time series agrees well with the GRACE TWSA time series for 2003–2014, showing that correlation coefficients (R) of 0.97 and 0.90 at the basin and grid scales, respectively, which demonstrates the reliability of the RF model. Furthermore, this method is used to reconstruct the historical TWSA time series for 1980–2002. Moreover, the discharge can be obtained by subtracting the evapotranspiration (ET) and RF-built terrestrial water storage change (TWSC) from the precipitation. The comparison between the discharge calculated from the water balance method and the observed discharge showed significant consistency, with a correlation coefficient of 0.89 for 2003–2014 but a slightly lower correlation coefficient (0.86) for 1980–2002. The methods and findings in this study can provide an effective means of reconstructing the TWSA and discharge time series in basins with sparse hydrological data.

Metadata Schema for Folktales in the Mekong River Basin

The aim of this study was to analyze the content, context, and structure of folktales from the Mekong River Basin, and to develop a metadata schema for data description and folktale storage. The research was conducted using the MAAT metadata lifecycle model, which comprises the following four steps: (1) conducting an information content analysis; (2) creating metadata requirements, (3) developing a metadata schema; and (4) carrying out a metadata service and evaluation. The folktale analysis, based on Anne Gilliland’s information object analysis, revealed the following: (1) the folktale content consists of types of tales, and the morals, beliefs, and parts they incorporate; (2) the folktale context consists of and names distributors, characters, scenes, magical objects, ethnic groups, languages, countries, relationships between tales, and their sources; (3) the folktale structure includes verbal, non-verbal, and mixed forms. The metadata schema development adopted the functional requirements for bibliographic records concepts and existing metadata standards, resulting in metadata with the following 18 elements: identifier, title, creator, contributor, description, relation, language, medium, sources, date, rights, keyword, character, moral, ethnic group, motif, place, and country. The metadata elements were described using the categories: name, definition, format, example, and note.

The Indus and Mekong River Basins: Cooperation, and Dispute

The Indus Waters Treaty (IWT) and the Agreement on the Cooperation for the Sustainable Development of the Mekong River Basin are two of the most important transboundary water treaties signed between member states that have a history of disputes and wars. Due to the character of these relationships, often other bilateral issues impinge on water-related issues. In the case of India and Pakistan, voices to scrap the IWT in both countries are made chiefly because of their day-to-day bitter relationships. The treaty nevertheless remains in effect. The Mekong River Basin countries have had sour relationships in the past, and even after the agreement was signed in 1995 some political differences and disputes between them have remained. In both the Indus and Mekong basins, China is an important upper riparian. This article discusses the IWT and Agreement among the Mekong basin countries and examines the convergences and divergences between the two. It then analyses the role of China, as an upper basin to Indus and Mekong.