Technical Paper Series
Joint Environmental Monitoring Programme at Two Mekong Mainstream Dams: The Don Sahong and Xayaburi Hydropower Projects
The report provides an overview of activities conducted and resulting recommendations from monitoring two mainstream dams: Don Sahong and Xayaburi hydropower projects. It summarizes the pilot monitoring results from the first pilot site report for each hydropower project and the Combined Annual Report in a way that illustrates how findings in hydrology, sediment, water quality, aquatic ecology, and fisheries can be interpreted together. Based on the findings, it provides some initial suggestions for mitigation and adaptive management of construction and operation of hydropower projects. It also concludes with recommendations for revisions to the guidelines and monitoring protocols that can then be incorporated into the JEM Programme document.
This paper reports on the condition of the Basin in 2019, including its hydrology/water flow, flood and drought. The year saw recorded unprecedented flow conditions in the Mekong mainstream and from tributaries. Erratic climatic fluctuations were also found, ranging from extreme dry to extreme wet within short periods of time. The report ends with key recommendations, looking forward.
This reports on the results of the monitoring of water quality across 48 stations in the LMB. The report shows the water quality in the Mekong and Bassac Rivers was still of good quality with the slight improvement compared with 2016. There was only a small number of measurements of chemical oxygen demand (COD) and dissolved oxygen (DO) that violated the MRC Water Quality Guidelines for the Protection of Human Health (WQGH) and the MRC Water Quality Guidelines for the Protection of Aquatic Life (WQGA). Most exceedances were recorded in the Delta. Of a slight concern was the DO level at Chau Doc, which violated the WQGH for all sampling occasions causing water quality for the protection of human health to be downgraded from ‘good’ in 2017 to ‘moderate’ in 2018.
Report on 2018 baseline survey of the Lower Mekong mainstream and floodplain areas
SIMVA 2018 is the third survey of its type and was conducted in the same sites and used the same methods of collecting primary household and village data, as the SIMVA 2014 and 2011 exercises. Covering 2,800 households in 200 villages the 2018 survey shows that communities in the Mekong mainstream corridor were still dependent on the river resources for their livelihoods, income, and well-being. As such, they are still vulnerable to changes in the Mekong water resources. However, their overall dependency has decreased with other, non-water resources-related livelihood activities playing increasingly important roles. From 2014 to 2018 the percentage of households engaging in fishing decreased across the region from 50% to approximately 37%. The study also indicates growing incidence of flooding, possibly as a result of climate change and other factors, including water infrastructure development. Government support in livelihood diversification and disaster coping strategies is essential and there is much room for improvement in this regard.
The report is the first ever large-scale study to consider both spatial and temporal variations of fish abundance and diversity in the LMB, using the MRC’s long-term fisheries monitoring data. The monitoring was conducted daily between 2007 and 2018 by professional fishers at 38 stations along the Mekong mainstream and its major tributaries. But only 25 sites were selected for the study due to incomplete data. Eleven of the 25 monitoring stations were in Cambodia, four in Lao PDR, and five each in Thailand and Viet Nam. The study found 617 fish species, belonging to 21 order and 80 families in the LMB from 2007 to 2018. Some 37,530,460 individuals, corresponding to 1,095,848 Kg of fishes were collected. Temporally, both fish diversity and catch have increased during the survey period in the Tonle Sap and the Mekong upstream in southern Laos and Thailand, informing the high diversity of these areas and that sampling effort is still growing.
The report was prepared to support the prior consultation process for the proposed Luang Prabang hydropower project. It provides a scientific review of the documentation submitted to the MRC by the Lao National Mekong Committee, covering hydrology and hydraulics, sediment and geomorphology, water quality and aquatic ecology, fish passage and fisheries, navigation, dam safety, and socio-economic aspects.
The report describes the biological indicator groups sampled during 2017, uses this information to derive biological indicators for the sites examined, and use biometric indicators to evaluate these sites.
Joint Transboundary Action Plan In the Sesan and Srepok River Basin and the Mekong Delta of Cambodia and Viet Nam
The Joint Transboundary Action Plan sets out management arrangements to support transboundary cooperation between Cambodia and Viet Nam to strengthen sustainable water resources management and development of the Sesan and Srepok River Basins (2S River Basins) and Mekong Delta.
MRC Technical Report No.1
This report provides details on how the irrigation database was designed and metadata were gathered and processed. It reviews the current situation of irrigation in the Lower Mekong River Basin (LMB) and provides recommendations for further database improvement.
MRC Technical Reference Paper No.65
This technical reference paper presents the review by the MRC Secretariat on the design change made for the Xayaburi hydropower project. It analyses how the revised design of the project addresses the recommendations of the Xayaburi Technical Review Report and concerns raised during the prior consultation process.
MRC Technical Paper No.64
The SIMVA report is the largest socio-economic survey and study conducted along the Mekong mainstream and floodplain areas to understand the occurrence and impacts from floods, droughts and extreme weather, and identification of longer-term trends at community level.
The report provides the status of water quality in the Mekong River in 2016, assesses water quality monitoring data monitored by the Water Quality Monitoring Network laboratories, and provides recommendations for future monitoring.