Assessment of surface water resources in Dong Nai river basin to serve sustainable development goals in the context of climate change - 2

Map 3.5. TSS monitoring map of Dong Nai river basin in the period 2011 - 2015 98

Map 3.6. Vulnerability assessment map of climate indicators

in Dong Nai river basin 115

LIST OF ABBREVIATIONS

Climate change

Biosphere Reserve

EVI Environmental Vulnerability Index

Environmental vulnerability index

GIS Geographic Information Systems

Geographic information system

IPCC Intergovernmental Panel on Climate Change

Intergovernmental Panel on Climate Change

LVS River Basin

SOPAC South Pacific Applied Geoscience Commission

South Pacific Applied Geosciences Commission

TDBTT Vulnerability TCVN Vietnam Standard

UNICEF United Nations International Children's Emergency Fund

United Nations Children's Fund

UNESCO United Nations Educational Scientific and Cultural Organization

United Nations Educational, Scientific and Cultural Organization

UNEP United Nations Environment Program

United Nations Environment Programme

Office of the National Assembly Office of the National Assembly

WHO World Health Organization

World Health Organization

INTRODUCTION

1. Urgency of the thesis

Practice shows that in our country, as well as in other countries around the world, the exploitation and use of surface water resources in river basins have caused negative impacts on the environment and socio-economic development. Therefore, the issue of assessing surface water resources of river basins over a long period of time with actual measurement data will be of great significance for proposing directions for the reasonable use and protection of this natural resource, thereby being able to forecast their impacts on socio-economic development in the future.

Many countries in the world have paid attention to the issue of integrated management of resources and environment according to river basins [52] such as Australia, the US, Germany, Denmark, Malaysia... especially for large, international river systems such as the Danube, Rhine, Colorado, Mekong... However, due to the characteristics of each river basin, the use of existing experiences in specific conditions needs to be carefully considered and reviewed to ensure the rationality and effectiveness of the management method.

In Vietnam, the issue of assessing surface water resources of river basins has been of interest and research by scientists in recent years, especially after Vietnam attended the Informal Consultative Conference on Water and Environment in Copenhagen - Denmark (1991), the International Conference on Water and Environment in Dublin - Republic of Ireland (1992) .... The issue of research, assessment and management of water resources has also become an important content of many Ministries, Branches; many Institutes and scientific research facilities, management as well as teaching in postgraduate training courses. In the context of climate change with increasingly complex developments, unpredictable impacts on surface water resources globally, including Vietnam. Therefore, promoting research on surface water resources in river basins, especially large river basins, is extremely important to ensure sustainable socio-economic development.

Dong Nai River Basin is a river basin with an area of ​​37,400 km2 , most of the area is located in Vietnam, mainly including the areas of Lam Dong province.

Dong Nai, Binh Phuoc, Binh Duong, Ho Chi Minh City, Dak Nong, Tay Ninh and part of Long An and Binh Thuan provinces. The Dong Nai River basin is the third largest basin in Vietnam, after the Mekong and Red River basins.

Currently, along with the rapid development of agriculture, aquaculture, transportation, mineral exploitation, etc., in the Dong Nai river basin, many irrigation reservoirs and hydroelectric dams have been, are being and will continue to be built to serve socio-economic development [34]. However, the rapid development of economic sectors has caused significant impacts on natural conditions, landscapes and people's living conditions.

– society… Dong Nai river basin is a hot spot of sustainable development for policy makers, especially in river basin planning and management.

Faced with that reality, the thesis "Assessment of surface water resources in the Dong Nai River Basin to serve the goal of sustainable development in the context of climate change" hopes to develop future water flow scenarios after assessing some surface water quality indicators, environmental vulnerability through a set of climate indicators, finding the correlation between rainfall and water flow to clarify the fluctuation trend of surface water resources in the basin, thereby proposing sustainable solutions in the rational use of surface water resources for development activities in this river basin.

The research contents of the thesis contribute to clarifying the picture of surface water resource use and management in the Dong Nai river basin in the context of climate change.

2. Objectives and tasks of the thesis

2.1. Objectives

The objective of the thesis is to assess the current status and changing trends of surface water resources in the Dong Nai river basin in the context of climate change; propose some recommendations for the rational use of these resources.

2.2. Research tasks

To achieve the above objectives, the thesis focused on implementing the following tasks:

- Overview of surface water resource research of some typical river basins in the world and Vietnam to serve the rational use of surface water resources.

- Collect and process documents and data related to surface water resources of Dong Nai river basin.

- Analyze natural, economic and social factors affecting surface water resources of Dong Nai river basin.

- Assess the current status of surface water resources in Dong Nai River Delta: water reserves, water quality, environmental vulnerability of climate indicators related to surface water resources in the River Delta.

- Trend of change in surface water resources of Dong Nai River Basin.

- Proposing some solutions for rational use of surface water resources of Dong Nai River Basin in the context of climate change.

3. Subject and scope of the thesis research

3.1. Research subjects

The research object of the thesis is surface water resources on the rivers of Dong Nai River Basin.

3.2. Scope of research

- In terms of space: Dong Nai River Delta is located in Vietnam with 9 provinces and cities (Dak Nong, Lam Dong, Binh Phuoc, Binh Duong, Dong Nai, Tay Ninh, Ho Chi Minh City, Binh Thuan and Long An).

- About content:

+ Apply a set of parameters to assess environmental vulnerability related to surface water resources.

+ River water quality analysis.

+ Develop water flow fluctuation scenarios for the river basin based on climate change and sea level rise scenarios in Vietnam.

- Limitation of research issues: Within the scope of a thesis, I would like to limit some issues as follows:

+ When applying the vulnerability assessment index set of the South Pacific Applied Geosciences Committee (SOPAC), it is limited to 4 indicators in the climate group related to water resources, while other parameters cannot be implemented due to time constraints and the ability to respond to the data series.

+ When assessing the current status of water quality, it is only limited to 5 parameters: pH, BOD5 , COD, DO and TSS due to lack of necessary data.

4. Significance of the topic

4.1. About theory

- Contribute to the assessment of LVS water quality based on 5 main criteria according to Vietnamese Standards (QCVN).

- Assess the vulnerability of climate indicators related to surface water resources of the river basin in different stages.

- Develop water flow change trends based on the Climate Change (CC) and sea level rise scenarios for Vietnam of the Ministry of Natural Resources and Environment for Dong Nai River Basin.

4.2. In practice

Contribute to the assessment of total volume and quality of surface water in Dong Nai River Basin to serve the rational use and management of surface water resources, on that basis it can be applied to other river systems in Vietnam.

5. Defense arguments

Argument 1: Natural, economic and social factors have directly affected the reserves and quality of surface water resources in Dong Nai River Basin.

Thesis 2: The reserve and quality of surface water in Dong Nai River basin are differentiated in space and change over time. The reserve tends to increase slightly over time and has strong fluctuations between years in the coming period (2020 - 2065).

6. New points of the thesis

- Assess the vulnerability of climate indicators related to surface water resources of Dong Nai River Basin in space and time for the two periods 2010 - 2014 and 2015 - 2019.

- Determine the trend of water flow change in Dong Nai River Basin in the period of 1986 - 2018, based on applying the Climate Change and Sea Level Rise scenarios for Vietnam of the Ministry of Natural Resources and Environment (2016) according to the RCP 4.5 and RCP 8.5 scenarios to establish water flow scenarios for the two periods of 2020 - 2035 and 2046 - 2065.

7. Structure of the thesis

The thesis consists of 147 pages. In addition to the Introduction, Conclusion, References and Appendix, the main content of the thesis is presented in 3 chapters:

Chapter 1. Overview and scientific basis for assessing surface water resources of river basins for sustainable development in the context of climate change.

Chapter 2. Factors affecting surface water resources in the Dong Nai River basin

Deer.

Chapter 3. Assessment of surface water resources of Dong Nai river basin in the context of

climate change