MINISTRY OF EDUCATION

AND TRAINING

VIETNAM ACADEMY OF

SCIENCE AND TECHNOLOGY

GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY

……..….***…………

TRINH PHI HOANH

STUDYING THE SPATIO-TEMPORAL

VARIATION OF TIEN RIVER CHANNEL

BELONGS TO DONG THAP PROVINCE FOR

NATURAL DISASTER ADAPTIVE CAPACITY

Major: Natural Resources and Environmental Geography

Code: 62 44 02 19

SUMMARY OF GEOGRAPHY DOCTORAL THESIS

Ho Chi Minh City - 2017

The study completed at Graduate University of Science and

Technology, Vietnam Academy of Science and Technology

Supervisor 1: Assoc.Prof. Dr. Nguyen Tham

Supervisor 2: Dr. Vu Thi Thu Lan

Reviewer 1:

Reviewer 2:

Reviewer 3:

The doctoral thessis will be presented by candidate and commented

by the Assessment Council at Graduate University of Science and

Technology, Vietnam Academy of Science and Technology

. Time: Date…. month …. 2018

Readers con find the thesis at:

- The library of Ho Chi Minh City Institute of Resources Geography;

- The library of Graduate University of Science and Technology;

- National Library of Vietnam.

1

INTRODUCTION

1. THE PROBLEM STATEMENT

Mekong River is the longest river in Southeast Asia and is ranked

as the 12th longest river over the world. Therefore, it plays a crucial

role in the socio - economic development of countries into this area.

Tien River is located in the downstream of Mekong River Basin

which passes through the upper Mekong River Delta and a part of the

river which belongs to Dong Thap province plays vitally important

role for developing of socio - economic activities in the province.

However, the variation of river channel, includes erosion and

deposition in recent years, has considerably happened that is not only

frequency, but also space.

Against those milieu, there have been a myriad of studies and

projects published to implemented on limit the fluctuations,

especially in erosion. In fact, some measures have been tried and

initially successful in a certain scale but they used to apply an

independently, while hydrological modeling methods require a large

number of input data. Hence, solutions for the change of Tien River

channel have not still enough authentication.

It is really necessary to assessing the changing process as well as

identifying the agents which cause for them based on the background

of general geography. These documents provide a scientific

knowledge for both notifying and proposing the measurements to

cope with the change of Tien river channel flowing through Dong

Thap province. These challenges are so hard to overcome but they

are in emergency, which need to solve as soon as possible to prevent

the negative effects of Tien river channel changes. Altogether, the

study has a potential meaning of scientific research and in practical

life. On the other hand, identifying the causes and process of Tien

river channel changes can help to apply to conduct research in other

river zones belonged to Mekong river system and other rivers that

has the same geographic features.

Hence, the author/candidate would choose the topic “Studying the

spatio-temporal variation of Tien River channel belongs to Dong

Thap province for natural disaster adaptive capacity” as do research

on doctoral thesis of Geography.

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2. OBJECTIVIES AND MISSIONS OF THESIS

2.1. Research objectives

(i) Assessing manifestation, finding out reasons, and warning risk

of changes in Tien river channel belongs to Dong Thap province

(ii) Proposing solutions for adaptive capacity with changes in Tien

river channel belongs to the study area.

2.2. Research tasks

To accomplish the goals on top, the doctoral student has to do the

mentioned duties below:

- Collecting, analyzing, synthesizing related documents to the topic.

- Studying literature review based on generally geographic

standpoint/ point of view.

- Assessing manifestation, developing, and main agents which

cause for changing of Tien River channel.

- Filtering optimal approaches for proposing adaptive capacity on

risk of variation in the study area, includes: preventative solutions,

evasive remedies, and protective solutions.

3. SCOPE OF RESEARCH

3.1. Space: A part of Tien River that flows through Dong Thap

province by administrative border including the opposite channel’s

banks that is owned by An Giang province.

3.2. Time: Assessing the development of Tien River channel for 100

years; of which, the thesis only concentrates during period of 1965 –

2016 and warns about trends in the future.

3.3. Contents: In this dissertation, Tien river’s channel changes are

analyzed in both of planar section and cross section. In particular, the

doctoral student focus on calculating Tien River channel changes for

planar section. The variations in the shore is caused by developing of

the river bed in highly influential.

4. DATABASE FOR THESIS

This thesis is completed based on many reliable resources.

Meteorological and hydrological data, muddy and sandy data are

provided by Mekong River Commission (MRC) [10-16] and

Southern Regional Hydro-Meteorological Center [17].

Manifestation of river’s channel change is collected by using the

result of annual reports from Departments of Agriculture and Rural

3

Development of Dong Thap province and the results of other

published studies [9].

Main content of the doctoral thesis has been developed

continuously from my master thesis and several projects [18-20].

5. THESIS STAMENTS

1. The channel of Tien River which flows through Dong Thap

province is undertaking on the mechanism of braided river, fluid

flow, erosion and accretion often occur along the cross section and

along the river.

2. Activities of dwellers have impacted on developing spatio-

temporal variation of Tien River belongs to Dong Thap province.

3. It is predicted based on dynamic morphology and testing

hypotheses via general geography approach.

6. THE INNOVATION OF THESIS

1. Found out features and reasons which create variations of the

channel by applying historical and random approaches.

2. Analyzed in some respect the directly consequences of residents

on the Tien River channel process in Dong Thap province.

3. Warning and recommending solutions for reducing effects on

socio-economic development in the study area based on synthetic

geography approach. It is also scientific foundation for proposing to

natural disaster adaptive capacity.

7. SCIENTIFIC AND AUTHENTIC OF THE THESIS

7.1. Scientific significance

The results of the thesis is able to contribute to supplement and

perfective methodology for river channel’s changes in the upper of

tributary and braided river type. This document can be used as reference

material for the both studies and teaching.

7.2. Practical implication

The research provides evidence for administrative managers in Dong

Thap province and they base on this document can plan and propose for

reducing as well as adaptation the natural disaster impacts (river channel’s

changes). All of them lead to sustainable development and stability.

8. THE STRUCTURE OF THESIS

The thesis presented in 148 pages A4, includes: 43 tables, 88

figures and maps, 145 documents, and appendices. Besides, the

4

introduction (5 pages) and conclusion (3 pages), the main contents

are structured into three chapters:

Chapter 1. Literature review in 46 pages A4 including 7 tables,

15 figures and maps; Chapter 2. Assessing the variation Tien River

channel belongs to Dong Thap province in 67 pages A4 including

20 tables, 65 figures and maps; Chapter 3. Warning and proposing

for responsive solutions to adaptive with variation Tien River

channel belongs to Dong Thap province in 27 pages A4 including

16 tables, 7 figures and maps.

Chapter 1. LITERATURE REVIEW OF THE RESEARCH

1.1. DEFINATIONS

1.1.1 River channel

There is a difference in several terms relating to components

within river basin (figure 1.1) [3], includes:

A subterranean stream, also known as the thalweg river, is the line

defining the lowest points along the length of a river bed or valley.

River bottom (river bed) is a channel occupied (or formerly occupied)

by a river. The river channel is the route course (between bed and

banks) that a river flows. The flow of the river is often described as

channel flow. Riverbank is the land along the edge of a river. In this

study, the term of riverbank is included riverbanks and mudflats (alc,

river bar, and island). River bar is an elevated region of sediment

(such as sand or gravel) that has been deposited by the flow.

The morphology river is the study of the channel pattern and the

channel geometry at several points along a river channel, including

the network of tributaries within the drainage basin. Also known as

channel morphology; fluviomorphology; stream morphology. The

relationship between the river bed and the flow velocity, combining

with erosion and decomposition is formed the dynamic morphology.

The channel change is a changing process of river bed and

structure of the river over time due to the influence of water currents,

climatic factors, tectonic factors and economic activities of local

residences.

According to Brice I.C. Braided rivers are characterized by having

a number of alluvial channels with bars and islands between meeting

5

and dividing again, and presenting from the air the intertwining effect

of a braid. [26, pp. 47]. Braided rivers have different types of

classification. The braided areas often have distinct characteristics in

comparison to other types of rivers in terms of hydrology and river

bed morphology. There are two basic conditions that made up the

formation of the braided river: its river is relatively wide enough for

the river bar develop completely; Differences between in the position

of the thalweg between flood and dry season. The basic characteristic

of the braided river is strong current, thus, the change of river

channel takes place frequently (the unstable branches), leading to

accumulate of the abundant sediment and the raw material. The

braided river usually grows on one side.

1.1.2. Natural Disater

According to Point 1, Article 3 of the Law on Natural Disaster

Prevention and Control [2], “A natural disaster is a major adverse

event resulting from natural processes of the Earth; examples include

floods, hurricanes, tornadoes, volcanic eruptions, earthquakes,

tsunamis, and other geologic processes. A natural disaster can cause

loss of life or property damage, and typically leaves some economic

damage in its wake, the severity of which depends on the affected

population's resilience, or ability to recover and also on the

infrastructure available”. Channel change, especially river bank

erosion, are considered as a type of natural disaster that needs to

study for finding solutions.

1.2. The history of doing researches relating to river process

1.2.1. In the world

1.2.1.1. The studies approach to channel change

Based on analyzing the results of researches on the river channel

change, in my opinion, there were a variety of methods and approaches

on this stage. Overall, there are three specific approaches: conditions of

river morphology, flow dynamic, and integrated approach.

1.2.1.2. Researching on braided river

Study of braided river was suggested firstly by Peale A.C., US

Geological Survey (1879) with studies in Western Wyoming -

tributary of the Green River. Studies of braided river concentrated on

a number of countries which they continued to develop studies

relating to riverine dynamics in previous period (Western Europe,

6

North America) or the regions where owned many authentic

problems with large tributaries (China, India ...). Nowadays, there are

three field-researches for doing projects on braided river: (i)

hydropower-driven of the river section for projecting variations of

braided river; (ii) based on morphological factors to access and

predict divergent river morphology, and field of braided river by

combination both (i) and (ii).

1.2.2. In Vietnam

1.2.2.1. Channel change

Researches on field of river channel changes by Vietnamese

scientists also focused on three primary approaches. Of which, the

area around morphology of river channel has been interested

scientists from the Institute of Geology, Institute of Geography of

Vietnamese Academy of Science and Technology and scientist from

Faculty of Geography, University of Science - Hanoi National

University. The area around flow conditions has been cared by

scientists in the field of hydrology such as Institute of Water

Resources Research, Hanoi University of Water Resources,

University of Civil Engineering,… Scientists from Institute of

Geography, Vietnamese Academy of Science and Technology have

been interested in the integrated study.

1.2.2.2. Braided river

It is initially researched in large river systems, such as: the Red

River Delta and the Mekong River Delta.

1.2.3. In Mekong River Delta and particularly Dong Thap

province

In recent years, the change of river banks, especially riverbank

erosion, have been happening quite commonly in the Mekong Delta

and have received the attention of many different scientists. Many

studies would assess the erosion of the Mekong River Basin in

general and Tien River in particular, as well as the application of

remote sensing data to assess river bank erosion; all of them

generally found out several methods of coastal erosion which enable

predict to several major areas, such as river bank in Sa Dec city and

in Hong Ngu town. It can be mentioned on several scientists, such as

Le Manh Hung, Dinh Cong San [62-65], Hoang Van Huan [36],

Truong Thi Nhan, Nguyen Anh Tien [78], To Quang Toan [91-97] ...

7

Regarding the braided river is typical forms of river in the

Mekong Delta. However, the number of studies which focused

significantly on this issues still in limitation. Le Ngoc Bich - a

scientist from the Southern Institute of Water Resources Research

have several projects on morphological morphology [9].

Furthermore, scientists such as Luong Phuong Hau, Le Manh Hung,

Dinh Cong San, Hoang Van Huan and so on with their scientific

topics and projects have focused on analyzing the real situation,

causes and warning of landslides of river bank in main areas based on

mathematical models, physical models and experience formulas

based on flow dynamics and conduction morphology.

In recent decades, it is necessary to mention on the PhD thesis of

Tran Ba Hoang [27] and Ho Viet Cuong [30] and Nguyen Nghia

Hung [112]. Tran Ba Hoang. They discovered an overview of the

braided river in the Mekong Delta, formed morphological

relationships with the distribution of tributaries that offered for the

science of applying flow correction equations and distribution rate for

Tan Chau - Hong Ngu branch on Tien river. Ho Viet Cuong

constructed relationship among flow diversion, sediment separation

ratio with hydraulic elements, and river morphology. He also found

out the fluctuations of the hydraulic regime caused by sand dredging

operations via using mathematical and physical models. Moreover,

the results of project applied for the branched area on Hau river pass

through the Long Xuyen city (An Giang province).

1.2.4. Evaluation of contributions and gap on researches

The results of researches on the river bank in general and

riverbank changes in particular showed several accomplishments:

- Methods: It showed via analyzing material of measurement;

modelling; and application of remote Sensing and GIS.

- Regarding the trend of studying the change of river bank: it

concentrated on three primary approaches, such as: conditions for

river formation; flow formation and synthetic area.

- The results of the study focused on assessing the progress of the

channel change (mainly erosion), analyzing the causes (mainly

natural causes), influenced factors on the variation, and then

prediction for the trend of landslide by various methods and

particularly modelling.

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- Proposing solutions for reduce of change as well as damaging

consequences caused by riverbank fluctuations in the study area;

particularly, focusing on constructing solutions (embankments,

soldering iron ...).

Until now, besides the actual measurement methods used to

identify channel change, studies have focused on evaluating the

evolution of individual, sectoral methods. Hence, their results of

research are still limited around area; for instance, the erosion and

accretion can be prevented in this area but the neighbor areas will be

eroded. On the other hand, because of the complicated channel

change, especially in international basin all over the world, the

problem of evaluating channel change is still considered a part of the

world, not thoroughly resolved. In addition, the impacts of local and

river basin exploitation (eg watershed destruction, hydropower

construction, irrigation, sand mining, etc.) have not been studied.

Based on a comprehensive analysis of river basin studies in

general, the main content of the dissertation will be considered Tien

river basin as the major research subject. Therefore, the thesis will

focus on analyzing and clarifying specific issues:

- Assessing channel change (vertical, horizontal) of Tien River in

Dong Thap province in the period of 1965 - 2015. Of which,

concentrate on complicated areas.

- Analyzing the causes, agents which impact on channel process,

and the relationship among them on the basis of a synthetic and

random approach. In particular, focus on the impact of human

activities on the basin and the local area at different times.

- Warning on the trend of changing channel river based on the

morphological analysis of Mekong River's navigation dynamics

according to the integrated geographical approach.

- Applying the results for assessing, identifying the causes and

warning trends to proposing solutions for deal with change of Tien

river channel, particularly, focusing on constructing solutions

(adaptation and reduce).

1.3. APPROACHES AND METHODS

1.3.1. Approaches: In the process of performing the tasks of

research, the author has selected 3 approaches: synthesis geography,

history, and random.

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1.3.2. Perspective: During the study, the author based on 3

viewpoints to conduct research tasks: synthetic, system, landscape,

and sustainable development

1.3.3. Methods: Inherent of literature review, field trip, analysis,

synthesis, map and geographic information system, and make

interview experts

1.3.4. Steps: Research process of change river channel consists of 4

steps in Figure 1.10 1.4. OVERVIEW THE STUDY AREA

1.4.1. Natural, socio-economic conditions of Mekong river basin

The Mekong River is one of the major rivers in the world, with a

variety of geological features, geomorphology and natural geography.

There were about 65 million persons, who are living in the basin

(2015). Of which, there were about 29.6 million people living along

the river (about 15 km from the river bank). The average economic

growth rate in the basin was 4.3 - 7.0% per year. The main economic

activity is agriculture, forestry and fisheries, of which forests play an

important role in water resources management and sustainable

development.

In recent decades, the exploitation of the catchment area has been

increased, especially in agricultural, hydropower and irrigation. Basin

exploitation activities under the MRC Strategic Environmental M & E

Strategic Assessment conducted by the International Center for

Environmental Management (ICEM) for the Mekong River

Commission in 2010 assessed Vietnam as “having Greatest possible

economic loss” due to the potential impact, if mainstream dams were

built. The negative results that Vietnam can suffer cannot be calculated,

but several consequences can be forecasted including [90, pp. 82]:

(i) Reducing the flow in dry season, coupling with the effects of

climate change and rising sea levels, leading to increase salt water

intrusion and impact on agricultural and aquacultural activities in the

Mekong Delta River;

(ii) Felling down the account for suspended sediment from the

current 26 million tons / year to 7 million tons / year;

(iii) Aquaculture will be affected with an estimated loss of at least

$ 500 million to $ 1 billion per year.

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1.4.2. Characteristics of Tien River in Dong Thap province

Tien River which its section flowing through Dong Thap

province, is located in the upper part of the delta and at the end of the

floodplain of the Mekong River. Therefore, this area is characterized

by special geological structure, geomorphological characteristics as

well as hydrological processes. The flow of Tien River in Dong Thap

province is dominated by upstream, tide and rain flow in the locality.

Tien River in Dong Thap province is located in the upper part of

the delta, located at the end of the floodplain of the Mekong River.

Therefore, this area is characterized by geological structure,

geomorphological characteristics as well as hydrological processes.

The Tien River flow in Dong Thap province is dominated by

upstream, tide and rain flow in the locality.

The Tien River plays a crucial role in Dong Thap province, the

natural boundary between the northern part of the Dong Thap Muoi

and the southern part of the province between the Tien and Hau

rivers. Currently, large cities (3/3 cities and towns are located along

the Tien River), residential areas are concentrated along the river.

CONCLUSION OF CHAPTER 1

1. Studies of change river channel focused on three major ways:

river morphology, flow formation, and aggregate orientation. In

particular, channel change study for proposing on reducing measures

is a fundamental research problem of the branches of Geological

Sciences in the direction of synthesis. Regarding researches on the

braided river was initially studied in Vietnam as well as in the field of

thesis implementation.

2. Mekong River is one of the longest river in the world and its role

has been approved through the related countries, especially countries

located in the downstream. Nowadays, the development of socio-

economic activities (construction of hydroelectricity, irrigation,

watershed, river bed exploitation ...) has created impacts on the

change of both river tide and river bed generally.

The section of Tien River belonged to Dong Thap province is

located in the upper part of the Mekong River Basin and it has been

obviously impacted by the implications of the upstream flow (major

11

factor) and the tide of the East Sea. The Tien River morphology is

characterized by braided river.

3. There are three main basic ways which the project is going to

apply for solving issues that the proposed objective, including

employing the general Geography method as the major one to

understand the whole problems that the study needs to conduct,

followed by the method of using Historical factor for understanding

the whole forming and developing process of Tien river; along with

approaching accidentally to determine the unusual factors that impact

on the change of river channel. In addition, other methods such as

inheritance, remote sensing and GIS, field survey, experts and

analyzing are going to use for accomplishing the objectives.

Approaches and methods of the study are shown in the content of

Chapters 2 and 3, and followed by the diagram in Figure 1.10.

Chapter 2.

ASSESSING THE VARIATION OF TIEN RIVER CHANNEL

BELONGS TO DONG THAP PROVICE

2.1. THE CHANGE OF TIEN RIVER CHANNEL THE

PERIOD 1965 - 2015

2.1.1. The vertical change of Tien River channel

2.1.1.1. The change in riverbank

During period of 1965 - 2013, Tien riverbank which section across

Hong Ngu district continuously fluctuated, especially in the middle

island and the riverside. It can be seen the “progress” of the island

toward the downstream. Prior to 2003, the process of shifting the banks

of the North Branch of the Long Khanh Island which belongs to Hong

Ngu Township (now is town) took place rapidly. From 2003 until now,

the braided river of Long Khanh Island has been changing more

increasingly. The river banks of Long Khanh A, Long Thuan and Phu

Thuan B communes have been widely eroded.

The change of Tien river bank flowing through Thanh Binh district

happened mainly in the Tay island and concave (Binh Thanh commune).

The other areas were eroded and decomposition alternatively at slow speed.

12

In the Cao Lanh City and Cao Lanh District more broadly: The river

bank in this area marked varies in the branched area (Tre Island, Dong

Dinh Island, Cao Lanh town) and the confluence of curved rivers (My

An Hung commune, Lap Vo district; Binh Hang Trung commune, Binh

Hang Tay, Cao Lanh district).

The river bank of Tien River in Sa Dec - Chau Thanh area

changes quite complicatedly. The left of the river bank of Ward 3, 4

is continuously eroded while the right of the river bank located in the

Linh Island changed continuously (it is similar with the result of of

Hoang Van Huan, 2008). Look at period of 1969-2002, at An Hiep

area in Chau Thanh district was landslide around 1,200m with mean

speed at 33m per year. On the other hand , at the opposite side of the

river bank at Con Linh (Binh Thanh commune, Cao Lanh district),

there was a decomposition at width about 1,400 m and the average

deposition rate is 39 m/year.

2.1.1.2. The change of thagwel river

The changing process of Tien River channel, the section flows

through Hong Ngu district - Hong Ngu town, was associated with the

formation and development of islands, middle islands and coastal as

well as ”transfer” the flow or the change of main braid river and side

braid river of Long Khanh island. This is one of the areas which the

changing process of channel has been quite fluctuated over the last

century and till now

- Vietnam - Cambodia boundary likely Thuong Phuoc 1, 2:

channel change accordance with the mechanism of the river's

branching. Erosion only concentrated on the tip of the reef, which

pushed the river current into the opposite side of the island; the upset

occurred at the end of the island.

- Long Khanh island: channel change is associated with the

transition of the current between the north and south islets. Prior to

2003, the erosion occurred seriously at the riverbanks of Thuong

Thoi Tien, Hong Ngu town while decomposition happened in the

Southern branch. After 2003, the trend reversed which is completely

matched with the main channel - change between two canals.

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Fluctuations of river banks and deep streams of Tien river in

Thanh Binh district are correlated. The area that frequent eroded are

often deep in the creek (Binh Thanh commune, Tan Binh commune

...) and vice versa.

Deep water creek area. Cao Lanh - Chau Thanh District:

- From 1895 to 2004 showed that the erosion holes were growing

deeper increasingly in accordance to the development of deep

waterways of An Hiep - My Thuan river. The erosion at the

meandering Sa Dec river dredged up by 15 m between 1895 and

2000 by the river flow. The deep scour hole in Sa Dec tended to

move to the downstream in An Hiep commune and in My Thuan

deep 28.45 m (from 1895 to 2003) [78]. Almost all creeks in the river

have been lowered.

- In the period of 2007 - 2015: changes in thagweg in Sa Dec -

Chau Thanh area has been occuring severely. The deep stream

continued to deviate from 6 to 10 meters and moved toward the

downstream.

After analyzing the longitudinal developments (river banks and

river bottoms) of Tien River in Dong Thap province during the

period 1965 - 2015, it can be mentioned that:

- The area with the highest level of fluctuation occured in the river

section that runs through Hong Ngu district - Hong Ngu town; Sa

Dec - Chau Thanh section and Cao Lanh city. Over the period 1969-

2002, the section river in An Hiep Commune eroded toward the

riverbank at 78 m in depth, while the opposite bank deposited by 164

m. The sloping and sloping gully, declining from 6 to 10 m during

2007 - 2015 toward the right bank of Ward 3 and 4 (Sa Dec city) and

An Hiep commune, Chau Thanh district.

- The river sections where are often fluctuated have typical

morphological such as braided river (for examples, Thuong Phuoc 1

and 2, Thuong Thoi Tien, Long Khanh islet...) and the curved of

meandering river at Tan Chau town, An Giang province , My An Hung

B, Lap Vo district, Ward 3 and 4, Sa Dec, An Hiep, Chau Thanh. These

areas, the banks of the islet, and the river bank, were continuously

14

eroded. By contrast, the island's tail, the opposite side of the convex

bank was deposited and extended the caudal and the shoreline.

- Coastal changes are consistent with changes in deep creeks and

local erosion pits. The large erosion areas often have extensive

offshore creeks associated with local scour holes. This is evidenced at

large erosion sites such as An Hiep commune, Chau Thanh district;

Tan Chau Town, An Giang; Binh Thanh Commune, Thanh Binh

District; Ward 11, Cao Lanh city...

2.1.2. The horizontal change of Tien River channel

It can be seen that the general trend of the river channel is consistent

with the change in depths and coastlines over the cross sections. Areas

along the coastline often have deep creeks (thagweg lines) toward

strongly to the shore; The river morphology of the cross-section has a V-

shape and its bottom toward the riverbank . In addition, in the cross-

sectional area with the middle island (island) the changing process of

river channel also takes place strongly.

2.1.3. The relationship between the progression of Tien river

toward the vertical and horizontal direction

The change of river channel toward the vertical direction is

associated with the horizontal direction, for examples:

The erosion sites that are seriously eroded at the surface its cross-

section is usually V-shaped and its bottom side deflects toward the

landslide or the middle-shaped (exists island, the riverbank between

the river). If there is considerable erosion at the upper course of

middle island, the lower course is deposited. The typical areas which

has seriously variation in river channel illustrated for river process of

erosion and deposition in recent years such as Thuong Phuoc 1

commune, two districts of Hong Ngu; Long Khanh island area; The

west island; Binh Thanh of Thanh Binh district; Tan Thuan Dong

island area; Sa Dec - Chau Thanh area

The channel change on the site is suitable for deep-water channel

evolution (flow dynamics, thalweg close to erosion banks or deep

wells close to shore). MRC survey results [14] showed that Tien river

in Dong Thap province has 13 deep pools (V001 - V013) where the

15

erosion have occurred seriously inrecent years, including Tan Chau,

Binh Thanh, My An Hung B, An Hiep ….

2.1.4. General characteristics of the change in Tien river channel

The process of Tien River is quite complicated but it still follows

the natural "rules" and has several general features: (i) Tien river

channel changed toward the rule of erosion and deposition of braided

channel ; (ii) erosion and deposition, two phenomena having a

correlated relationship; (iii) river channel changes are affected by the

upstream flow greater than those affected by rivertide; (iv) river bed

erosion following a downward trend; (v) Channel change is located

in the ancient riverbed.

The “patterns of development” in the study river is constructed via

analyzing the characteristics of the variation of Tien River channel

belongs to Dong Thap province and is illustrated in table 2.7.

2.2. THE CAUSES OF THE VARIATION OF TIEN RIVER

CHANNEL

2.2.1. Impact of natural factors

2.2.1.1. Geology

In general, the river bed of Tien River is composed of several new

sediment layers because they have not yet compacted, causing

unassembled particles which are very porous. The new alluvial layers

are weak soils with average compressive strength of 0.24 - 0.7

kg/cm2, binding force 0.10 - 0.29 kg/cm2. Moreover, this new type of

sediment is usually of origined from mixed river-sea sediments

containing fine small particles and plenty of soluble salts.

On the other hand, the river bed flows through the loose sediments

containing two types sediment layer. The upper layer is fine sandy or

fine clay mixed with sand which its thickness of 18-20 m, the remain

layer is coarse sand which is 13-25 m thickness. Sand layer is a

relatively watery, pressure-bearing aquifer with water from Tien

River (Figure 2.54). As the flow regime changes, the aquifer in the

sand changes, causing a rearrangement of disturbed sand particles.

This change can cause drift sand and followed by erosion.

- 15 -

Table2.7. The dynamic modelling of the river section at the study area

No. Morpho-

logical

characte-

ristics

Features, causes,

evolutions

Typical areas

1 Braided

river

1.1. The erosion has

been strong at top of

islets, islands and two

opposite sides of the

isle. Accumulation has

been at the bottom of

islets. It is caused by the

direct flow dynamics on

the top of islets.

- Liet Si islet (formerly Tao islet)

and Beo islet where are located at

Thuong Phuoc village 1 and 2, in

Hong Ngu District erosion has

been concentrated at the top of

islets and the left bank in Thuong

Phuoc village 1; deposition at

bottom of the Beo islet led to

“Drifting”

1.2. Changes in the

order of the river

branches, includes:

erosion at major river

branches and

accumulation at

tributary conversely.

River braches at North and South

of Long Khanh islet

- From 1940s to 2000: erosion

occurred mainly at the main river

branch which is throughout Hong

Ngu town and sedimentation took

place at Long Khanh river branch.

- After 2000 until now: the main

branch of river switch to the Long

Khanh river branch; therefore,

erosion of river channel arose at

Long Khanh A and Long Thuan

village; accumulation has been a

part of the North river branch.

1.3. In the later part of

the river branches, there

are often deep holes

Binh Hoa hamlet, Binh Thanh

village, Thanh Binh district, a part of

My Hung B village, Lap Vo

district…

- 16 -

2 The river

bends

- Erosion at concave

bank due to the

dynamic of stream

flowing forces directly

into it combined with

turbulent flow, then the

river bed often has

deep holes deviated to

the concave bank.

- Sedimentation took

place at the opposite

bank

- A part from Sa Dec to Chau

Thanh district which is located at

bends of river; erosion mainly

occurred at right bank (ward 3 and

4, Sa Dec city, and An Hiep

village, Chau Thanh district;

convex bank at Binh Tan islet,

Linh islet, Binh Thanh village are

deposited alluvia

- Erosion befalls at Tan Chau

district, An Giang province and

deposition arises at convex bank of

Thuong Phuoc 2 and Thuong Thoi

Tien village, Hong Ngu district.

3 The river

section is

relatively

straight

Erosion and accretion

intertwine but they still

retain the characteristic

of morphology. The

primary reason was

caused by the position of

river section located at

area of tectonic fault line

Left bank of West islet, Thanh

Binh district, Dong Thap province

16

When the riverbank is impacted with a relatively large velocity

(0.5 - 3.0 m/s), the standard velocity causing without erosion is low,

the lower sand layers are washed out faster than the upper clay layer

which creates subterranean frogs with a high potential for coastal

erosion [63], [77], [78]. In addition, fine clay layer, and clay powders

are also of low mechanical nature, leading to lose their bond in the

water environment due to high disintegration and are susceptible to

external influences because of their high modulus.

2.2.1.2. The morphology of the channel

The morpholgy of Tien River belongs to Dong Thap province

especially the horizontal and vertical cross section also partly impacts

the changing process of river channel. The results of Nguyen Sinh Huy

et al. [90], Nguyen Quang My et al. [81], Vu Van Vinh et al [77].

- Clusters along Tien River: On the river bed of Tien River, there is a

sudden change in the depth of the river bottom due to the continuous

arrangement of deep pools (erosion pits) and shallow fields (rapids). This

arrangement is consistent with the morphology and order of the river

fluctuations. The greater the degree of variation, the greater the density

and size of the rapids. Deep pools are usually found in the main

meanders of the meandering section, where the water flow is turbulent

and especially when there is flooding. The depth of the river in this

area reaches 30-40m, which is one of the direct causes of shoreline

erosion at many locations in Tien river such as Thuong Phuoc 1, 2,

Thuong Thoi Tien (Hong Ngu district), Hong Ngu town, Sa Dec, My

Thuan, Phuong 11 (Cao Lanh city) [9]. According to Le Manh Hung et

al. (2008) [64], the Tien River section from Tan Chau to Cho Lach has

12 deep pools, with 12 shallow rapids, the average distance between

deep pools is 12.5 km.

- The cross-sectional area is of two types: the middle ground type

(involving sand dunes, alcoves, islands - typical for braided river beds)

and the riparian banks (shallow banks), a deep slope, with local erosion

for erosion - erosion.

Both horizontal and vertical displays along the river create

favorable conditions for the channel changeto occur.

17

2.2.1.3. Hydrological

The effect of the erosion of the river bed at a fast or slow speed,

strong or weak depends on four factors [62], [63]: the magnitude of

the flow, the duration of the flow capacity, The direction of the flow

of water to the shore, the ability to transport the sediment of the flow.

According to the analysis, all four elements in the Tien River in

Dong Thap province have facilitated the flow of erosion.

In addition, under the influence of climate change has increased

the backflow, change the flow structure ... contribute to complicate

the channel process.

2.2.1.4. The relationship among morphology and flow dynamics,

erosion, accretion

The erosion and sedimentation of the river bed is the result of the

frequently interaction between the two direct elements, namely flow

and river valleys.

Flow plays an important role and proactive in regulating

mechanism, rate of erosion, deposition of river bed. It contributes to

the creation of locations and areas with the risk of erosion and

deposition. The conductor represents in geometric form the results of

the effects of erosion, accretion, fluid flow, including hydrological

factors. It reflects the dynamics of the flow, as well as factors that can

change the dynamics axis, directly or indirectly cause erosion and

shore accretion. Therefore, studying for prediction of channel change

can be considered as the main research object is the river bed [81]. The

conductor not only contains the content that reflects the consequence

of the interaction between flow and conduction, but also take in the

content of the projection. Areas frequently occurring landslides in the

Tien River are (i) in the curved section of the river, the force acting on

the embankment to create deep holes; (ii) where the flow of the two

streams flows; (iii) where the river has narrowed one or both.

2.2.2. Impact of human activities

Over the years, local and basin-based mining has increased. In

particular, there are exploitation activities that adversely affect the

river flow such as deforestation (the rate of forest cover, especially

primary forest decreased continuously, average 0.53% per year);

Construction of many hydroelectric and irrigation dams (there are

18

currently about 11 mainstream hydropower dams and 125 dams on

tributaries already and will be built); Excessive sand mining and

unplanned sand mining both in the basin and in the locality. In

addition, other local activities such as overloading to the riverbank

edge, aquaculture, high speed and high speed trains, building

infrastructure systems and enclosed embankments river ...lead to

change the river flow, make development of the erosion of the river.

Catch operations in the basin and in the local area have continuously

increased in scale and scale after 2000. The most worrying is the

construction of a system of mainstream hydropower dams, Alluvial as

the water flow to the delta caused the phenomenon of "starvation" and

the extraction of sand in the river bed excessive, not planned to make

the status of channel change complex.

The impact of socio-economic development on the river bank is

twofold: (i) increasing shoreline load (increasing the river's slip force);

(ii) alter the distribution, distribution and structure of water flows, alter

the morphology of the river bed, the steepness of the roof, etc., reducing

the river slip resistance.

CONCLUSION CHAPTER 2

1. In the period of 1965 - 2015, the variation of Tien River

channel was complicated but still obeyed the law and mechanism of

the branching river (erosion and accretion occurring frequently along

the cross sections along the river); Unstable development points

concentrated river sections with characteristic morphology (braided

rivers: Liet Si, Beo, Long Khanh, Tay, Tre, Dong Dinh; Curved river

sections: Ward 3, 4 Sa Dec Town - An Hiep Commune, Chau Thanh

District, Tan Chau Town - An Giang, My An Hung - Lap Vo ...). In

addition, erosion and sedimentation are two persistent phenomena in

which erosion is predominant; Erosion tends to reverse downstream;

river channel change complex but river channel change range takes

place in ancient riverbed area, the upper riparian area has river

channel change level greater than tidal area.

2. Variation of Tien River channel is the result of the combined

effect of natural factors and human activities on the relationship

between river bed and river flow. The conduction is the result of the

19

flow but at the same time the conduction of change (morphology,

structure ...) affects the distribution, flow dynamics. Therefore, when

studying the river channel change on the basis of the geographical

synthesis approach, the author considers the river bed as the main

research object.

3. The watershed activities in the basin and locality are causes of

the increase and complexity of the river channel process in recent

years. Concern and in particular concern about the impact of human

activities on the river channel change are the construction of

upstream hydroelectric dams and the over-exploitation of river basin

material as well as local resources that are lacking depletion of silt,

change of river flow dynamics causes large river bed erosion.

4. Identification of changes; the cause of river channel change is

crucial authentic basis in warning the prospect of channel change in

the future.

Chapter 3.

WARNING AND PROPOSING FOR RESPONSE SOLUTIONS

TO ADAPTIVE WITH VARIATION TIEN RIVER CHANNEL

BELONGS TO DONG THAP PROVINCE

3.1. WARNING VARIATION TIEN RIVER CHANNEL

3.1.1. Basement of alarming

There are a myriad of various methods for warning the trend of

river process. Each method has its advantages and disadvantages. In

the study area, the author uses three warning methods: (i) trend-based

warning methods; (ii) flow dynamics warnings; (iii) Geographic

Synthesis. Based on the currently situations, rules, causes, and trends

of river basin and factors that may influence on the change of flow

(scenarios of socio-economic development of countries into the

basin, and climate change) to warn the trend of Tien river in Dong

Thap province until 2030.

3.1.2. Methods for warning

Based on application of three methods: trend analysis method, flow

dynamics method, geographic synthesis method, warned of the trend of

changes in Tien river channel by 2030 (table 3.14 and table Figure 3.4).

- 19 -

Figure 3.4. Map of warning for changes of Tien River channel

belongs to Dong Thap province until 2030 year

20

3.2. PROPOSED SOLUTIONS

3.2.1. Viewpoint: The proposed solution have to be integrated,

systematic, legacy and sustainable exploitation and use of the river.

3.2.2. Background of the proposition: The proposed solutions are

based on the currently state of the situation, causal analysis and

influencing factors; mechanisms and trends (chapters 2 and 3 of the

thesis); natural, socio-economic characteristics and local

development planning.

3.2.3. Solution for adaptive capacity

3.2.3.1. Preventative solutions

Channel changes preventive solutions are essentially non-

constructive solutions to mitigate adverse impacts, increasing the

impact on the channel change. Precautionary measures include

measures such as strengthening cooperation with countries in the

basin; Intensify propaganda to raise people's awareness, especially

people living on the river and on the river; Improved management of

river exploitation; Protection and reforestation, greening bare land

and bare hills in the basin.

3.2.3.2. Evasion solution

These are measures to minimize the damage caused by channel by

avoiding layout, construction, development planning in areas where it is

occurring or the risk of occurrence of diarrhea, Especially high erosion.

This solution includes the following basic measures: corridor

forecasting and risk warping; Relocate people out of high risk areas;

Development planning is appropriate.

3.2.3.3. Resistance defense solution

Anticipatory measures are essentially a system of construction

measures implemented in high risk areas to limit the impact of water

flow to the riverbank. Depending on the level of protection of the

work, we divided into two groups of solutions: the group of passive

protection solutions and the group of resistance solutions are active in

21

preventing river fluctuations. Resistance solutions include passive

solutions (reinforced by embankments, grass ...) and active solutions

(welding torches, dams, currents).

CONCLUSION CHAPTER 3

1. Based on the geographic point of view, the thesis has developed

criteria and warned areas at risk of river channel change at levels

(high, medium, low) as the basis for proposing solutions. Response,

mitigation. The thesis uses three trend-based warning methods,

according to flow dynamics and geographic synthesis based on

dynamic morphometric approach. The results of the general

assessment show that the large fluctuation areas are identified as the

Tien River flowing through Hong Ngu district, Hong Ngu town and

Bac Tay Island in Thanh Binh district and Ho Chi Minh city. Sa Dec

- An Hiep commune, Chau Thanh district.

2. River channel change warning in general and shore bank

erosion on the basis of the required river basin morphometric analysis

is required according to the integrated geographic approach.

3. In order to deal with the changes of Tien river channel, Dong

Thap province should implement solutions in a systematic manner:

both preventive and evasive solutions are available. Protective

measures; There are both structural and non-structural measures.

4. In order to timely overcome and limit the phenomenon of river

channel change in Tien River, it is necessary to prioritize investment

in erosion sites, which is more complicated and badly affecting local

socio-economic activities. However, due to the limited funding

sources and the river channel change is the natural law, so it is

necessary to prioritize the construction according to the level, only

use the construction solution when really necessary and be calculated

and carefully consider before construction.

22

CONCLUSIONS AND RECOMMENDATIONS

1. CONCLUSIONS

Through the thesis “Studying the spatio-temporal variation of Tien

River channel belongs to Dong Thap province for natural disaster

adaptive capacity”, PhD candidate draws some basic conclusions:

1. The thesis synthesizes and analyzes the results of research on

river channel change in the world and in Vietnam:

1.1. Research on channel change in general and braided river in

particular are diverse in terms of research methodology. In it, focus

on three main directions: river morphological conditions are often

taken care by scientists in the field of geology - geomorphology;

Flow dynamics approach was investigated by hydrological,

hydrological and geoscientist scientists studying channel change in

the direction of synthesis.

1.2. The dissertation uses an integrated geographic approach to

analyze and evaluate the characteristics, processes, causes and

warning trends of Tien river basin in Dong Thap province. In it, the

river lead the main research object.

2. The dissertation has clarified the characteristics and causes of

the changes of Tien River channel on the basis of historical approach

and random approach:

2.1. The variation of Tien River channel belong to Dong Thap

province takes place in a braided river system in terms of planes,

longitudinal and transverse sections. In it, the strongest manifestation

and the most complicated is the change of shoreline. Tien river bank

fluctuation is a type of disaster occurring on a large scale,

complicated evolution; created a lot of damage in Dong Thap

province. At present, Tien river bank (with river bank erosion is

dominant phenomenon) occurs in 9/9 districts / town where the river

flows through. Of which, districts like Hong Ngu, Cao Lanh city, Sa

Dec - Chau Thanh has the highest level of river bank fluctuations.

2.2. The variation of Tien River channel belongS to Dong Thap

province is complicated but still has a "rule": (i) River channel

changes according to the development of braided river, fluid flow,

erosion, frequent accretion on the cross section, along the river ; (ii)

23

river bank segments that are affected by upstream flows are more

likely to experience greater fluctuations than tidal affected river

sections; (iii) river bank accretion usually occurs at the end of the

isle, the convex ridges, opposite the eroded river bank; (iv)

fluctuations tend to shift downstream; (v) River channel changes only

occurs within the ancient river bed.

2.3. The variation of Tien River channel belong to Dong Thap

province is closely related to many factors. Inside:

- The water flow is the main active principle combined with soft

geological structure with two types of typical profile (alluvial - island

formed by the activity of the river and the original delta formed

before Rivers) are susceptible to change under the influence of the

external force, the characteristic riverbed shape of tributary river and

curved river create favorable conditions for the process of

fluctuations (erosion, accretion) river conduction occurs.

- Local socio-economic and social activities (such as watershed,

river and riverine buildings, illegal sand mining, navigation, and

aquaculture) contribute to make the process of Tien river channel more

complicated. Thus, human activities in the basin and in the locality,

especially in the construction of hydropower dams, illegal sand

mining, alter the flow dynamics, resulting in a lack of sediment. The

increase and complexity of the river process.

3. On the basis of geographic aggregation, the thesis warned and

proposed appropriate solutions to deal with Tien River:

3.1. To forecast future river channel change can use many

different methods. In particular, the geographic synthesis method has

many advantages because it is a combination of different methods.

Therefore, the river river channel change trend warning is based on

the analysis of the river valleys dynamics of credibility required by

the integrated geographic approach. Based on the synthesis of three

methods (trend trends, flow dynamics and geographic synthesis), the

thesis has alerted the Mekong River Delta trend until 2030. In which,

flows through Hong Ngu district; North Tay Island; Cao Lanh city

and Sa Dec - Chau Thanh.

3.2. To actively respond to mitigation losses by the change of

Tien river channel in Dong Thap province should systematically

24

implement solutions: there are solutions and non-works solutions;

There are groups of solutions for prevention purposes, groups of

solutions to evade and a group of solutions that are protective. In

particular, the priority of non-structural solutions by erosion-

accretion is the rule of the rivers. Construction solutions are only

implemented in areas with strong changes that protect areas of

significant socio-economic, security and national defense and should

be carefully considered and evaluated on a scientific basis prior to

construction.

2. RECOMMENDATIONS

1. Strengthen the management of the exploitation and use of

rivers, especially in the field of exploitation of river bed material

(river sand), construction of above and riverside works, irrigation

works ... Minimize the impact to increase the level of Mekong River

Delta in particular and the Mekong River in general. In addition, it is

necessary to strengthen cooperation with countries and localities

sharing basins in the management, exploitation and use of the basin.

2. Dong Thap province should carry out a survey, assess the

synchrony and specific points of the river bank of Tien Giang so as to

select the most reasonable and effective solutions (solutions must

conform to natural characteristics Territory and socio-economic

conditions of the locality). At the same time, in urban development

planning, residential areas need to focus on identifying erosion

corridors (fluctuations) to avoid population disposition, socio-

economic bases, and infrastructure in areas high risk of erosion. In

other words, Dong Thap province should have a master plan for the

exploitation and management of Tien River to ensure the stable and

sustainable development of the river section running through the

province in particular, to the Mekong Delta region in general.

3. Channel change research needs close cooperation between local

authorities, people in the area and scientists. On the other hand, the

team of scientists also need coordination between different fields

such as Mechanics, Hydraulics, Geology, Geomorphology,

Geography, Environmental Resources, GIS and Remote Sensing.

i

THE INNOVATION OF THE DOCTORAL THESIS

Theoretical points for defending:

1. The channel of Tien River which flows through Dong Thap

province is undertaking on the mechanism of braided river, fluid

flow, erosion and accretion often occur along the cross section and

along the river.

2. Activities of dwellers have impacted on developing of the

spatio-temporal change in channel of Tien River belongs to Dong

Thap province.

3. It is predicted based on dynamic morphology and testing

hypotheses via general geography approach.

The innovation of the thesis:

1. Found out features and reasons which create variation of the

channel by using applying historical and random approach.

2. Analyzed in some respect the directly consequences of

residents on the Tien River channel process in Dong Thap province.

3. Warning and suggesting solutions for reducing effects on socio-

economic development in the study area based on synthetic

geography approach. It is also scientific foundation for proposing to

natural disaster adaptive capacity.

ii

THE PUBLICATION OF ARTICLES

1. Articles in Journal of Science

1. Trinh Phi Hoanh, La Thuy Huong, Study of riverbank erosion of the

Tien river in Dong Thap province on the viewpoint of general physical

geography, Scientific Jounal of Saigon University, 2013, No 18, pp. 77-85.

2. Trinh Phi Hoanh, The reality of riverbank of Tien river in Dong Thap

province during the period 2009 - 2013, Jounal of Sciences, Ho Chi Minh

City University of Education (Special issue: Natural Sciences and

Technology), 2014, Vol 92, No 58, pp. 161-171.

3. Trinh Phi Hoanh, A study of natural environmental hazards in Dong

Thap province and solutions top prevent and mitigate the damage, Jounal of

Sciences, Ho Chi Minh City University of Education (Special issue: Natural

Sciences and Technology), 2014, Vol 95, No 61, pp. 185-198.

4. Trinh Phi Hoanh, The impacts of economic - social activities on the

channel change of Tien river in Dong Thap province, Jounal of Sciences,

Ho Chi Minh City University of Education (Special issue: Natural Sciences

and Technology), 2014, Vol 98, No 64, pp. 127-138.

5. Trinh Phi Hoanh, Assessing the situations and causes of riverbank

erosion of Tien river in Dong Thap province, Scienctific Jounal of Tra Vinh

University, 2015, No. 20, pp. 61-67.

6. Trinh Phi Hoanh, Pham The Hung, The relationship between the sand

exploitation activities and changes of Tien’s riverbank in Dong Thap province,

Jounal of Science, An Giang University, 2016, Vol 12, No 4, pp. 92-103.

2. The articles in proceedings workshop, information science

2.1. The article was published in foreign country

1. Trinh Phi Hoanh, Le Van Luyen, Phung Thai Duong, The causes

increase erosion of Tien river's bank - a tributary of Mekong river that run

through Dong Thap province, Vietnam, Proceedings of Young Scientists

Conference on Earth Research 7th Novosibirsk National University, 2014,

pp. 236-237, ISBN: 978-5-4437-0313-8, Russia, 17-21th, November 2014.

iii

2.2. The articles were published in domestic

1. Trinh Phi Hoanh, Nguyen Tham, Vu Thi Thu Lan, The rules of

riverbank of Tien river in Dong Thap province, Proceedings of the 8th

National Scientific Conference on Geography (Vol 1), Ho Chi Minh city

University of Education Publishing House, 2014, pp. 424- 432.

2. Trinh Phi Hoanh, Nguyen Tham, Vu Thi Thu Lan, Pham The Hung

and La Van Hung Minh, Overall solutions to prevention, demaging mitigation

caused by changing of Tien river in Dong Thap province, Proceedings of the

8th National Scientific Conference on Geography (Vol 2), Ho Chi Minh city

University of Education Publishing House, 2014, pp. 244-250.

3. Trinh Phi Hoanh, The impact of sand exploitation on change of Tien

river in Dong Thap provice, Proceedings of Workshop help in University of

Social Sciences and Humanities, Viet Nam natinonal University Ho Chi

Minh City, pp. 30-42.

4. Trinh Phi Hoanh, The causes increase change of Tien river's chanel

that run through Dong Thap province, Information of Science and

Technology of Dong Thap Press, 2014, No 05, pp. 14-19.

5. Trinh Phi Hoanh, Pham The Hung and La Van Hung Minh,

Application of GIS and Remote sensing technology to analyze changes of Tien

river's bank that run through Dong Thap province from 1966 to 2013,

Proceeding of Conference for 40 years of Vietnam Academy of Science and

Technology (Earth Science section), October 2015, pp. 214-216, Hanoi.

6. Trinh Phi Hoanh, The regularity changes of Tien river's bank that

run through Dong Thap province period from 1966 to 2013, Proceeding of

Conference for 40 years of Vietnam Academy of Science and Technology

(Earth Science section), October 2015, pp. 217-219, Hanoi,.

7. Trinh Phi Hoanh, Overview of research in change of river bed,

Proceedings of the 9th National Scientific Conference on Geography (Vol 1),

Publishing House for Science and Technology, 2016, pp. 686-695.

8. Trinh Phi Hoanh, Identifying research issues of forecasting the

development of Tien river’s channel that run through Dong Thap province

based on the viewpoint of synthesis geography in The challenges to

sustainable development in Mekong River Delta, Ho Chi Minh City National

University Publishing House.2017, pp. 84-103, ISBN: 978-604-73-5237-1.