Investigation of Coastline Change in Relation to ...

Investigation of Coastline Change in Relation to Climate Conditions and Human Activities: A Case Study of Ngoc Hien District, Vietnam

by

Duong Thanh Thoai

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management

Examination Committee:

Nationality: Previous Degree:

Scholarship Donor:

Prof. Nguyen Thi Kim Oanh (Chairperson) Dr. Oleg Shipin (Member) Dr. Theo Ebbers (Member)

Vietnamese Bachelor of Science in Forestry University of Agriculture & Forestry, Vietnam International Fellowships Program-Ford Foundation, USA - AIT Fellowship

Asian Institute of Technology School of Environment, Resources and Development Thailand May 2013

Acknowledgements

First of all, I would like to express my deep gratitude to Ford Foundation Scholarship Program (IFP) and Mrs. Minh Kauffman – Director of IFP in Viet Nam for giving me the chance to come to AIT and also thanks for Center for Educational Exchange with Viet Nam (CEEVN) support and encouragement during my study at AIT. I have a great pleasure to express my deep thanks to my Supervisor, Prof. Nguyen Thi Kim Oanh, for her constant supervision and guidance during my study. Sincere regards and thankfulness are given to my committee member Dr. Oleg Shipin, for his supporting during my coursework also my thesis work. I am more than grateful to my committee member, Dr. Theo Ebbers, for his supporting during my thesis work and also thank for supporting from his project, Wetlands Alliance Outreach supported a grant for my thesis. I would like to express my sincere appreciation to staffs and faculty members of EEM department for their helps during the coursework, especially the EEM secretary, Khun Suchitra for her kindly support and guidance me during my time in AIT. Grateful acknowledgement is also given to Doctoral Candidate Mrs. Nguyen Thi Hong Diep and Msc. Mrs. Phan Kieu Diem, Land Resources Department College of the Environment and Natural Resources Can Tho University for their helps during my thesis work. Special thanks are extended to Department of Agriculture and Rural Development (DARD), Department of Natural Resources and Environment (NoNRE), and Department of Forestry of Ca Mau province for their help during my thesis work, and as well as to local people in Ngoc Hien district, Ca Mau province for their cooperation during my field work. Sincere thanks from deep of my heart to my dearest mother, my wife Mrs. Nguyen Bich Thuy, my sweet daughter, Ms. Duong Nguyen Thao Vy and my siblings who are always being with me in my life and for their encouragement me during my study. Finally, I would like to extend my appreciation to my relatives and friends for their helps, suggestions and encouragement.

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Abstract

The goal of this study was to provide a better understanding of the coastline change in Ca Mau, Vietnam. The effects of climate conditions and human intervention were considered. Remote sensing technology and GIS, the time series satellite images included Landsat TM, ETM+, which cover the time frame between 1990 to 2011 were used. Coastline changes, land use structures change in Ngoc Hien district of Ca Mau province were quantified and mapped out. In the study period from 1990 to 2011, Ngoc Hien area lost 2,206 ha land. The change was divided into four periods. From 1990 to 1995, this region lost 1,675 ha but gained deposited 795 ha land in period 1995 – 2000, thus resulted in a net loss of 880 ha. The next period, from 2000 – 2005, this region lost 617 ha land and it continued erosion 708 ha land in period 2005 – 2011. During period 1990 – 2011, forest land reduced 17,952 ha while aquaculture area increased 11,933 ha. The causes of forest area change were erosion, deforestation or change in land use purpose. Area for infrastructure increased 3,092 ha. Water body increased 722 ha. There was a significant effect of coastline change on structure of land use in Ngoc Hien. Coastal zone of Ngoc Hien eroded 2,206 ha from 1990 to 2011 lead to the change in land use structure along the coast Human interventions such as deforestation, dredging rivers and construction along coastal zone were recorded as the important causes of coastline change in the study period in Ngoc Hien. In this period, the effect of climate conditions, such as rainfall, storm on coastline change were worth considering, but these climate conditions are complexly related hence could not quantified in this study. The valuation of coastal zone change, climate conditions (rainfall, storms) and human activities (deforestation, dredging river and infrastructure) were analyzed during the period which revealed similar pattern of five years average of these considered factor. The relationship between these variables existed and potentially significance. However, these may be complex and multivariate relationship that still can not be quantified using the time series analysis employed in this study. The out come of this study provided a basic for local people, decision makers to develop appropriate solutions for coastland management.

Key Works Coastline change, Land use structure change, satellite image, remote sensing, climate condition, human intervention, Principal Component Analysis, PCA, Ngoc Hien, Vietnam

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Table of Contents Chapter

Title Title Page Acknowledgement Abstract Table of Contents List of Figures List of Tables List of Abbreviations

Page ii iii iv v vi vii

I

Introduction

1

1.1 1.2 1.3 1.4 1.5

Background of the study Statement of the Problem and Rationale Objectives Scope of study Null Hypothesis

1 1 2 2 2

II

Literature Review

3

2.1 2.2 2.3 2.4 2.5 2.6

Application of remote sensing for coastline change investigation Coastal changes Coastland change in Vietnam Effects of coastline change Coastal zone management practices in the world Summary and research gaps

3 5 10 19 21 22

III

Materials and Methodology

23

3.1 3.2 3.3

Methodology framework Study site Methodology

23 24 25

IV

Results and Discussions

31

4.1 4.2 4.3

Coastline change measurement Causes of coastline change The effects of coastline change on land use of study area

31 39 49

V

Conclusions and Recommendations

56

5.1 5.2

Summary and Conclusions Recommendations

56 56

References

58

Appendix

61

iv

List of Figures

Figure 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 3.1 3.2 3.3 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20

Title Spectral Bands of ASTER Thematic Mapper Coastal erosion sites in Asia and Indian Ocean countries Factors causing coastal change The complex processes of coastal erosion and deposit Cliff coast structure Construction for protection Coastline erosion in the central of Vietnam Wind and wave direction in Southern area of Vietnam Coastline change in Ngoc Hien and Nam Can commune, Ca Mau during the period 1973 – 2008 General Circulation in the winter and in the summer on the East Coast. Storms affected Vietnam and Ca Mau in the period 1990 – 2011 The deforestation in Ca Ma in period 2005 – 2007 Land use status current in Ca Mau Comparison mangrove forest in Ngoc Hien, Ca Mau in 1965 - 2001 Methodology framework Study area, Ngoc Hien district, Ca Mau province Mapping process Coastal zone change in Ngoc Hien district, Ca Mau in period 1990 –2011 Coastline change map of Ngoc Hien in period 1990 - 1995 Coastal zone change in Ngoc Hien in this period in different communes. Coastline change map of Ngoc Hien in period 1995 - 2000 Coastal zone change of Ngoc Hien in 1995 – 2000 in different communes Coastline change map of Ngoc Hien district in period 2000 - 2005 Coastal zone change of Ngoc Hien in 2000 – 2005 in different commune Coastline change map of Ngoc Hien district in period 2005 - 2011 Ngoc Hien coastal zone change in stage 2005 – 2011 The trend of coastal zone change of Ngoc Hien in different communes Variation of annual average rainfall in each five years period in study time Storm affected Ngoc Hien, Ca Mau province in period 1990 – 2011 The change of sediment volume dredging from rivers during 1990 –2011 The relationship between coastline change and rainfall, storms. The relationship between coastal line change and human activities Land use map of Ngoc Hien district, Ca Mau in 1990 Land use map of Ngoc Hien district in 1995 Land use map of Ngoc Hien district in 2000 Land use map of Ngoc Hien district in 2005 Land use map of Ngoc Hien in 2011

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Page 3 6 7 8 10 12 14 15 16 18 19 20 21 23 25 29 31 32 33 34 35 35 36 37 38 38 41 43 45 46 47 50 51 52 53 54

List of Tables

Table 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.1 3.2 3.3 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19

Title Characteristic of the Three ASTER Sensor Subsystems Spectral Property of Various Versions of Landsat Images Overview of the Coastal Erosion Intensity in the Red River Delta Rate of Coastal Erosion in Different Sections Coastal and River Mouth Erosion of Southern Provinces Distribution of the Annual Monsoon in Ca Mau Storm Affected in Viet Nam in the Period 1990 – 2011 Overview Land Use Status Current in Ca Mau Land Use Distribution in Forest Region in Ca Mau Characteristics of Zones in Ngoc Hien The Land Use Types Identified in the Study Area Indications Used for Trend Analysis of Climate Condition and Human Intervention Coastal Zone Change in Ngoc Hien During 1990 – 2011 Area Change Identify in the Study Region in Period 1990 - 1995 Area Change Identify in Study Region in Period 1995 - 2000 Area Change Identify in Study Region in Period 2000 - 2005 Coastal Zone Change Identify in Study Region in Period 2005 - 2011 Monthly and Annually Average Rainfall in Ngoc Hien in 1990 –2011 Monthly and Annually Average Rainfall in Ngoc Hien in 1990 –2011 Coefficient of Variation of Monthly and Annually Rainfall (Cv; %) Storms Affecting Coastal Zone Binh Thuan - Ca Mau in 1990-2011 Number of TC Affecting Ca Mau at Different Degrees/ Levels Forest Area of Ngoc Hien Change in Period 1990 - 2011 The Relationship Between Coastal Line Change and Human Activities Experts and Households Opinion on Causes of Coastal Zone Change Land Use Classes of Ngoc Hien District in 1990 Land Use Classes of Ngoc Hien District in 1995 Land Use Classes of Ngoc Hien District in 2000 Land Use Classes of Ngoc Hien District in 2005 Land Use Classes of Ngoc Hien District in 2011 Land Use Structure of Ngoc Hien in period 1990 - 2011

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Page 4 5 11 13 14 16 18 20 21 26 26 27 32 33 34 36 37 39 40 40 42 43 44 44 48 50 51 52 53 54 55

Abbreviations ACIA

Arctic Climate Impact Assessment

ASTER

Advanced Space borne Thermal Emission and Reflection Radiometer

CAD

Computer Aided Design

CM

Ca Mau province

CNC

Computer Numerical Control

DARD

Department of Agriculture and Rural Development

DoMH

Department of Meteorology and Hydrology

DoNRE

Department of Natural Recourses and Environment

EOS

Earth Observing System

EOS

NASA’s Earth Observing System

EROS

Center for Earth Resources Observation and Science

GIS

Remote sensing and geographic information systems

HDF

Hierarchical data format

IPCC

Intergovernmental Panel on Climate Change

LGED

Local Government Engineering Department

LP DAAC

Land Processes Distributed Active Archive Center

MSS

Multispectral Scanner

NH

Ngoc Hien district

TC

Tropical cyclone

TD

Tropical depression

TM

Thematic Mapper

USGS

U.S. Geological Survey's

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1. Chapter 1 2. Introduction 1. 1 Background Coastal line is mentioned by the line of contact between land and water body. Controlling the change of coastal line is a very important part of coastal zone protection. The change of coastline including erosion and deposit (accretion) has got special attention because of the multiple effects on environment, natural resources, ecology systems, social-economy, culture and defense security. The coastlands are most vulnerable areas because of the effects of climate conditions and human activities. The coastland erosion and deposit have become global problems. There are about 70% of the sandy beaches on the world are recessional (Bird, 1985); 86% of the United States East coast barrier beaches have experienced erosion during the past hundred years (Galgano et al., 2004). The phenomenon also occurred in California (Moore et al., 1999) and in the Gulf of Mexico (Morton and McKenna, 1999). In Asia, the change of coastal is complex happened. According to Bilan (1993), the erosion rate in the northern part of Jiangsu province in China is serious with average of 85 m/year; Hangzhou Bay is 40 m/year, and Tianjin is from 16 to 56 m/year. Othman (1994) reported that in Malaysia nearly 30% of coastline is undergoing erosion. During the past decade, net erosion of Thailand was approximately from 1.3 to 1.7 m/year (Thampanya et al., 2006). Viet Nam coastline was complicated changing during past decades. In the North coast region, coastland was eroded 17m/year during 1930 – 2005. The coastland erosion was also happened in the Central region with the higher ratio, from 30 to 60m/year with the same period 1930 – 2005 (Tien et al., 2005). Coastal line in the Southern of Vietnam has been under erosion continuously at a rate of around 50 m/year during last century (Mazda et al., 1997; Cat et al., 2006). Among which, the erosion of coastal area in Ca Mau province during 100 past years is very serious with a total eroded area of 280 km2 and averagely 2.8 km2/year, equivalent 280 ha per year. The average rate of erosion is from 26 to 30 m/year, particularly from 50 to 67 m/ year at Bo De river mouth. This erosion mostly caused by wave and current activities. However, vanishing mangrove vegetation by the long-term impacts of human activities since the late nineteenth century also caused erosion. Moreover, human-induced change within watersheds which has decreased the sediment provides to the shore (Lap et al., 2012). 1.2 Statement of the Problem and Rationale Vietnam has more than 3,260 km of seashore stretching from the North to the South. With a special geographic position, Vietnam coastland is adversely affected greatly by climate conditions and human activities. Ca Mau Cape of Vietnam is a typical instance of coastal change. About a decade ago, Ca Mau cape was reported to expand toward the sea and gain hundreds of meters per year. However, recently the opposite trend has been reported. The area is eroded hundreds of meters leading to forest loss, damaged infrastructure, insecure livelihood etc. Various reasons lead to coast changes, including extreme climate conditions (rainfall, storm, sea level rise etc.), hydrographic phenomena (flow, tide, wave, etc.), and development projects around the area. Investigation of the causes, trends of coastal change, including erosion and deposit, in Ca Mau cape is therefore a very important task. The result of such study will help local people to improve the adaptation strategies to minimize 1

adverse effects of coastline changes on their life. In addition, this study is able to help the policy makers, developers, competent authorities, regulators, and regional planners to find out appropriate solutions to reduce the impacts in the region. 1.3 Objectives The goal of this study is to reduce vulnerability reduction of local people through better understanding of the improved management for coastline protection and environment protection in coastland area of Ca Mau, Vietnam. The following concrete objectives are pursued to achieve the goal:  To assess coastline changes in the study area during the period 1990 - 2011.  To identify and assess the major potential causes of coastline changes, including climate conditions and human intervention during period 1990 – 2011.  To assess the effects of coastline change on land use of study area. 1.4 Scope of Study The spatial scope of this study is Ngoc Hien district of Ca Mau coastal zone that is located in the Southern region of Vietnam. The temporal scope is from 1990 to 2011. The study estimated the change of coastline from 1990 to 2011 in correlation with meteorological conditions and human activities. The data of coastal change, forest resource change; causes of coastline change; effects of coastline change on study area from 1990 to 2011 available in maps, satellite images, statistic data etc., were collected and analyzed. This study just only assesses the variation of climate conditions (rainfall, storm) and human intervention (deforestation, infrastructure and rivers dredging) during the study period. To estimate the effects of coastline change on land use during the period 1990 – 2011, the study focused on forest area change, coastal zone change, and land use structure change. 1.5 Null Hypothesis  Coastline change has no relation to meteorological conditions.  Coastline change has no relation to human activities.

2

3. Chapter 2 4. 5. Literature Review 2.1 Application of Remote Sensing for Coastline Change Investigation Remote sensing (RS) and geographic information systems (GIS) are two modern technologies that are universally used to control coastal line change. Satellite images have been used to study about changes in vegetation cover (Damizadeh et al., 2000). According to Mas (1999), satellite data has become a major application in change detection because of the repetitive coverage of the satellites at short intervals. ASTER is a high spatial resolution, multispectral imaging system flying aboard TERRA, a satellite launched in December 1999 as part of NASA’s Earth Observing System (EOS). An ASTER scene covering 61.5 x 63 km includes data of 14 spectral bands (Table 2.1). ASTER is comprised of three separate instrument subsystems representing different ground resolutions. The three bands in the visible and near infrared spectral are range (VNIR, 0.52- 0.86 μm) with 15 m partial resolution. Six bands in the shortwave infrared spectral are range (SWIR, 1.6 - 2.43 μm) with 30 m resolution. And five bands in the thermal infrared spectral range (TIR, 8.12 – 11.65 μm) with 90 m resolution (Figure 2.1).

VNIR

SWIR

TIR

0.52 – 0.86(µm) 1.6 – 2.43(µm) 8.12 – 11.65 (µm) Figure 2.1 Spectral bands of aster thematic mapper (Source: Abramsetal.,2009) In the VNIR, one nadir looking (3N, 0.78 - 0.86 μm) and one backward-looking (3B, 27.7° off-nadir) telescope provide black-and-white stereo images, which generate an along-track stereo image pair with a base-to-height ratio of about 0.6. ASTER is capable of recording 771 digital stereo pairs per day, and cross-track pointing out to 136 km allows viewing of any spot on Earth at least once every sixteen days. ASTER images can be purchased from the U.S. Geological Survey's (USGS) Center for Earth Resources Observation and Science (EROS) through the Land Processes Distributed Active Archive Center (LPDAAC) and the data are provided in hierarchical data format (HDF)-Earth Observing System (EOS) (HDF-EOS).

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Table 2.1 Characteristic of the Three ASTER Sensor Subsystems System

Band no

Spectral range (µm) 0.52 – 0.6 0.63 – 0.69 0.78 – 0.86 0.78 – 0.86 1.60 – 1.70 2.145 – 2.185 2.185 – 2.225 2.235 – 2.285 2.295 – 2.365 2.360 – 2.430 8.123 – 8.475 8.478 – 8.825 8.925 – 9.275 10.25 – 10.95 10.95 – 11.65

1 2 3N 3B 4 5 SWIR 6 (Short Wave 7 Infrared) 8 9 10 11 TIR 12 (Thermal Infrared) 13 14 (Source: Abrams et al, 2002) VNIR (Visible Near Infrared)

Spatial resolution (m) 15

30

90

Landsat instruments is a good example of showing continuous improvement in radio metric and spectral property of images enabling better understanding of land resources. The Landsat satellite had been provided repetitive, synoptic, global coverage of high resolution multispectral imagery since 1972. Landsat 7 was made by the US governmentin1999 demonstrated the evolution of long history and reliability have made them a popular source or documenting changes in land cover and land use over time (Turneretal., 2003).

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Table 2.2 Spectral Property of Various Versions of Landsat Images

Serial No 2

Name of satellite Landsat 4-5

Sensor

Band number

Band wavelengths (µm)

pixels (m)

1 2 3 4 1 2 3 4 5 6 7 1 2 3 4 5 6 7 4

0.5 -0 .6 0.6-0.7 0.7-0.8 0.8-1.1 0.45-0.52 0.52-0.6 0.63-0.69 0.76-0.9 1.55-1.75 10.4-12.5 2.08-2.35 0.45-0.52 0.52-0.6 0.63-0.69 0.76-0.9 1.55-1.75 10.4-12.5 2.08-2.35 0.5-0.9

82 82 82 82 30 30 30 30 30 120 30 30 30 30 30 30 60 30 15

MSS

TM

3

Landsat 7

ETM+

Pan

Size of

(Source: Engineering manual 2003) The satellite images are applied popularly in coastland management. For instance satellite was applied to manage Urmia Lake coastline extraction (in Iran) by extracted images from ETM+ and TM imagery for the years 1989, 1998 and 2001 (Alesheikh, 2004). 2.2 Coastal Changes 2.2.1 Understanding coastal change In this study, coastal change is mentioned by physical change to the shoreline, such as erosion, and coastal deposit. Coastal zone contributes a very important role in diversified ecosystem, economic, culture, social and defense security. However, coastal zone has changed around the world. According to Bird (1985), there was about 70% of the sandy beaches are recessed in global. In Asia, coastal erosion is the main cause lead to sea level continues to rise. A rise of 30cm in sea height may cause by 45m of land loss. Rising sea level and declining sea ice because of coastal erosion consent to higher wave and storm surge to hit the shore in Boreal Asia (ACIA, 2005). The coastal erosion may append up to 500 to 600 m in 100 years, equivalent a rate of 4 to 6 m/year. The coastal depression because of thermal abrasion is expected to accelerate by 1.4 to 1.5 times in the last 50 years of the 21st century as compared to the current ratio (Leont’yev, 2004). Coastal erosion is generally caused by decrease sediment in monsoonal Asia region. There are many evidences demonstrate a tendency of sediment in rivers to further decrease that will tend to get worse coastal erosion in Asia (Liu et al., 2001). Harasawa, et al., 2007 reported 5

on IPCC 4th Assessment Report states that the South East Asia coastal lines are greatly vulnerable to the effects by climate change and human intervention. Moreover, the geology and geography of some of the coastal regions, the growing density population and infrastructure in the coastal zones are also important causes lead to coastal change. In addition, large level variations of tidal, storms, resonated with the potential rising annual rainfall in region, suggest the potential for increased coastal risk. The large deltaic regions of Bangladesh, Myanmar, Viet Nam, and Thailand, and the low-lying areas of Indonesia, the Philippines, and Malaysia are the regions with crowded density, low topography, lying on coastal zones. Thus, these areas are easy vulnerable by coastal erosion and flooding (Figure 2.2).

Figure 2.2 Coastal erosion sites in Asia and Indian Ocean countries (Source: ARC, 2004) Coastal changes are result of a complement of several factors, such as erosion and deposit are two sides of a matter. The factors which lead to coastal erosion and deposit are closely related to each other and interact among them in a unified system. These phenomenons follow the nature law and are closely controlled by human (Figure 2.3). Thus, when one of the factors is changed, other factors are also changed to create a new balance (Tien et al., 2005). Natural processes take place over a range of time. They may happen in reaction to smaller-scale events, or in response to large-scale (long-term) events. The factors, such as wind, waves and currents are natural forces which effortlessly erode the unconsolidated sand and soils in the coastal area, follow-on quick changes in the shoreline. Moreover, human intervention along the coast, such as land reclamation, port development, shrimp farming, deforestation, within river catchments (river dredging) in combination with these natural forces are also the important causes which often exacerbate coastal erosion in many regions (Tien et al., 2005).

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Endogenous - Neotectonic activities and modern movement - Geological settings Exogenous - Waves and currents, coastal sediment flow - River and sea flow, sediment flow - Wind (storm, monsoon) and special weather conditions. - Sea level, tide - Physical-chemical properties

Coastline Change

Human activities - Hydraulic engineering, civil works. - Mining, extraction of construction material. - Deforestation watershed and mangrove forest Figure 2.3 Factors causing coastal change (Source: Tien et al., 2005) One of three main groups including exogenous, endogenous and human or a combination of 2 or 3 of those groups are caused coastal erosion or deposit (Tien et al., 2005). If the coastal shores characteristics are not carefully investigated, the erosion issues become worse when countermeasures are applied. For example, hard or soft structural, options applied is inappropriate, improperly designed, built, or maintained are not appraised. This problem is mostly attributed to insufficient knowledge of coastal processes and the protective function of coastal systems (Prasetya, G., 2001). Understanding the coastline change and the accuracy of measurement is important. The results derived can be properly applied for planning purposes. Long-term changes have more value for planning compared to short-term changes. In opposite, the latter may not capture the seasonal changes provided by the former that could be critical. Many researches have used different datum to measure coastal zone change. For example, a legally defined coastline which varies from country to country, vegetation line, seaward foot of coastal dunes and coastal scarp are the popular datum used to measure coastal change (Raju et al., 2010). The difference datums or coastal features will be obtained different values. The oldest reliable topographic maps are usually used as a baseline for longer term coastal line change whereas short term changes employ field techniques to detect small changes in coastline position. 2.2.2 Causes of coastline change The angles of sediment motion because of wind, wave and tidal; beach dynamics within a sediment; and human intervention along the coast, within river catchments and offshore, both at spatial and temporal scales are complex processes caused coastal erosion and deposit that need to be investigated. In terms of temporal scales, the phenomenon of sealevel rise is complex and produces a range of environmental issues. Sea level increase lead to the water depth increases and the wave base becomes deeper. The energy from waves can erode and transport greater quantities of sediment. As a result, the coastal line starts to 7

adjust to the new sea level to maintain a dynamic equilibrium. Figure 2.4 below lists the processes of coastal erosion and deposit, as well as natural factors and human activities.

Natural Factor

Human Activities

Climate Change

Winds

Rainfall

- Within the river catchments - Along the coast - Off shore

Tide Storm surges

Waves Currents

Sea level rise

Water seepage

Lands side

Sediment scouring and transport

Coastal deposit

Damage to coral reefs, sea grass

Prograding beaches, siltation

Dams

Coastal infrastructure

Sediment deficit

Coastal erosion

Breach of coastal loading defense

Coastal flooding

Habitat loss (eg. Beaches, wetland)

Destruction of building

Decrease of income

Figure 2.4 The complex processes of coastal erosion and deposit (Source: Prasetya & Gegar, 2001) The causes of coastal change can be grouped into two respects, external and internal factor. a) External factor: The external factor is understood as natural effects, such as rainfall, storm, wave, tide, flow, and human intervention, including within the river catchment, along the coast, off shore. Natural factors of coastal change are winds, storms, waves, tide, climate change (sea level rise), rainfall and other factors. The waves that ripple across on the surface of sea are created by winds. Then these waves are broken and crash into the shore. Wind direction in some areas approach the coastal line at oblique angles lead to waves approach coastal in the same to wind direction. A slight angle between the land and the waves will also create currents which transport sediment along the coast. These long shore currents are a primary agent of coastal movement. They are important causes of sand migration along barricade and mainland beaches. Tides are used to 8

determine where the waves break. The waves are low on the beach at low tide, high on the beach at high tide, where sand is deposited and eroded. Depending on characteristics of coastal and other phenomenon, these forces will impact coastal change on different levels. Not only the natural cause, but human activities also add another layer of complexity to the natural processes of coastal lands. The coasts change may cause by direct or indirect human activities. The activities may impact sources of new sediment to the coast and the movement of sediment within the coastal environment. They may promote changes in sea level, both local and global. Human interventions are often conducted without or less an adequate understanding of coastal geology and processes. Thus, coastal may difficult to control or they can lead to unforeseen degradation of coasts. These natural processes are affected through the human intervention. Although human activities intended to protect or improve the coast but without or less adequate understanding of coastal geology and processes may inadvertently increase negative effects on coastal. Aquaculture farming is known as important group actions which affect coastal change. Shrimp farming development in coastal zone has had a significant effect on the hydrology of mangrove forest zone. Many of the remaining mangroves forest are surrounded by levee banks, or situated in areas where tidal access is hindered. In mixed farms, mangroves forests are enclosed within a levee surrounding the farm, normal tidal flooding and flushing is prevented by the more or less constant water level in the pond.. Under outstanding value of shrimp, the competition between aquaculture area and forest area is became critical situation, forest area has been reducing but aquaculture area has been increasing. Constructions are also an important cause lead to coastal erosion. They are including civil, economic development and defenses as well as coastal protection construction always have advantages and disadvantages. On the one hand, the constructions serve human needs and interests. These are buildings, transportation systems (roads, bridges, and ports), architecture protection works, border protection works as well as sea protection works (sea walls), etc. While serving the human needs, these constructions also create direct or indirect effect on coastal. The constructions break coastal structure; contribute to coastal collapse and subsidence. Moreover, the flow along the coast will be changed under constructions effects. These adverse effects contribute to coastal change. b) Internal causes of coastal change: They are understood as coast characteristics (coast structure, shoreline direction, etc.) and surface coating material (forest, vegetable, etc.). Depending on internal cause characteristics could lead to coastal erosion or deposit. Coastal structure is divided in to 5 main types that are cliff coast, clayey bank coast, intertidal/muddy coast, sand dune coast, and sandy coast. Cliff coast can be classified as “hard” coast as it was formed from resistant materials such as sedimentary or volcanic rocks (Figure 2.5). Clayey bank coast is classified as a “semi-hard” coast, consisting of cohesive soils (Appendix 1). It is common on estuarine coastlines and often has nearly vertical banks ranging from one to five meters in height. Intertidal coast (muddy coast) is characterized by fine grained sedimentary deposits, predominantly silt and clay that come from rivers; it can be classified as a “soft” coast (Appendix 2). Sand dune coast consists of unconsolidated material, mainly sand, some pebbles and shells. It can be classified as a soft coast (Appendix 3), this type of coast can act as a barrier for the area behind the dunes. Sandy coast (Appendix 4)consists is of unconsolidated material mainly sand from rivers and eroded headlands, broken coral branches (coralline sand) and shells from the fringing reefs. Most erosion is caused by loss of (1) the protective function of the coastal habitat, especially coral reefs (where they are found) that protect the coast from wave action; and (2) coastal trees that protect the coast from strong winds. During extreme events, healthy

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coral reefs and trees protect coasts to some extent by reducing wave height and energy as well as severe coastal erosion.

Clayey bank wave base

Zoom of wave sediment interaction Storm wave base Sediment below wave – no wave interaction Zoom of storm wave sediment interaction

Wind below storm wave base

Zoom of Tsunami wave interaction

Figure 2.5 Cliff coast structure (Source: modified from ARC [2000] and French [2001]) 2.3 Coastland Change in Vietnam 2.3.1 Overview coastal change in Vietnam Vietnam has a long coastal zone of 3,260 km, extending through the territories of 24 provinces and cities that include 127 urban and rural districts, 21 towns and 6 cities. In the coastal zone, there have occurred a series of interactive processes between the land and the sea, between the dynamic forces of rivers and the sea, between the natural forces and human processes. On average, there is a river mouth in every 20 km along the coast of Vietnam (Cat et al., 2006). The coastal zone terrains of Vietnam are multiform and diverse. The coastal zone of Vietnam also receives many natural calamities leading to multidirectional impacts on the nature and socio-economic conditions. In particular the coastal erosion is causing many difficulties for the life of the coastal population. The status of coastal erosion and sedimentation in Vietnam is diverse from area to area, depending on the lithological composition of the coast and the river - marine dynamic regime. According to Cat et al., (2006), in the North region, coastal erosion usually associates with sedimentation and occurs in a complicated manner depending on many natural and human factors, of which the main ones are the lithological composition of the coast and hydrographic and oceanographic dynamic regime. The coastal erosion in Quang Ninh area occurs only locally within short coastal sections. However, in the coastal zone of the Red river delta the coastal erosion occurs in relatively long coastal sections between the coastal sections with sedimentation near river mouths (Table 2.3). Remarkably from Mong Cai to Hau Loc, six coastal sections including Cat Hai, Bang La, Thuy Xuan, Xuan Thuy, Hai Hau, Hau Loc continuous erosion from 1930 to present have been recorded, of which two areas of very serious erosion are Cat Hai and Hau Loc. 10

Table 2.3 Overview of the Coastal Erosion Intensity in the Red River Delta Area

Erosion indentify 1930 - 1965 1965-1990 1990 - 2005 (km) km % km % km % Erosion length 25.12 19.07 1.8 Low (0 – 2.5 0.67 3.5 Do Son – Moderate (2.5 – 5) Ba Lat High (5 – 10) 15.52 61.78 4.9 25.7 Very high (> 10) 9.6 38.22 13.5 70.8 1.8 100 Erosion area 17.2 ha/year 9.87 ha/year 2.0 ha/year Erosion length 21.26 39.9 22.75 Low (0 – 2.5 3.3 15.5 Ba Lat – Moderate (2.5 – 5) 2.5 11.8 2 5 Lach High (5 – 10) 3.8 17.9 8.2 20.6 0.8 3.5 Truong Very high (> 10) 11.6 54.8 29.7 74.4 21.95 96.5 Erosion area 15.1 ha/year 37.98 ha/year 26.08 ha/year Erosion length 46.38 58.97 25.45 Low (0 – 2.5 3.3 7.1 Do Son – Moderate (2.5 – 5) 2.5 5.4 2.67 4.5 Lach High (5 – 10) 19.32 41.7 13.1 22.2 1.3 5.1 Truong Very high (> 10) 21.26 45.8 43.2 73.3 24.15 94.9 Erosion area 32.33 ha/year 47.85 ha/year 27.43 ha/year (Source: Tien et al., 2005) The coastline in the Central region of Vietnam is 1,765 km long (from Thanh Hoa to Binh Thuan province), of which 392 km are being eroded, accounting for 22% of the total coast line. In this area, there are 263 erosion sites have been recorded. The erosion area covers from 1.4 ha to 262.8 ha in the period 1990 - 2003. The total area of coastal erosion in this period is 8,839 ha. In this region, the coastal erosion occurs at different rates (Table 2.4). The areas with irregular, rugged landform, with many bays and peninsulas, bedrock, river mouth areas erosion occurs with small extent, low to medium intensity. In convex coastal sections facing wind and wave direction, with sand being the main shore-building material, erosion occurs from strong to very strong. There are up to 268 erosion sections composed of sand, accounting for 93.7% of the total erosion sections (Tien et al., 2005).

11

Figure 2.6 Construction for protection Coastline erosion in the central of Vietnam (Source: http://talkvietnam.com/2011/11/central-coast-ruin)

12

Table 2.4 Rate of Coastal Erosion in Different Sections Rate of erosion inland

Provinces

Coastal sections

Thanh Hoa Very high > 30 m/year

Hoang Thanh (Hoang Hoa district) Ngu Loc (Hau Loc district) Xuan Hoi (Ngu Xuan district) Phuoc Thuan, Tuy Thuan, Hoai Thanh, Hoai Nhon Phu Dong, Nha Trang Tam Hai (Nui Thanh district) Nghi Hai (Nghi Loc district) Cam nhuong (Cam Xuyen district) Hai Thanh, Dong Hoi Vinh Hien (Phu Loc) Hai Duong (Thuan An) Duy Hai (Duy Xuyen), Binh Minh (Thang Binh), Tam Tien (Nui Thanh) Duc Loi (Mo Duc), Phuoc Thuan (Tuy Phuoc), Nhon Chau (Quy Nhon), Nhon Phuc (An Nhon) Song Cau (Tuy Hoa) Van Gio, Dai Lanh, Van Ninh

Ha Tinh Quang Ngai Khanh Hoa Quang Nam Ha Tinh Quang Binh Thua Thien – Hue

Rate of erosion period 1999 – 2000 40 – 60 meters/year

Quang nam Quang Ngai

Phu Yen Khanh Hoa (Source: Cat et al., 2006)

The Southern coast of Vietnam, from Ho Chi Minh City to Kien Giang province, is composed of young unconsolidated alluvial sediments (modern Holoxen age - Late Pleistoxen) with a mostly brown clay silt, mud brown clay containing sand and creatureplants carcasses. The solid rock coast is concentrated only in Hon Dat of Kien Giang (Lap et al., 2000; Hoi et al., 2003; Oanh et al., 2002; Hieu et al., 2005, Xue et al., 2010). With its typical geological structure, waves characteristic and wind direction (Figure 2.7), if surface vegetation texture sparse or without vegetation surface, just moderate driving force of waves is enough to break the bank. Due to soil grain compositions are very fine; most bank materials after break will be converted to suspended sediment, which are transferred easily to other places by coastal waves and currents. In the strong erosion areas of Southern region as Go Cong Dong (Tien Giang), Vinh Chau (Soc Trang), when the protective forest belt pioneer outer is degraded, the erosion process will happen continuously, with increasing speed.

13

(A) (B) Figure 2.7 Wind and wave direction in Southern area of Vietnam, (A) wind direction in Ben Tre coastal in period 2000 – 2008; (B) wave direction in off-coast of the Southern coast sea – 28km far from the coast. (Source: Hung et al., 2012) The coastal erosion has been happening complexly in this region. The extent of coastal erosion in South region is increasing from the past to present. From Vung Tau to Ha Tien coastal zone, there were not erosion before 1940. In stage 1940 - 1950, coastal erosion happened in the river mouths of the region with low ratio. However, coastal erosion had been rather common almost all over the coastal zone of the provinces in the Southern plain in period 1960 to before 1995. Since 1995, coastal erosion has been occurring in a rather complicate manner, in many areas in the Southern plain lead to serious consequences. The intensity and extent of the erosion occurring are also different in each province, region or zone such as, Can Gio of Ho Chi Minh City, Dong Hai of Tra Vinh province; Ngoc Hien, Dam Doi and Tran Van Thoi of Ca Mau province are strongest erosion areas (Cat et al., 2006), as shown in Table 2.5. Table 2.5 Coastal and River Mouth Erosion of Southern Provinces No 1 2 3 4 5 6 7 8

Province Ho Chi Minh City Tien Giang Ben Tre Tra Vinh Soc Trang Bac Lieu Ca Mau Kien Giang Total

Erosion Average Width (m) 550 1,225 479 369 433 300 1,033 115

Area (m2) 9,757,000 4,150,000 18,644,000 11,350,300 8,562,000 1,844,000 69,338,400 460,000 124,105,700

(Source: Tien et al., 2005) For the average width of erosion point in the period 1995 – 2005, Tien Giang coastal is the largest erosion point in the Southern coast. Ca Mau coastal is the second largest erosion, (Table2.5).

14

2.3.2 Coastal change in Ca Mau Ca Mau is a typical of coastal erosion in southern provinces that is located with three sides contiguous to the sea, including the east, west and the south; another side, the north is contiguous to An Minh district of Kien Giang province (Figure 2.8). The Ca Mau has 254km of seashore stretching from Ranh Hao river mouth, which is the boundary between Bac Lieu and Ca Mau province to Tieu Dua arroyo that is the boundary between Ca Mau and Kien Giang province. The Ca Mau coast that is located in a wide and flat alluvial fan and bordered by tidal rivers fringed by wide mangrove swamps and has been under erosion continuously at a rate of approximately 50m/year since the early twentieth century (Mazda et al., 1997; Cat et al., 2006). Among which, the erosion of coastal area in Ca Mau province during 100 past years is very serious with total eroded area is 280 km2 and averagely 2.80 km2 /year accordingly. The average rate of erosion is from 26 to 30 m/year, particularly from 50 to 67m/year at Bo De river mouth (Lap et al., 2012). Under coastal change effects, government, local government and local people have implemented measures to mitigate or adapt to the coastal changes. Ca Mau coast has been eroded by several causes that are discussed below.

East Sea

Figure 2.8 Coastline change in Ngoc Hien and Nam Can commune, Ca Mau during the period 1973 – 2008 (Source: Thuy et al., 2009) a) Influence of winds: Wind, the main exogenous factor that create waves, is one of natural factors that cause coastal change. Ca Mau coastland area is governed by tropical monsoon climate, therefore the research area is regulated by the monsoon with the main directions are North-east and South-west. In addition, the monsoon also creates general circulation and coastal flow which are reverse direction including summer flow (southwest monsoon) that goes from south to north, and winter flow (northeast monsoon) that goes from north to south (Table 2.6).

15

Table 2.6 Distribution of the Annual Monsoon in Ca Mau Transition season Seasons

Dry season

Transition

Rainy season

Months

I II III IV V VI VII VIII IX Northeast Monsoon Transition Southwest monsoon monsoon

X

Dry season XI XII Northeast monsoon

Transition monsoon The Southwest monsoon usually begins in May until the end of September. The wind direction is West-Southwest, Southwest and West, in which mainly direction is the southwest (Figure 2.9). The wind average velocity in this direction is from 4 to 6m/s, the maximum speed is about 8 to 10m/s. Southwest monsoon period is also rainy season, which has abundant silt from the rivers. This wind direction is opposite with East Sea coastal opening direction where rivers mouth converged, lead to deposit phenomenon in most regions, erosion phenomenon does not virtually happen. This monsoon direction adversely affects to the western coastal part only. However, due to the wind intensity is not large and the west coastal is also very sloping and wide, hence wave action created by winds is limited. The erosion area will be accreted in the northeast monsoon period, as a result, shoreline in this area is relatively stable (Hung et al., 2012).

Figure 2.9 General Circulation in the winter and in the summer on the East Coast. The arrows indicate the average flow direction, the Figure s represent the average flow speed in units kn (1 kn ≈ 0.51 m / s) (Source: U.S. Naval Office Oceanographic, 1957) The Northeast monsoon usually starts from November of year to March of next year. The wind direction is usually North-East, East and South-East, however east and northeast is main wind direction. The wind speeds average is from 8 to 10m/s, the highest is 16 m/s. With a remarkable frequency and wind speed is greater than the other direction; the wind direction almost opposite with the open coastline of the East Sea. The northeast monsoon is the wind direction that contributes to erosion process of coastal in the region. Wave caused by the Northeast monsoon will dig the majority of sediment deposition in the Southwest monsoon as well as erodes the shore walls that are not protected by vegetation. As a result, coastal flow is generated which resonates with the tide transfers sediment to 16

the south. This is main direction of sediment transfer on the Southern coastal (from Ho Chi Minh City to Ca Mau). The wind speed and wind direction on April and October are inflexible because those are transition period between dry season and rainy season. b) Influence of waves and flow: Waves are generated by offshore and near shore winds, which blow over the sea surface and transfer their energy to the water surface. In the deep sea, waves often coincide with wind direction. However, on shore, waves energy is consumed, wave height is reduced (shallow water effects), and wave direction is changed depending on coastland terrain (the wave refraction phenomenon) under the action of sea friction. As they move towards the shore, waves break and the turbulent energy released stirs up and moves the sediments deposited on the seabed. The wave energy is a function of the wave heights and the wave periods (SAARC, 2012). When the wave transmits to the critical depth region, wave breaking phenomena will occur. A part of wave energy will be released; other part will transfer into secondary waves. The waves breaking process may occur one or several times depending on beach slope. The more wave is broke, the more energy is consumed. The energy release process will occur when waves approach the shore (waves pounding the shore). The wave action process, breaking waves as well as waves pounding the shore, is the main disturbance, abrasion, breaking the surface/ bottom shore structure. The process also creates flow that transfers sediment to another place. In the West coast sea of Ca Mau, from Ca Mau cape to Ong Trang and Go Cong, the tide characteristic is irregular diurnal. When tide rises, flow direction is from Ca Mau cape to Ong Trang. When tide recedes, flow direction is completely opposite, from Ong Trang to Ca Mau cape. The speed average of tide in the region is about 30 to 50 cm/s in the tide rise period. In the Eastern shore, from Ganh Hao mouth to Ca Mau cape, the tide characteristic is irregular semi-diurnal. Tide characteristic is forward/reverse and flows almost parallel to the shoreline with the speed average of tide in the region about 50 to 100 cm /s. Under the influence of monsoon, the wave regimes in the east and the west coast areas are very different. The main wave direction along the east coast is from east-northeast to eastsoutheast, in which the east has highest frequency. Thus, during the southwest monsoon, the east coast is generally calm; the west coast is affected strongly by waves with wave direction nearly perpendicular to the shore with the wave height about 0.5 to 0.9m; at the storm the height of wave can reach 1.5 to 2.5m. In the northeast monsoon, the west coast is relatively calm; in contrast, the east coast area is affected strongly by wave with the height of wave is usually about 0.8 to 1.2m. In case the strong northeast monsoon combined with high tides, the height of wave can reach 1.8 to 3.5m, shoreline erosion processes occur seriously and sedimentary material is transported to Ca Mau cape and west coast by flow. c) Influence of storm: In the period 1990 – 2011, Viet Name coast was affected by 118 storms, while Ca Mau coast was affected by 14 storms in this period (Table 2.7& Figure 2.10). The combination of rain, wind and heavy surf tends to pick up and drag sand and earth from vulnerable beaches, washing it up and out into other areas. While the natural tides and waves perform similar movements, their impacts are light compared to that of storms. Hurricanes especially provide enough water and force to erode coastlines, sometimes into unrecognizable shapes.

17

Table 2.7 Storm Affected in Viet Nam in the Period 1990 – 2011 2011

20102008

20072005

2004- 2001- 1998- 19952002 1999 1996 1993

1992 1990

Number of storm effected in Vietnam

4

35

21

8

10

15

13

12

Number of storm effected in Ca Mau

-

4

3

-

0

4

1

-

(Source: Viet Nam Environment and Resource Ministry, 2012)

No.

Number of storms affected Vietnam

Number of storms affected Ca Mau

4

15

2010

2008

2006

2004

2002

2000

1998

1996

1994

1990

2010

2008

2006

2004

2002

2000

1998

1996

0 1994

0 1992

1 1990

2

5

1992

3

10

(B)

(A)

Figure 2.10 Storms affected Vietnam (A), and affected Ca Mau (B) in the period 1990 – 2011 d) Human intervention: Human activities add another layer of complexity to the natural processes of coastal lands and materials. These activities may have direct or indirect effects on our changing coasts. In Ca Mau coast, a southern region of Viet Nam, human intervention can alter these natural processes through the following actions:  Aquaculture field: Aquaculture farming along the coastal, including shrimp farming and fish farming is one of the main causes of coastal change. Hydrology of mangrove forest in Ca Mau province was significantly affected by aquaculture development. Many of the remaining mangroves forest are surrounded by dikes, or situated in areas where tidal access is hindered. In mixed farms, mangroves are enclosed by a dike surrounding the farm, normal tidal flooding and flushing is prevented by the more or less constant water level in the pond. The situation for mangrove areas located outside the pond on farms using the separate farming system is less clear. Moreover, under outstanding value of shrimp, the competition between aquaculture area and forest area is became a critical situation (Appendix 5). The ratio between aquaculture and forest area is increasing; it means that the forest area is decreasing. According to the Decision No 186/2006/QĐ-TTg (2006) of Viet Nam’s Premier for “Promulgation Forest Management Regulation” that was decided on 14/8/2006, and “Forest Protection and Management Law”, the ratio of Mangrove forest/ shrimp pond is 60/40. However, in the recent, the ratio is mangrove forest 55%; shrimp is 45% (Minh et al., 2010). Not only shrimp farming, human activities on coastal like catch crab, oysters, clams and marine have also adverse effects on coastline. In the year 2011, “Clams disaster” happened in Ca Mau Cape of Viet Nam. Thousands people gathered 18

clams in Khai Long beach, Ca Mau cape, lead to the serious damage of coastal. As a result, mangrove forest along coastal is degraded, leading to coastline erosion due to loss of vegetation (Appendix 6)  Deforestation: Beside area competition between aquaculture and forest, deforestation for house building, fuel, is also a hazard to Ca Mau coastal region. With a length of coastline 254 km, forest along Ca Mau coast is difficult to protect from people destruction in the region. In the period 2005 – 2007, number of deforestation in Ca Mau was increased, with 90 points in 2005 and 117 points in 2007 (Figure 2.11). Number of deforestation points in Ca Mau

150 100

50 0

2005

2006

2007

Figure 2.11 The deforestation in Ca Ma in period 2005 – 2007 (Source: Ca Mau DARD, 2008)  Building constructions: Construction in study region has been happened complexly during past decade. In 2001, general project named Ca Mau cape Culture-Tourist Park that occupies on 150 ha was approved. In the year 2003, the project was realized on 45 ha. In 2005, a project named Ly Thanh Long resort was built on 76 ha including 26 ha for infrastructure (offices, commercial services, hotels, resort, restaurants, etc.) and 50 ha for shrimp farming (Appendix 7). Tourism improvement is cause of population density, infrastructure and public work increase. As a result the coast will be changed under direct or indirect effects of constructions. 2.4 Effects of Coastline Change 2.4.1 Effects on human life The people who live along the coast are affected easily by coastal change. Constructions, houses, livelihood (aquatic farms, fishing) associated with coastal. Hence when coastal change, it will damage everything (Appendix 8). Beside the effects of coastline change on infrastructure it also effect on human livelihood. According to the report of the Department of Fisheries of Hai Phong city, there were 8,000 hectares aquaculture destroyed by typhoon no 2 in 2005. As a result, 1,000 tons of shrimps, 250 tons of crabs and 2,000 tons fish were lost. Moreover, this storm was also caused the loss 4,535 hectares shrimps at Yen Hung district, Quang Ninh province. The total loss in Hai Phong and Yen Hung reached 9 million USD. Furthermore, according to General Department of Meteorology and Hydrology (2005), 150 kilometers coast line and 11 kilometers national sea dike were destroyed by typhoon no 7 in 2005 in the coast of Thanh Hoa and the coastal provinces of the Red river delta during 3 days from 26 to 28 August 2005. 19

2.4.2 Effects on land use According to statistics in 2010, the total land area of Ca Mau is 5 3 2 , 9 1 6 h a ,of which agricultural, forest and aquaculture land occupies 474,202ha (89%), non-agricultural land occupies 48,413 ha (9.1%) and the unused land remaining is 10,301ha (1.9%) as shown in Table 2.8 and Figure 2.12A. Agriculture land (474,202 ha) is divided into 4 parts (Figure 2.12B), land for agriculture production is 140,745 ha (29.9%); land for forest development is 108,898 ha (22,7%); land for aquaculture 222,207 ha (46.9%) and other land use is 2,352ha (0.5%). Table 2.8 Overview Land Use Status Current in Ca Mau Land Use I. Agriculture land a) Agriculture land b) Forest and land for forest development (Forest land) c) Aquaculture land d) Other land use II. Non- Agriculture land III. Unused land remaining Total land

Area (ha) 474,202 140,745 108,898

Percentage (%) 89 29.7 23.0

222,207 2,352 48,413 10,301 532,916

46.9 0.5 9.1 1.9 100

(Source: Ca Mau DARD, 2011) Agriculture land classification in 2010 Other land 0.5% Aqua. land 46.86%

Agri. land 29.68%

Forest land 22.96%

(A)

(B) Figure 2.12 Land use status current in Ca Mau

Forest land is the strength of Ca Mau and is one of the most important resources. The total 108,898 ha is planned for forest (including forest and land for forest development), distributes in 6 districts (Table 2.9). There are 43,019 ha of brackish forest (39.5%) distribution in the West-North region (distribution in U Minh and Tran Van Thoi district). In the East- South region, there are 65,879 ha mangrove forest (60.5%) (distribution in Dam Doi, Nam can, Ngoc Hien and Phu Tan district) that is very important for the people who live along the Sea.

20

Table 2.9 Land use distribution in forest region in Ca Mau Land use types

Area (ha)

Nam Can 26,540

Districts Ngoc Phu Hien Tan 65,602 6,870

Total natural land in forest region I. Agro-forestry and Aquaculture land

167,660

Dam Doi 11,196

39,525

3,078

7,237

17,562

1,347

8,156

2,145

II. Forest Land - for forest development

108,898

7,710

14,660

39,181

4,328

33,741

9,278

100,388

7,624

13,647

37,120

4,288

29,282

8,427

86

1,013

2,061

40

4,459

851

-

1,966 1,966

3,749.0 396 3,749 396

321 -

289 -

2,677

5,111

321 2,539

289 984

a) Forest area

b) Land for Forest 8,510 planning III. Quagmire area 6,721 a) Alluvial area 6,111

b) Erosion area 610 IV. Other use 12,516 407 (Source: Ca Mau DARD, 2011)

798

U Minh 44,756

Tran V Thoi 12,696

 Forest land change: Camau mangrove forest area has been changed during 5 past decades. According to An et al., (2005) and Sam et al., (2005), in the year 1965s, mangrove forest in Ca Mau is 90.364 ha and it reduced to 38,300ha in the year 2001 (An et al, 2005), as shown in Figure 2.3.

(A) (B) Figure 2.13 Comparison mangrove forest in Ngoc Hien, Ca Mau in 1965 (A) and 2001 (B) (Source: An et al., 2005) 2.5 Coastal Zone Management Practices in the World Coastal zone management solutions have been become a universal interest. Many practices for coastal zone management were implemented, included soft solution and hard solution. However, Coastal areas with natural protective features can reestablish themselves after natural traumas or long-term changes such as sea-level rise. The role of coral reefs in coastal protection has been studied for some time and recent efforts have focused on the role of coastal vegetation, especially mangrove forest and saltmarshes. Scientific 21

investigations on how coastal vegetation provides a measure of shoreline protection have been conducted by Sale, 1985; Kobayashi et al., 1993; Mazda et al., 1997; Massel et al., 1999, etc. These field, laboratory and numerical studies show that mangrove forest and other coastal vegetation of certain density can reduce wave height considerably and protect the coast from erosion, as well as effectively prevent coastal sand dune movement during strong winds. Healthy coastal forests such as mangroves and saltmarshes can serve as a coastal defence system where they grow in equilibrium with erosion and accretion processes generated by waves, winds and other natural actions. In India and Bangladesh, especially at the mouth of the Ganges, scientific investigation demonstrated that mangrove forest were able to heal cyclonic wounds and maintain the extent of their total area through natural succession without human interference. Mangroves in these regions have withstood highly adverse environmental conditions such as muddy soils with high salt and water content, destructive tidal effects and strong winds over the flat areas where they have grown in geological terms since the Tertiary (lower Miocene) Period. Via their root systems, mangroves can stabilize the substrate where they occur. According to studies, most erosion is caused by diversion of river flow to coastal areas and mangrove regression due to human activities that convert them for agriculture or aquaculture purposes (Gegar, 2006). In Viet Nam, an experimental model of planting sea dike protection mangrove forests in Tan Thanh commune, Kien Thuy district, Hai Phong city implemented by the Forest Ecological Center of the Vietnam Institute of Forestry in 2001 – 2002. The experimental sea dike protection mangrove forest is a mixed forest, consisting of Sonneratia caseolasis O.K. with density of 1000 trees/ha, and Kandelia Candel (L) Duc) with density 8250 trees /ha (Kandelia Candel (L) Duc with spacing 1m x 1m, Sonneratia caseolasis O.K. with spacing 3.3m x3m). The actual results have proved that for protecting the coast from erosion and sea dike system from collapse and breaking due to strong winds and typhoons mangrove forest belts beyond the beach near the coast and the dike must be established for detaining the wave. The mangrove forests are" green walls" for protecting the coastal and river mouth areas, limiting the impacts of waves and storm winds (as a highly effective anti-erosion method with low cost) but for planting effectively the mangrove forest it must be based on the limatic conditions of each area, the tidal regime, the soil type, soil maturity to select the suitable type of mangrove forest to plant (Cat et al., 2006). 2.6 Summary and Research Gaps The change of coastal line including erosion and deposit , has got special attention because of their multiple effects on environment, natural resources, ecology systems, socialeconomy, culture and defense security. Many countries, especially the countries have coastal zone invest to protect coastal zone and also research on this phenomenon. However, because of time, human resources, and finance lead to limit study. Thus, there were not much study could shown enough causes of coastal line change. Ngoc Hien district of Ca Mau province is also the same situation. There was not any research on coastal line change relative climate and human activities. Perhaps there were some researches on coastal line construction but did not have any research on causes of change. It is necessary to research on causes of coastal line change in multiple respect by interlink climate conditions and human activities.

22

6. Chapter 3 7. Materials and Methodology 3.1 Methodology Framework SELECT REGION FOR STUDY

(Object 1)

(Object 2)

Satellite images 1990, 1995, 2000, 2005, and 2011

Climate conditions - Storms - Rainfall

Human activities - Deforestation - Infrastructure - Rivers dredging

GIS Tools

Excel tools

Coastline change maps

Causes of coastline change

Coastline change

(Object 3) Effects indicators - Aquaculture area change - Forest area change - Infrastructure area change

Effects on land use of study area

Propose solutions for coastland sustainable development

Figure 3.1 Methodology framework

23

3.2 Study Site Ca Mau is the province in the Southern tip of Viet Nam with geographical coordinates from latitude 8030 - 9010 North and longitude 10408 - 10505 East. The province adjoins Kien Giang and Bac Lieu provinces on the North, the East Sea on the East and South (Figure 3.2). The Thailand Gulf adjoins Ca Mau on its western side. Ca Mau province covers an area of 5,208.8km2, accounting for 1.57% of the country area, and 13.6% of the Mekong Delta. Southernmost Ca Mau province with its advantages on seafood, large crude oil reserves and mangrove and cajuput forests has the potential to attract domestic and foreign investment. With a coastline of 254 km and almost 250,000 ha of water surface for shrimp rising, Ca Mau is one of four key fishing grounds in Viet Nam. The study is carried out in Ngoc Hien district of Ca Mau province, a coastal southern region of Vietnam. This district is typical a coastal sub-region representative for the erosion and deposit of the area by the impacts of climate forces and human activities in the province. Recent years, the area has experienced serious consequences by coastal change that was caused by storm, waves, flow, tide, sea level rise as well as human activities. Both natural conditions and human activities led to cumulative effect on the area. Ngoc Hien district has a special geographical location with three sides are contiguous to sea, including the east, west and the south (Figure 3.2). The north is contiguous to Cua Lon River, which is the boundary between Nam Can district and Ngoc Hien district. Ngoc Hien occupies 65,602ha, which is the largest district in Ca Mau province. The district has many prominent aspects. First of all, it contains the national landmark number zero and is also the country's southernmost mainland. Secondly, Ngoc Hien contains a National Park named “Ca Mau Cape National Park” which is listed as a “Ca Mau Cape Biosphere Reserve” by UNESCO since May, 2009 (UNESCO, 2009).

24

Figure 3.2 Study area, Ngoc Hien district, Ca Mau province (Sources: Google Earth) 3.3 Methodology To achieve the proposed objectives, the study uses the following methods, (i) Satellites analysis, (ii) climate conditions data and human activities analysis, (iii) Forest area change, coast land change analysis, and (iv) Field survey for coastline change influence on land use change. The study needs to use both primary and secondary data. 3.3.1 Data collection a) Primary data collection: The survey is conducted to get opinion of people in the study area and experts (mostly government officers) on causes of coastline change. The questionnaires details are included in Appendix 9. Due to limit time of this study, it was decided to interview 30 households in each commune of three zones of the study area. In total 90 households were collected. Details of zone and are given in Table 3.1.

25

Table 3.1 Characteristics of Zones in Ngoc Hien Zone Coastal zone Buffer zone River zone

No commune 5 1 1

Household 17,314 1,963 1,684

Interviewed (person) 30 30 30

Ngoc Hien district is divided into three zones, including coastal zone, buffer zone and river zone based on their characteristic. Coastal zone is the zone where all or all most area closes to the sea. This zone include 5 communes (Tam Giang Tay, Tan An, Rach Goc, Dat Mui and Vien An). It has a capacity 17,314 households (population 68,564 people). Buffer zone is the area which has characteristics of coastal zone and river zone. Vien An Dong is classified into buffer zone with 1,963 households and population 7,913 people while Tan An Tay is divided into river zone with 1,684 households equivalent to 6,675 people. The research collected each commune in each zone. Thus, totally in this research, 90 households in 3 communes including Tan An Tay, Vien An Dong and Dat Mui commune (30 households per commune) and five experts were interviewed. Key persons interview (Experts interview): Key person interview is carried out with people who have lived and worked/researched in the study site for a long time and individuals affiliated to government offices such as department of agriculture and rural development (DARD), Department of Natural Recourses and Environment (DoNRE), Department of Ca Mau Cape Biosphere Reserve. Particularly, individual from the department of meteorology and hydrology was also interviewed to get the information and understanding about the changes of rainfall, storm, etc. The information was collected via open questionnaires. b) Secondary data collection:  Satellite images: Satellite images are use for classification of the land cover types into 4 major classes as follows: i) Forest land area ii) Aquaculture area iii) Water body area iv) Infrastructure area (constructed area) The description of the land use types is given in Table 3.2. Table 3.2 The Land Use Types Identified in the Study Area Land use types Forest

Description Including dense forest, low dense forest and planted forest

Aquaculture area The area for aquaculture (mixing farm and specializing farm) Water body

Including river, irrigation canal, and arroyo water

Infrastructure

Including housing land, transport systems, and construction along coastline (coastline protection system, tourist service construction. and other land )

26

The classified images were exported to Arc GIS for map preparation. Five coastline maps for the five different images of the date: 7 August 1990, 11 July 1995, 10 July 2000, 8 August 2005 and 5 July 2011 were produced.  Climate conditions and human activities data: The data for study was collected with the details in Table 3.3. The climate conditions are collected every month (storm) and everyday (rainfall) during the study period 1990-2011 from Meteorological stations in Ngoc Hien, Ca Mau. The human activities data including deforestation, aquaculture area, houses building and rivers dredging were collected for every year during study period 1990 2011. They were collected from Local Government Engineering Department (LGED), such as Department of Natural Resources and Environment (DNRE), Department of Agriculture and Rural Development (DARD). Table 3.3 Indications Used for Trend Analysis of Climate Condition and Human Intervention Indications Climate conditions

Description - Monthly data 1990 – 2011, referred from Ngoc Hien meteorology station.

- Annual rainfall (mm) - For storms from 1990 – 2011, referred from Vietnam - Number of heavy rain days National Meteorological Center (VNMC), available at (days) http://www.thoitietnguyhiem.net/BaoCao/BaoCaoBao.aspx Detail on the storm data in the description which Latitude - Number of storms (numbers) and Longitude areas of the storms effects are considered. Human Intervention - Deforestation (ha) - Aquaculture farming (ha) - Infrastructure (ha)

Annual data from 1990 to 2011 ware collected from relevant governmental offices and also from satellite images analyzed.

- Rivers dredging (m3)

 Effects indicators: In this study, the effects of coastal change on the study area are estimated by the changes over the study periods in forest area, coastal zone, aquaculture area and area for infrastructure. They were collected for every year during the study period (1990 – 2011) from Local Government Departments. 3.3.2 Data analysis The software used includes image processing (EDARS Imagine 9.2), MapInfo software (ArcGIS9.3), GIS software, and Microsoft Excel. As shown in the framework of study (Figure 3.1) the following steps were used for the data analysis.

27

a) Questionnaires of interview analysis:  Household information analysis: the changes of land use asset and causes of change perceived by the people living in the study area are obtained. The indicators are selected including land owning and land use structure.  Key information analysis: The information collected from experts were analyzed to refer causes of coastline change, effects of coastline change on land use, trend of coastline change and solution for coastline sustainable development. b) Coastline mapping using satellite images to create coastline change maps: Analysis and interpretation of satellite data was done by digital image processing. There are various methods for coastline extractions from optical imagery have been used. Extraction the coastline change maps from satellite in this study is divided into 4 steps. Step 1. Radiometric calibration: In this step, radiometric calibration consists in linking pixels intensities to a physical parameter. Its main goal is to allow comparisons of spectra from different origins and also measurements of important physical parameters. This operation is all-important since the flux distribution in the raw spectrum is very different from what has been emitted by the observed object (Astrosurf, 2012). Step 2. Extract maps: The coastline can be extracted even with single band (Figure 3.3), the histogram thresholding method on band 5 for separating land from water is utilized because the reflectance of water is nearly equal to zero in reflective infrared bands, and reflectance of absolute majority of land covers is greater than water. The transition zone is the effect of mixed pixels and moisture regimes between land and water. If the reflectance values are sliced to two discrete zones, they can be depicted water (low values) and land (higher values). However, this method is difficult to find the exact value. The band ratio between band 4 and band 2 and also, between band 5 and band 2 is used for more exactly value. This method can separate directly water from land. For water, the ratio of b2/b5 is greater than one and the ratio is less than one for land in large area of coastal zone. This law is exact in coastal zones covered by vegetation, but not in land without vegetative cover. This law mistakenly signs some of the non-vegetative lands to water. The ratio b2/b4 is greater than one for water and less than one for land in large area of coastal zone. This law is true in coastal zones covered by soil, but not in land without soil cover. Actually by this law, some of the lands without soil cover are mistakenly signed to water. To solve this problem, two ratios are combined. With this method, the maps can extract the coastline with higher accuracy. When a threshold value has been selected; it will be exact in some area, but not in all areas. Therefore threshold value is chosen as all water pixels have been classified to water and majority of land pixels have been classified to land. In this case, few land pixels mistakenly have been classified to water pixels but not vice versa. Then water pixels are labeled one and land pixels is labeled zero. Hence a binary image is achieved. This image is named “image No. 1”. For image obtained from band ratio technique, water pixels were also labeled to one and land pixels to zero. This image is named “image No. 2”. Step 3. Multiplication of images: The two images (No 1 and No 2) are multiplied together to get final binary images.

28

Step 4. Raster to vector conversion: This step needed because a raster image could be loaded into Computer Aided Design (CAD) program. However, no changes can be made to the image. This is because CAD and CNC (Computer Numerical Control) programs can only work with vectors. To do this, the raster image must be redraw manually by using CAD program, or use raster to vector conversion software. Raster to vector software attempts to convert the raster image to vector automatically. When converted a raster image to a vector image and saved it as a vector file it can be edited easily.

TM and ETM + Imagery

Radiometric calibration (Step 2a) Histogram thresholding on band 5

Image No 1

(Step 2)

(Step 1)

(Step 2b) Applying the b2/b4> 1and b2/b5 > 1 condition images

(Step 3)

Image No 2

Multiplication of images

Final binary image

Raster to vector conversion (Step 4) Coastline map

Figure 3.3 Mapping process (Source: Alesheikh et al., 2004)

29

c) Analysis climate conditions and human activities: In this study the methodology data from only one station in Ngoc Hien are used. In this step, the land use data, climate data and human intervention were used as input of Excel program to analysis the multiple relationships. The causes of coastline change, and clarification how does climate conditions and human activities affect the change of coastline are the principle outcomes of this analysis. d) Analysis the coastline change effects: The effect indicators are selected, including forest area (ha), coastland area (ha), infrastructure area and aquaculture area. The data is collected every year during the study period, and Excel tools are used to estimate the change. The relationship between climate conditions and coastline change; between human intervention and coastline change would be recognized and potential solutions for coastland sustainable development would be proposed.

30

8. Chapter 4 9. Results and Discussions 10. 4.1 Coastline Change Measurement Five coastline maps for the five different dates: 7 August 1990, 11 July 1995, 10 July 2000, 8 August 2005 and 5 July 2011 were produced. The maps show the land use classes for the year 1990, 1995, 2000, 2005 and 2011 were produced. Ngoc Hien coastal zone change was divided into four stages, period 1990 – 1995, 1995 – 2000, 2000 – 2005 and period 2005 – 2011. During study period 1990 – 2011, Ngoc Hien had lost 2,206 hectares land (Table 4.1). Total /net change of Ngoc Hien distributed in seven communes (Figure 4.1). In which, total erosion area was 4,219 hectares and total deposit area was 2,093 hectares. Total of coastline length of Ngoc Hien is 98 kilometers which is divided into two sides, East Sea 72km and West Sea 26 km. The erosion area focuses in East Sea coast and deposit area focuses in West Sea coast. The average coastline erosion in East Sea coast of Ngoc Hien during 1990 – 2011 was 586 meters (total erosion 4,219 ha divides by 72 kilometers length is 586 meters width). However, the coastline erosion was not regular. The widest erosion position was in Tan An commune and the narrowest erosion position was in Dat Mui commune (Figure 4.1). The deposit area focuses in West Sea. The average coastline deposit in West Sea coast of Ngoc Hien during 1990 – 2011 was 805 meters (total deposit 2,093 ha divides by 26 kilometers length of West Sea is 805 meters width).

Rach Goc

Figure 4.1 Coastal zone change in Ngoc Hien district, Ca Mau province in period 1990 –2011

31

Table 4.1 Coastal Zone Change in Ngoc Hien District During Study Period, 1990 – 2011. 1990 - 1995

1995 - 2000

2000 - 2005

2005 - 2011

Erosion Deposit Erosion Deposit Erosion Deposit Erosion Deposit Location Tam Giang Tay -767 -187 45 -426 -395 Tan An -433 -180 13 -284 -316 Tan An Tay -5 -42 -22 Vien An Dong -364 -75 8 -142 22 -142 Rach Goc -181 -112 62 -199 31 -253 45 Dat Mui -425 172 -45 791 -99 312 -63 249 Vien An -37 365 -12 528 -35 226 0 166 Coast change (ha) - 2,212 + 537 - 653 + 1,447 - 1,207 + 591 - 1,169 + 460 Net change (ha) -1,675 794 -616 -709

Total change (ha)

-1,730 -1,120 -69 -693 -607 892 1,201

-2,206

Figure 4.2 shows the change during the period from 1990 – 1995, as an example. The change in the area during this period is given in Table 4.2.

Rach Goc

Figure 4.2 Coastline change map of Ngoc Hien in period 1990 - 1995

32

Table 4.2 Area Change Identify in the Study Region in Period 1990 – 1995 No

Commune

1 2 3 4 5 6 7

Tam Giang Tay commune Tan An commune Tan An Tay commune Rach Goc commune Vien An Dong commune Vien An commune Dat Mui commune Total change (ha)

1990 - 1995 Erosion (ha) Deposit (ha) - 767 - 433 -5 - 181 - 364 - 37 + 365 - 425 + 172 - 2,212 + 537

Total change (ha) - 767 - 433 -5 - 181 - 364 + 328 - 253 - 1,675

Table 4.2 shows in the period of 1990 – 1995, there was a significant change of coastal zone, including erosion and deposit in the study area. In general, Ngoc Hien district lost 1,675 ha land during this period. Total erosion area in this stage is 2,212 ha. Among seven communes, Tam Giang Tay commune had the highest erosion plate with 767 ha land lost (or 34.7% of total coastal zone erosion) during six years. Tan An commune was the second highest erosion location. This commune lost 433 ha land (19.6% of total erosion) in the same time. Dat Mui commune was the third highest erosion location with 425 ha (19.2% of total area of erosion) land lost. Other communes, Vien An Dong, Rach Goc and Vien An were ranked 4th, 5th and 6th with the rate of coastal zone erosion 16.5%, 8.2% and 1.7%, respectively. Tan An Tay commune had the lowest erosion, only 5 ha land lost (0.2% of total erosion area) during this period. On the other hand, there was also amount of land deposited during 1990 – 1995 in study region. Total land deposited in this period was 537 ha. The distribution of land deposited was mainly in Vien An and Dat Mui commune. There was 365 ha land deposited in Vien An commune while 172 ha land deposited in Dat Mui commune in this stage. The change of coastal zone is shown in Figure 4.3 for 1990 – 1995.

Coast zone change of Ngoc Hien in the period 1990 - 1995

400 200

328

0 -433

Tam Giang tay

Tan An

Area change -766.8

-432.5

Area change (ha)

-767

-200

-5

-364

-181

-253

-400 -600 -800 -1000

Tan An Vien An tay Dong -5

-363.8

Rach Goc -180.9

Dat Mui Vien An -252.6

326.5

Figure 4.3 Coastal zone change in Ngoc Hien in period 1990 – 1995 in different communes 33

The map of coastal zone change during 1995 – 2000 is shown in Figure 4.4.

Rach Goc

Figure 4.4 Coastline change map of Ngoc Hien in period 1995 - 2000 Table 4.3 Area Change Identify in Study Region in Period 1995 - 2000 No

Commune

1 2 3 4 5 6 7

Tam Giang Tay commune Tan An commune Tan An Tay commune Rach Goc commune Vien An Dong commune Vien An commune Dat Mui commune Total change (ha)

1995 - 2000 Erosion (ha) Deposit (ha) - 187 + 45 - 180 + 13 - 42 0 - 112 + 62 - 75 +8 - 12 + 528 - 45 + 791 - 653 1447

Total change (ha) - 142 - 167 - 42 - 50 - 67 + 516 + 746 + 794

In general, Ngoc Hien district had a deposit 794 ha from 1995 – 2000 (Table 4.3). Total erosion area in this stage is 653 ha. Tam Giang Tay commune had the highest erosion location with 187 ha land lost during the time, consistory of 28.7% of total coastal zone erosion of Ngoc Hien in the period. Tan An commune was the second highest erosion location. The coastal zone of this commune was lost 180 ha, occupied 27.5% of total erosion in the same time. Rach Goc commune was the third highest erosion location with 112 ha, occupied 17.2% of total area erosion of Ngoc Hien. The other communes, Vien An Dong, Dat Mui, Tan An Tay and Vien An ranked the number 4th, 5th, 6th and 7th with the rate of coastal zone erosion was 11.5%, 6.9%, 6.4% and 1.8%, respectively. Overall, there was a significant deposit in the region in this period. Total land deposited in this period was 1,447 ha which were distributed in six communes. Dat Mui commune was number one with 791 ha gained equivalent to 54.7% land deposited in stage 1995 – 2000 while Vien An commune was the number two with 528 ha (36.5%) land deposited. Rach Goc and Tam 34

Giang Tay commune were number three and number four with land deposited 62 ha (4.3%) and 45 ha (3.12 %) of total land deposited in study area, respectively. Tan An and Vien An Dong ranked number five and number six with lower than 1% of total land deposit during this stage while Tan An Tay commune did not have any significant land deposit in this period. The change of coastal zone study is shown in Figure 4.5.

Figure 4.5 Coastal zone change of Ngoc Hien in period 1995 – 2000 in different communes The map of land use change in 2000 – 2005 is show in Figure 4.6

Rach Goc

Figure 4.6 Coastline change map of Ngoc Hien district in period 2000 - 2005

35

In stage 2000 – 2005, Ngoc Hien district was eroded 1,207 ha while there was 591 ha land deposited in this region (Table 4.4). Tam Giang Tay commune was the highest erosion location with 426 ha land lost during the time. Tan An commune ranked the second highest erosion location with 284 ha land lost while Rach Goc commune was the third highest erosion location with 199 ha coastal zone lost. The other communes, Vien An Dong, Dat Mui, Vien An and Tan An Tay commune ranked number 4th, 5th, 6th and 7th with the land loss of 142 ha; 99 ha; 35 ha and 22 ha, respectively. There was a significant deposit in this period. Total land deposited in this period was 591 ha which were distributed in four communes including Dat Mui, Vien An, Rach Goc and Vien An Dong. Dat Mui commune ranked the number one deposit zone with 312 ha. Vien An commune was the number two with 226 ha land deposited in the same time. Rach Goc and Vien An Dong commune were ranked number three and number four with the land deposited 31 ha and 22 ha, respectively. The change of coastal zone in study region in stare 2000 – 2005 is shown in Figure 4.7. Table 4.4 Area Change Identify in Study Region in Period 2000 – 2005

No

Location

1 2 3 4 5 6 7

Tam Giang Tay commune Tan An commune Tan An Tay commune Rach Goc commune Vien An Dong commune Vien An commune Dat Mui commune Total change (ha)

2000 - 2005 Erosion (ha) Deposit (ha) - 426 0 - 284 0 - 22 0 - 199 + 31 - 142 + 22 - 35 + 226 - 99 + 312 - 1,207 + 591

Total change (ha) - 426 - 284 - 22 - 168 - 120 + 191 + 213 - 616

Figure 4.7 Coastal zone change of Ngoc Hien in stage 2000 – 2005 in different commune The map showing the coastal line change in the study district during 2005 – 2011 is presented in Figure 4.8.

36

Map of coastline change in Ngoc Hien, in period 2005 - 2011

Rach Goc

Figure 4.8 Coastline change map of Ngoc Hien district in period 2005 - 2011 In stage 2005 - 2011, Ngoc Hien district was eroded by 1168 ha while there was 460 ha land deposited in this region (Table 4.5). Total erosion area in this stage was divided into five communes of district. Tam Giang Tay commune was the highest erosion zone with 395 ha land lost during the time. Tan An commune ranked the second highest erosion location with 316 ha land lost in this stage. Rach Goc commune was the third highest erosion location with 226 ha coastal zone lost. The other communes, Vien An Dong and Dat Mui, commune occupied position number fourth and fifth with the number of land loss were 142 ha and 63 ha, respectively. On the other hand, there was a significant deposit of region in this period. Total land deposited in this period is 460 ha which were distributed in three communes including Dat Mui, Vien An and Rach Goc commune. Dat Mui commune ranked the number one deposit zone with 249 ha. Vien An commune was the number two occupied with 166 ha land deposited while Rach Goc commune ranked number three with 45 ha land deposited in the same time. The change of coastal zone in study region in stare 2005 - 2011 is shown in Figure 4.9. Table 4.5 Coastal Zone Change Identify in Study Region in Period 2005 – 2011 No

Location

1 2 3 4 5 6 7

Tam Giang Tay commune Tan An commune Tan An Tay commune Rach Goc commune Vien An Dong commune Vien An commune Dat Mui commune Total change (ha)

2005 - 2011 Erosion (ha) Deposit (ha) - 395 -316 0 -253 + 45 - 142 0 + 166 - 63 + 249 - 1,169 + 460 37

Total change (ha) - 395 - 316 0 - 208 - 142 + 166 + 186 - 709

Figure 4.9 Ngoc Hien coastal zone change in stage 2005 – 2011 In general, the fluctuation of coastal of Ngoc Hien in period 1990 – 2011 was significant. The change varied not only in time but also in location (Figure 4.10). The trend of change can be divided in three parts. Part one, from 1990 to 1995, the trend of most communes of Ngoc Hien was erosion, except Vien An commune deposited. In this part, Tam Giang Tay commune was the highest erosion commune and Tan An Tay commune was the lowest erosion location while Vien An commune was the highest deposited location. In part two, from 1995 to 2000, the trend of Ngoc Hien was deposit. However, five of seven communes of Ngoc Hien eroded in this period, except Dat Mui and Vien An commune. In part three, from 2000 to 2011, there was a significant increase of erosion. Dat Mui and Vien An commune were deposit but the ratio dramatically decreased. The trend of Tan An Tay was quite stable in this part while the trend of four other communes was dramatic erosion.

Area change (ha)

The trend of coastal change in different communes of Ngoc Hien (1990 - 2011) 1000 800 600 400 200 0 -200 -400 -600 -800 -1000

1990 – 1995 1995 – 2000 2000 – 2005 2005 - 2011

Tam Giang tay

Tan An

Tan An tay

Rach Goc

Dat Mui

Vien An

Vien An Dong

Figure 4.10 Net gain (positive) and net loss (negative) in area of different communes of Ngoc Hien 38

4.2 Causes of Coastline Change 4.2.1 Climate conditions  Rainfall variation: Table 4.6 shows that annual rainfall of Ngoc Hien district during study period time (1990 – 2011) varied in a wide range between 1906 mm/year (2004) and 3549 mm/year (1999). The monthly rainfall variations show higher rainfall in the wet season (Jun, July and August) and lower rainfall during dry season (December, January, February, and March). Especially, low rainfall was observed from January to March each year. The change of rainfall during 4 sub-periods is presented in Table 4.8 November and April is transition season between dry and wet season. Table 4.6 Monthly and Annually Average Rainfall in Ngoc Hien in the Period 1990 – 2011 Year 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 AVG

Jan

Feb March Apr

Monthly rainfall (mm) May Jun July Aug

Sep

Oct

Year (mm)

Nov Dec

1

-

-

214

184

340

204

245

292

297

188

44

2,009

0

17

49

182

163

203

548

384

232

301

156

23

2,258

14

81

0

96

206

433

312

589

204

461

86

37

2,520

5

1

4

30

284

594

471

316

315

329

246

48

2,641

23

-

38

13

448

419

398

456

447

104

65

77

2,490

35

-

18

28

205

463

267

197

493

378

108

108

2,299

63

16

6

238

191

257

473

253

277

690

265

43

2,772

0

57

28

145

262

337

441

402

322

323

232

8

2,556

-

-

-

9

83

285

271

355

420

749

287

137

2,596

116

62

78

447

262

496

407

321

286

475

372

229

3,549

14

6

77

159

395

286

367

376

150

618

146

-

2,594

35

58

147

108

237

447

160

287

237

427

194

57

2,393

4

-

1

0

274

354

146

541

391

191

374

53

2,328

3

-

-

39

210

295

522

355

412

445

202

23

2,504

3

-

-

133

200

260

303

396

258

207

147

-

1,906

-

-

7

5

213

227

400

166

380

497

207

161

2,263

69

0

0

116

231

324

475

450

374

241

80

27

2,387

38

-

39

86

174

322

421

371

307

508

339

-

2,604

113

8

-

94

272

381

332

260

429

348

270

172

2,678

23

101

2

201

342

169

414

210

488

208

66

20

2,244

1

-

-

5

112

223

277

299

227

442

357

20

1,963

19

-

91

18 ±31

242 36 ±83

370 340 ±104

298 359 ±112

237 594 187 339 343 383 ±108 ±110 ±168

243 210 ±98

78 62 ±62

2,446

26 ±35

87 26 ±39

111 ±105

39

2,455

Table 4.7 Monthly and Annually Average Rainfall in Ngoc Hien District in the Period 1990 – 2011 Period Jan Feb March Apr May 1990- 13 16 18 1995 ±14 ±32 ±21 1996- 38 28 38 2000 ±50 ±29 ±38 2001- 9 12 31 2005 ±15 ±26 ±65 2006- 44 18 21 2011 ±41 ±41 ±36

94 ±86

Jun

July

Aug

Sep

Year (mm)

Oct

Nov

Dec

331 312 248 409 367 365 ±106 ±130 ±130 ±144 ±116 ±119

142 ±68

56 2,369 ±31 ±227

199 239 ±161 ±114

332 ±96

392 ±78

341 ±57

291 ±97

571 ±172

260 ±82

83 2,813 ±98 ±420

57 ±60

227 ±30

317 ±87

306 349 ±160 ±138

336 ±82

353 ±143

225 ±87

59 2,279 ±62 ±227

99 ±63

229 ±79

298 ±84

369 ±78

403 322 226 53 2,387 ±131 ±132 ±126 ±64 ±259

305 ±91

Rain fall variation in the study area is classified via standard deviation SD (mm) and coefficient of variation Cv (%). Standard deviation of annual rainfall over the whole study period (Table 4.7) mostly varied from 225 – 260 mm. The area study specifically had the annual rainfall standard deviation highest in the period 1996 - 2000, around 420 mm. The standard deviation SD of annual rainfall is higher than monthly rainfall and SD of month with higher rainfall is also higher than month with lower rainfall. In the opposite, coefficient of variation Cv of annual rainfall is always smaller than monthly rainfall and Cv of rainy season is usually smaller than dry season (Table 4.9). Table 4.8 Coefficient of Variation of Monthly and Annually Rainfall (Cv; %) Period 1990 - 1995 1996 - 2000 2001 - 2005 2006 - 2011

Jan

Feb March Apr May Jun July Aug Sep Oct Nov Dec Year

108 131 165 94

196 104 224 222

117 100 211 167

92 81 106 64

43 48 13 35

32 29 28 28

35 20 52 21

40 17 40 30

35 33 24 32

38 30 41 41

48 32 39 56

55 118 105 121

10 15 10 11

Over the study area, fluctuation of annual rainfall has the following characteristic:  Fluctuation of annual rainfall: Fluctuation of annual rainfall varies from 10% to 15% of annual rainfall over most of study area, representing the unstable of annual rainfall here during the study period of 1990 - 2011.  Fluctuation of monthly rainfall: Fluctuation of monthly rainfall in rainy season was low and quite stable. It was commonly at 28 - 40%. Fluctuation of monthly rainfall in dry season was normally high, over 80 - 130% (Table 4.8).  Tendency of variation in rainfall: The average value of rainfall series 1990 - 2011 is called average years - AY. Average value of five year period – is abbreviated A5P. Figure 4.11 represents statistic results of total rainfall in each five years period and the deviation with average years of series 1990 – 2011.

40

Figure 4.11 Variation of annual average rainfall in each five years period during study time Analyze the total annual average rainfall over each period in the study area, Figure 4.11 shows that period 1990 – 1995 had a decrease in total annual average rainfall. The fowling period, 1996 – 2000, was the stage of increasing total rainfall. This is the highest rainfall stage during study time with a peak of annual average rainfall at 2,813 mm/year. During 2001 - 2005 there was a decrease in total annual rainfall. This is a lowest annual rainfall with an average of 2,279 mm/year while the period 2006 – 2011 had an increase annual rainfall in corporation to period 2001 - 2005.  Storm variation: Storm is particularly dangerous phenomenon, because of very strong winds and extreme heavy rain, causing severe flooding, sometimes becomes catastrophe. According to the data from National Hydro-Meteorological Service, within 22 years (1990 - 2011) there were 12 hurricanes directly affected the coast from Binh Thuan to Ca Mau. On average, each year had 0.55 storms affecting the study area. Storm unevenly distributed in a year. There were months with no storms (February to April, July to September, and December), but there were months higher frequency of storms. Storms focus mainly in January, June, October and November, with an average of 0.14 hurricanes /month (Table 4.9).

41

Table 4.9 Number of Storms Affecting Coastal Zone from Binh Thuan to Ca Mau in Period 1990 – 2011 Months Year

Total I

II

III

IV

V

VI

VII VIII

IX

X

XI

XII

1990

0

0

0

0

0

0

0

0

0

0

0

0

0

1991

0

0

0

0

0

0

0

0

0

0

0

0

0

1992

0

0

0

0

0

0

0

0

0

0

0

0

0

1993

0

0

0

0

0

0

0

0

0

0

0

0

0

1994

0

0

0

0

0

1

0

0

0

0

0

0

1

1995

0

0

0

0

0

0

0

0

0

0

0

0

0

1996

0

0

0

0

0

0

0

0

0

0

1

0

1

1997

0

0

0

0

0

0

0

0

0

1

0

0

1

1998

0

0

0

0

0

0

0

0

0

0

1

0

1

1999

0

0

0

0

0

0

0

0

0

1

0

0

1

2000

0

0

0

0

0

0

0

0

0

0

0

0

0

2001

0

0

0

0

0

0

0

0

0

0

0

0

0

2002

0

0

0

0

0

0

0

0

0

0

0

0

0

2003

0

0

0

0

0

0

0

0

0

0

0

0

0

2004

0

0

0

0

0

0

0

0

0

0

0

0

0

2005

0

0

0

0

0

0

0

0

0

0

0

0

0

2006

0

0

0

0

0

0

0

0

0

0

1

0

1

2007

0

0

0

0

0

0

0

0

0

0

2

0

2

2008

2

0

0

0

0

0

0

0

0

0

0

0

2

2009

0

0

0

0

0

0

0

0

0

0

1

0

1

2010

1

0

0

0

0

0

0

0

0

0

0

0

1

2011

0

0

0

0

0

0

0

0

0

0

0

0

0

Total

3

0

0

0

0

1

0

0

0

2

6

0

12

0.1

0.27

AVG 0.14

0.05

0.55

The number of storms affected Ngoc Hien district, Ca Mau province was the highest during 2006 – 2011 (7 storms) as seen in Figure 4.12

42

Number of storm affected Ngoc Hien, Ca Mau in stage 1990 - 2011 8 Number of storm

7

7

6 5

4

4 3 2 1 0

Number of storm

1

0

1990 - 1995

1996 - 2000

2001 - 2005

2006 - 2011

1

4

0

7

Figure 4.12 Storm affected Ngoc Hien, Ca Mau province in period 1990 – 2011 The magnitude of Tropical Cyclones (TC) is degrees through levels of TC in periods. Table 4.10 shows that TC appeared least in the period 1990 – 1995 and 2001 – 2005. I n the opposite, number of storms with severely strong level stayed at highest rate in the periods 2006 – 2001 and the second highest was the period 1996 – 2000. Both these stages contributed 91.67% of storms of study period. Table 4.10 Number of TC Affecting Ca Mau at Different Degrees/ Levels

Period

Types of Tropical Cyclone Strong TC Normal storm Strong storm Very strong level 8-9 Level 6-7 Level 10-11 storm level ≥ 12

1990 - 1995

1

1996 - 2000

3

2001 - 2005 2006 - 2011

6

Total

10

Total 1

1

4

1

0 7 12

1 0

Note: - Level 6 – 7: Wind speed = 39 61 km/h - Level 8 – 9: Wind speed = 62 88 km/h - Level 12 - 13: Wind speed = 118 133 km/h

43

1

4.2.2 Human intervention Human activities create direct or indirect effects on coastal zone change. This research focuses on deforestation, infrastructure and dredging activities which are related to coastline change.  Deforestation: Forest area reduced during 1990 – 2011 and the reduction was divided into two categories including deforestation and change of use purpose. Deforestation is defined by cutting forest without plan or agreement from organization in charge. Change of use purpose is defined as change the area of forest into defense purpose (Forest land is delivered from civil organizations to army), public construction (roads, schools, electric systems, etc), economic development (forest land is delivered to aquaculture purpose, etc). Table 4.11 shows the change of forest area in study period. Table 4.11 Forest Area of Ngoc Hien Change During 1990 – 2011 1990 - 1995

1996 - 2000

2001 - 2005

2006 - 2011

Total (ha)

10,400

657

3,857

3,039

17,952

8,527

385

3,540

2,901

15,352

1,873

272

317

138

2,600

Total change (ha) Change in land use purpose (ha) Deforestation (ha)

There was 17,952 ha forest lost in the period 1990 - 2011. The forest lost because of deforestation was 2,600 ha while 15,352 ha forest disappeared because of change of land use purpose. The period 1990 – 1995 had the highest change with 10,400 ha forest lost. The stage 1996 – 2011 had the lowest forest loss. The deforestation was distributed in seven communes of study region (Table 4.12). Table 4.12 Deforestation Distribution in Study Region During 1990 – 2011 Period 1990 – 1995 (ha) 1996 – 2000 (ha) 2001 – 2005 (ha) 2006 – 2011 (ha) Total forest area lost (ha)

Tam Tan Giang Tay An 591 349 82 61 61 36 25 15 759

461

Tan An Rach Vien An Vien Tay Goc Dong An 27 281 277 76 16 43 31 22 12 69 29 32 8 21 13 8 63

414

350

138

Dat Mui 272 17 78 48

Total (ha)

415

2,600

1,873 272 317 138

The stage 1990 – 1995 had the highest deforestation with 1,873 ha forest was damaged that was equivalent to 72% of total forest area loss. The period 2006 – 2011 had the lowest deforestation with 138 ha forest lost. The deforestation in the region was unevenly distributed in seven communes. Tam Giang Tay had the highest deforestation with 759 ha forest lost during this time. Tan An commune had the second highest deforestation rate with 460 ha forest damaged. Both Rach Goc and Dat Mui commune ranked the third highest in deforestation with around 414 ha forest lost. 44

 River dredging in study area: River system of Ngoc Hien including six main rivers, Cua Lon River is the longest river in Ngoc Hien. It starts from Bo De sea mouth until Ong Trang sea mouth with 58 kilometer length. Five other rivers are sub-rivers of system, including Hoc Nang river, Rach Lung river, Rach Goc river, Cai Moi river and Rach Tau river. The river system is very important for transportation, aquaculture development, and also for social economic development. However there were many unreasonable human activities that affected the environment of region. The change of volume sediment dredging from rivers of Ngoc Hien during 1990 – 2011 is shown in Figure 4.13. 5,622

6,000 5,058

Volume of Sediment

5,000 4,000 2,820

3,000 2,000

2,320

2,254 1,525 517

1,000

400

347

138

185

397

215

675

475

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

1996

1995

1994

1993

1992

1991

1990

0

Year Figure 4.13 The change of sediment volume dredging from rivers of Ngoc Hien during 1990 – 2011 The sediment volume from rivers dredging was the highest in 2011. The second highest sediment volume dredging was in 1997. The years 2005, 2001 and 1993 and 1990 were the 3rd, 4th, 5th and the 6th highest sediment volume dredging with amount of sediment dredged from 1,500 thousands to 2,800 thousands cubic meters per year. The sediment volume dredging of other years were from 138 thousands to 675 thousands cubic meters, except the years 1995, 1996, 1998, 2000, 2004, 2008 and 2009 had not dredging. It is also shown that the dredging activity was not taken every year. 4.2.3 Potential cause of coastal line change The relationships between coastline change and potential causes of change were estimated based on two aspects, from statistics analysis and indigenous knowledge. a, Statistical analysis  The relationship between coastline change and climate conditions: The relationship between coastal zone change and annual rainfall and storms are analyzed using the five year period data. Figure 4.14 shows that the trend of coastline deposit increased in stage 1990 – 2000 (graph C) and there were 1,675 ha land lost in stage 1990 – 1995, while 794 ha land deposited in stage 1996 – 2000. The five year average rainfall was changing following the same portent (graph C). This shows the relationship between the rainfall and coastal line change. Similar trend was also observed for storm frequency. However, the 45

trend of storms was more drastic with zero storms observed during 2001 – 2005 (graph A). It is also noted that although rainfall column and storms are related the number of storms does not necessary represent the rainfall column. Thus, for come years there was no storm but rainfall may still be substantial.

(A)

(B)

(C)

Figure 4.14 The relationship between coastline change and rainfall, storms. It is shown in Figure 4.14 that there were relations between these factors which would not be readily explainable. Thus, more investigation or required to reveal the relationships. In particular, the season/annual land loss/gain should be analyzed with season/annual meteorological conditions. The five-year average data may be of too coarse resolution to study the effects of meteorological conditions. Other variables/factors such as the currants along the coastal line should be considered.  The relationship between coastal zone change and human activities: The graphs showing the coastal line change in relative to deforestation, rivers dredging and infrastructure activities are shown in Figure 4.15.

46

(A)

(B)

(C)

(D)

Figure 4.15 The relationship between coastal line change and human activities In Figure 4.15, graph (A) and (D) show the relationship between coastal zone change and volume of river dredging sediment in Ngoc Hien during study time was not the same during different sub period. The volume of drivers dredging in Ngoc Hien increased during 1990 – 2000 (graph A). At the same time, the coastal zone of Ngoc Hien also dramatically increased in this period (graph D). It means that when coastal zone had deposit, people need to dredge rivers system to remove the sediment. However, after dredging, coastal zone would be easily got erosion. This phenomenon was perhaps demonstrated in the next stage, from 2000 – 2011. When coastal zone was eroded dramatically in 2000 – 2005 and 47

continued erosion until 2011. In conclusion, there were cause – effects relationship between rivers dredging and coastal zone change in Ngoc Hien during study period. Graph (B) and (D) show the inverse trend of area deforestation in Ngoc Hien and the land loss due to the coastal line change. The area of deforestation of Ngoc Hien dramatically decreased during 1990 – 2000 (graph B). During the period, coastal zone of Ngoc Hien dramatically increased (graph D). The area of forest was highly damaged during 1990 1995 (1873 ha forest lost), the area of coastal was also dramatically lost in the same time (1,675 ha land lost). During 1996 – 2000, forest area of Ngoc Hien lost 272 ha and coastal zone also deposited 795 ha. In next stage, 2001 – 2005, the area of deforestation slightly increased and coastal zone erosion also increased. It means that the relationship between coastal line change and area of deforestation was highly significant in period 1990 - 2005. However, during the stage 2006 – 2011, the area of deforestation in Ngoc Hien slightly decreased while coastal zone erosion was slightly increased. Thus, the relationship between the change in both deforestation area and coastal zone area during 2006 – 2011 was not significant. The relationship between coastal zone change and infrastructure is shown graph (C) and (D). There was a higher increase rate of construction area in stage 1990 – 1995. From 1995 – 2011, there was a slight increase of area of infrastructure in Ngoc Hien. However, there were observed many construction sites along coastal zone in this period, including residential quarters, roads and construction for tourism. These construction sites directly or indirectly affected coastline structure. There was, however, no clear association between the construction area change and coastal zone change for whole Ngoc Hien district. b, Relationship between coastal zone change and causes of change based on opinion of stakeholders. Five experts and 90 households were interviewed. The result is shown on Table 4.13. Table 4.13 Experts and Households Opinion on Causes of Coastal Zone Change

Causes of coastal zone change

Experts response (Total 5 experts) Agreement Percentage (%)

Human activities Deforestation Infrastructure Dredging Rivers Other causes (explain) Climate conditions - Rainfall - Storms

Households response (Total 90 households) Agreement

Percentage (%)

5 5 5 4

100 100 100 80

88 82 84 78

97.7 91.1 93.3 86.6

4*

80

78

86.6

100

85

94.4

5

*

(*) Open answers.

48

One hundred percentage of experts (all five experts) who were interviewed answered that deforestation, dredging rivers and infrastructure along coastal zone were three main causes of coastal zone change. Four experts or eighty percentages thought that “other causes” such as coastal protection systems liked sea walls, breakwater along the coast were also the causes of coastal change. They gave evidences to demonstrate citing the West Sea of Ca Mau. In the past, this side was always deposited hence gained land. In 1985 a concrete dike was established from An Minh district, Kien Giang province to Phu Tan district, Ca Mau province with 93 kilometer length. After the dike was made, the deposit rate reduced until 1997 and erosion took place. Other evidence was referred to Ca Mau cape of Ngoc Hien. In period 1995 – 2000, many public works, roads, tower, and restaurants were established in this area. Then this area was eroded dramatically during next decade. The experts concluded, in short term from 1990 – 2011, human intervention included deforestation phenomenon, dredging rivers, and infrastructure along the coast directly affected coastline change. All most experts agreed that climate conditions such as rainfall, storm significantly affect the coastline. However, climate conditions were not independently effects on coastal line change but it coordinated human activities. It means that, when human activities effects coastal zone, such as deforestation, dredging rivers, infrastructure along the coast, climate condition (rain, storms) significantly affects the coastline. Local people who were interviewed also showed their opinion. Their opinions were concord with experts. There was 86.6 % respondents thought that “other causes” such as aquaculture style also impacted coastal zone change. They gave evidence that aquaculture specialization, which is well known as only aquaculture style without forest dramatically impacted coastal zone, while extensive farming style (including aquaculture and forest in farm) was not worth considering. All most local people (around 90%) thought that climate condition coordinated human activities significantly affected coastal zone change. They gave some evidence that after storm or heavy rain, coastal line is eroded, especially in the region without forest; in construction area, etc. However, they do not know what cause is more effect. 4.3 The Effects of Coastline Change on Land Use of Study Area 4.3.1 Land use structure in Ngoc Hien in 1990 Figure 4.16 and Table 4.14 below show that total area of Ngoc Hien district in 1990 was 71,824 ha. The region was divided into forest land 34,434 ha (occupied 47.9% of total area), aquaculture land 20,256 ha (occupied 28.2%), water body 3,924 ha (occupied 5.5%) and infrastructure land 13,210 ha (occupied 18.4%).

49

Tan

Tan An Rach Goc

Figure 4.16 Land use map of Ngoc Hien district, Ca Mau in 1990 Table 4.14 Land Use Classes of Ngoc Hien District in 1990 1990 Area (ha) Percentage (%) 34,434 47.9 20,256 28.2 3,924 5.5 13,210 18.4 71,824 100.0

Land use types Forest land Aquaculture land Water body Infrastructure Total

4.3.2 Land use structure of Ngoc Hien in 1995 The land use of Ngoc Hien in 1995 is shown in Figure 4.17 and Table 4.15 below. In 1995, aquaculture land occupied the highest area in Ngoc Hien land use structure. Aquaculture area was 27,032 ha equivalent to 38.5% while forest land was 24,034 ha, occupying 34.3% of total land structure. Infrastructure land and water body shared position respectively by 15,041 ha and 4,042 ha of the land area.

50

Ta

Tan An Rach Goc

Figure 4.17 Land use map of Ngoc Hien district in 1995 Table 4.15 Land Use Classes of Ngoc Hien District in 1995 1995 Area (ha) Percentage (%) 24,034 34.3 27,032 38.5 4,042 5.8 15,041 21.4 70,149 100.0

Land use types Forest land Aquaculture land Water body Infrastructure Total 4.3.3 Land use structure of Ngoc Hien in 2000

The land use of Ngoc Hien in 2000 is shown in Figure 4.18 and Table 4.16 below. The aquaculture area had the highest share of 39.7%, equivalent to 28,137 ha. Forest land shared 33% of total land structure, equivalent to 13,377 ha. Infrastructure was ranked the third with 15,286 ha, equivalent to 21.6% while water body had the lowest share with 5.7% of the total area.

51

Ta Tan An Rach Goc

Figure 4.18 Land use map of Ngoc Hien district in 2000 Table 4.16 Land Use Classes of Ngoc Hien District in 2000 2000 Area (ha) Percentage (%) 23,377 33.0 28,137 39.7 4,143 5.7 15,286 21.6 70,943 100.0

Land use types Forest land Aquaculture land Water body Infrastructure Total 4.3.4 Land use structure of Ngoc Hien in 2005

The land use structure of Ngoc Hien in 2005 is shown on Table 4.17, Figure 4. 1. The aquaculture area of Ngoc Hien occupied 30,381 ha or 43.2% of total land area in 2005. The second highest land use type in this year was forest land with 19,520 ha (occupied 27.8%). Infrastructure land and water body had area of 15,873 ha and 4,553 ha, respectively.

52

Ta

Tan An Rach Goc

Figure 4.19 Land use map of Ngoc Hien district in 2005

Table 4.17 Land Use Classes of Ngoc Hien District in 2005 2005 Area (ha) Percentage (%) 19,520 27.8 30,381 43.2 4,553 6.4 15,873 22.6 70,327 100.0

Land use types Forest land Aquaculture land Water body Infrastructure

4.3.5 Land use structure of Ngoc Hien in 2011 There was a great displacement between forest area and aquaculture area in 2011. Table 4.17 and Figure 4.20 show that aquaculture area was nearly 1.5 times higher than the forest area. Infrastructure area held the third position with only 0.3% lower than forest area while water body area ranked the fourth position with 6. 7% of the total area of Ngoc Hien.

53

LAND USE MAP IN NGOC HIEN DISTRICT, CA MAU IN 2011

T a Tan An Rach Goc

Figure 4.20 Land use map of Ngoc Hien in 2011 Table 4.18 Land Use Classes of Ngoc Hien District in 2011 Land use types

Area (ha) 16,482 32,189 4,646 16,302 69,618

Forest land Aquaculture land Water body Infrastructure Total

2011 Percentage (%) 23. 7 46.2 6. 7 23.4 100.0

4.3.6 Land use structure of Ngoc Hien during 1990 – 2011 A summary of land use types of Ngoc Hien district varied greatly during the study period (Table 4.19). Forest land started at 34,434 ha in 1990 dropped dramatically in 2011 to 16,482 ha. Forest land was lost more than 50% during the 22 years. Over the same time period, aquaculture area increased dramatically. In 1990, aquaculture area was 20,256 ha, reached a peak in 2011 of 32,189 ha. Infrastructure area was gradual increasing from 13,210 ha in 1990 to 16,302 ha in 2011. Water body was also slightly increased in this period. It was increased by 3,924 ha in 1990 to 4,646 ha in 2011. The change of land use types in this period is also shown in Figure 4.21.

54

Table 4.19 Land Use Structure of Ngoc Hien During 1990 - 2011 Land use types (ha) Forest land Aquaculture land Water body Infrastructure Total

1990 34,434 20,256 3,924 13,210 71,824

1995 24,034 27,032 4,042 15,041 70,148

55

2000 23,377 28,137 4,143 15,286 70,943

2005 19,520 30,381 4,553 15,873 70,327

2011 16,481 32,189 4,646 16,302 69,618

11. Chapter 5 12. Conclusions and Recommendations 5.1 Summary and Conclusions There was a significant change of coastal zone of Ngoc Hien in the study period from 1990 to 2011. In this stage, the study area lost 2,206 ha land. The change was divided into four periods. From 1990 to 1995, Ngoc Hien district lost 1,675 ha but gained deposite 795 ha land in period 1995 – 2000, thus resulted in a net loss of 880 ha. The next period, from 2000 – 2005, this region lost 617 ha land and it continued erosion 708 ha land in period 2005 – 2011. Human interventions were recorded as the important causes of coastline change in the study period in Ngoc Hien. Coastline was significantly affected by deforestation. Construction along coastal zone also greatly impacted coastline change. Dredging rivers system was recorded as the third cause of coastline change. Moreover, solid construction site along coastal zone and aquaculture farming styles were also recognized as other important causes of coastline change. In this period, the effect of climate conditions, such as rainfall, storm on coastline change were worth considering, but these climate conditions are complexly related hence could not quantified in this study. Land use structure had changed in period 1990 – 2011. Forest land reduced 17,952 ha while aquaculture area increased 11,933 ha. The causes of forest area change were erosion, deforestation or change in land use purpose. Area for infrastructure increased 3,092 ha. Water body increased 722 ha. There was a significant effect of coastline change on structure of land use in Ngoc Hien. Coastal zone of Ngoc Hien eroded 2,206 ha from 1990 to 2011 lead to the change in land use structure along the coast. The coastal line change and land use structure change are interlinked in a cause – effects relationship. 5.2 Recommendations 5.2.1 Application of research results The research estimated that Ngoc Hien lost 2,200 ha land along the coast during 1990 – 2011 This is a serious threat to thousands of people in the region. The change of coastline affects land use structure, regional planning development, degradation of land resources, and biodiversity. Therefore, to deal with coastline change, it is required to have regional solutions appropriate to take action to minimize their impact to human livelihood in the region. The recommendations are made including technique solutions and management solutions. Technique solutions:  Intensify and promote the implementation of forest protection and planting programs for rehabilitation mangroves forests along the coast.  Limit dredging rivers in the place vulnerable to effects of natural phenomenon and human activities.  Constrain using solid materials to construct along coastal zone. 56

 Choose useful farming model for aquaculture, such as extensive farming (mixing forest and aquaculture). Beside of technique solutions, the management solutions also should be applied:  Enhance communication to raise awareness of local authority and people on the methods and plans for mitigation, capacity building for integrated management of coastal zone effectively.  Inform the society about the inevitable deal with coastline change and its impacts to natural, economic, social and national security.  The above solution should be implemented in a synchronous manner and according to economic capacity of the region, the international cooperation to determine levels of response and cope with coastline change in each period certain. 5.2.2 Recommendation for future study  Future studies should be done to reveal and quantify the contribution of natural (climate) and man – made activities on the coastal line change in the Ca Mau Cape beyond the Ngoc Hien district.  The effects of the coastal line change on the livelihood should also be considered.  The effects of climate factors on the coastal line change should be simulated using an integrated modeling system.

57

References Abrams, M., Hook, S. & Ramachandran, B. ( 2009). ASTER User Handbook, Version 2. Jet Propulsion Laboratory, California, Institute of Technology, USA. ACIA (Arctic Climate Impact Assessment), (2005): Impacts of a Warming Arctic: Arctic Climate Impact Assessment. (p. 140). Cambridge: University Press. Alesheikh, A. A., & Ghorbanali, A. (2004). Map Asia 2004. An, N. T., & Thu, P. M. (2005). Assessment on Mangrove forest change in Mekong Delta by Remote sensing and GIS. ARC. (2000). Auckland regional council, 2000. Technical Publication No. 130. Coastal Erosion Management Manual. Bilan, D., (1993). The preliminary vulnerability assessment of the Chinese coastal zone due to sea level rise. Proceedings of the IPCC eastern hemisphere workshop, Tsukuba, Japan. Bird, E.C.F. (1985). Coastline Changes. (p. 219). New York: Wiley & Sons. Ca Mau DARD. (2011). Forestry protection and development planning in period 2011 – 2020. Cat, N.N., Tien, P.H., Sam, D.D. & Bien. N.N. (2006). Status of coastal erosion of Viet Nam and proposed measures for protection. Retrieved Nov 25, 2012, from http://www.fao.org/forestry/11286-08d0cd86bc02ef85da8f5b6249401b52f.pdf CLIA, (2008). CLIA cruise market overview - Statistical cruise industry data through 2007. Cruise Lines International Association, INC. Cruz and San Diego Counties, California‟. Journal of Coastal Research, 28 (Special Issue), 121–139. Damizadeh, M., Saghafian, B. & Greske, A. (2000). Studying vegetation responses and rainfall relationship based on NOAA-AVHRR images. Decision No. 186. (2006). (issued on August 14, 2006). Promulgating the Regulation on forest management. From Vietnam Prime Minister. Website: http://english.luatvietnam.vn. Duadze, S.E.K. ( 2004). Land-use and land-cover study of the Savannah ecosystem in the Upper West region (Ghana) using remote sensing. Engineering Manual. (2003). Remote sensing, Engineer Manual No. 1110-2-2907, Department of the Army, US Army Corps of Engineers Washington, DC. French, P.W. (2001). Coastal defences: processes, problems & solutions. Florence, KY, USA, Routledge. Retrieved from: http://site.ebrary.com. Galgano, F.A., Leatherman, S.P., & Douglas, B.C. (2004). „Inlets Dominate U.S. East Coast Shoreline Change‟, J. Coastal Research, in press. Gegar Prasetya. (2006). Coastal protection in the aftermath of the Indian Ocean tsunami: “What role for forests and trees?”. Chapter 4: Protection from coastal erosion. FAO, RAP publication. GeoSTAC, (n.d). Retrieved topomaps/ index.htm.

from:

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Exercise/

Hall, C.M. (2001). Trends in ocean and coastal tourism: the end of the last frontier? Ocean & Coastal Management, 44, 601-618. Harasawa, H., Lal, M., Wu, S., Anokhin, Y., Punsalmaa, B., Honda, Y., & Jafari, M. (2007). Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, chapter 10. Asia. Huang, Z.G. & Xie, X. D. (2000). Sea Level Changes in Guangdong and Its Impacts and Strategies. (p263). Guangdong: Guangdong Science and Technology Press. Hung, L. M., Khang, N. D & Chuong, L. T., (2012). Vietnam Southern coastland Erosion and accretion from Ho Chi Minh city to Kien giang province. Science and Technology journals, Vietnam academy for water resources. Kien Trung reporter. (2011). http://talkvietnam.com/2011/11/central-coast-ruin/ Kovacs, J.M. (2000). Perceptions of environmental change in a tropical coastal wetland. Land Degradation & Development, 11, 209–220. Lap, N.V & Oanh, T.T.K., (2012). Sedimentary characteristics of tidal flats and coastline changes in Ca Mau coastal area, Mekong River Delta. Leont‟yev, I.O. (2004). Coastal profile modelling along the Russian Arctic coast. Coast. Eng., 51, 779–794. Liu, B.L. & Zhou, C. H. (2001). Climatic variation and desertification in West Sandy Land of Northeast China Plain. Journal of Natural Resources, 16, 234-239. Mas, J. F., (1999). Monitoring land cover changes; a comparison of change detection techniques .International journal of remote sensing, 20 (1), 139-152. Mazda, Y., Magi, M., Kogo, M. & Hong. N. P. (1997). Mangroves as a coastal protection from waves in the Tong King delta, Viet Nam. Mangroves and Salt Marshes, 1, 127–135. Miller, A.B., Bryant, E.S. & Birnie, R. W. (1998). An analysis of land cover changes in the Northern Forest of New England using multitemporal LANDSAT MSS data. International journal of remote sensing, 19 (2), 215-265. Minh, T. H., Yakupitiyage, A., Macintosh, D.G & Phuong, N.T. (2010). An assessment for the management practices of integrated mangrove-aquaculture farming systems in Ca Mau Province, Vietnam. Moore, L. J., Benumof, B. T., & Griggs, G. B. (1999). „Coastal Erosion Hazards in Santa. Orams, M.B. (1999). Marine tourism: development, impacts and management, London: Routledge. Othman, M.A. (1994). Value of mangroves in coastal protection. Hydrobiologia, 285, 277–282. Raju, D. K., Santosh. K., Chandrasekar, J. & The. T.S. (2010). Coastline change measurement and generating risk map for the coast using Geographic information system. Archives, 38, 492–497. SAARC. (2012). South Asia Association of Regional Cooperation (DMC) Disaster Management Center. Retrieved from: http://saarc-sdmc.nic.in/coast.asp.

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Thampanya, U., Vermaat, J.E., Sinsakul, S. & Panapitukkul, N. (2006). Coastal erosion and mangrove progradation of Southern Thailand. Estuarine. Coastal and Shelf Science, 68, 75–85. Thuy, L.T. (2009). Impacts of climate change and human activities on environment in the Mekong delta, Vietnam. Tien, P. H.S. et al. (2005). Forecasting the erosion and sedimentation in the coastal and river mouth areas and preventive measures. State level research project. Hanoi, p497. U.S. Naval Office Occeanographic. (1957). The Hydrographic Surveys Department of the US Naval Oceanographic Office_1966_318.pdf. UNESCO reported. (2009). UNESCO International Coordinating Council of the Man and the Biosphere (MAB) Programme, 21st session, Jeju KAL Hotel, Grand Ballroom (Jeju, Republic of Korea) 25 - 29 May 2009. Available on http://portal.unesco.org/science/en/ev.php-URL_ID=6794&URL_DO=DO_TOPIC &URL_SECTION=201.html. Yusuf, A. A., & Francisco, H. (2004). Climate Change Vulnerability Mapping for Southeast Asia Vulnerability Mapping for Southeast Asia. East. Zhang, K., Douglas, B.C., & Leatherman, S.P. (2004). „Global Warming and Costal Erosion‟, Laboratory for coastal Research and International Hurricane Research Center.

60

Appendix 1. Clayey bank type coast (modified from ARC [2000] and French [2001])

2. Intertidal/muddy coast (modified from ARC [2000] and French [2001])

61

3. Sand dune coast (modified from ARC [2000] and French [2001])

4. Sandy coast (modified from ARC [2000] and French [2001])

62

5. Mangrove forest in Ca Mau, along coast (A) and Shrimp pond with less forest (B)

(A)

(B)

6. People gathered clams in Khai Long beach, Ca Mau cape, Vietnam

(B)

(A)

63

7. Construction along Ca Mau Cape

64

8. Coastal change affects human lives in Ca Mau coast. Along East Sea coastal (A), (C); West Sea coastal (B)

(A)

(B)

(C)

65

9. Questionnaires A. Questionnaires Survey for Livelihood I.

General Information

1. Name of respondent:_______________________________________ 2. Age: ___________ 3. Caste:_________________ 4. Sex: Male ( ) Female ( ) 5. Relation to head of household 6. Family size: ______________ 7. Education level of family members

Relation to respondent

Sex

Age

Occupation

Education

Have any changes in occupation of the members in your family? What are the reasons? 8. How long does the family live in this area __________ (year) 9. Major occupation: _______________ a. Aquaculture ( );

b. Business ( );

c. Outside employment ( ); d. Forestry ( )

If a, how long does the family do farming? _______________

66

II. Perception of farmer about coastline change and causes of change 10. Have you ever heard about coastal line change? Yes ( );

No ( )

If yes, which source have you heard? 11. Do you know any changes? Yes ( ), No ( ). a. If yes, how and where? b. If not, do you think coastal line will change? 12. Does change of coastline affect on aquaculture production? Yes ( );

No ( )

a. If yes, how? b.If not, why? 13. How do you feel about the rainfall compared to the past, 10 years, 20 years (longer is better) Increase ( )

Decrease ( )

Stable ( )

14. Does change in rainfall pattern (erratic and irregular rainfall) effect on aquaculture production? Yes ( );

No ( )

a. If yes, how ? b. If not, why? 15. How do you feel about the storm compared to the past, 10 years, 20 years (longer is better) Crops Frequency of storm Intensity of storm Change in time of storm coming

Increase/how/when

Decrease

16. Does change in storm affect aquaculture production? Yes ( );

Remark

No ( )

a. If yes, how ? b. If not, why? 17. Could you give your opinion about causes of coastal line change? 18. In your opinion, between climate conditions and human activities, what are more effects on coastal line change? 67

B. Questionnaires Survey for Experts I.

General Information

1. Name of respondent:_______________________________________ 2. Caste:_________________ 3. Sex: Male ( ) Female ( ) 4. How long do you work/ live in this area __________ (year) 5. Major occupation: _______________ a. Manager ( );

b. Researcher ( );

c. Officer ( );

II. Outlook on coastline change and causes of change 6. Have you ever heard about coastline change? Yes ( );

No ( )

If yes, which source have you heard? 7. Do you know any changes? Yes ( ), No ( ). a. If yes, how and where? b. If not, do you think coastline change? 8. Do you have any research/engage in discussion on coastline change? Yes ( ); No ( ) If yes, how do you think about coastal line change in Ca Mau? 9. In your view, what are causes of coastline change in Ca Mau? 10. Comparison between natural causes and human intervention, what is more effect on coastline change? How? 11. How do you feel about the rainfall compared to the past, 10 years, 20 years (more long is better) Increase ( )

Decrease ( )

Stable ( )

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12. How do you feel about the storm compared to the past, 10 years, 20 years (more long is better) Crops Frequency of storm Intensity of storm Change in time of storm coming

Increase/how/when

Decrease

Remark

13. Do you think coastland protection constructions are causes of coastline erosion? Why and how? 14. How does coastline change affect human livelihood? 15. How to reduce coastline erosion? 16. What is role of mangrove forest on coastline protection? 17. How do you think about local people responsibility on coastline protection? 18. How do you think about government, local government responsibility on coastline protection? 19. How do you think about other stakeholders’ responsibility on coastline protection? 20. How to develop and manage coastline sustainability?

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