Water balance for ma river basin in context of climate change thesis of master degree major integrated water resources managemen

impact of climate change on temperature and annual rainfall also has to concern as its negative influence to water supply capacity.. The objectives of research are to analyze the water b

ABSTRACT

Water is one of the most common and most important substances on the earth's surface It is essential for the existence of life, and the kinds and amounts of vegetation occurring on various parts of the earth's surface depend more on the quantity of water available than on any other single environmental factor (Kramer, Paul J.; Boyer, 1995) Facing with water crisis has singled out as a major worldwide concern Under the main impact of Climate change, it is considered as an added driver for many of the societal and environmental problems of the 21st century Climate change may affect water systems through increased/unusual spatio-temporal variability, long-term temperature and water balance changes, and sea-level rise which in turn have implications for water security, food security, energy security, health of human and ecosystems, and human livelihoods (Vörösmarty et al 2000; Richardson et al 2011) Water availability will be increasingly affected by climate change, which in Africa could expose 250 million people to greatered water stress In some countries drought could halve the yields from rain-fed agriculture by 2030s Across Sub- Saharan Africa and South and East Asia drought and rainfall variations could lead to large productivity losses in cultivated food staples (Development, 2015) By the contrast of the decrease of water availability and the increase of water demand gather with the conflict between different interests of stakeholders become a huge water management task

The Ma River basin is one of the largest rivers in central Viet Nam, orginated from the southern of Dien Bien province, flowing through the Ma river district of Son La province, through Laos and into Vietnam by Ba Thuoc district, Thanh Hoa province

Ma river basin has abundant water resources However, the demand for water is rising day by day under the pressure of population and development - social growth Moreover, the uneven distribution of water resources in time and space with the

impact of climate change on temperature and annual rainfall also has to concern as its negative influence to water supply capacity

The objectives of research are to analyze the water balance in the basin in three scernarios: baseline (2002-2012), future scenarios with socio-economic development text into account impacts of climate change (RCP4.5 and RCP8.5) in 2030s The water use activities in this basin such as irrigation, industry, domestic… are also taken into account In order to get these objectives, WEAP model is implemented to simulate the water balance in the basin MIKE-NAM model is used to simulate the inflow to ungauged basins CROPWAT model is applied to estimate the water requirement for crop

The results shows that the imbalances between water supply and water demand occur

in the dry season In 2030s, the system cannot supply sufficient water quantity for the projected growing demand of socio-economic development scenario The unmet demand is going up compared to the current scenario However, the situation is much more severe in the scenario in which the climate change impacts are considered

DECLARATION

I hereby certify that the work which is being presented in this thesis entitled, “Water balance for Ma river basin in context of climate change” in partial fulfillment of the requirement for the award of the Master of Science in Integrated Water Resource Management, is an authentic record of my own work carried out under supervision of

Dr Ngo Le An and Associate Professor Nguyen Thu Hien

The matter embodied in this thesis has not been submitted by me for the award of any other degree or diploma

Date:

ACKNOWLEDGMENT

I would like to express my deepest gratitude and sincere appreciation to my advisor, Doctor Ngo Le An, who is the Deputy Head of ThuyLoi University’s Hydrology and Water Resources Division and my co-advisor, Associate Professor Nguyen Thu Hien, Dean of Thuyloi University’s Water Resources Engineering Faculty for their patient, valuable advice and continuous encouragement throughout the process of this thesis work

I would especially like to thank my colleagues in the National Centre of Water Resource Planning and Investigation (NAWAPI), where I am working for supporting

me in many ways during the time I am busy with my thesis

I would also like to acknowledgement my friends from Thuyloi University including

Ms Vu Thi Thu Phuong, Mr Syphachan Phommachan and many others for their help

to prepare input for models

Finally, I must express my very profound gratitude to my parents and to my husband for providing me with unwavering support and continuous encouragement throughout

my years of study and through the process of researching and writing this thesis This accomplishment would not have been possible without them Thank you

TABLE OF CONTENTS

ABSTRACT i

DECLARATION iii

ACKNOWLEDGMENT iv

LIST OF FIGURES vii

LIST OF TABLE ix

CHAPTER 1: INTRODUCTION 1

1.1 Background 1

1.2 Problem statement 1

1.3 Research Objectives 2

1.4 Research questions 3

1.5 Methodology 3

1.6 Structure of the thesis 3

CHAPTER 2: LITERATURE REVIEW 5

2.1 Water balance 5

2.2 Climate change impact on water resources 6

2.3 Climate change scenarios 8

2.4 Models for Integrated Water Resource Management (IWRM) 10

2.4.1 Water Balance Modeling - WEAP 10

2.4.2 Rainfall – runoff Modelling: MIKE 11- NAM 11

2.4.3 CROPWAT 8.0 13

CHAPTER 3: DESCRIPTION OF STUDY SITE 15

3.1 Geographical location and topography 15

3.1.1 Geographical location 15

3.1.2 Topography 16

3.2 Climate 17

3.3 Population - economic and social conditions 20

3.4 Hydrology 23

3.4.1 Main River network 23

3.4.2 Stream network 25

3.4.3 Hydraulic structures 25

3.5 Climate change scenarios for the study areas 25

3.6 Scenarios for water balance 28

CHAPTER 4: WATER BALANCE SIMULATION FOR MA RIVER BASIN 31

4.1 Schematization of the Ma River Basin 31

4.2 Input data 32

4.2.1 Runoff 32

4.2.2 Water demand 42

4.3 Water balance for current scenario in the basin 54

4.4 Water balance calculations for climate change scenarios in the period 2020-2039 (2030s) 57

CHAPTER 5: CONCLUSION AND RECOMMENDATION 66

5.1 Conclusion 66

5.2 Recommendation 67

REFERENCES 70

APPENDICES 72

LIST OF FIGURES

FIGURE 1.1: THE MA RIVER BASIN 1

FIGURE 2.1: RADIATIVE FORCING OF THE REPRESENTATIVE CONCENTRATION PATHWAYS 9

FIGURE 2.2: THE SCHEMATIZATION OF THE MA RIVER BASIN 11

FIGURE 2.3 PROCESSES OF NAM MODEL 13

FIGURE 3.1: THE MA RIVER BASIN 16

FIGURE 3.2.: EXAMPLES OF HADGEM2-AO MODEL’S OUTPUT IN ASIA 26

FIGURE 3.3: GRID OF HADGEM2-AO MODEL (RED DASH-LINE) WITH RAIN GAUGE STATIONS IN THE MA RIVER 26

FIGURE 3.4: RESCALING FACTORS BETWEEN AVERAGE MONTHLY RAINFALL IN THE FUTURE PERIOD AND HISTORICAL PERIOD FOR RCP4.5 27

FIGURE 3.5: RESCALING FACTORS BETWEEN AVERAGE MONTHLY RAINFALL IN THE FUTURE PERIOD AND HISTORICAL PERIOD FOR RCP8.5 28

FIGURE 3.6: THE OPERATION CURVE OF TRUNG SON RESERVOIR 29

FIGURE 4.1: SCHEMATIZATION OF THE MA RIVER NETWORK 32

FIGURE 4.2: FOUR SUB-BASINS IN THE MA RIVER BASIN 33

FIGURE 4.3: OBSERVED AND SIMULATED HYDROGRAPH IN CALIBRATION PERIOD (1966-1971) (M3/S) 36

FIGURE 4.4: OBSERVED AND SIMULATED HYDROGRAPH IN VALIDATION PERIOD (1973-1981) (M3/S) 36

FIGURE 4.5: OBSERVED AND SIMULATED HYDROGRAPH IN SIMULATION PERIOD (2002-2012) (M3/S) 39

FIGURE 4.6: OBSERVED AND SIMULATED HYDROGRAPH IN

FIGURE 4.8: MONTHLY INFLOW TO THE BASIN IN THE PERIOD 2002-2012

(106 M3) 42

FIGURE 4.9: METEOROLOGICAL DATA IN CROPWAT 45

FIGURE 4.10: RAINFALL DATA IN CROPWAT 45

FIGURE 4.11: CROP DATA IN CROPWAT 46

FIGURE 4.12: SOIL DATA IN CROPWAT 46

FIGURE 4.13: THE IRRIGATION REQUIREMENT FOR EACH AREA (L/S/H) 47 FIGURE 4.14 THE FREQUENCY CURVE OF THE DRIEST MONTHLY FLOW IN CAM THUY STATION (M3/S) 51

FIGURE 4.15: WATER REQUIREMENT BY SECTORS IN THE PERIOD 2002-2012, CURRENT SCENARIO (106 M3) 55

FIGURE 4.16: UNMET DEMAND BY MONTHS IN THE PERIOD 2002-2012, CURRENT SCENARIO (103 M3) 56

FIGURE 4.17: MONTHLY INFLOWS TO THE AREAS IN KB4.5 SCENARIO 59

FIGURE 4.18: MONTHLY INFLOWS TO THE AREAS IN KB8.5 SCENARIO 59

FIGURE 4.19: COMPARISON OF MONTHLY INFLOWS BETWEEN PAST SCENARIO(BASELINE), KB4.5 AND KB8.5 SCENARIOS 60

FIGURE 4.20: UNMET DEMAND BY MONTHS IN THE PERIOD 2020-2039, KB4.5 SCENARIO (106 M3/S) 61

FIGURE 4.21: TURBINE DISCHARGE AND HYDROPOWER GENERATION OF TRUNG SON RESERVOIR, KB4.5 SCENARIO 62

FIGURE 4.22: UNMET DEMAND BY MONTHS IN THE PERIOD 2020-2039, KB8.5 SCENARIO (106 M3/S) 63

FIGURE 4.23: TURBINE DISCHARGE AND HYDROPOWER GENERATION OF TRUNG SON RESERVOIR, KB8.5 SCENARIO 64

LIST OF TABLE

TABLE 2.1: DESCRIPTION OF EACH REPRESENTATIVE CONCENTRATION

PATHWAYS (RCPS) (IPCC, 2014) 10

TABLE 3.1: MONTHLY AVERAGE TEMPERATURE IN THE MA RIVER BASIN 18 TABLE 3.2: MONTHLY AVERAGE HUMIDITY IN THE MA RIVER BASIN 18

TABLE 3.3: ANNUAL AVERAGE RAINFALL IN THE MA RIVER BASIN 19

TABLE 3.4: THE ELEVATION –AREA - STORAGE RELATIONSHIP OF TRUNG SON RESERVOIR 30

TABLE 4.1: DESCRIPTION OF SUB-BASINS 34

TABLE 4.2: NAM PARAMETER EXPLANATION AND BOUNDARIES (SHAMSUDIN & HASHIM, 2002) 34

TABLE 4.3: THE RELIABILITY OF NASH COEFFICIENT 35

TABLE 4.4: PARAMETERS FOR SUB-BASIN 1 37

TABLE 4.5: FLOWS INSIDE OF SUB-BASIN 2 37

TABLE 4.6: PARAMETERS FOR SUB-BASIN 3 38

TABLE 4.7: FLOWS INSIDE OF SUB-BASIN 3 39

TABLE 4.8: PARAMETERS FOR SUB-BASIN 4 41

TABLE 4.9: FLOWS INSIDE OF SUB-BASIN 4 41

TABLE 4.10: IRRIGATION AREAS OF THE MA RIVER BASIN IN THANH HOA 43

TABLE 4.11: LAND AREA OF RICE CULTIVATION IN EACH AREA 44

TABLE 4.12: VIETNAMESE STANDARD FOR LIVESTOCK CONSUMPTION 48 TABLE 4.13: THE QUANTITY OF LIVESTOCK IN THE REGION 48

TABLE 4.14: VIETNAMESE STANDARD FOR DOMESTIC WATER USE 49

TABLE 4.15: POPULATION OF EACH AREA IN THANH HOA PROVINCE 49

TABLE 4.16: INDUSTRIAL PRODUCTION BY REGION IN CURRENT 50

TABLE 4.20: LAND AREA OF RICE CULTIVATION IN EACH AREA IN 2030S53 TABLE 4.21 WATER SURFACE AREA FOR AQUACULTURE IN THE BASIN

CHAPTER 1: INTRODUCTION

1.1 Background

Figure 1.1: The Ma River basin

The Ma river basin is located in the eastern of Truong Son, West North northern and Central Laos The basin is located in the geographic location from 19037’30” to

22037’33”north latitude and from 103005’10” to 106005’10’’ east longitude Ma river originates from the southern slopes Pu Huoi Long range in Tuan Giao Dien Bien province, and runs from the northwest - southeast through Son La, Sam Nua (Laos), Hoa Binh, Thanh Hoa and then flows into the sea at 3 inlets: Lach Sung, Lach Truong and Cua Hoi North of the Ma River basin borders Da River and Boi River basin; West

of the Ma River basin borders Mekong River basin, Sourth borders Hieu River and Yen River, East borders East Coast

regions contain of Northwest and Truong Son, Ma River basin has formed many regions have different natural conditions, from the Northwest (Lai Chau, Son La Peace) to coastal North Central region (Thanh Hoa, Nghe An) Besides, it plays an important role in economic development & social, ecological environmental protection

of Thanh Hoa province in particular and the North Central region in general

Although Ma river basin has much potential for development of economic, it is difficult to promote the potential of natural resources, especially financial water resources Moreover, basin always appear natural catastrophes related to flows like floods, flash floods, drought to hinder the process of economic and social development there Also, in recent years in the dry season in some parts of the Ma River basin appear salinity intrusion significant impact to production operations and activities of the people in the region Climate change is also the “hot” issue in the water resources problems The climatic impact on the water regime may also exacerbate other environmental and social effects of water management For instance, the decrease runoff can cause pollutants or exacerbate the spread of water-borne disease Climate change will greatly complicate the design, operation, and management of water-use systems (Gleick & Shiklomanov 1989) On the other hand, climate change that increases overall water availability could either be beneficial or could increase the risk of flooding Regions with an arid and semi-arid climate could

be sensitive to even insignificant changes in climatic characteristics (Linz et al 1990)

Moreover, using of water resources still appears conflicts between water demand and water availability Water demand is increasing rapidly during amount of available water decline In order to stabilize the lives of the people, ensuring sustainable development in the basin, finding solutions to operators, rational use of water resources of the Ma River basin has become urgent practical needs to ensure a balance between supply and demand

1.3 Research Objectives

- Possibility of water supply and current situation of using water in Ma River basin

- Establishment of water balance model on basin and assess the level of water shortage between supply and demand for water

- Proposed management measures

1.4 Research questions

Some questions are given to answer in order to get the objectives

1 What is the water status in each region of Ma River Basin currently?

2 What are suitable tools to assess water availability and water demand in the river basin?

1.5 Methodology

In this study, relevant data and information in the study area must be collected The data collection contain of: (1) time series of hydro-meteorological data; (2) water demand of all water use activities in each region (if lack of data, must be calculated); (3) Characteristics of infrastructures in the basin such as reservoir (4) Topography, landuse, soiltype maps Rainfall-runoff model is used to simulate the runoff for ungauged basin Then, water balance model is employed to estimate the water balance

in the basin in different scenarios (including Climate change scenarios) Finally, base

on the result of modelling, some analysis and recommendations will be proposed

Due to the lack information of water requirement in Dien Bien province and in Laos territory, the research only focus in the Ma river basin in Thanh Hoa province

1.6 Structure of the thesis

This thesis is present in five main chapters including the introduction, literature review, the description of study area, the simulation of water balance in Ma River Basin and the result analysis, and last chapter is the conclusions and recommendations

water resources management in the basin In addition, a set of research questions and the methodology are also given

Chapter 2: Literature review shows an overview of “water balance”, “climate change impacts on water resources.”

Chapter 3: The chapter presents overview of area which contain of characteristic of

Ma River Basin with regard to Geographical location and topography, the climate conditions, the socio-economic development, the illustration of river network, the current water use activities, and the water storage

Chapter 4: In this chapter, the simulation of models in Ma River Basin is showed The schematic basin is brought out; the data requirements for applying the WEAP model are focused and demonstrated Moreover, this chapter also defines main scenarios After calculating, the results of the main scenarios with respect to the water supply and water requirement will be brought out and analyzed in this chapter It illustrates and compares the water shortage in needs of each water user node corresponding to each scenario

Chapter 5: The chapter focuses on the main findings and recommendations for the future planning

CHAPTER 2: LITERATURE REVIEW

2.1 Water balance

In every business, there are some types of accounting procedure In fact, it is essential for a good business, not an option For water, we also need a good accounting of water supplies, changes in storage, and water destinations for proper management of the resource For irrigation engineers, proper irrigation scheduling – both timing and amount, control of runoff, minimizing deep percolation, and the uniform application of water – are of primary concern In field level, water requirements of the plants are met

by the storage of soil, supplies from irrigation and rainfall, and to some extent, from shallow groundwater tables Losses of water from the field include surface runoff from the field, deep percolation out of the root region, transpiration by plants, and evaporation from the soil surface

Field water supply has been a major focus of agricultural research and management The soil-water balance is a widely used method of tracking soil water supply in a field Water balances are essential for making wise decisions regarding water conservation, water management, and irrigation scheduling Water conservation implies that within the boundaries of interest, the available water is to be conserved Accurate computation of water balance can help to avoid past errors and improve for the future The components of water balance change over time, from day to day, from year to year, etc

According to Ali, the field water balance is an account of all quantities of water added

to, subtracted from, and stored within a given volume of soil during a given period of time in a given field The water balance is merely a detailed statement of the law of conservation of matter, which states simply that matter can neither be created nor

Inflow - Outflow = Change in storage (Ali, 2010)

Water balance calculation requires two types of boundaries: (i) physical or spatial boundary, and (ii) temporal (time) boundary Water balance can be studied for a field, farm, irrigation district, or a hydrological basin The principle is the same for all units, but one must specify which boundary is being talked about when making computations Similarly, a time boundary should also be specified (Ali, 2010)

Besides, follow different aspect from Zhang, Water balance is based on the law of conservation of mass: any change in the water content of a given soil volume during a specified period must equal the difference between the amount of water added to the soil volume and the amount of water withdrawn from it In other words, the water content of the soil volume will increase when additional water from outside is added

by infiltration or capillary rise, and decrease when water is withdrawn by evapotranspiration or deep drainage The control soil volume for which the water balance is computed is often determined arbitrarily (Zhang et al, 2002)

Summary, a water balance equation can be used to describe the flow of water in and out of a system A system can be one of several hydrological domains, such as a column of soil or a drainage basin Water balance can also refer to the ways in which

an organism maintains water in dry or hot conditions It is often discussed in reference

to plants or arthropods, which have a variety of water retention mechanisms, including

a lipid waxy coating that has limited permeability

2.2 Climate change impact on water resources

In recent years, and particularly since the outcome of the second and third assessment reports of the Intergovernmental Panel on Climate Change (IPCC, 1996) and (IPCC, 2001), it has become clear that global climate change is a scientific reality An increasing awareness that global climate change will affect water resources has also clearly emerged and this has been reflected in a rapidly growing body of scientific literature

Actually, water resources are arguably the most important domain to be considered in

a climate change impact assessment study This importance stems from the fact that climate change has direct impacts on the availability, timing and variability of the water supply and demand, and is also related to the significant consequences of these impacts on many sectors of our society Water is used for human consumption, industrial purposes, irrigation, power production, navigation, recreation and waste disposal, as well as for the maintenance of healthy aquatic ecosystems Its availability and the occurrence of extreme events like floods and droughts condition the location

of urban, industrial and agriculture areas, power generation plants and trading centers The IPCC Third Assessment Report (IPCC, 2001) estimates a global increase of mean annual temperature of 0.8°C to 2.6°C by 2050 and 1.4°C to 5.8°C by 2100 The study also reports results that indicate an increase in annual rainfall induced by climate change in high and mid latitudes and most equatorial regions, as well as a general decrease in the subtropics Results also show that flood magnitude and frequency is likely to increase, due to the concentration of rainfall in winter in most areas of the globe Simultaneously, the decrease of low flows in many regions associated with higher temperatures constitutes a serious threat to the quality of water resources As regards the impacts of climate change in Europe, the IPCC studies suggest that Southern Europe, and namely the Mediterranean region, will be particularly affected in

a negative way This will be especially true in the Iberian Peninsula, south of river Tagus, where a considerable increase in temperature and a reduction in rainfall and runoff is expected by 2100

As pointed out by Moss et al (2010), the research community currently needs new scenarios First, more detailed information is needed for running the current generation

of climate models than that provided by any previous scenario sets Second, there is an increasing interest in scenarios that explicitly explore the impact of different climate policies in addition to the no-climate-policy scenarios explored so far (e.g SRES)

across the different disciplines involved in climate research The need for new scenarios prompted the Intergovernmental Panel on Climate Change (IPCC) to request the scientific communities to develop a new set of scenarios to facilitate future assessment of climate change as given by report in 2007

The IPCC also decided such scenarios would not be developed as part of the IPCC process, leaving new scenario development to the research community The community subsequently designed a process of three phases (Moss et al 2010):

1) Development of a scenario set containing emission, concentration and land-use trajectories—referred to as “representative concentration pathways” (RCPs)

2) A parallel development phase with climate model runs and development of new socio-economic scenarios

3) A final integration and dissemination phase (Vuuren et al., 2011)

2.3 Climate change scenarios

RCPs are the third generation of scenarios The first set - IS92 - were published in

1992 In the year 2000, the second generation - SRES - were released The latest, now

in use, are the RCPs

Climate change scenarios are Representative Concentration Pathways (RCPs) which have been developing and updating by IPCC since 2013 (IPCC, 2014) Four RCPs were selected and defined by their total radioactive forcing (cumulative measure of human emissions of GHGs from all sources expressed in Watts per square meter) pathway and level by 2100 The RCPs were chosen to represent a broad range of climate outcomes, based on a literature review, and are neither forecasts nor policy recommendations

Figure 2.1: Radiative Forcing of the Representative Concentration Pathways

While each single RCP is based on an internally consistent set of socioeconomic assumptions, the four RCPs together cannot be treated as a set with consistent internal socioeconomic logic For example, RCP8.5 cannot be used as a no-climate-policy socioeconomic reference scenario for the other RCPs because RCP8.5’s socioeconomic, technology, and biophysical assumptions differ from those of the other RCPs Each RCP could result from different combinations of economic, technological, demographic, policy, and institutional futures For example, the second-to-lowest RCP could be considered as a moderate mitigation scenario However, it is also consistent with a baseline scenario that assumes a global development that focuses on technological improvements and a shift to service industries but does not aim to reduce greenhouse gas emissions as a goal in itself (similar to the B1 scenario of the SRES scenarios) Four RCPs used a common set of historical emissions data to initialize the integrated assessment models Description of each RCP at the table below:

Table 2.1: Description of each Representative Concentration Pathways (RCPs)

(IPCC, 2014)

RCP 8.5 Rising radiative forcing pathway

leading to 8.5 W/m2 in 2100

MESSAGE

RCP6 Stabilization without overshoot

pathway to 6 W/m2 at stabilization after 2100

AIM

RCP4.5 Stabilization without overshoot

pathway to 4.5 W/m2 at stabilization after 2100

GCAM (MiniCAM)

RCP2.6 Peak in radiative forcing at ~ 3 W/m2

before 2100 and decline

IMAGE

Following the description of each scenarios, it is appeared that the RCP4.5 and RCP8.5 are the most suitable scenarios with the socioeconomic assumptions as well as the current conditions of Ma River Basin, therefore, this study will reveal the insight of the balance between water availability and water demand at the present as well as in projected future circumstances considering RCP4.5 and RCP8.5 characteristics as the primary influence factors

2.4 Models for Integrated Water Resource Management (IWRM)

2.4.1 Water Balance Modeling - WEAP

WEAP model is used to simulate the water balance in the basin WEAP, developed by the Stockholm Environment Institute (SEI), is a practical tool for water resources planning, which incorporates both the water supply and the water demand issues in addition to water quality and ecosystem preservation, as required by an integrated approach to basin management (SEI 2007) The model is semi-theoretical, continuous time, deterministic and semi-distributed As the model is semi-theoretical, it needs calibration and verification

WEAP is a laboratory for examining alternative water development and management

system with basic principles of water accounting on a user-defined time step; it computes water mass balance for every node and link in the system for the simulation period (SEI 2007), (Yilmaz & Harmancioglu, 2010) Simulation allows the prediction and evaluation of “what if” scenarios and water policies such as water conservation programs, demand projections, hydrologic changes, new infrastructure, and changes in allocations or operations (Hamlat, Errih, & Guidoum, 2013)

WEAP model has two primary functions (Sieber et al., 2005):

 Simulating the processes of hydrology such as runoff, evapotranspiration in order to assess the availability of water inside a basin

 Simulating activities of anthropogenic which superimposed on the natural system to influence water resources and their allocation to enable evaluation

of the impact of water users

Figure 2.2: The Schematization of the Ma river basin

This model need input data for running, these data will be collected by models were used in this thesis: MIKE 11-NAM to calculate insides flow in each sub-basin and CROPWAT model to compute water requirement for irrigation

models are becoming higher and higher, leading to the need of enhancing existing models and even of developing new theories Existing hydrological models can be classified into three types, namely, 1) empirical models (black-box models); 2) conceptual models; and 3) physically based models To address the question of how land use change and climate change affect hydrological (e.g floods) and environmental (e.g water quality) functioning, the model needs to contain an adequate description of the dominant physical processes

The use of simulation models should be considered as an important tool in water resources management and related decision-making Hydrological models are well-developed and a long tradition of application exists Rainfall – Runoff modeling is the process of transforming rainfall into catchment runoff Almost all rainfall - runoff models take as input data, at least, rainfall and potential evapotranspiration and calculate as result catchment runoff The MIKE 11 is a powerful hydrological modeling system which can be used in water resources management The system, developed by DHI, was designed to simulate water flow in rivers and open channels It

is composed by several modules namely rainfall-runoff (RR), hydrodynamic (HD), advection-dispersion (AD) etc., which in some cases can be used in combination and

in others cases as standalone simulators (DHI 2009)

In order to simulate the process of hydrology, NAM model was chosen to apply in this thesis The NAM (Nedbør Affstrømnings Model) model is a deterministic, lumped conceptual rainfall-runoff model which is originally developed by the Technical University of Denmark Nielsen and Hansen (Nielsen, 1973) Each sub-basin is one unit, so the parameters and variables are considered for representing average values for the all sub-basins The result is a time series of the runoff from the basin throughout the period which set up in model So, the MIKE 11 NAM model provides both peak and base flow conditions that accounts for antecedent soil moisture conditions over the modeled time period The processes of NAM model is shown in Figure 2.3

Figure 2.3 Processes of NAM Model

Because of the limited of data and research conditions, this thesis only focus on surface storage and snow is not appear in the research area The thesis is only concentrate about surface water balancing withour considering groundwater Input data required in this model are daily rainfall and evaporation, and then the output data

of the model is the runoff

2.4.3 CROPWAT 8.0

CROPWAT 8.0 for Windows is a computer program for the calculation of crop water requirements and irrigation requirements based on soil, climate and crop data In addition, the program allows the development of irrigation schedules for different management conditions and the calculation of scheme water supply for varying crop patterns CROPWAT 8.0 can also be used to evaluate farmers’ irrigation practices and

The crop water requirement is the amount of water needed for various kinds of crops

to grow optimally, and it depends mainly on the climate conditions, crop types, and the growth stage of crop In this method, most of the equation parameters are directly measured

or can be readily calculated from weather data The equation can be utilized for the direct calculation of any crop evapotranspiration (ETc)

CHAPTER 3: DESCRIPTION OF STUDY SITE

3.1 Geographical location and topography

3.1.1 Geographical location

Ma River Basin is located in the eastern of Truong Son Mountain Range, which is located in Central Vietnam, Central Laos and Northwest of Northern Vietnam The basin is located in the geographical location from 22o37'33" to 20o37'33"N, from

103o05'10 "to 106o05'10" E The basin has the following boundaries:

- Northeastern part is the divided watershed between Da River and Ma River

- Southwestern part is adjacent to the Mekong River basin

- Southern part is adjacent to Ca River basin

- Eastern part is the East Coast

Mainstream of Ma River originates from the southern slopes of Pu Huoi Long mountain range in Tuan Giao of Dien Bien Province, and flows in the Northwest – Southeast direction through Son La, Sam Nua (Laos), Hoa Binh, Thanh Hoa and then flows into the sea at 3 estuaries: Sung, Lach Truong and Cua Hoi

The Ma River system includes the mainstream of Ma River and two major tributaries which are Chu River and Buoi River This river system has a total length of 881 km,

the annual total average flow is 19.52 billion m3 Network of Ma River develops in the form of tree branches, the shape factor is 0.17, drainage network density is 0.66 km/km2

The total area of Ma River basin is 28,490 km2 and it is stretched over the territories of Laos and Vietnam In which, the basin area in Vietnam territory is 17,720 km2, and the basin area in Laos territory is 10,680 km2

Figure 3.1: The Ma River basin

3.1.2 Topography

A highlight characteristic of Ma River basin is mainly topography of plateau, located

in the middle-stream and upstream The relative elevation is not high, the splited extent is low The basin is located between two parallel mountain ranges under the northwest - southeast direction, the right range is from Tuan Giao to Hoi Xuan, the left

has peaks of mountain with height from 1800m to 2000m Thanh Hoa province with

diverse terrain, lower from West to East, the Northwest is the hills with a height from

1000 to 1500 m and gradually sloping, stretched and expanded to the southeast The hilly area accounted for 3/4 of total provincial area, creating huge economic potential

of forestry, abundant forest products, rich natural resources

The topography is divided into 3 regions:

- The mountainous and mid-land region: This region accounts for most of Thanh Hoa area, particularly the mid-land hilly region which occupies a narrow area and is fragmented, discontinuous The average altitude of the mountainous region ranges

from 600m to 700m, the slope is upper 25o; the mid-land regions has an average altitude of between 150m to 200 m, the slope is from 15o to 20o

- Delta region: The delta region of Thanh Hoa province occupies the half of the area of Northern Central delta This regions is alluvial region by the system of Ma River, Bang River, Yen River and Hoat River The average height is from 5m to 15m, interspersed with low hills and independent limestone mountain

- Coastal region: This region accounts for 10.89% area of the whole province area The area has a coastline of 102km, the terrain is relatively flat Along to the coast are the estuaries, favorable for aquaculture and development of industrial regions and marine economy The coastal sandy area has an average altitude from 3m to 6m

3.2 Climate

Thanh Hoa is located in the tropical monsoon climate with two distinct seasons: Hot summer with high humidity and rainfall, and it is influenced by the hot, dry Southwest Wind and winter is cold and with low rainfall

a) Temperature

Ma River basin has two regions with different temperature regimes:

- In mountainous areas, the cold season begins from November to February, the hot season begins from March to May Temperature in this area coincides with the temperature in the Northwest area

- In Ma River’s downstream delta: The annual average temperature is higher than that

of mountainous areas Winter ends earlier than Northern part of Vietnam from 15 -20 days

Table 3.1: Monthly average temperature in the Ma River basin

(Unit: 0 C)

Tuan Giao 14,6 16,3 19,5 22,6 24,6 25,1 25,2 24,8 23,9 21,6 18,3 15,0 21,0 Son La 14,6 16,5 20,0 22,8 24,7 25,1 25,0 24,6 23,7 21,7 18,2 15,0 21,0 Song Ma 16,1 18,5 21,2 24,3 26,1 26,4 26,3 25,9 25,1 22,8 19,6 16,3 22,4 Yen Chau 15,9 17,9 21,7 24,8 26,8 27,0 26,9 26,3 25,2 22,8 19,4 16,4 22,6 Moc Chau 11,8 13,3 16,8 20,2 22,5 23,0 23,1 22,4 21,2 18,9 15,7 12,8 18,5 Hoi Xuan 16,6 18,0 20,7 24,5 26,9 27,6 27,6 27,0 25,6 23,5 20,5 17,6 23,0 Lac Son 15,9 17,3 20,2 24,0 27,2 28,0 28,3 27,6 26,3 23,7 20,4 17,3 23,0 Bai Thuong 16,5 17,5 20,1 23,9 27,0 28,2 28,4 27,6 26,6 24,3 21,2 18,0 23,3 Thanh Hoa 17,0 17,3 19,8 23,5 27,2 28,9 29,0 28,2 26,4 24,5 22,4 18,6 23,6 Nhu Xuan 16,5 11,3 20,0 23,6 27,3 28,6 28,9 27,8 26,5 24,2 20,8 17,9 23,3 Yen Dinh 16,7 17,6 20,2 23,6 27,2 28,5 28,9 28,0 26,8 24,4 21,2 18,1 23,4 Tinh Gia 16,8 17,1 19,6 23,2 27,2 28,9 29,5 28,3 26,8 24,5 21,2 18,1 23,4

b) Humidity

Air humidity in the basin ranges from 82% - 86% Maximum humidity usually occurs

in March and April each year (89-94%) Minimum humidity occurs in May, Jun or July with values of only 6.12%

Table 3.2: Monthly average humidity in the Ma River basin

(Unit: %)

Tuan Giao 84,0 81,0 79,0 80,0 82,0 86,0 86,0 88,0 86,0 86,0 88,0 85,0 84,0 Son La 79,0 76,0 73,0 75,0 78,0 84,0 85,0 87,0 85,0 83,0 81,0 80,0 80,0 Song Ma 81,0 77,0 75,0 76,0 79,0 85,0 87,0 88,0 86,0 84,0 84,0 83,0 82,0 Yen Chau 77,0 74,0 71,0 74,0 73,0 81,0 83,0 86,0 84,0 83,0 81,0 79,0 79,0 Moc Chau 87,0 86,0 84,0 82,0 82,0 85,0 86,0 88,0 87,0 86,0 86,0 85,0 85,0 Hoi Xuan 86,0 85,0 85,0 84,0 83,0 85,0 86,0 88,0 88,0 87,0 87,0 86,0 86,0 Lac Son 86,0 86,0 87,0 85,0 82,0 84,0 84,0 87,0 87,0 85,0 85,0 84,0 85,0 Bai Thuong 86,0 87,0 88,0 88,0 84,0 84,0 83,0 86,0 86,0 84,0 83,0 83,0 85,0 Thanh Hoa 86,0 88,0 90,0 88,0 84,0 82,0 81,0 85,0 86,0 84,0 83,0 83,0 85,0 Nhu Xuan 87,0 89,0 90,0 89,0 82,0 81,0 80,0 85,0 87,0 85,0 84,0 84,0 85,0 Yen Dinh 85,0 87,0 89,0 89,0 85,0 84,0 83,0 87,0 88,0 86,0 83,0 83,0 86,0 Tinh Gia 89,0 91,0 93,0 91,0 85,0 81,0 79,0 85,0 87,0 85,0 84,0 85,0 86,0

c) Rainfall

Rainfall in the Ma River basin divides into three regions with different characteristics Upstream part lies in rainfall regimes of the Northwest of the North of Vietnam Rainy season comes and ends earlier than the Central of Vietnam The Chu River basin is the North Central rainfall regime, thus rainy season comes later than the North of Vietnam from 15 to 20 days and it also ends later than the North from 10 - 15 days Downstream of Ma River delta has many characteristics rainfall regimes of the North, with rainy season starts from May and ends in November every year There are 2 distinct seasons in a year, dry season and rainy season Rainy season in upstream of the Ma River begins from May and ends in November Rainy season of the Chu River begins in late June and ends in early December The total rainfall of 2 seasons varies significantly The total rainfall in rainy season accounts for 65-70% of the total annual rainfall, the total rainfall in dry season accounts for only 30-35% of the total annual rainfall

Table 3.3: Annual average rainfall in the Ma river basin

Station Xo (mm) High rainfall year Low rainfall year

3.3.2 Population

In 2014, the total population of the province is 3,496,081 people, in which the urban population accounted for 14.7%, the rural population accounted for 85.3% The population density is 314 people/km2

Thanh Hoa is a province with many ethnic groups, with the 7 major ethnics which are: Kinh, Muong, Thai, Tho, Dao, Mong, Kho Mu Kinh people are the majority of the province’s population and they are widely distributed across the area, while other ethnics have smaller population and narrower distribution, like Khomu people only living mainly in 2 villages in Doan Ket commune, Ten Tan and Suoi Lach commune, Muong Chanh commune of Muong Lat rural district

3.3.3 Economic and social conditions

Industry

According to data from the General Statistics Office, in the first 6 months of 2009, index of industrial development rose 8.2% across the province, which is higher than the national average increase of 4.6% In the ranking of the Provincial

Competitiveness Index of Vietnam in 2011, Thanh Hoa province ranked at 24 out of

63 provinces

Up to 2009, Thanh Hoa province has five industrial regions:

- Bim Son Industrial Region - Bim Son Town

- Nghi Son Industrial Region (located in Nghi Son Economic Region) - Tinh Gia Rural District

- Le Mon Industrial Region - Thanh Hoa Provincial City

- Dinh Huong Industrial Region - Thanh Hoa Provincial City

- Lam Son Industrial Region – Tho Xuan Rural District

Currently, Thanh Hoa is constructing Nghi Son economic region, which is located in the south of Thanh Hoa province and 200 km from Hanoi, with national road and rail running through and deep-water ports for docking of large ships Nghi Son Economic Region is a powerful center of the planned South Thanh Hoa and North Nghe An Region, which is also rated as key development areas in the southern part of the North

Po-mu (Fokienia), Sa-mu (Cunninghamia), Green Lim (Erythrophleum fordii), Tau (Vatica odorata), sen (Madhuca pasquieri)… In addition to forestry products other than wood such as may, song (Calameae), herbs, cinnamon trees… Forests grown for economic development focus on several plants such as: Luong (Dendrocalamus membranaceus Munro), thong (Pinus latteri), Ecalyptus, phi lao (Casuarina equisetifolia), cao su (Hevea brasiliensis)

Integrated forestry development of Thanh Hoa is planned in the trend of combining between conservation, research, education and eco-tourism with special-use forests like: Ben En National Park, Cuc Phuong National Park (located in Thach Thanh Rural District), Pu Luong Conservation Area, Pu Hu Conservation Area and Xuan Lien Conservation Area The forestry is also diversely developed with the raising of wild animals such as: deer, bears and tigers

Fishery

Thanh Hoa has 102 km of coastline and 17.000 km2 of territorial waters, with lots of fish and shrimp grounds with high products There are five large bays along the coast, favorable for docking As of 2014, Thanh Hoa province has 7308 offshore fishing vessels

Service

a Banking

Along with State Bank, the banking system in the Province includes Vietin Bank, Bank for Investment and Development of Vietnam (BIDV), Vietnam Bank for Agriculture and Rural Development (VBARD), Vietnam Bank for Social Policies (VBSP) Currently, banks are implementing innovation and diversifying forms of capital mobilization, application of advanced technologies in the express transferring, interbank payments, international payments, ensuring safety and effectiveness Annual total funds mobilized is more than 3,000 billion VND

b Trade - services

In the process of renovation, the trade in Thanh Hoa has had significantly developments In the areas, the wholesale and retail system have been formed, with the participation of many economic sectors, facilitating the circulation of goods conveniently serve the needs in people’s life and production Export turnover has steadily increased over the years, in 2000 it was over 30 million, reached 43 million in

2001 and in 2002 reached 58 million The export market is increasingly expanding, besides Japan, Southeast Asia, some enterprises have exported goods to USA, Europe The main export products of the province are: agricultural products (peanut, sesame, cucumber, millet, peppers, coffee ), seafood (shrimp, crab, dried squid, seaweed), leather goods, garment, handicraft goods (manufactures bamboo, lacquer, sedge), paving stones, chrome ore

3.4 Hydrology

3.4.1 Main River network

Thanh Hoa province has a high density network of rivers From North to South there are four major river systems, which are: Hoat River, Ma River, Chu River, Yen River and Bang River, with a total length of 881km, the total basin area is 39,756 km2, the total annual average water volume is 19.52 billion m3 Rivers in Thanh Hoa flow through many complex terrains, with average stream network density is about 0.5 - 0.6 km/km2 and many areas with a very high stream network density such as Am river, Muc river with values ranging from 0.98 to 1.06 km/km2 This is a great potential for hydropower development, however, there are large variations of water between years and seasons

Hoat River System: Hoat River is a small river with isolated basin and originates

from Thanh Tam commune, Thach Thanh district, flows through Ha Trung district, Nga Son district Hoat River is a tributary flowing into Len River at Bao Van mouth and flows into the sea at Van Lach estuary Hoat River basin covers an area of 250

2

navigation lock has also been constructed to separate flood water and prevent salinity intrusion Therefore, Hoat River becomes a tributary of the Len River and second-order tributaries of the Ma River Hoat River has now become irrigation and water supply channel for Ha Trung area

Ma River system: Mainstream of Ma River originates from Phu Lan mountain (Tuan

Giao - Lai Chau) at an altitude of 800 m - 1,000 m The river flows in the Northwest - Southeast direction At Chieng Khuong, the river flows through Laos and flows back

to Vietnam at Ten Tan - Muong Lat, then flows through the districts of Quan Hoa Ba Thuoc, Cam Thuy, Yen Dinh, Thieu Hoa, Hoang Hoa, Quang Xuong, then finally flows into the sea at Lach Hoi estuary The total area of Ma River basin is 28,490 km2,

in which area on Vietnam territory is 17,810 km2, with a length of 512 km, the part which flows through Thanh Hoa has a length of 242 km Ma River has 39 major tributaries and two distributaries

Chu River system: This is the largest first-order tributary of the Ma river Originating

from the high mountains on Laos territory and mainly flows in the West Northwest – East Southeast direction Chu river flows into the Ma River at the Giang confluence, which is about 25.5 km from the upstream mouth of Ma River Mainstream length of Chu River is 392 km, in which the length of the river’s section on Vietnam is 160 km The total area of Chu river basin is 7,580 km2 From Bai Thuong to Chu River’s mouth, the river flows between two dykes, with large sandbanks, wide and sloppy river’s bed, which creates the good drainage characteristic of Chu River Chu river has many large tributaries such as Khao River, Dat River, Dang River and Am River

Yen River system: Yen River originates from Xuan Nhu rural district, flows through

Nhu Thanh, Nong Cong, Tinh Gia, Quang Xuong rural districts and then flows into the sea at Lach Ghep, with 1.996km2 of river basin’s area, 89 km of river’s length First river’s section from Nhu Xuan rural district to Nong Cong is called Muc River, the rest

of the river from Yen So confluence to the sea is called Yen river The average total flow across the years is about 1,129 million m3 and the total flow during dry season is about 132 million m3

Bang River system: Bang River originates from Nhu Xuan, flows through Tinh Gia

and then flows into the sea at the Lach Bang mouth, with the river basin area of 236

km2, river’s length of 35 km, the average total flow across the years is about 112.9 million m3 and the total flow during dry season is about 9.0 - 10 million m3

3.4.2 Stream network

Thanh Hoa is the province with steep terrain from northwest to southeast, thus there are many large streams and medium, small rivulets There are 264 interlacing streams and rivulets of four river systems: Yen River, Ma River, Hoat River and Bang River

In which, the major streams are Sim stream, Quanh stream, Xia stream along with several rivers such as: Luong River, Lo River, Hon Nua, Buoi River, Cau Chay River, Chu River, Khao River, Am River, Dat River…

3.4.3 Hydraulic structures

Thanh Hoa province has about 1,760 lakes, dams and pumping stations managed by the State Business such as: Irrigation Mining Company of Chu River, Irrigation Mining Company of North Ma river, Irrigation Mining Company of South Ma River and local government at all levels; There are 525 reservoirs, with large operating reservoirs such as: Cua Dat irrigation and hydropower reservoir; Song Muc Lake; Cong Khe Lake; Reservoirs are under construction: Trung Son hydropower, The main functions of reservoirs are water storage, flood prevention, power generation, water supply for irrigation and aquaculture

3.5 Climate change scenarios for the study areas

Due to the available data accessible, two climate change scenarios RCP 4.5 and RCP 8.5 of HadGEM2-AO model are selected The description of the model is given by Johns et al in 2006 This model is also one of the 21 climate models used for AR5 (Fifth Assessment Report) of IPCC The resolution of the output’s model is 1.875o x 1.25o covering most of area in the world The Ma river basin is covered by 4 grid cells

The output of HadGEM2-AO model is a series of daily data of rainfall, temperature and other climatic variables The model simulates in two periods which are historical period (1860-2005) and climate projections period (2006-2100)

Figure 3.2.: Examples of HadGEM2-AO model’s output in Asia

Figure 3.3: Grid of HadGEM2-AO model (red dash-line) with rain gauge stations in

the Ma River

Because there are differences in observed and corresponding simulated climatic variables, the output of climate model can not be used directly for hydrologic models And the resolution of the climate model is coarse, so a simple method could be used to estimate the climate in the future in each station

The delta change method approach is a method that makes the output of climate model suitable with basin scale The method is based on the use of a rescaling factor between

an averaged value in the future and historical run (Astrid Ruiter, 2012) Multiplying each value in the time series by the appropriate rescaling factor produces a simulated time series for a single location

Pj,future = Pj,obs * (Pj,future sim/Pj,historical) where Pj,future, Pj,obs, Pj,future sim, Pj,historical are average of rainfall in future, average of observed rainfall, average of simulated rainfall in future, average of simulated historical rainfall j denotes the month j Pj,future sim/Pj,historical is the rescaling factor

The rescaling factor between average monthly rainfall in the future period (2020-2039) and in historical period (1860-2005) are given in the Figure 3.4 and Figure 3.5

Figure 3.4: Rescaling factors between average monthly rainfall in the future period

Figure 3.5: Rescaling factors between average monthly rainfall in the future period

and historical period for RCP8.5

The temperature in each scenario is estimated in the same way with rainfall The

“future” rainfall and temperature will be the input for hydrologic model and CROPWAT software in order to estimate the “future” runoff and “future” water demand in the future period (2020-2039)

3.6 Scenarios for water balance

In this research, based on climate change scenarios described in 3.5 and overall planning of Economic and Social Development in Thanh Hoa Province by 2030, three different scenarios for water balance are selected

- Current Scenario: In this scenario, Precipitation and temperature are taken in the period from 2002 – 2012 Other water demands such as irrigation, domestic, industry, aquaculture…are based on current data of Thanh Hoa (According to the Statistical Yearbook of Thanh Hoa province, in 2014) Trung Son reservoir is not appeared in this scenario

- KB4.5 scenario: In this scenario, the future climate (precipitation and temperature)

is followed the RCP4.5 projection Other water demands such as irrigation, domestic, industry… are estimated on the overall planning of Economic and Social

Development in Thanh Hoa Province by 2030 The period of the scenario is

2020-2039 (2030s) Trung Son reservoir will start operating from 2017

- KB8.5 scenario: The future climate is based on the RCP8.5 projection Other water use activities are similar with KB4.5 The period of the scenario is also the same with KB4.5 Trung Son reservoir will start operating from 2017

- Storage capacity: 348.5 MCM

- Dead storage: 236.4 MCM

- Operation curves

Table 3.4: The elevation –area - storage relationship of Trung Son reservoir