Thesis of master degree: Water balance in the Huong river basin in context of climate change

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WATER BALANCE IN THE HUONG RIVER BASIN IN

CONTEXT OF CLIMATE CHANGE

NONG BAO ANH

MSc Thesis on Integrated Water Resources Management

May 2015

WATER BALANCE IN THE HUONG RIVER BASI

CONTEXT OF CLIMATE CHANGE

‘Major: Integrated Water Resources Management

THESIS OF MASTER DEGREE

1 Assoc Prof, Nguyen Thu Hien

2 Dr Ngo Le An

This reseacrch is done for the partial fulfilment of requitement for

Master of Science Degree at Thuy Loi University(This Mater Programme is supported by NICHE ~ VNM 106 Project)

May 2015

TABLE OF CONTENTS ABSTRACT 3

1.3, Research questions 15

1.4 Methodology 161.5, Structure ofthe thesis 18(CHAPTER 2: LITERATURE REVIEW 19

2.1, Water allocation: An overview 192.2 Integrated Water Resources Management 20

2.3 Climate change impacts on water resources 22.4, Climate change scenarios 242.5, Models for IVRM 26

(CHAPTER 3: DESCRIPTION OF STUDY SITE 323.1, Geographical location and topography 323.2 Climate 3

3.2.1 Temperature B3.2.2 Humidity 33.2.3, Evaporation 3

3.2.4, Rainfall 35

3.2.5 Hydrology conditions 373.3 Socio-economic development 403.3.1, Population 403.3.2 Economy structure 4l

3.4, River network 41

3.5, Water Storage 413/6, Water use activities 43

CHAPTER 4: WATER BALANCE SIMULATION FOR THE HUONG RIVER BASIN

4.1, Schematization of the Huong River Basi,

4.3 The computation of scenarios

CHAPTER 5: RESULTS ANALYSIS

5.1, Water supply and water requirement results

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ABSTRACTWater is essential for human, however, is finite and vulnerable (ICWE, 1992) Inrecent years, water crisis has been singled out as a major worldwide concem.World-wide water demand has been reported to increase by over six times during,the last century (Gourbesville, 2008) It is claimed to be the consequence of growth

ăn world population, which has been tripled during the last century, and speedyindustry enlargement as well as agriculture development As a result, developingcountries are those who mostly have to face with water scarcity Moreover, inrecent years, the impacts of climate change on water scarcity have become anemerging concerned Extreme weather events, increasing uneven distribution ofseasonal water leading to drought, floods and, for example, are some negativeimpacts of climate change, which has been alarmingly threatening the water balance

in developing countries

‘This research investigates the water availability and water demand in Huong RiverBasin in order to find out appropriate management measure to mitigate the watershortage problem in dry season

Huong River Basin which lies within Thu Thien Hue province, located in thespecific monsoon climate area of Central Part of Vietnam with severe hydrologicalregime: very long dry season, short rain season but often with very large runoff.This area usually witn season, Bearing the stress water shortage in the long dr

of explosive inc se of water demand from excessive population growth andblossoming economic development, combined with the decrease of water supply indry season as a result of climate change impacts, the Huong River Basin’s water

‘management need to be exquisitely investigated

‘The water use activities in this basin inelude domest livestockinrigation, industrand aquaculture, The purposes of this study are to analyze the water balance ofHuong River Basin in three scenarios, the current scenario in 2010 and the futurescenario in the future with the projected socio-economic development as well as

‘changes in the climate system characteristic according to B2 scenario To completethis task, the WEAP model is implemented to simulate the water balance in thebasin with the help of MIKE-NAM model to calculate the water inflow to riverbasin from rainfall data and CROPWAT to compute the water requirement for crop.

‘The research shows there are currently imbalances between water supply and water

‘demand in the dry season especially in March and April In 200, the system cannotsupply sufficient water quantity for the projected growing demand of socio-

‘economic development scenario in June and July which are in dry season, right afterthe periodic flood, The unmet demand is slightly go up compared to the currentscenario, However, the situation is much more severe in the scenario in which theclimate change impacts are considered The water deficit is about four times biggerthan it was in the scenario which only reflects the socio-economic development.Moreover, it appears from February to July within different areas

After analyzing the results of simulation models, several structure and non-structuresolutions are proposed,

DECLARATIONThereby certify that the work which is being presented in this thesis entitled, “Waterbalance in the Huong River Basin in context of climate change” in partialfulfillment of the requirement for the award of the Master of Science in IntegratedWater Resource Management, is an authentic record of my own work carried out

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

Date:

| would like to express my deep gratitude to many people who helped to completethis Thesis at its best

First and foremost I wish to thank to my supervisor, Associate Professor Nguyen

‘Thu Hien, Dean of Thuyloi University's Water Resources Engineering Faculty, forher instruction, understanding and also, patience during the time I conducted this

‘Thesis With her considerable guidance and shared experience from many year ofbeing water resources expert, I am able to bring this research into fruitionHowever, it is not only just during this time she is supporting me, but also forall theway long of seven years I have leamt in this University from my Bachelor Degree

to this Master course, she always be there willing to instruct me about professionalresearching skills, turning me into an independence thinker which assists me to

grow as a lecturer, a researcher and a better learner

1 would also wish to express my deeply gratefulness to my second supervisor,Doctor Ngo Le An, who is the Deputy Head of Thuyloi University's Hydrology andWater Resources Division for his tutor and corrections in the application ofsimulation models, the field which I had very few experience His mentorship wasparamount in providing a well rounded experience consistent my long-term careergoals He was the one to point out for me the importance of balancing the

theoretical knowledge and ability to mastering in models use in Water Engineering

and Water Management, at the same time, was the one enable me to do so He

‘encourages me to run all the models used in my thesis on my own but was alwaysthere as a blanket to help me to learn from mistakes, I am not sure manypostgraduate students are given such treasured opportunity like mine

For everything you have done for me, Assoc Prof Hien and Dr An, I thank you

1 would especially like to thank the Management Board including members from

‘Thuyloi University, Hanoi University of Natural Resources and Environment

University and UNESCO-IHE for organizing this wonderful Master course andproviding me a chance to sharpen my professional knowledge,

Many thanks to my colleagues in the Department of Climate Change andSustainable Development, HUNRE where Ï am working for supporting me in manyway during the time I am busy with my Thesis

1 would also like to acknowledge my friends from Thuyloi University including Ms.Dao Thi Xuyen, Mr Nguyen Son Tung and many others for t ir help with thepreparing input for models

Finally, words cannot express how grateful T am to my parents and my girlfriend

ho is currently staying in England for theirs unwavering support and continuous

‘encouragement throughout my year of study and through the process of researchingand writing this Thesis This achievement would not be possible without them,thank you

ABBREVIATIONSCMS Cubic Meter per Second

DARD _ Department of Agriculture and Rural Development HRB Huong River

Basin

FAO Food and Agriculture Organization

Gwe bại Water Partnership

HUNRE Hanoi University of Natural Resources and Environment

IMHEN Institute of Meteorology, Hydrology and Environment

IWRM —— Integrated Water Resources Management

MONRE Ministry of Natural Resources and Environment

MARD Ministry of Agriculture and Rural Development

MCM Million Cubie Meter

Mw MegaWate

NCAP the Netherlands Climate Assistance Program

NWC National Water Commission

TLU ——ThuyLoi University

uN United Nation

VNCID Vietnam National Commission on Irigation and Drainage

WRS Water Resources System

LIST OF FIGURESFigure 1.1: The location of Huong River Basin, B

Figure 2.1: Cycle diagram of climate change impacts 2B

Figure 2.2: The Schematization of Huong River Basin, 28

Figure 2.3: The general structure of NAM model (Nielsen & Hansen, 1973) 30

Figure 3.1: Huong River Basin 3

Figure 32: The annual average rainfall of observe stations 36

Figure 3.3: Monthly average rainfall of observed stations a7

Figure 34: The annual runoff in the petiod from 1977 to 2010 38

Figure 35: Monthly inflow to the basin in the period 1977-2010, 39

Figure 3.5: Map of cultivated area ane)

Figure 41: Schematization of Huong River Network as

Figure 4.2: Map of 9 sub-basins in the Huong River Basin 49

Figure 4.3: The variance between observed and simulated discharge in Thuong,Nhat Station, 33

Figure 4.4: The variance betwen observed and simulated discharge in Binh Dien

Station ““

Figure 4.5: The variance between observed and simulated discharge in Co Bi

Station “

Figure 8.1: The inflow to branches in 2010, 68

Figure 52: Water roqutements by sectors in 2010, SCI scenario «

Figure 5.8: Unmet demand by months in 2010, SC1 scenario 70

Figure 5.4: The monthly inflow to the upstream area of Bo River in SCI scenario

n

FigureS.5: The monthly water requirement of upstream Bo River Agriculture area

in SCI seenario : 7

Figure 5.6: Ta Trach Reservoirs Hydropower turbine flow and power generation,

73

Figure 5.7: BinhDien Reservoir hydropower turbine flow and power generation.74

Figure %8: Huong Dien Reservoir hydropower turbine flow and power

generation kì

Figure 59: The total inflow in 2010 in SC2 scenario 16

Figure 5.10: The unmet demand in 2010 in SC2 scensrio _

Figure 511: Monthly inflow lo region in 2010 in SC2 scenario 1

Figure 5.12: Monthly unmet demand in 2030, SC3 scenari số

Figure 5.13: The changes in the inflow of SCA scenario compared to SC3 scenario,

81

Figure $.14: Monthly unmet demand in 2030, SC4 scenario, 82

Figure $.15: Monthly inflow to the area 82

LIST OF TABLES

Table 2.1: The changes in average temperature (°C) compared to the period

1980-1999 in Thua Thien Hue province by seasons in B2 scenario, 25

Table 2.2: The changes in average rainfall compared to the period 1980-1999 in

‘Thua Thien Hue province by seasons in B2 scenario 26

Table 3.1: Monthly average temperature in Huong River Basin from 2009 to 2012

34

‘Table 3.2: Average humidity in Huong River Basin from 2009 to 2012 3

‘Table 3.4: Mean evaporation in Huong River Basin from 2009 to 2012 34

Table 3.5: Hydrological and hydro-metcorological stations network in the Huong

River Basin 38

Table 36: Average population by Gender and by District in 2010, 40

Table 3.7: Average population by Distt from 2009.2012 40

Table 3.8: Location and area of industial zones 4

Table 41: Description of sub-basins so

Table 4.2: NAM parameters explanation and boundaries (Shamsudin & Hashin

2002) sĩ

Table 4.3: The reliability of Nash coefficient 2

Table 44: Calibrated parameters 32

Table 45: Nash coefficient 33

Table 46: Vietnamese standatd for domestic water use 56

Table 47: Vietnamese standard for livestock consumption 37

Table 4.8: Water requirement for aquacultare 58

Table 4.9: The scenarios development 59

‘Table 8.1: Population by District in 2030 64

‘Table 5.2: The increasing rate of the amount of livestock

"_-Table 5.3: Monthly water requirement of nodes in SCI and SC2 scenario 67

‘Table 5.4: Monthly water requirement of nodes in SC3scenatio 67

Table 5.5: Monthly water requirement of nodes in SC4 scenario 67

‘Table 5.6: Comparison of water requirement by sectors between SC2 and §C3

79

‘Table 5.7: Comparison of water requirement by sectors between SCI, SC3 and SC4

—- ¬ - 81

CHAPTER 1: INTRODUCTION

1.1, Background

Huong River, with its length of 128 km, is the largest river system in Thua ThienHue province The river lies within the province and covers 3/5 of the total areawhich is the consist of Nam Dong, Huong Thuy, Huong Tra, Phong Dien District,part of A luoi, Quang Dien, Phu Vang, Phu Loc District and Hue city The drainage

area is 3000 kh, In 2010, the population of Huong River Basin is about 1,137,962

people, most of them are living in the rural area which accounted for 92% of the

population The topography of the river basin is complex including mountainous

area, hills, lagoon, coastal plain and coastal sand dune Huong River is the mainwater source in this province which supplies water for almost all domestic usageand economic development activities

5 = =F

Figure 1.1: The location of Huong River Basin

1.2 Problem statement

Huong River basin lies in ‘Thua Thien Hue Province, which located in the specificmonsoon climate area of Central Part of Vietnam with severe hydrological regime:very long dry season, short rain season but often with very big flow and discharge.Every year, this area has to bear number of extreme weather events such astyphoons, tropical cyclones which bring heavy rain with high density Moreover,the topography of the basin changes rapidly from the upstream high mountain zonedown to the plain and large lagoon system, with hardly any transition area Thisresults in a high runoff in the rainy season, and large floods and inundationsdownstream The annual average rainfall of this basin is 2800-3200 mm; however,nearly 80% of rainfall concentrates in the 4 months of rainy season causing unevenwater distribution in the research area, Additionally, the high temperature in dryseason also increases the chance of losing water through evaporation Manyreservoirs had been built to mitigate the water shortage in dry season by storingwater from the rainy season, Nevertheless, water shortage in dry season is stillappeared as an emerging issue

Besides, the population growth and the development of water demand in everysector in this area leading to extremely high competing requirements of differentstakeholder which exaggerate the water shortage status and intensify the pressure onwater management tasks Also, Tran Thục (2010) proved in his project “Impact ofclimate change on water resources in the Huong River basin and adaptationmeasures” that the decrease of rainfall results in the decline of river flow in dryseason and the increase of evapotranspiration due to higher temperature is appeared

in most of the climate change scenarios,

All of the water use activities in Thua Thien Hue province, consisting irrigation,aquaculture, domestic, livestock, and industry as well as power generation depend

imbalance:

mainly on Huong River There are currently large between wateravailability and water demand in this region as the existing system cannot supply

sufficient water for all stakeholders in dry season; as well as the exaggeratedsituation might appear in the future under the pressure of inereasing demand andnegatively influences on water supply due to climate change impacts To deal withthis set of troubles and moving toward a sustainable society, there is a newparadigm which was proved ils effectiveness in many regions with the similarsituation such as South Africa, Myanmar, ete with s own holistic approach,Integrated Water Resources Management (TWRM) As there are inter-links betweenall sectors to the Water Resources System (WRS) (Armell, 1999), as well as thelose interaction from the three components of WRS itself, the holistic approach ofIWRM offers an ultimate solution to ease the increasing water scarcity fordeveloping countries However, before drawing any optimal solutions and specificstrategy for planning, IWRM requires huge numbers of exquisite analysis of WRS

‘components Therefore, this study was brought out in order to contribute to IVRMplanning with an insight of the balance between water availability and water

‘demand among different stakeholder at the present as well as in projected futurescenarios under climate change context, Then, management measures will beproposed after considering changes within problems To achieve this goal,hydrological model MIKEII-NAM, Crop water requitement simulation modelCROPWAT 8.0 and river basin simulation model (WEAP) are employed to addressthe impacts of changing water availability and water demands under different

3 How climate change impacts can affect the water shortage status in theriver basin?

4, What are the recommended solutions to mitigate the water shortage in dry

season with the consideration of climate change scenario in 2030?

1.4, Methodology

In order to carry out this research, relevant data and information in the study area

must be collected, analyzed and simulated, Basically, the data collection comprises

(1) time series of the river discharge; (2) water demands of all water use activities in

each region, including agriculture, aquaculture, domestic, livestock, industry and

‘environment in the present and the forecast of those water use activities inthe future

‘under Climate Change Scenarios; (3) the characteristics of the infrastructures in thebasin such as reservoirs (initial water level, operational rule curves, stage-area-volume curve, time series of rainfall and evaporation, linkages to users, priority of

delivery, linkages to upstream) The set of information included the potential

‘proposed measures that can be implemented to mitigate water shortage status in dry

season of research area The methodology applied to conduet the Thesis can be

summary in the following framework

Data analysis Devoloping.

and simulation scenarios

Proposing management

measure

‘The approach of the study is using models to simulate the water status in HuongRiver Basin, therefore, a conceptual framework of basic step (0 apply models wasdeveloped.

a

The focus is on WEAP model” simulation; however, itis possible only when theinput data of water supply and water demand are carefully evaluated The watersupply input is the runoff calculated by MIKE-NAM The water demand input isthe

‘combination of the requirement of five main water use sectors, including irigation

mputed by CROPWAT 8.0 as wellrequirement which wa s domestic, livestoc!

industry, aquaculture which were evaluated based on Vietnamese statistic yearbookand Vietnam standard After that, WEAP was applied to examine the current waterstatus in 2010 as well as alternative projected situation in 2030 based on developedscenarios both with and without the changes of climate system

1.5 Structure of the thesis

‘This thesis is divided into six main chapters including the introduction, literaturereview, the description of study a the simulation of water balance in Huong,River Basin, the result analysis, and finally, the conclusions and recommendations

Chapter I: The chapter provides a brief overview of the physical characteristic ofHuong River Basin as well as brings out the problem statement about waterresources management in the basin In addition, a set of research questions whichobjectify the purpose of the research and the methodology are also mentioned,

Chapter 2: The literature review shows an overview of “water allocation”,

“Integrated water resources management”, “climate change impacts on water

“Climate change scenarios” and “Models for IVRM""

Chapter 3: This chapter gives a closer look into the characteristics of Huong RiverBasin with regard to the Geographical location and topography, the climate

the

conditions, the socio-economic development, the illustration of river networ

‘current water tu e activities, and the water storage

Chapter 4: In this chapter, the simulation of models in Huong River Basin isdescribed, The s‘chematization of the basin is brought out; the data requirements forapplying WEAP model are demonstrated Moreover, this chapter also defines three

main scenarios,

Chapter 5: The results of the three scenarios with respect to the water supply andWater requirement will be brought out and analyzed in this chapter It illustrates and

‘compares the water shortage in of each water user node corresponding to each

Chapter 6: Conclusions and recommendations will b shown in this chapter

CHAPTER 2: LITERATURE REVIEW

2.1 Water allocation: An overview

Water access entitlement was defined under the National Water Initiative as the

‘exclusive right to access an amount of water from the executive water supplier,Which fitted in water master plan (National water commission, 2011) The wateraccess entitlement is determined through an allocation process which basically aims

fying the needs of different individual consumers The requirement forachieving an effective water allocation plan in any country all over the world

initiated from the 1992 UN Conference on Environment and Development where

water was asserted as a vulnerable resource that can be vanished over time by theexcessive use without conservation of human’s activities,

Water allocation plan is created based on the water allocation system which is theset of policies and rules for maintaining the equilibrium between water availabilityand water demand without disrupting the sustainable development process of 4

‘country and its environment Fundamentally, there are two approaches of waterallocation system, the non-volumetic systems and volumetric systems (NWC,2011) The non-volumetric systems control the use of water based on the input andoutput of water rather than the particular amount of water for each sectors On the

‘ther hand, the volumetric systems, which are the mostly used one, relied on

‘quantity of water used through some methods such as block tariff, market-based

1002), Recently, it isproved that the water allocation process shows its highest efficiency when it ispricing, single rate or multi rates (Tsur, Dinar and Doukkali

‘evolved in basin level However, allocation focuses on basin level still need to take

in to account the national level water allocation plan and variety of stake-holders"agreements (Speed, 2013), The objective of water allocation lies under the umbrellaterm “balancing water supply and demand”, within this concept, there are four mainfocus including equity, environment protection, development priorities andpromoting efficiency use of water (Speed, 2013)

According to the National Report on Water Resources in 2012, Vietnam has ricksources of water considering the total amount of surface water, However, among,

‘eight main basins over the country, only four of them have enough water to satisfy

‘demands in dry season, That fact raises a challenge for water resources planningtask to balancing the uneven seasonal rainfall, then to achieve maximum efficientwater use, Water allocation systems in Vietnam are created based on volumetricsystems varies within sectors The institutional arrangement in Vietnam is referred

to a hierarchi al organization structure, with the centralized Government Therefore,the water resource are managed by the Government, at highest level, then, at thelower level, the Ministry of Natural Resources and Environment and the Ministry ofAgriculture and Rural Development are cooperated to building the overall waterresources planning to propose to the Government The subordinate level of Ministry

is the provincial local authorities including provincial People’s committees, theDepartments which are directly under Ministries (VNCID, 2010) The overlay ofauthorities is also a challenge while applying Integrated water resources

management

2.2 Integrated Water Resources Management

Date back to the past, where the water mana; sment approaches only consider aboutseparate Sectors such as water supply, itrigation, sanitation, and energy generation

In 1977, attention of international experts was still pay in the water supply andsanitation in UN Conference in Mar de Plata; the water related issue waspronounced in Brundtland Report of the World Commission on Environment andDevelopment in 1987 is about pollution and water supply (Savenije& Van DerZang, 2008 Until 1992, when the UN Conference on Environment andDevelopment was held in Rio de Janerio and the International Conference on Waterand Environment was held in Dublin, the concepts of IWRM as well as its keyprinciples were widely discussed The principles of IWRM are based on the DublinPrinciples which emphasized that water is finite, vulnerable, and essential forinable development and affirmed the vital role of woman in water

management Moreover, itis stated that participatory approach is eructal in watermanagement as well asthe consideration of water as social economic good has to beadded in water management plans The prevalent use of term “Integrated WaterResources Management” was appeared in the late 1990s by the promotion of it uses

by the Global Water Partnership (Biwas, 2008) In 2002, a the Johannesburg WorldSummit on Sustainable Development (WSSD), The Technical Advisory Committee

of the Global Water Partnership defined Integrated Water Resources Management

“as a process, which promotes the coordinated development and management ofwater, land and related resources in order to maximize the resultant economic andsocial welfare in an equitable manner without compromising the sustainability ofvital ecosystems” (GWP, 2000)

As the new challenges in the new era put pressure on every aspects of waterresources, IWRM with it holistic system view approach is widely accepted by manyscholars and practitioners due to several reasons: it provide a comprehensive eross-

‘cutting approach through all types of resources and sectors; it creates a connectionbetween livelihood of the catchment and resources perspective; it also focus on thecollaboration between elements of good government as well as stakeholders (Gain

& Schwab, 2012) From that perspective, IWRM itself specifically enhances the

traditional water resources management in three ways: cross-sectoral of goals andobjectives, the spatial focus on river basin instead of on administrative boundary,the participation of stakeholders in decision-making process (Cap-net, 2009) InParticular, Gooch and Stalnacke (2003) indicated that the distinction between

IWRM or Integrated River Basin Management (IRBM) and “Traditional” Water

Resources Management relies on the scope and sphere of operation of the two The

traditional” one only focused on sa fying the perceived demand with

sector-‘oriented approach while the “integrated” one attempts to bring out water resourcemanagement on the demand, supply, and use of water with a cross-sectoralapproach, This new paradigm was applied to many river basins in South Africa,Australia, Europe, and Mozambique

However, the concept of integrated water management considering climate changehas not been well discussed and reported in literature (Lin et al, 2010) Further, dueatention has not been given to such practices in developing countries (Qin and Xu,2011) A few attempts have been made to address the water resources managementissues considering one or another issue of climate change (Ragab and Prudhomme,2002; Mitchell et al., 2007) However, integrated water management consideringIntegration of various possible water sources (0 sa isfy the demands of differentusers, environment protection, land and urban planning have not been considered

2.3 Climate change impacts on water resources

On the Global scale, among various environment factors influenced by climatechange, water resources are of the major concern (Frederick and Major, 1997)Global warming due to the increase of greenhouse concentration is likely to havesignificant effects on the hydrological cycle (IPCC, 1996) Inthe researching of therelationship between climate change and water resources, especially the impacts ofclimate change, Yang Nan, Bao-Hui and Chun-Kun emphasized that thehydrological cycle is the theoretical basis; they also sum up the relationship into acycle diagram of climate change impacts:

Intergovernment Panel on Climate Change was about the growing trend of floods

in Huong River Basin which was done by the cooperation between VietnameseInstitute of Meteorological, Hydrological and Environment (IMHEN) and TheNetherlands Climate Assistance Program (NCAP) called “Climate Change Impacts

in Huong River Basin and Adaptation in its Coastal District PhuVang, ThuaThienHue province” Another separated research was brought out by Tran Thục (2010)Which is contributed to NCAP's Project The two projects share the same ideal isthat climate change causes high river flow resulted inthe appearance of more floods

‘due to the intensive rainfall in rainy season and the decline in rainfall a long withthe rise of evapotrans ration causing more droughts in dry season under mostscenarios However, specific management measures still remain unrevealed

2.4 Climate change scenarios

‘Climate change scenarios are Special Report on Emissions Scenarios (SRES) whichhave been developing and updating by IPCC since 2000 (IPCC, 2000) The changes

of green house gases emissions were approved to be used as the references for themajor changes in natural factors such as physical characteristic of hydrologicalsystems, temperature, sea level ct6.SRES is the set of projections of future greenhouse gases emission with considering the changes of population, economies,politcal structure and lifestyle in the next few decades (Amell, 1999) Eachscenario stats with a storyline which describes the way these factors change, Thestorylines were gathered into four scenario families which contained six scenarios.these four families can be characterized as follow:

AI: intensive population growth, very rapid economic development, increase ingeneral wealth with convergence between regions and reduced differences inregional per capita income, Materialist-consumerist predominant with rapidtechnological change AI family was sub-divided into three assumption aboutsources of energy: focusing on fossil fuel (AIFD), non-fossil fuel (AIT), andbalance between these resources (A1B)

BỊ: same population growth as Al, however, economic development focuses onenvironmentally sustainability with cooperation and regulation within global scale.Green and efficient technologies are developed.

‘A2: the economic is heterogeneous, market-led, less rapid growth than AI but fasterpopulation growth, The underlying theme is self-reliance and preservation of localidentities Economic growth is regionally oriented, and hence both income growthand technological change are regionally diverse

B2: Population increases at lower rate than A2 but at higher rate than Al and BỊ,the general development follows environmentally, economically and sociallysustainable locally oriented pathways

Due to these characteri 3, the scenarios can be classified into three groups; thehigh emission group contains AIFI and A2, the medium one is B2 and the least

therefore, this study will reveal the i sight of the balance between water

availability and water demand at the present as well as in projected futurecircumstances considering B2 scenario physical characteristics as the primaryinfluence factors These factors are shown in the following tables:

Table 2.1: The changes in average temperature (°C) compared to the period 1980:

1999 in Thua Thien Hue province by seasons in B2 scenario

“The time mark in XXT century

2020 | 2030 | 2040 | 2050 | 2060 | 2070 | 2080 | 2090 | 2100Winter ffom XIIoII | 05 | 08 | 11 | 14 | 17 | 20 | 23 | 25 | 28

Spring from HItoV— | 06 | 09 | 12 | 16 19 | 22 [as [30

05 | 07 10/1215 | 18 | 20) 22 24

Autumn tromIXtoXI | 05 | 07 | 10 | là l6 | 19 | 21) 23) 25

Trin

Table 2.2: The changes in average rainfall compared to the period 1980-1999 in

Thua Thien Hue province by seasons in B2 scenario

“The time mark in XXT century

2020 | 2030 | 2040 | 2050 | 2060 | 2070 | 2080 | 2090 | 2100Winter fom XIIolI | -09 | 12) 17| 22 27|-32| 36) 39) 43

Spring from HIteV | -L7 | 24 | 34 | 44) 34 | 63 | T1 | 78) 85

Summer from VIto vit | 14 | 20 | 28 | 36 44 | 51 | 58 | 64 69

Autumn tom IXtoXI | 24 | 35 | 49 | 64) 78 | 91 | 102] 113 122

mm

2.5 Models for IWRM.

In a river basin, there are numerous factors which influent water resources,however, it can be classi «into two major kinds of factors, namely Internal factorsand external factors The internal factors are the direct influences to the wateramount in supply side and demand side ineluding hydrological conditions, demand

of different stakeholders or sectors These factors are always changing in time andspace Besides, the extemal factors such as economic growth, policy orientation,production prices, ete constrain internal factors and it changes so fast that poseurgent threats of developing tools to respond to variety circumstances Moreover,there must be tools to fill the gap between watershed hydrology and water

‘management through combining physical components of hydrological process andintegrated water management context (Yates et al, 2009) Throughout the lastdecade, along with the excessively growth of technology, simulation modelprogressively developed to support decision making process with the approach ofIntegrated water resources management

MIKE-BASIN

MIKE BASIN is an integrated water resource management and planning computermodel which is fully integrated into the ArcGIS environment (DHI, 2006)Basically, this model represents mathematically the simulation of water availabilityand water demand In the working environment, a network model is created with

the river and their tributaries are represented by a network containing branches andnodes The branches represent individual tributary sections and the nodes representconfluence, locations where certain water activities may occur and importantlocations where model results are required MIKE BASIN model calculates a massbalance equation in every node and branch of river basin where multi-sectoralallocation and environmental issues can be schematized (Seppelt &Voinov et al,2012)

‘mass balance formulated as a Linear Program following a monthly time step (Yate

ct al, 2009) The system is represented in terms of its various sources of supply (e.g.rivers, groundwater, and reservoirs), withdrawals, transmission, wastewater

treatment facilities, water demands (e, user-defined sectors but typically

‘comprising industry, mines, irrigation, domestic supply, etc), and ecosystem

requirements,

WEAP model has two primary functions (Sieber etal 2004):

+ Simulation of natural hydrological processes (e.g, evapotranspiration,runoff and infiltration) to determine the availability of water incatchment

+ Simulation of human activites that have effect on the natural system toinfluence water resources and their allocation (ic, consumptive and non-

‘consumptive water demands) to evaluate these impacts

WEAP represents a water system in a schematization of main supply, demandnodes and their reaches The data layer and level of data can be customized (e.g, by

‘combining demand sites) to fit with the particular purpose of analysis, and minimize

data shortage issues The physical characteristics of the network are visualized by

graphical boundary which can highly cooperate with ArcGIS environment

One of the most important tools in WEAP is the developing altemative scenariostool which can be applied by adjusting parameters such as reservoir operation

‘curves, hydropower generation capacity, ete and the hydrology characteristics such

as rainfall, runoff, evaporation, ete as well as the impact of different developmentscheme and management practices

By setting priorities and supplying references for each node, the allocation rules ean

be created or changed following scenarios, The priorities of all demand sites arebetween 1 and 99, where 1 is the highest priority and 99 the lowest

WEAP is being applied in a number of international projects such as the JordanRiver basin, study of the hydrologic, economic, ecological, health, and institutional

‘dimensions of small reservoir ensemble planning and management in the Volta(Ghana), Limpopo (Southern Africa), and Sao Francisco (Brazil) basins It can beapplied in data-rich basin such as Neckar basin, Germany and data-scarce basin inOueme, Benin (Hoff et al., 2007)

In order (o provide input for WEAP in water allocation proves:

‘were used in this thesis such as MIKE 11-NAM (Nedbør Affstromnings Model) tocalculate inflow in supply side and CROPWAT to compute water requirement forinrigation in demand side

MIKE H1 - M

Due to its ability to simulate the hydrological process in detail, NAM was chosen toapply in this project NAM is “a deterministic, lumped conceptual rainfall-runoffmodel which is originally developed by the Technical University of Denmark”(Nielsen & Hansen, 1973) Particularly, hydrological cycle is considered as thebasis of quantitative simulation of the runoff in watershed and the evaluation ofparameters is the average value of the whole watershed based on physical process

(Shamsudin and Hashim, 2002) The general structure of NAM comprises 4

storages, including snow storage, surface storage, lower zone storage andunderground storage that shown in Figure 2.3

However, within the scope of this thesis, only the surface storage was taken intoaccount sinee there is no snow in the research area and the thesis is only aboutsurface water balancing Basically, the input data required in this model are daily

rainfall and potential evaporation, and then the outcome of the model is the basin

runoff over time

CROPWAT FOR WINDOW 8.0 is a decision supporting tool developed by theLand and Water Development Division of FAO The model helps developing

inrigation scheme under various management and water supply scenarios by

providing result of the calculations with regard to evapotranspiration, crop waterrequirement, and irrigation requirement (NaZeer, 2009) The crop water requirement

s the amount of water needed for various kinds of crops to grow optimally, and itdepends mainly on the climate conditions, crop types, and the growth stage of crop.The potential evapotraspiration (ETO) was calculated by Penman-Monteithequation, the equation can be developed into direct calculation of any cropevapotraspiration (Ete) (Nazeer, 2009),

9000.408.4(R, ~ G)+ y 200.

“ =O 7 Mir ° a+ rs 0:34, (,-«.)

ETo = reference evapotranspiration [mm day-1]

Rn = net radiation at the crop surface (MJ m-2 day-1]

G= soil heat flux density (MJ m-2 day-1]

‘T= mean daily air temperature at 2 m height (°C]

[U2 = wind speed at 2 m height [m s-1]

saturation vapour pressure [kPa]

‘ea = actual vapour pressure [kPa]

68 - ea = saturation vapour pressure deficit [kPa]

plone vapour pressure curve {kPa C1]

= psychrometric constant [kPa °C-1}

To carry out this thesis, WEAP was chosen to calculate water balance in Huong

River Basin, Additionally, to provide input for WEAP, MIKE-NAM was employed

to define the inflow from the rainfall data and CROPWAT was adopted to compute

the water requirement for irrigation,

CHAPTER 3: DESCRIPTION OF STUDY SITE

3.1 Geographical location and topography

Huong River Basin totally fits in Thua Thien Hue province, which is located in

‘coastal area of Northern Central Vietnam, The area of Huong River basin is about

3000 km", occupied nearly 3/5 of province's area, It is situated between 15059"—

16036°N and 107009" - 107051°E, Huong River Basin is adjacent to the lagoonsystem Tam Giang Cau Hai to the North, Da Nang City, Quang Nam Province tothe South, Asap~A Luoi River Catchments and O Lau River Catchment to the Westand Nong River Catchment to the East, including all or a part of districts: Nam

Source: VACNE, 2012

Figure 3.1: Huong River Basin

‘The topography of Huong River Basin is mostly mountainous area oceupied 70% of,

the area, the distance from the mountainous area to the plain is short resulting in a

steep slope The West and South-Western part of the province is the location of

‘Truong Son Mountain with the average elevation of 100m, The direction of the

‘mountain's peak combines with the South-East circulation created one of thehighest rainfalls among other area,

“The elevation of mountainous area in the West and South-Western part of theprovince varies from 250 ~ 750 m in the low area and 750 ~ 1800 m in the higharea The mountains form a curvy shape surrounding the plain, plus, the degree ofthe cliff's slope is about 35 degree and the length of the river here is short

‘Therefore, itis not only causes the increase in the inflow, it also creates flood to thedownstream area

The hilly region which separated into 3 typical types, the low area with theclevation of 10 ~ 50 m, the medium area with 50-125 m and the high area with 125

250 m The direction of this region is vague and the hydrology regime iscomplicated then, it is hard to determine the sub-basin, However, this kind oftopography creates many valleys which are extremely important for building multi-purposes reservoirs such as Binh Dien reservoir, Duong Hoa reservoir, ete

“The coastal plain concentrated in the North and North-Eastern part of the province,

adjacent to the lagoon system The sand dune which the elevation is 20-30 m

surrounds the Tam Giang- Cau Hai lagoon to the East and protect the lagoon fromthe ocean circulation impacts

3.2 Climate

3.2.1 Temperature

The temperature in Huong River Basin varies from 19-29°C January has the lowest

average temperature of about 21°C in the plain and 19°C in the mountainous arca

“The highest monthly average temperature usually appears in June or December of

25°C in the mountainous area and 28°C in the coastal plain since the South-West

wind strikes

Table 3.1: Monthly average temperature in Huong River Basin from 2009 to 2012

Sve T1 [n fa W fv [vr [vm vailax |x ft J ver

Mus 2i |312|337.261|393 [204 [ae 4l5i41213|2361313 [ea

Mam Doug [26338 [34-1967 [395 [288383 273|209/315) 29 [a3 [ae

‘tan [iso[a19 [at 935 [as3 aer[asr[aei[3s9 arena) ies ans

‘Source: Viemomese Sait yearbook 2012

hit 5%

3.2.2, Humidity

Huong River Basin is one of the areas which has highest humidity in Vietnam, The

average humidity varies from 84% to 87%

Table 3.2: Average humidity in Huong River Basin from 2009 to 2012

sae fe fw fm w| v |v [val oc] x | xt [var

His J9R0)906/s02 m0 ia] 778 ar ayaa a |Nam Doag_|92 |e 82] sh 1 1

‘ta eo} ou 90s [soe | sa [Reo 3 0121916 908 [7

‘Source: Vietwomese Sitti Yearbook 2012

‘nit 5%

3.2.3 Evaporation

‘The average annual evaporation in the coastal area is about 900-1000mm and in the

‘mountainous area is about 800-900mm, equivalent to 30-40% of the total annualrainfall

Table 3.4: Mean evaporation in Huong River Basin from 2009 10 2012

3.2.4, Rainfall

‘There are 10 gauge stations and 8 hydrological stations in this basin, Among these 8hydrological stations, there are 5 stations that observed the water elevation and

runoff, the others 3 station only collected data of water elevation,

Table 3.5: Hydrological and hydro-meteorological stations network in the Huong

x Hour 1977-2010

10 Kim Long x

yelogical sation m Hour oe

Source: National center for documentation, Ministry of Natural Resources and Environment, 2014

‘Thua Thien Hue province has one of the largest amounts of rainfall in Vietnam with

annual average rainfall of 2800-3800mm in the period 1977-2010 However, the

rainfall slightly varies different parts ofthis province The highest annual rainfall of

approximately 3800 mnva which had been recorded concentrated in the south-west

part including Aluoi, Nam Dong and Phu loc District The least exprerienced annual

rainfall of about 2741 mnva_are in the Norther Part consisting Co bi and Phu Oc

stations which are located in Phong Dien and Quang Dien District, respectively

‘The central part received the annual rainfall of nearly 2980 mưa

son, 3500

3000 | 2500

‘Anal Rainfall

(nmMyew) 200°

1500 1000 san

° hức aluoi nam thương phước binhden coi talương

đong - nhất

Stations

Figure 3.2: The annual average rainfall of observe stations

In this province, there are two typical seasons including rainy seasons and dry season, The rainy season starts from September to December, and the rest of the

year is dry season This area witnesses the tremendous unevenly distribution of

monthly rainfall since the amount of rainfall concentrate mostly in the four months

‘of rainy season, oceuping 70% of total monthly average which is 2232 mm, During

the rest 8 months of the year which belongs to dry season, the total monthly average

rainfall is 958 mm, take the other 30% of total amount The average number of

rainy day in the plain region is 200-220 days and in mountainous area is 150-170

days,

Monthly Average Rainfall (mm/month)

in Ta Trach River ofthe total annual inflow In low flow season, the average annualdischarge is about 30% in Bo River, 34% in Huu Trach River and 36% in Ta TrachRiver ofthe (otal annual runoff

‘The annual average surface water inflow of the basin is approximately 6258

MCM/a in the period of 1977-2010 Overall, the total annual inflow of this area

witnesses a significant increase,