Study on the pollution of song cai river under the impact of climate change and suggestion of remedies for recovering the water quality

MINISTRY OF EDUCATION AND TRAINING NHA TRANG UNIVERSITY ---o0o--- TA LE DANG KHOI STUDY ON THE POLLUTION OF SONG CAI RIVER UNDER THE IMPACT OF CLIMATE CHANGE AND SUGGESTION OF REMEDIE

MINISTRY OF EDUCATION AND TRAINING

NHA TRANG UNIVERSITY

-o0o -

TA LE DANG KHOI

STUDY ON THE POLLUTION OF SONG CAI RIVER UNDER THE IMPACT OF CLIMATE CHANGE AND SUGGESTION OF REMEDIES FOR RECOVERING THE

WATER QUALITY

MASTER THESIS

KHANH HOA - 2017

MINISTRY OF EDUCATION AND TRAINING

NHA TRANG UNIVERSITY

-o0o -

TA LE DANG KHOI STUDY ON THE POLLUTION OF SONG CAI RIVER UNDER THE IMPACT OF CLIMATE CHANGE AND SUGGESTION OF REMEDIES FOR RECOVERING THE

WATER QUALITY

MASTER THESIS

and Climate Change

Code:

Topic allocation Decision 772/QĐ-ĐHNT dated 20/9/2016

Decision on establishing the

Suppervisors:

Assoc Prof NGO DANG NGHIA

Prof SIGURD STEFANSSON

Prof HENRIK GLENNER

Chairman:

Assoc Prof PHAM QUOC HUNG

Faculty of Graduate Studies:

KHANH HOA - 2017

UNDERTAKING

I undertake that the thesis entitled: “ Study on the pollution of Song Cai River under the impact of climate change and suggestion of remedies for recovering the water quality “ is my own work The work has not been presented elsewhere for

assessment until the time this thesis is submitted

Khanh Hoa, Day month year 2017

Author

Ta Le Dang Khoi

ACKNOWLEDGMENT

I would like to express the deepest appreciation to The Institute for Biotechnology and Environment of Nha Trang University for helping and giving best conditions me finish my thesis

My special thanks go to Assoc Prof Ngo Dang Nghia for the continuous

support of my Ph.D study and research, for his patience, motivation, enthusiasm, and immense knowledge His guidance helped me in all the time of research and writing of this thesis

Last but not least, I would like to thank my family: my parents and to my brothers and sister for supporting me spiritually throughout writing this thesis

Thank you!

Khanh Hoa, Date month year 2017

Author

Ta Le Dang Khoi

TABLE OF CONTENTS

Chapter 1 GENERAL 1

1.1 Introduction 1

1.2 Imperiousness 7

1.3 Natural characteristics 8

1.3.1 Geographical location 8

1.3.2 Climate Features 9

1.3.3 Features of major rivers and streams in Khanh Hoa Province 13

1.3.4 Current situation of water resources exploitation 13

1.4 Economic and social characteristics 14

1.4.1 Population and population distribution 14

1.4.2 Economic growth 14

1.5 Scientific and practical meaning 15

1.5.1 Scientific meaning 15

1.5.2 Practical meaning 15

Chapter 2 SUBJECT AND RESEARCH METHODS 16

2.1 Object of research 16

2.2 Subject and scope of research 16

2.2.1 Subject of research 16

2.2.2 Scope of research 16

2.3 Research content 17

2.4 Research methods 17

2.4.1 Surey, sampling and analysis methods 17

2.4.2 Method of building water quality indicators 18

2.4.3 Method of mathematical models (MIKE 11 model) 24

2.4.4 Calculation grid establishment in MIKE 11 27

2.4.5 Climate change scenarios 30

Chapter 3 RESULTS AND DISCUSSION 33

3.1 The current status of waste discharge sources 33

3.1.1 Sources of waste affecting the water quality of the Cai river 33

3.1.2 Direct waste sources 33

3.1.3 Discharge sources through tributary river and canal systems 36

3.2 Assessment of surface water quality in the study area 38

3.3 Evaluation of the trend in surface water quality with water quality index (WQI).41 3.4 Sources of water pollution in the future 44

3.4.1 Sources of industrial waste water 44

3.4.2 Forecast of wastewater from urban and residential areas 46

3.5 Forecasting the influence of waste water on the water quality of Cai river (Mike 11) 48

3.6 The simulation of water quality with the impact of climate change, according to different emission scenarios 48

3.6.1 Climate change scenarios 48

3.6.2 The result of Scenario simulation under the impact of climate change in 2020 49 3.6.3 The result of Scenarios simulation under the impact of climate change in 203057 LIST OF REFERENCES 68 APPENDICES

CCME: Canadian Council of Ministers of the Environment

DO: Dissolved Oxygen

EQI : Environment Quality Index

GIS: Geographic Information System

IC: Industrial Cluster

IP: Industrial Park

OWQI: Oregon Water Quality Index

QCVN 40:2011/BTNMT: National technical regulations on industrial waste water quality

QCVN 14:2008/BTNMT: National technical regulations on household waste water quality

QCVN 08-MT:2015/BTNMT: National technical regulations on surface water SS: Total Suspended Solid

TC: Total Coliform

WQI: Water Quality Index

LIST OF TABLES

Table 1.1 Average temperatures in the years 2012, 2013, 2014, 2015 9

Table 1.2 Monthly rainfall (mm) 11

Table 1.3 Morphology of rivers and streams in Khanh Hoa 13

Table 1.4 Population in the research area in 2014 14

Table 2.1 Locations of sampling the surface water in the Cai River 17

Table 2.2 Results of classification of water quality according to BC Index 19

Table 2.3 Specified values qi, BPi 21

Table 2.4 BPi and qi values corresponding to DO% saturated 22

Table 2.5 Specified BPi and qi values with pH parameter 22

Table 2.6 Water quality assessment 23

Table 3.4 Positions of the tributary rivers and canals flowing into the Cai River in the study area 37

Table 3.7 Locations of sampling the surface water in the Cai River 38

Table 3.8 The results of calculating WQI of Cai River in the rainy season 41

Table 3.9 The results of calculating WQI of Cai River in the dry season 42

Table 3.11 Prediction of wastewater flow generated from the IPs and ICs in 2020, 2030 45

Table 3.18 Prediction of population in reseach area until 2020, 2030 46

Table 3.26 The load of domestic wastewater sources under 3 scenarios in 2020 47

Table 3.27 The load of domestic wastewater sources under 3 scenarios in 2030 48

Table 3.28 The amount of change in precipitation (%) compared to the baseline period from 1980 to 1999 of Khanh Hoa province, according to the average emissions scenario (B2) 49

Table 3.29 The amount of change in precipitation (%) in comparison to the baseline period from 1980 to 1999 of Dak Lak province, according to the average emissions scenario (B2) 49

Table 3.30 The amount of change in temperature (oC) in comparison to the baseline period from 1980 to 1999 of Khanh Hoa province, according to the average emissions scenario (B2) 49

LIST OF FIGURES

Figure 1.1: The map of research area 8

Figure 1.2 The distribution of average temperature in Khanh Hoa province 10

Figure 1.3 The distribution of rainfall in the dry seaso 12

Figure 1.5 The distribution of total annual rainfall in Khanh Hoa Province 12

Figure 2.1: Diagram of research area 16

Figure 2.2: Locations of sampling the surface water in the study area 18

Figure 2.3: Description of continuity equation 24

Figure 2.4: Diagram of flow between 2 calculated cross sections 25

Figure 2.5: Research area sitemap 27

Figure 2.6: Calculation grid in MIKE 11 28

Figure 2.7: Cross section location 28

Figure 2.8: Edited cross sections in MIKE 11 29

Figure 2.9: Sub-basins in the reseach area 30

Figure 2.10: Four families of greenhouse gas emission scenarios 31

Figure 3.1 Positions of the discharge sources in the study area 35

Figure 3.2 The tributary rivers and canals flowing into the Cai River 37

Figure 3.3: Locations of sampling the surface water in the study area 40

Figure 3.4 Current status of water quality in Cai River is represented by WQI in the dry season 43

Figure 3.5 Current status of water quality in Cai River is represented by WQI in the rainy season 43

Figure 3.6 DO changes in some locations according to Scenario 1 50

Figure 3.7 BOD changes in some locations according to Scenario 1 50

Figure 3.8 NH4 changes in some locations according to Scenario 1 51

Figure 3.9 PO4 changes in some locations according to Scenario 1 52

Figure 3.10 DO changes in some locations according to Scenario 2 52

Figure 3.11 BOD changes in some locations according to Scenario 2 53

Figure 3.12 NH4 changes in some locations according to Scenario 2 53

Figure 3.13 PO4 changes in some locations according to Scenario 2 54

Figure 3.14 DO changes in some locations according to Scenario 3 54

Figure 3.15 BOD changes in some locations according to Scenario 3 55

Figure 3.16 NH4 changes in some locations according to Scenario 3 56

Figure 3.17 PO4 changes in some locations according to Scenario 3 56

Figure 3.18 DO changes in some locations according to Scenario 1 57

Figure 3.19 BOD changes in some locations according to Scenario 1 57

Figure 3.20 NH4 changes in some locations according to Scenario 1 58

Figure 3.21 PO4 changes in some locations according to Scenario 1 58

Figure 3.22 DO changes in some locations according to Scenario 2 59

Figure 3.23 BOD changes in some locations according to Scenario 2 59

Figure 3.24 NH4 changes in some locations according to Scenario 2 60

Figure 3.25 PO4 changes in some locations according to Scenario 2 60

Figure 3.26 DO changes in some locations according to Scenario 3 61

Figure 3.27 BOD changes in some locations according to Scenario 3 61

Figure 3.28 NH4 changes in some locations according to Scenario 3 62

Figure 3.29 PO4 changes in some locations according to Scenario 3 62

ABSTRACT

The Cai river played a huge role in providing fresh water, serving people's livelihood, economic development - social, however due to the waste water of production facilities, business and domestic wastewater untreated, wastewater has been directly into the river and make the river water quality decline, many indicators such as BOD5, COD, TN, TP higher than standards allow Currently, due to the pace

of development population, industry, agriculture, tourism and services are increasing, require the demand to use and discharged large amounts of waste, but has not invested commensurate in infrastructure so most of the water from these areas are not treated and discharged directly into canals, polluting the environment increasingly severe, especially the surface water environment

To solve these problems exist above, practitioner perform build arguments based

on scientific grounds, realistic assessment of river water, polluting sources, evolutions and trends in future for the Cai river basin, therefore implementing the thesis “ The study of determining the scope and level of the Cai river pollution (section crossing Dien Khanh district and Nha Trang city), analysing the causes and proposing protecting solutions” is necessary and urgent The results of the research performed will generalise the current status of the water environment at the research area, is the basis of scientific and practical to help management agencies policies planning, development planning of the social economy pertain to protection and sustainable development of the environment, especially the Cai river water environment

Chapter 1 OVERVIEW

1.1 Introduction

General management of river basin is strongly and closely related to water resources management In 1977, Mar del Plate Conference started the water decline in the world and proposed International Water Program in 10- year-period (1980-1990) Then in Dublin Conference 1992, International Association chose some basic principles of substantial water use In recent years, there are many researches and practices about general management and water resources use based on river basin in the world and they have high theoretical and practical results

In other nations in the world, pollutions or qualities of surrounding environment are zoned in a certain period, about once 5 years or 10 years, for example, in the years

1990, 2000 and 2005 In terms of the status quo of economic and social development and defined zoned pollution time, the variety of pollution situation of surrounding environment is mainly based on natural conditions Environmental rivers pollution is based on their flow rates, speeds, movement directions and water temperatures,…Therefore, in many nations in the world, there are 2 main approaching methods to zone pollutions or qualities of surrounding environment as below:

Calculation method according to the model of diffusing environmental pollution

by using Geographic Information System (GIS): This method requires enough data

about waste sources causing environmental pollution (location, flow rate, kind of waste, means of release and physical properties of waste sources) and about climate, river, sea, topographical, hydrogeological conditions of researched area In this method, contour lines can be drawn quite exactly, which means that the researched area can be zoned and divided into different sections with different pollution rates Method of summarizing, analysing, counting statistics of observing real environment: This method requires a system of complete observation stations and distribution of measured points which cover the whole researched area and the thicker measured points are distributed, the more exact zoning pollution is Observation time must be suitable so that the observation results reflect environmental pollution situation correctly The zoning pollution based on analysing and counting data of environment observation often has approximately right value, but it is basic, practical

and often used in many nations in the world In many cases in which there is a lack of environment observation data, the calculation method of according to the model of diffusing environmental pollution is combined to zone pollution or qualities of surrounding environment

To evaluate environmental pollution level or classify environmental qualities in the world, Environment Quality Index – EQI is used AQI is used for air environment, WQI is used for water surface environment, SWQI is used for inshore environment EQI model was first proposed and applied in America in 1965-1970 and is currently widespread in many states Nowadays, this model has deployed applied researches in many nations such as India, Canada, Chile, England, Taiwan, Australia, Malaysia, EQI is considered as an effective method to environment managers in supervising, checking and managing environment qualities, evaluating how effective policy-planners are Before 1990, EQI used to be environmental quality indexes to each separate parameter (pollutant) After 1990, general environmental quality indexes have been used synthesizing many special pollutants of each defined environment such

as synthesized EQI to air environment, surface water of basin river environment and inshore environment The way of classifying pollution level based on individual pollutant has many disadvantages:

(1) It is difficult to classify environmental quality for one certain purpose of using, For example, to surface water environment, according to Vietnamese regulation named QCVN 08:2008/BTNMT about river water quality column A (type A1- meet standards of Domestic Water Supply) and column B (type B1- not meet standards of Domestic Water Supply) to parameters of dissolved oxygen (DO), total suspended solid (SS) and total coliform (TC) equivalent to DO ≥ 6 mg/L and 4 mg/l; TSS = 20 mg/L and 50 mg/L, TC = 2500MPN/100ml and 7500MPN/100 mL However, in reality, one river meets type A1 about TSS and TC, while the other meets type A1 about TSS, but both of them do not meet type A1 about DO and TC or meet type A1 about DO, TSS but not meet type A1 and B1 about TC,… Therefore, this river or the other meets the water quality to what type of surface water? This cannot be answered based on analysis of environment quality index to each parameter

(2) In the other hand, depending on different purposes of using, each parameter has a different importance For example: turbidity and total coliform are important to

direct access (taking shower, swimming), but they are not important to agricultural irrigation supply Temperature, salinity, NH4+ are not important to bathing water but very important to aquaculture water…Obviously, in these cases, it is quite difficult to conclude that water quality of a river or a stretch of the river meets type A1, A2, B1 or B2 and water quality which meets standards of a purpose, but not meet the other purpose But this leads to a difficulty in zoning areas, classifying water quality, deciding in exploitation ability of a river or a stretch of the river for one or some purposes of using

(3) When evaluating water quality based on many separate indexes, the development of general water quality of a river or a stretch of the river cannot be seen Hence, it is quite difficult to compare water quality in a period with that in other ones (according to months or seasons), present water quality with that in the future Therefore, it is quite difficult to supervise the development of water quality and evaluate the effect of investment in protecting water sources and monitoring water pollution,

(4) When evaluating water quality based on many separate indexes, only scientists or specialist managers in water can understand the results, hence it is quite difficult to inform the water quality to the public and state management agencies, leaders to make right decisions on water sources protection and exploitation

To overcome these difficulties, there needs a index or a system of indexes allowing to quantify general environmental quality (which means reflecting environmental quality index according to a unified band score) and be able to describe the combination of many chemical, physics and biological ingredient concentration and the importance of each pollutant index to one certain purpose One of these indexes is Water Quality Index(WQI) Basically, WQI is means of Maths to calculate values of experiments to release results of indexes reflecting water quality of a certain basin such as lake, river, runnel In other way, WQI is a Maths formula simulating pollution level of river, lake water sources based on values analysing special parameters about water quality According to it, we can know about quality and pollution level of a stretch of the river in each period, then we can know whether the water source is used for living, shrimp and fish farming, irrigation, or not

Nha Trang city belonging to Khanh Hoa province is one of the most developing cities in Vietnam It is a centre of tourism, resort, services and commercial transactions of Vietnam and the world Besides tourism, the city develop many industries such as seafood processing, garments and port services

fast-Together with an unstoppable development of economy, environmental quality of the city has been reduced Cai River is used for domestic water supply of the city but the content of suspended matters, organics, and microorganism is higher than standards of water supply Water quality in many bridges in the city like Binh Tan, Sat, Bong,… is seriously polluted by many living households near polluted areas, especially smell pollution Domestic waste is an urgent concern of the city Besides, the featured thing of Nha Trang is smell pollution from in-shore aquaculture villages These pressing problems are preventing from city development The side-effects of economic and social development are pollution and damaging natural environment and living environment

Economic and social development put pressure under natural resources like soil, water, air, biological resources,… An increase in waste from many sources like: domestic waste, production, tourism; waste from aquaculture cages, tourist boats, waste oil from means of river transport, means of sport transport, untreated waste water or partially untreated waste water from hotels, tourist attractions, entertainment areas, factories, living households,…will potentially raise inshore water pollution Economic and social development will lead to a change in a purpose of using land for development activities like the constructions of residential areas, new urban places, hotels, tourist attractions, mining,… or a decrease in the size of mangroves, natural land, surface water,… due to deforestation, land reclamation to build sea reclamation constructions, burning forest for farming,…also increases the depression level of natural views

In recent years, there are many researches on the field of proper use of water resource Especially, for example:

- The mission of defining cause, range, affecting level of the environment in Ba Cheo Channel basin, Long Thanh Province, Dong Nai city was executed by Resources and Environment Institute and Associate Professor, Doctor Nguyen Van Phuoc was a

chairman in 2012 The mission evaluated the pollution level and range of water quality

in the river basin affected by waste release of Sonadezi Long Thanh industrial zone which influences economic activities of the residents [14]

- State research project 08.04 “Research on building the model of integrated management of resources and the Da river basin environment” was hosted by Scientific Irrigation Institute and Doctor Nguyen Quang Trung was a chairman in 10/2001 to 9/2004 This project built the record of Da River Basin and the methodology and proposed 2 models of integrated management of Da River Basin: Expanded model of planning management of Hong River Basin (legal model) and the model of integrated management of resources and Da River Basin [15]

- State-levelled topic KC.08.25: “Research on general solutions of reasonable use

of resources and environmental protection of the basins of Ba and Con River was hosted by Geography Institute and Associate Professor Doctor Nguyen Van Cu was a chairman from 1/2004 to 12/2005 The main results were to build up general solutions

of general management aiming at reasonable use of resources and environmental protection of the basins of Ba and Con River, set up data about natural, resources, environmental, economic, and social conditions of the basins of Ba and Con River to help researchers and natural resources managers update information fast and synchronously on the whole basin [16]

- State-levelled topic KC.08.27: “Research on general solutions of reasonable use

of resources, environmental protection and natural disasters prevention on the basis of

Lo and Chay River was hosted by Hydrometeorology Institute – Resources and Environment Department and Doctor, researcher La Thanh Ha was a chairman from 1/2004 to 12/2005 The main results were to evaluate the status quo, process of exploiting and using resources on the basis of Lo and Chay River; environment quality and environmental catastrophe on the basins; causes and effects of the recession procedure of resources and environment on basins; propose solutions of reasonable exploitation and use, environmental protection of Lo and Chay Basin River; set up database about resources and environment of the basins [17]

- State-levelled topic KC.08.18/06-10 “General management of basin river and reasonable use of water resources of Dong Nai river system” was hosted by Doctor Do

Tien Lanh – Southern Science Institute of Irrigation in 2007 - 2010 The main goals were to set up a suitable mechanism to share water source to solve conflicts of water use, operate water reservoir system on the basin and propose practical solutions of reasonable use and water sources pollution control on Dong Nai Basin River [18]

- Nguyen Van Hop and his assistants used the model NSF- WQI (America) to evaluate variation water quality of Huong River from 5/1998 to 12/2002 for the purpose of representative evaluation From January to December, 2004, they used the improved method WQI of Bhargava (India) to classify and zone water quality Huong River as well as other rivers of Quang Tri Province (2005) and Thua Thien Hue (2006) The results showed that the improved method WQI of Bhargava (India) had higher sensitivity than the model NSF- WQI (America) [6]

- Ton That Lang applied the method Delphi to inquiry experts’ ideas and used the model NSF- WQI (America) to set up index water quality serving the practices of managing and controlling water quality of Dong Nai River system in 2003 – 2005 [12]

- In 2007 – 2008, in the sphere of municipal - levelled “Research on zoning water quality based on water quality indexes (WQI) and evaluation on water use capability

of rivers, canals in Ho Chi Minh City” of Le Trinh, water quality index was applied widely to zone water quality rivers, canals in the city based on applying and improving

2 basic models WQI: NSF- WQI (America) and Bhargava (India) The author proposed 3 water quality models for specific conditions of Ho Chi Minh city (noted WQI – NSF/HCM, HCM – WQI and WQIB – HCM) with 10 typical indexes (DO, BOD, SS, total coliform, pH, total N, opaque level, oil, COD, total P), inquiry experts’ ideas and used the method Delphi to set up value Simultaneously, he calculated the value of indexes for 35 survey sites in the city [4]

- In 2009, on the basis of Research on setting up water quality indexes (WQI) serving the practices of planning water sources of Pham Gia Hien [7], WQI was proposed to be counted :

WQI-2: WQI was based on CCME-WQI but had a change in coefficient

CCME-WQI was used to calculate annual year, in which WQI-2 was proposed to calculate a monthly data If a month has many series of data, the result WQI-2 of a month is calculated based on the average of these series

732 1 3 2 1

WQI-WQI-4: WQI-4 is proposed based on the method of NSF – WQI, in which

diagrams convert data value to secondary index created by comparing with limited value (standards water qulity are chosen according to use purposes) and weight of WQI is consulted from experts’ ideas and from many practical comparisons Proposed WQI includes 8 parameters: pH, TSS, turbidity, total Nitrogen, BOD5 and coliform

- In 2009, Topic “Research on defining total daily maximum waste release serving to set up a release quota in Sai Gon River (from Thu Dau Mot to Nha Be)” hosted by Nguyen Ky Phung also applied water quality index America (NSF-WQI) to sort out and evaluate generally about water quality of Sai Gon River [5]

1.2 Imperiousness

Any form/scale of the socio-economic development is always involved in the exploitation, the use of natural resources and the disposal of waste which is believed to cause pollution and environmental degradation Among them, water is an indispensable resource in every socio-development activity The increase in population and the urbanization process together with the formation of more and more industrial parks, industrial clusters, the industrial production base; the development of tourism services, waterway transportation, agriculture etc are the inevitable trends over the basins

The Cai River in Nha Trang is one of the three major rivers in Khanh Hoa province playing an important role in providing fresh water to serve public welfare, socio- economic development, but it is not out of the mentioned rules, especially the fact that it flows through big towns and cities such as Nha Trang, Ninh Hoa, Dien Khanh etc Currently, due to population growth, development in industry, agriculture, tourism and services, large amount of waste is released Yet, the infrastructure in the areas is inadequate, so untreated sewage is discharged directly into waterways, leading much more serious environmental pollution, especially in the water surface

In Khanh Hoa , there is neither research nor special management program focused at Cai river basin and the river water Climate change have an increasing impact on natural, social economic and environmental conditions on Earth Therefore,

it’s necessary to conduct research on current status and to forecast the pollution of the river water due to the socio-economic development activities under the impact of climate change to invent premise for construct solutions and limit the impact of water quality in Cai river

From the mentioned clues above, the subject “Study on the pollution of Song Cai River under the impact of climate change and suggestion of remedies for recovering the water quality” is necessary and practical to implement

1.3 Natural characteristics

1.3.1 Geographical location

The research area belongs to Dien Khanh district and a part of Nha Trang city, Khanh Hoa province Cai River originates from Gia Le mountain which is 1.812 m in height, flows through Khanh Vinh, Duyen Khanh district and Nha Trang city and then pours into the sea at Dai Cu Huan Cai river has 7 estuaries that originate from the height from 900 to 2000 m but are short, about under 20 km, so the slope is very high, which causes many falls in the upstream

The upstream of Nha Trang River has many falls From the Cho sea mouth and above, there are Dong Trang, Ong Hao, Da Lua, Nhet, Mong, Vong waterfalls In the research area, the number of falls is smaller, however, the part of the river has received waste release from production, living and many small river branches The part of Cai River flows through Dien Khanh province and Nha Trang city is shown in figure 1.1

Figure 1.1: The map of research area

1.3.2.1 Heat mode

Daily temperatures usually varify from 5°C to 7°C, reaching the highest in 6, 7, 8 and the lowest in 11, 12 High temperature oscillations in the summer months are due

to strong ground radiation reducing low temperatures

While the hottest month, in the majority of cases, falls in June (45-80 %), in other cases, it falls in May (20 %) The hot season may begin as early as February, and the latest month beginning the hot season is March The season has the first ending in November, at the latest in December

Table 1.1 Average temperatures in the years 2012, 2013, 2014, 2015

Highest month 31.6 (June) 31.0 (May) 29.4 (June) 31.9 (July)

Lowest month 23.1 (January) 23.1 (December) 23.1 (January) 21.1 (January)

Source: [2]

Figure 1.2 The distribution of average temperature in Khanh Hoa province

1.3.2.2 Wind regime

In winter monsoon season (from October, November last year to March, April next year), north-east directed winds prevail The frequency of the prevailing wind direction is approximately 30 %, and up to 60 % in some places with wind directions focusing on the North and North-East Some places have northwest wind direction Summer monsoon (from May, June to September, October) has the main component as southwest wind, affecting Khanh Hoa from 2 directions: to the west when it crosses the arc of mountains, blowing into the plain in the cases of the early monsoon or strengthened west flows; to the south and south-east when a joint line changes its direction In Nha Trang, in the winter months, the percentage of winds which have speeds of 2 to 5 m/s exceeds 65 % The figure for the summer months is rarely less than 55 % and winds which have speeds reaching 5m/s only account for 10

% of cases

1.3.2.3 Mode rain

Like as the climate of Khanh Hoa Province Nha Trang and Dien Khanh is divided into two distinct seasons: rainy and dry seasons The dry season from January

to August, the rainy season usually starts in September and ends in December

The annual average rainfall from 1,400 mm to 1,800 mm The rainfall focus of the four-month rainy season with the average rainfall total for years 1000 - 1200 mm, accounting for 65-75 % of the annual rainfall In the dry season, total rainfall is about

350 - 550mm, accounting for 25 - 35 % of the total annual rainfall, particularly in October and November accounted for 35 % to 45 % of annual rainfall

Table 1.2 Monthly rainfall (mm)

Figure 1.3 The distribution of rainfall in

the dry season

Figure 1.4 The distribution of rainfall in

the rain season

Figure 1.5 The distribution of total annual rainfall in Khanh Hoa Province

1.3.3 Features of major rivers and streams in Khanh Hoa Province

The rivers in Khanh Hoa are short and steep overall The province has about 40 rivers which are 10 km or more in length, forming a thick distribution network of rivers Most rivers originate from the western mountains in the province and flow into the sea to the east Along the coast, there is an estuary per each 5 to 7 km This system

is governed by topographical features and climatic conditions The two largest rivers are Cai River (Nha Trang) and Dinh River (Ninh Hoa)

Table 1.3 Morphology of rivers and streams in Khanh Hoa

Height of river sources

The length Basin

area

Average slope of catchment area

1.3.4 Current situation of water resources exploitation

The river basin has a total inflow of approximately 2.078 billion m3 per year With a population of about 546,124 people, the average per capita is approximately 3,804 m3 per year, lower than the national average and the average of the world According to the world ranking, the country achieving under the 4,000 m3/person / year is poor in terms of water, so the Cai river basin are is poor in water However, the

problem is that the total flow of 4 months in flood season (September -Decmber) accounts for 65 - 66 % of annual flow, and the flow of 8 months in dry season (January-August) only constitutes 34 - 35 % of annual flow Compared with the demand for water, the flow distribution between the two seasons as above is uneven and very detrimental to production

1.4 Economic and social characteristics

1.4.1 Population and population distribution

The rate of average annual population growth in 2012 - 2013 is 1.06 % per year

In 2013, the population in the research area is 60.885 people with females accounting for 50.5 % The average population density is 205 people/km2 In which the population

in the research area is shown in Table 1.4

Table 1.4 Population in the research area in 2014

Dien Khanh province Nha Trang city Population

Economic growth rate reaches an annual average of 7.2 %; the economic structure shifts towards an increase in the share of services - tourism, industry - construction Service and commerce industries are invested to develop with an average increase of 12.6 %/year; total retail sales of goods and services in 2015 reached 25,488 billion, increasing by 82 % compared to 2011 The facilities and the quality of tourism services are better and better than the needs of travelers in and out country

1.5 Scientific and practical meaning

Chapter 2 SUBJECT AND RESEARCH METHODS

2.1 Object of research

The evaluation and affection of waste sources in the Cai river, the estimation of current status of the river water and the prediction of discharge sources, the solution for control pollution and protect the water quality of Cai river under the impact of climate change are proposed

2.2 Subject and scope of research

- The selection of research area: This place have a lot of factories with scattered distribution and non-tight management, so the risk of water pollution from these waste sourses is enormous

Figure 2.1: Diagram of research area

2.3 Research content

- To assess the water quality in Cai river basing on the results of river quality sample

- To assess and predict the status of waste sources until 2020, 2030

- To forecast the water quality in Cai river, taking into account the impact of climate change relying on results of MIKE 11 model

- To propose specific solutions to control waste sources and to protect the water environment in Cai river

2.4 Research methods

2.4.1 Survey, sampling and analysis methods

To implement the project, conducted sampling at 10 points in the Cai River in the rainy season (2015) and the dry season (2016) and compared as well as referred to the monitoring data of Khanh Hoa Center for Environmental Monitoring to assess the surface water quality The sampling locations are presented in Table 2.1 and Figure 2.2

Table 2.1 Locations of sampling the surface water in the Cai River

1 The Cai River – upstream of the

2

The Cai River – after receiving

water discharged from Phuoc Lac

Tho canal

NM2 109°2'2,73'' 12°16'4,36''

3

The Cai River – after receiving

water discharged from Khoi

Nguyen Joint stock Company

NM3 109°5'10,69" 12°15'40,56"

4 The Cai River - after receiving water

discharged from Ha Dua Canal NM4 109°5'17,61'' 12°15'32,96''

5

The Cai River – after receiving

water discharged from Hiep Hung

The Cai River – after receiving

water discharged from Ba Mang

canal

NM8 109°6'34,46'' 12°15'53,21''

9

The Cai River – after receiving

water discharged from Dien Phu

industrial park

NM9 109°7'3,82" 12°15'52,54"

10 The Cai River – after receiving water

discharged from Cau Voi canal NM10 109°7'18,02'' 12°15'51,93''

11 The Cai River – downstream of

the study area NM11 109°7'51,12" 12°15'45,17"

Figure 2.2: Locations of sampling the surface water in the study area

2.4.2 Method of building water quality indicators

In the world today, depending on the geographical location, natural conditions, the current status of water quality in each region and each country, there are various approaches to and models of WQI Some WQI models are commonly applied as follows

- Calculation method

2 2

3 (F

F

Index classification = Index/1,45

F1: calculated by parameters in excess of standards over the total number of parameters

F1 = (n/N)* 100

F2: calculated by the number of times parameters exceeding the standard measured over the total number of parameters measured

F2 = (m/M)*100

F3: calculated by the following formula:

F3 = Max [{(XMMi,j - Stdj)/ XMMi,j}*100]

2 3 2 2 2

F

Annotation:

F1 – the percentage between the non-standard parameters and the total of parameter total reviewed,

F2 – non-standard frequency, ie the ratio of non-standard samples with the total

of samples (all the parameters analyzed),

F3 – Substandard degree (amplitude)

2.4.2.2 Universal Water Quality Index apllied in some European countries –

i I w

1

Annotation:

wi weight of parameter i

Ii sub-index of parameter i

n: the number of parameters

Selected parameters and sub-index

Selected parameters for calculation: BOD, Nitrat, Asen, DO, Flo, the total of Phosphorus, Hg, Se, CN-, Cd, the total of coliform, pH With each of them, there are different formulas for calculating different sub-indices Ii and weights wi have different values and significance

2.4.2.3 Construction methods of WQI according to Handbook of Vietnam Environment Administration

On July 1, 2011 General Department of Environment issued Decision No 879 / QD-IDU on publishing Manual of WQI Calculation The manual is applied to state management agencies on the environment, organizations and individuals involved in environmental monitoring networks and the disclosure of information about the quality

of the environment for the community

* Calculation of WQI parameter

- WQI parameter (WQISI ) is calculated for the parameters: BOD 5 , COD, N-NH 4 ,

 1  11

i i

BP BP

q q WQI

Annotation:

BPi: the lower limit of concentration of monitoring parameter values specified in table 2.3 corresponding to i

BPi+1: the upper limit of concentration of monitoring parameter values spicified

in table 2.3 corresponding to i+1

qi: WQI value at i given in the table corresponds to the value of BPi

qi+1: WQI value at i+1 given in the table correspond to the value of BPi+1

Cp: The value of the monitoring parameter taken into account

Table 2.3 Specified values q i , BP i The specified value of BPi corresponding to each parameter

Step 1: calculate DO% saturation value:

+ Calculation of DO saturation value:

3 2

000077774

00079910

041022.0652

T: water temperature at the time of monitoring (unit: 0 C)

+ Calculate DO % saturation value:

DO%saturated= DOsolvable /DOsaturated*100

DO solvable : the value of DO monitored (unit: mg/l)

Step 2: Calculate WQIDO:

i i

i i

BP BP

q q

Annotation:

Cp: DO % saturation value

BPi, BPi+1, qi, qi+1 are corresponding values to i, i+1 in table 2.4

Table 2.4 BP i and qi values corresponding to DO % saturated

If DO% saturated ≤ 20, then WQIDO is equal to 1

If 20< DO% saturated< 88, then WQIDO is calculated through formula 2 and table 2.4

If 88≤ DO% saturated≤ 112, then WQIDO equals to 100

If 112< DO% saturated< 200, then WQIDO is calculated through formula 1 and table 2.4

If DO% saturated ≥200, then WQIDO equals to 1

Calculation of WQI with pH parameter

Table 2.5 Specified BP i and q i values with pH parameter

If pH≤5.5, then WQIpH is equal to 1

If 5,5< pH value <6, then WQI is calculated through formula 2 and table 2.5

If 6≤ pH value ≤8,5, then WQIpH equals to 100

If 8.5< pH value< 9, then WQIpH is calculated through formula 1 and table 2.5

If pH value ≥9, then WQIpH is equal to 1

* Calculation of WQI

After WQI is calculted with each parameter above, the calculation of WQI

is conducted with the following formula:

3 / 1 2

1

5

1 5

b a

a

pH

WQI WQI

WQI

WQI WQI

Annotation:

WQIa: the value WQI calculated with 05 parameters: DO, BOD5, COD, N-NH4, P-PO4

WQIb: the value of WQI calculated with 02 parameters: TSS, turbility

WQIc: the value of WQI calculated with the total parameter of Coliform

WQIpH: The value of WQI calculated with pH parameter

Note: WQI value will be rounded to integer after calculation

* Comparing WQI calculated with the evaluation table

After WQI being calculated, the WQI value table corresponding to water quality

assessment is used for comparision and assessment, namely:

Table 2.6 Water quality assessment

91 - 100 Good for water supply purposes Blue

76 – 90

Suitable for water supply purposes, but appropriate treatment measures needed

Green

51 – 75 Suitable for irrigation purposes

and other similar purposes Yellow

26 – 50 Used for water transportation

and other similar purposes Orange

0 – 25 Seriously polluted, treatment

measures needed in the future Red

In general, the classification and zoning of water quality in terms of physical, chemical and biological aspects have been paid attention to and studied by a number of domestic scientific researchers in recent years The most common point of those studies is to apply and improve foreign models of WQI to classify and evaluate the water quality of rivers and canals in Vietnam In this research, apply the calculation under the guidance of the General Department of the Environment

2.4.3 Method of mathematical models (MIKE 11 model)

MIKE 11 model is a specialized technical sofware invented and developed by Danish Hydraulic institute (DHI) in the past 20 years, applied to illustrate hydraulic regime, water quality and sediment transmission, irrigation system, channel and other systems of water conduit MIKE 11 contains a wide range of modules with different functions and missions For example: Rainfall – Runoff (RR), Hydro Dynamic (HD), Advection – Dispersion (AD), Ecolab và others…Among them, Hydo Dynamic (HD)

is the heart of this model, the basic format of other modules MIKE 11 HD solves synthetic vertical equations to ensure the continuity and momentum such as Saint Venant equation

In this report, MIKE 11 model is used to calculate the hydraulic elements; estimate and predict changes in the water quality at the suface of Cai River, Nha Trang

- the segment runs through Nha Trang city

A x

- Momentum equation:

02

Q Q g x

h gA A

Q x t

y – hydrodynamic coefficients; according to Maninh, y =1/6

Z – Water level at the time of calculation (m)

q – In-put flow per cubit of river channel (m2s-1)

t – Time (s)

x – Distance between cross sections (m)

Figure 2.4: Diagram of flow between 2 calculated cross sections

Input is the systematic characteristics and water resource throughout the system From the set of equations of Saint - Venant (1) and (2), it is possible to rewrite the

expressions of Q and h:

q t

h B x

Q Q g x

h gA A

Q x B t

Q





Resolving the mentioned set of differential equations leads to the identification of flow value and water level (leapfrogging) in the transection of river network every

moment in a fixed range of time

2.4.3.2 Mike 11 AD

In MIKE 11, the process of diffusion transmission is described by the equation:

Q C AKC x

C AD x x

QC t

q- In-put flow per cubit of river channel, m2/s

K-biodegradable coefficients, K is included when researched phenomenons and processes are related to biochemical reactions only

Diffision equation reflects 2 mechanism of transmissions:

of diffusion transmission of such components

Currently, Ecolab module of MIKE is built on the basis of open source – It means that users are able to establish algorithm to calculate all parameters of water quality to combie with HD and AD modules

2.4.4 Calculation grid establishment in MIKE 11

2.4.4.1 Introduction of research area - Calculation grid establishment

Figure 2.5: Research area site map

The study area is Cai river in Nha Trang - the segment flows through Dien Khanh district which lasts 20km With such area, the grid of calculation is proposed as Figure 2.6 to ensure the data source of transection as well as boundary conditions Therefore, this grid will be extended from Dong Trang station to sea

Figure 2.6: Calculation grid in MIKE 11

2.4.4.2 Cross section data

Figure 2.7: Cross section location

Cross section data collected from Hydro – Meteorological Station of South

Central region in the study area includes 10 sections shown in Figure 2.7

This data is edited, revised before entering MIKE under the format of xns11 file The result of edited cross sections is decribed in Figure 2.8

Figure 2.8: Edited cross sections in MIKE 11

2.4.4.3 Boundary data

With calculation grid as presented in Figure 4.6, the boundary conditions include:

- Upstream boundary: Đồng Trăng station – flow border (Q)

- Downstream boundary (Sea): Cầu Đá station- Water level border (Z)

If the terrain of research area is not too flat, the selected type of border will be

Q-Z with the best simulation