ACKNOWLEDGEMENTS
I would like to express my great appreciation to Assoc. Prof. Dr. Tran Quang Bao
from Vietnam Forestry University, my research supervisor, for his enthusiastic
encouragement and useful critiques on this research. Without his thoughtful and patient
guidance through every step of my research and her knowledge on how to correct and analyze
the data I collected, this thesis could not be completed. I also would like to say thanks to
lecturers, who have taught us for more than 4 years, and to the cooperation of Vietnam
Forestry University and Colorado State University, especially, the faculty of Forest Resource
and Environmental Management. I would like to extend my gratefulness to Mr.Sam Van
Thiet, the Chairman of Chau Hanh People’s Committe for accepting my research in Chau
Hanh commune.
And, I would like to express my gratefulness to Mr. Dang Manh Hung, the Head of
Quy Chau Hydrology Station, Department of Natural Resources and Environment, Nghe An
Province, Vietnam for providing information and documents.
Last but not least, I wish to thank Dr Bui Van Nang and Ms Nguyen Thi Ngoc Bich of
the Center of Laboratory and Practice of Vietnam Forestry University for providing me with
the measure instruments and helping me measure the indicators to complete my thesis.
Xuan Mai, 12th September, 2016
Student
Tran Thanh Quang

1


TABLE OF CONTENTS
ABSTRACT ................................................................................................................................ 1
1. INTRODUCTION .................................................................................................................. 2
2. RESEARCH OVERVIEW ..................................................................................................... 3
2.1. Water quality indicators....................................................................................................... 3
2.2. Literature reviews ................................................................................................................ 4
3. STUDY AREA ....................................................................................................................... 6

3.1. Natural conditions ............................................................................................................... 6
3.1.1. Geographic location ........................................................................................................ 6
3.1.2. Topography ..................................................................................................................... 6
3.1.3. Climate ............................................................................................................................ 7
3.2. Socio-Economic Conditions ................................................................................................ 7
3.2.1. Economic characteristics ................................................................................................ 7
3.2.2. Demographic characteristics ........................................................................................... 8
4. GOALS AND OBJECTIVES ................................................................................................. 9
4.1. Goal: .................................................................................................................................... 9
4.2. Specific objectives: .............................................................................................................. 9
5. METHODS ........................................................................................................................... 10
5.1. Data sources: ..................................................................................................................... 10
5.2. Data collection method:..................................................................................................... 10
5.2.1. Water sampling: ............................................................................................................ 10
5.2.2. Analysis of water samples collected: ............................................................................ 13
5.2.3. Interviewing: ................................................................................................................. 16
5.3. Data analysis method: ....................................................................................................... 16
6. RESULTS AND DISCUSSION. .......................................................................................... 17
6.1. Flow characteristics of Hieu river in study area. ............................................................... 17

2


6.2. Water quality ..................................................................................................................... 18
6.2.1. pH

............................................................................................................................ 20

6.2.2. Dissolved oxygen (DO) ................................................................................................ 20
6.3. Economic activities of study area in Hieu River. .............................................................. 23

6.3.1. Agriculture and forestry ................................................................................................ 24
6.3.2. Industry ......................................................................................................................... 24
6.3.3. Trade and services ........................................................................................................ 25
6.4. Efects of land use on water quality.................................................................................... 26
6.5. Solutions to improve water quality and sustainable water use in the study area .............. 29
6.5.1. Policy solution .............................................................................................................. 29
6.5.2. Solutions on land use and land planning ...................................................................... 29
6.5.3. Technical solution ......................................................................................................... 30
7. CONCLUSION ..................................................................................................................... 31
8. REFERENCES

3


LIST OF TABLE
Table 5.1. Sampling position: ................................................................................................... 11
Table 5.2. Limit values for surface water quality parameters – Follow QCVN 08:
2015/BTNMT ........................................................................................................................... 12
Table 5.3. Interviewing information on economic activities on Hieu River in Chau Hanh
commune: ................................................................................................................................. 16
Table 6.1. Some water indicator of Hieu river in Chau Hanh commune from the year 2008 to
2015: ......................................................................................................................................... 17
Table 6.2. Analysis indicator of Hieu river in Chau Hanh commune: ..................................... 19
Table 6.3. Characteristics of sample location ........................................................................... 27
Table 6.4. Analysis of water indicators and sampling locations .............................................. 27

4


LIST OF FIGURE

Figure 3.1. Position of Chau Hanh commune ............................................................................ 6
Figure 5.1. Sampling positions ................................................................................................. 11
Figure 6.1.The analytical result of temperature from the year 2008 to 2015 ........................... 17
Figure 6.2.The analytical result of average discharge from the year 2008 to 2015 ................. 18
Figure 6.3.The analytical result of suspended solids from the year 2008 to 2015 ................... 18
Figure 6.4. The analytical result of DO .................................................................................... 20
Figure 6.5. The analytical result of TDS .................................................................................. 21
Figure 6.6. The analytical result of TSS ................................................................................... 21
Figure 6.7. The analytical result of BOD5 ................................................................................ 22
Figure 6.8. The analytical result of COD ................................................................................. 22
Figure 6.9. Map of plant cover in study area ............................................................................ 23
Figure 6.10. Analytical results of water indicators and sampling locations ............................. 28

5


ABSTRACT
It has been widely accepted that there is a close relationship between the economic
activities and water quality. There have been some researches on this relationship about the
economic activities and land use impact on water quality in recent years. This study aims to
analyze the influence of economic activities, especially the various land use types on the
water quality of Hieu River in Chau Hanh - a commune in mountainous areas of Vietnam
based on the water quality indicator data with the characteristics of riparian buffer. The results
indicated that there was significant correlation between land use in the riparian buffer and the
water pollution. The loss of plant cover is proportional to the increase in the level of water
pollution. The results can provide scientific reference for the local land use optimization and
water pollution control.

1



1. INTRODUCTION
Water is a necessary resource and most important in river basin. Although river water
makes up only about 0.2 percent of all the fresh water on Earth, it plays a very important role.
Rivers are like roads. They carry water, sediment, organisms and nutrients. They also help
drain rainwater and provide habitats for many species of plants and animals. Today, water
requirements more and more (both quality and quantity) but the amount of untreated waste
water increasing so resulting in many areas, water resource was seriously polluted [1].
Today in the world, hundreds of river catchment management organizations were
established to integrated management of water, soil and other related resources in the river
catchment to maximize the economic benefit and social welfare but without damaging the
sustainability of environmental system in the catchment, maintain the environmental
conditions for human life. [2].
Hieu river is one of the major rivers in Nghe An province. Hieu river watershed
located in the northwest of Nghe An province is a strategic location for economic
development and national security of the province. This is an important watershed in the Lam
river system with an area of 5417 km2 [3]. In recent years, the districts in Hieu river
catchment are increasing resources for economic development with high growth rate and
leading to the inconsequential use of water resource and create the risk of recession and water
pollution more and more serious. If no control and protect, in the near future, Hieu river will
become a “dead” river [4]. Therefore restoring the old situation of Hieu river and make
measure to manage and protect the Hieu river catchment in a sustainable way, ensuring
maximize economic benefit and social welfare but not harm the sustainability of
environmental systems in catchment is a currently urgent problem. Based on this basis, I
proceed to implement the thesis project: “Impacts of economic activities to the water quality
of Hieu river in Chau Hanh commune, Quy Chau district, Nghe An province”. The thesis
aim to assess the current situation of water quality and compare with landuse in Hieu river,
thereby propose solutions for sustainable economic development associated with environment
protection in study area.


2


2. RESEARCH OVERVIEW
2.1. Water quality indicators
Water quality management: Water quality can be thought of as a measure of the
suitability of water for a particular use based on selected physical, chemical, and biological
characteristics. The measurement of water quality properties includes:
- pH: The pH of water determines the solubility (amount that can be dissolved in the
water) and biological availability (amount that can be utilized by aquatic life) of chemical
constituents such as nutrients (phosphorus, nitrogen, and carbon) and heavy metals (lead,
copper, cadmium, etc.). Excessively high and low pH can be detrimental for the use of water.
Pollution can change a water's pH, which in turn can harm animals and plants living in the
water [5].
- Dissolved Oxygen (DO): DO can tell us a lot about water quality. The oxygen
dissolved in lakes, rivers, and oceans is crucial for the organisms living in it. As the amount of
dissolved oxygen drops below normal levels in water bodies, the water quality is harmed and
creatures begin to die off. Dissolved oxygen in surface water is used by all forms of aquatic
life; therefore, this constituent typically is measured to assess the "health" of lakes and
streams [5].
- Total Suspended Solid (TSS) and Total Dissolved Solid (TDS): environmental
water may contain a variety of solid or dissolved impurities. In considering waters for human
consumption or other uses, it is important to know the concentrations of both suspended and
dissolved solids. The most common pollutant in the world is “dirt” in the form of TSS [5].
- BOD: Biochemical Oxygen Demand (BOD) is a measure of the quantity of oxygen
used by microorganisms in the oxidation of organic matter. Many animals need high oxygen
amounts to survive. If the BOD is high, that means that microorganisms are using most of the
Oxygen. This situation makes it difficult for larger aquatic animals to survive. However, if the

3



BOD is low, there is an abundance of Oxygen which leads to good water quality. The BOD is an
important water quality factor that is directly related to the overall health of the water body [5].
- COD: Chemical oxygen demand (COD) is a measure of the capacity of water to
consume oxygen during the decomposition of organic matter and the oxidation of in-organic
chemicals. The chemical oxygen demand (COD) test is commonly used to indirectly measure
the amount of organic compounds in water. Applications of COD determine the amount of
organic pollutants found in surface water (e.g. lakes and rivers) or wastewater, making COD a
useful measure of water quality [5].
This study also focus on the riparian buffers. Riparian buffers can be an important
component to stream stability, pollutant removal, and maintaining stream health. Ensuring the
integrity of these features, and restoring previous buffers, can have a positive impact on water
quality [6].
2.2. Literature reviews
Research on River catchment in Vietnam was done quite early, especially the intensive
research in the fields of: meteorology - hydrology, geomorphology topography… create
foundation for water quality research in river catchment recently developed stronger.
Vietnam has a dense river network. River with a length of over 10km total about 2732,
comprising 13 large river systems with a total area of 10 000 km2. The 13 river basins, 10 of
which are trans-boundary systems, cover 80% of the country’s territory. Basins of the 9
largest river systems, which include Red, Thai Binh, Bang Giang – Ky Cung, Ma, Ca, Thu
Bon, Ba, Dong Nai and Cuu Long, account for 90% of the total river basins nationwide. Each
river basin has typical natural resources characteristics as well as water resources. In practice,
management approaches vary from one basin to another, which has a close linkage depending
on socio-economic conditions, land use situation, environmental factors … [8].
Water quality is affected by nature factors as well as human. Human impacts on water
resource not only changes the amount of water, but also alter the water balance components,

4



hydrological regime of water and especially changing its quality. It was explained that the
majority of rivers and lakes in Vietnam is also the source of water supply and receiving public
sewage, industry and agriculture. The main types of economic activity that create largest
influence on the change of quantity and quality of water resources are: demand for water for
industrial and public needs, sewage dump, urbanization, building of reservoirs, irrigation and
flood the dry land, the activities of agricultural and forestry production ... [7].

5


3. STUDY AREA
Hieu river located in the northwest of Nghe An province is a major tributary of the Ca
river system. With an area of 5417 km2, Hieu river accounted 20% of the Ca river basin [3].
Thesis was conducted at Chau Hanh Commune, Quy Chau District, Nghe An Province. Chau
Hanh has an area of 129.6 km2 belong to upstream of Hieu river. The total length of Hieu
river in Chau Hanh commune is 12km.

Figure 3.1. Position of Chau Hanh commune
3.1. Natural conditions
3.1.1. Geographic location
From 190 27 'to 190 39' north latitude.
From 1050 01 'to 1050 09' east longitude.
Total natural area: 12684ha
3.1.2. Topography

6



Terrain in Chau Hanh commune is strongly divided by hills and streams. Chau Hanh
locality has eight different large and small streams, all of which streams are derive from the
high mountain, with large slope. Ke Ninh stream in the north flows to Hieu river from east to
west direction; Lan, Bong streams which derived from Bu xen mountain (583m) flows to
Hieu river in southwest - northeast direction; My and Minh Chau streams in the east derive
from Tung Ca mountain (625m) and Pu Nghin (435m).
3.1.3. Climate
Chau Hanh commune is located in North Central climate region and the western of
Nghe An. Common characteristics of climate in Chau Hanh commune is tropical monsoon,
hot and rainy. The hours of sunshine a year from 1580-1650 hours. The average annual
temperature of 240C – 280C; the average humidity from 80-86%. The rainy season starts from
August to October, the total rainfall every year from 1700 - 2000mm. The dry season from
November last year to March year after.
Chau Hanh annual influenced by two main wind seasons:
- Southeast wind season starts from October last year to April of next year.
Characteristics of this period the dry, it is easy to cause fire in the autumn – winter.
- Southeast wind season starts from April to June This is the season with hot weather
and heavy rain, high humidity and also season for local people to do shifting cultivation.
3.2. Socio-Economic Conditions
3.2.1. Economic characteristics
Economic structure of Chau Hanh commune mainly focus on agriculture and forestry
(85% of total proportion):
- Agricultural:
 Farming: the total cultivation area is 900ha, of which: The area of paddy rice (2
seasons): 510 hectares; Corn planted area: 130 hectares; sweet potato, cassava planted area:

7


60 ha; Peanut Area: 15ha; vegetables, legumes, cattle feed crops area: 50ha and 135ha of

sugarcane.
 Livestock: the commune has 7029 head of cattle, including: 2853 Buffalo; 1076 Cow:
and 3100 Pig. In addition, the commune has 27000 poultries and 12.5ha of aquaculture area.
- Forestry:
Chau Hanh commune has 11428.8 ha of forest land, accounting for 90.1% of
commune’s area, in which 5207.8 ha of production forest land, account nearly 50% of total
forest land in the commune. 4191 ha of production forest area is belong to family and
personal management.
- Industrial and others:
Industrial production in Chau Hanh commune closely related to the availability of raw
material in the area, which has the jobs: construction materials extraction, typically sand
mining and building stone; woodworking, carpentry…
Current service economy not yet developed much, mainly focus on transportation;
hotels and restaurants services.
3.2.2. Demographic characteristics
Total village: 18 villages.
Total demographic: 9306 people.
Total households: 2105 households, including poor households (according to new
criteria) are: 931 households (44%), 309 near- poor households (15%).
The rate of natural population growth each year: 1.25% / year.
Ethnic composition: residents in the Chau Hanh commune mainly composed of three
ethnic groups: Thai, Kinh, Tho. Where Thai ethnic percentages over 80%.
(Source: People's Committee of Chau Hanh commune)

8


4. GOALS AND OBJECTIVES
4.1. Goal:
Propose solutions for environmental protection of the Hieu river watershed in Chau

Hanh commune, Quy Chau district, Nghe An province.
4.2. Specific objectives:
Objective 1: Assess the situation of water quality in the Hieu river in Chau Hanh
commune, Quy Chau district, Nghe An province.
Objective 2: Assess the impacts of economic activities to the changing in water quality
of the Hieu river in Chau Hanh commune, Quy Chau district, Nghe An province.
Objective 3: Propose possible solutions for sustainable watershed management in
study area.

9


5. METHODS
5.1. Data sources:
To achieve the objectives, the thesis investigated the information on Chau Hanh commune to
support for assessing water quality. The information collected includes:
-

Documents, survey data from People's Committee of Chau Hanh commune on natural
conditions, socio-economic of the study area and the related reference.

-

Data on the natural environment such as forest area, water quality, land use, annual data
about the characteristics of Hieu river from Quy Chau hydrology station.

-

Collect relevant documents, policies, management and protection of forest resources and
water quality in the study area, the report on forest planning.


5.2. Data collection method:
5.2.1. Water sampling:
a. Sampling position:
The thesis took samples at 12 points in the stream.
All sample were taken at the:
- Depths: 30cm below the surface;
- Distance: 1m from the bank;
Time: 17th August, all samples were taken in 2 hours 8.00 am – 10.00 am;
Weather conditions: Rainy.

10


Table 5.1. Sampling position:

Sample

Coordinates
Latitude

Sampling location

Longitude

1

19°33'20.63"N

105° 3'29.15"E


2

19°33'56.57"N

105° 3'52.91"E

3

19°33'39.51"N

105° 4'13.71"E

4

19°33'22.87"N

105° 4'45.41"E

5

19°33'25.56"N

105° 5'16.01"E

6

19°33'36.30"N

105° 5'37.94"E


7

19°33'11.03"N

105° 5'52.71"E

8

19°33'13.86"N

105° 6'25.87"E

9

19°33'29.35"N

105° 7'2.80"E

10

19°33'54.33"N

105° 6'59.43"E

11

19°33'36.91"N

105° 7'18.48"E


12

19°33'33.71"N

105° 7'53.38"E

Before flow into the commune

After flow into the commune

Figure 5.1. Sampling positions
b. Tools and sampling methods:
Tools and methods used for sampling follows the standards:

11


1. TCVN 6663-1:2011 (ISO 5667-2: 2006) – Water quality- Sampling. Part 1: sampling
guides and techniques [13].
2. TCVN 6663-3:2008 (ISO 5667-3:2003) – Water quality- Sampling. Guidelines of sample
preserving and processing [14].
3. TCVN 6663-6:2008 (ISO 5667-6:2005) – Water quality - Sampling. Sampling guidelines
on rivers and streams [15].
Table 5.2. Limit values for surface water quality parameters – Follow QCVN 08:
2015/BTNMT
Limited value
No

Indicator


Unit

A

B

A1

A2

B1

B2

1

pH

-

6- 8.5

6- 8.5

5.5- 9

5.5- 9

2


DO

mg/L

≥6

≥5

≥4

≥2

3

TSS

mg/L

20

30

50

100

4

BOD5


mg/L

4

6

15

25

5

COD

mg/L

10

15

30

50

In which:
A1 - Good for domestic water and other purposes such as type A2, B1 and B2.
A2 - For the purpose of domestic water, but must apply appropriate treatment technologies;
conservation of aquatic flora and fauna, or using purpose as B1 and B2.
B1 - For irrigation purposes or other similar purposes as type B2.

B2 – Use for traffic other purposes with low water quality requirements.
-

Sampling instruments:

Clean bottle 500ml capacity. While sampling should clean the bottle and sampling at any
location have to rinse 3 times with water at that location. Additionally, when conducting
sampling, it is required to prepare tapes, markers, paper label cockroaches, sealed barrel
sponge…

12


-

Preserving and transporting of samples:
All water samples in bottles have to cool about 4oC and transport to the laboratory,

separate target pH, temperature and TDS measured directly in place. Make cold and put in the
dark place, most of the samples usually durable to 24 hours.
5.2.2. Analysis of water samples collected:
1. Temperature measurement:
Used a thermometer directly at the sampling location and record the results.
2.

PH measurement:

Follow the standard TCVN 6492: 2011 – Water quality – Determination of pH. PH was
measured by pH-meter to determine the pH of water.
3.


Dissolved Oxygen (DO) measurement:

Follow TCVN 7325:2004 (ISO 5814:1990) Water quality – Determination of dissolved
oxygen. Electrochemical probe method.
Use Electrochemical sensor to analysis dissolved oxygen.
4. Total Suspended Solid (TSS) measurement:
Follow TCVN 6625:2008 -Water quality- Determination suspended solids by filtration
through glass-fibre filters.
Used vacuum filter machine or pressure machine to filtering water samples through
glass fiber filter. Drying at 1050C and determine the sediment by scale.
Process:
Preparation of the glass fiber filter disk: Insert the filter disk onto the base and clamp
on funnel. While vacuum is applied, wash the disk with three successive 20 ml volumes of
reagent water. Remove all traces of water by continuing to apply vacuum after water has
passed through. Dry in an oven at 1030C -1050C for one hour in aluminum dish. When
needed, remove dish from the oven, desiccate, and weigh in dish.
Re-dry and re-weigh filter until weight change is less than 0.5 mg.

13


Select a sample volume (max. of 200 ml) that will yield no more than 200 mg of total
suspended solids.
Place the filter on the base and clamp on funnel and apply vacuum. Wet the filter with
a small volume of reagent water to seal the filter against the base.
Stir sample continuously while sub-sampling and quantitatively transfer the sample to
the filter using a 100 ml graduated cylinder. Remove all traces of water by continuing to apply
vacuum after sample has passed through.
Rinse the graduated cylinder onto the filter. Remove all traces of water by continuing

to apply vacuum after water has passed through.
Carefully remove the filter from the base. Dry at least one hour at 1030C -1050C. Cool
in a desiccator and weigh.
Re-dry and re-weigh filter until weight change is less than 0.5 mg.
Calculate Total Suspended Solids as follows:
(

)

In which:
A = weight of filter and dish + residue in mg
B = weight of filter and dish in mg
C = volume of sample filtered in ml
5. Total Dissolved Solid (TDS) measurement:
Use TDS measuring instrument to measure the amount of dissolved solid directly at
the sample positions.

14


6. Biological Oxygen Demand (BOD) measurement:
The samples analyzed were considered are very high levels of BOD5, they are diluted
to the appropriate factor before analysis. Water used to dilute the oxygen was bubbled to
saturation and the nutrients necessary.
After diluting the sample, measuring the value of DO0 at 200C then incubated in a
BOD dedicated pocket at 200C in 5 days. Re-measure the value of DO5 after incubating we
calculated the value of BOD5 (mg / L). BOD5 value is the value obtained after subtracting the
values of BOD5 in the blank sample.
BOD5= (DO0- DO5).f
In which:

BOD5: BOD values after 5 days (mg/L)
DO0: DO values at 200C after diluting (mg/L)
DO5: DO values at 200C after 5 days incubating at 200C (mg/L)
F: dilution factor
7. Chemical Oxygen Demand (COD) measurement:
TCVN 6491:1999 (ISO 6060:1989)-Water quality- Determination of Chemical
Oxygen Demand. Most types of organic matter are oxidized by a boiling mixture of chromic
and sulfuric acids. A sample is refluxed in strongly acid solution with a known excess of
potassium dichromate (K2Cr2O7). After digestion, the remaining unreduced K2Cr2O7 is
titrated with ferrous ammonium sulfate to determine the amount of K2Cr2O7 consumed and
the oxidizable matter is calculated in terms of oxygen equivalent. Keep ratios of reagent
weights, volumes, and strengths constant when sample volumes other than 50 ml are used.
The standard 2-h reflux time may be reduced if it has been shown that a shorter period yields
the same results. Some samples with very low COD or with highly heterogeneous solids
content may need to be analyzed in replicate to yield the most reliable data. Results are further

15


enhanced by re-acting a maximum quantity of dichromate, provided that some residual
dichromate remains.
5.2.3. Interviewing:
Directly interview 30 people, mainly focus on:
People who has farmland near the riverbanks, question designed about:
-

Do they use river water as domestic water?

-


Type of farming (plantation forest, rice, maize…)

-

Their cultivation methods (Do they burn the forest? Do they use plant protection
products?)

Interview people who have jobs or economic activities, who concern about the river
(boatman, meteorological station staff…) about their comments about the changes, evolutions
of the river.
Table 5.3. Interviewing information on economic activities on Hieu River in Chau Hanh
commune:
Name

Address

Type of farming

Area of farm land

Cultivation methods

Nguyen Van A
Nguyen Van B
…

5.3. Data analysis method:
Statistical table about the water quality properties which measured and data table of
interviewing result.
Analyze and evaluate the data obtained, compare with the published documents.

Comparison of changes in water quality before and after going through the study area.
Analyze data by Excel software.

16


6. RESULTS AND DISCUSSION.
6.1.Flow characteristics of Hieu river in study area.
Data on the characteristics of temperature; discharge and suspended load were
recorded by Quy Chau hydrology station. Data are presented in the following table:
Table 6.1. Some water indicator of Hieu river in Chau Hanh commune from the year
2008 to 2015:

Year

Temperature
(0C)

2008

Average

Total

Average
Discharge (m3/s)

Suspended
solids (mg/L)


Discharge
(m3)

Suspended
load (tons)

24.3

92.0

264

2.91 x109

0.768 x106

2009

25.5

88.2

235

2.78 x109

0.653 x106

2010


26.0

58.8

182

1.85 x109

0.335 x106

2011

24.0

94.6

217

2.98 x109

0.647 x106

2012

25.4

80.3

286


2.54 x109

0.843 x106

2013

25.1

73.4

207

2.31 x109

0.478 x106

2014

25.2

62.2

136

1.96 x109

0.267 x106

2015


26.1

45.8

123

1.44 x109

0.178 x106

Data Source: Quy Chau hydrology stations
Statistical results from Quy Chau hydrology station show that: flow characteristics of Hieu
river changes every year. In which:
Temperature of water in Hieu river from the year 2008 to 2015 tended to increase:

Temperature
27

25

26,1

26
25,5

26

Temperature ( )

-


25,4

24,3

25,1

25,2

24

24
23
Temperature

22
21

Linear
(Temperature)

20
2008

2009

2010

2011


2012

2013

2014

2015

Year

Figure 6.1.The analytical result of temperature from the year 2008 to 2015

17


-

Average flow discharge and the suspended solids changes in the same direction and
tended to decrease:

Average discharge
100

92

94,6
88,2

Average discharge (m3/s)


90

80,3
73,4

80
70

62,2

58,8

60

45,8

50
40

Average
discharge

30
20
10
0
2008

2009


2010

2011

2012

2013

2014

2015

Linear
(Average
discharge)

Axis Title

Figure 6.2.The analytical result of average discharge from the year 2008 to 2015

Suspended solids

Suspended solids (mg/L)

350
300

286
264
235


250

217

207

182

200

136

150

123

Suspended
solids

100
Linear
(Suspended
solids)

50
0
2008

2009


2010

2011

2012

2013

2014

2015

Year

Figure 6.3.The analytical result of suspended solids from the year 2008 to 2015
6.2.Water quality
The thesis took samples at 12 points in the stream.
Data are presented in the following table:

18


Table 6.2. Analysis indicator of Hieu river in Chau Hanh commune:
QCVN 08-MT:
Sample

Indica
No


Avera
2015/BTNMT

Unit
tor

ge
1

2

3

4

5

6

7

8

9

10

11

12


A1

A2

B1

B2

1

Temp

0

27.2

27.5

27.2

27.8

27.5

27.3

27.2

27.2


27.5

27.5

27.3

27.2

27.4

-

-

-

-

2

pH

-

7.2

6.7

7.2


6.8

7.3

7.0

7.5

7.7

7.8

6.8

7.1

7.3

7.2

6- 8.5

6- 8.5

5.5- 9

5.5- 9

3


DO

mg/L

5.62

5.20

5.49

5.44

5.60

5.21

4.99

5.62

5.60

4.85

4.91

4.99

5.31


≥6

≥5

≥4

≥2

4

TDS

mg/L

19.1

20.0

19.8

20.2

19.2

20.5

20.5

20.0


20.8

21.2

21.5

21.2

20.3

-

-

-

-

5

TSS

mg/L

713

779

731


831

755

805

765

740

723

874

860

895

789

20

30

50

100

6


BOD5

mg/L

31.1

29.2

31.9

33.2

30.5

34.4

35.1

33.8

34.3

34.7

38.8

35.5

33.5


4

6

15

25

7

COD

mg/L

105

112

109

131

97

112

109

110


117

143

121

135

118

10

15

30

50

C

Time: 17th August, all samples were taken in 2 hours 8.00 am – 10.00 am;
Weather conditions: Rainy

19


Analysis of each indicator:
6.2.1. pH
pH parameter of Hieu river water in Chau Hanh commune ranged from 6.7 to 7.8,

averaging about 7.2, satisfy with required quality of surface water for domestic purpose.
6.2.2. Dissolved oxygen (DO)
Measured values of DO in study area are shown in the following graph:

Dissloved Oxygen
7
6

5,69

5,62
5,2

5,44 5,6

5,21

5,62 5,6
4,99

4,85 4,91 4,99

DO (mg/L)

5
4
3
2
1
0

1

2

3

4

5

6

7

8

9

10

11

12

DO
A1 - QCVN
A2 - QCVN
B1 - QCVN
Linear (DO)


Sample

Figure 6.4. The analytical result of DO
The result show that: on average, DO value of Hieu river water in study area is satisfy
with the A2 standard (water quality for domestic purpose). However, after flow into Chau
Hanh commune, DO value tend to decrease from 5.62 mg/L to 4.99 mg/L.
6.2.3. Total dissolved solids (TDS)
Measured values of TDS in study area are shown in the following graph:

20