water quality zoning for the river basins

water quality zoning for the river basins

CAFEO 28, 2010

WATER QUALITY ZONING FOR THE RIVER BASINS IN HANOI AND HO CHI MINH CITIES BASED ON WATER QUALITY INDEXES (WQIs)

Le Trinh, Duong Thai Binh, Nguyen The Loc, Le Quoc Hung Vietnam Environment and Sustainable Development Institute (VESDEC) TÓM TẮT TIẾNG VIỆT:

Phân vùng chất lượng nước đóng vai trò rất quan trọng trong quản lý môi trường lưu vực

đầu nguồn và kiểm soát ô nhiễm nước Bài báo tóm lược nội dung phương pháp và kết quả thu được từ các đề tài "Nghiên cứu phân vùng chất lượng nước các sông, hồ trên địa bàn các thành phố Hồ Chí Minh và Hà Nội , đề xuất các giải pháp sử dụng hợp lý và bảo vệ " do Lê Trình và các CTV Viện Môi trường và Phát triển Bền vững thực hiện trong các năm 2007-2010

Dựa trên: (i) 10 lựa chọn các thông số đặc trưng điển hình cho chất lượng nước của sông

và hồ tại Hà Nội (và TP Hồ Chí Minh); (ii) các kết quả phân tích, quan trắc chất lượng nước (iii) các mô hình tính chỉ số chất lượng nước thiết lập cho riêng cho vùng TP Hà Nội và TP Hồ Chí Minh đã được phân loại chất lượng nước qua 50 điểm quan trắc trên các con sông chính ở

Hà Nội (sông Hồng, Cầu, Đuống, Nhuệ, Cà Lồ, Tô Lịch) và các hồ chính (Hồ Tây, Hoàn Kiếm, Bảy Mẫu, Trúc Bạch, Ba Mẫu, ) và 50 điểm quan trắc ở TP Hồ Chí Minh trên các sông Sài Gòn, Đồng Nai, Nhà Bè, Soài Rạp, Lòng Tàu, Cần Giuộc, Chợ Đệm, các kênh rạch 5 mức phân loại chất lượng nước ở tất cả các sông, kênh rạch, hồ đã được xác định: Loại I (very clean - ô nhiễm rất nhẹ); loại II (tốt, ô nhiễm nhẹ); loại III (trung bình, ô nhiễm trung bình); loại IV (ô nhiễm nặng) loại V (ô nhiễm rất nặng) Kết hợp kết quả của việc phân loại chất lượng nước tại các điểm quan trắc và kết quả của phương pháp đo chất lượng nước liên tục từ thượng nguồn đến hạ lưu các con sông, hồ đề tài đã triển khai thực hiện việc phân vùng chất lượng nước cho mạng lưới sông, hồ của TP Hồ Chí Minh (2007-2008) và TP Hà Nội (2008-2010) Từ những kết quả thu được của việc phân vùng chất lượng nước, các đề tài nghiên cứu này đã đề xuất các biện pháp khác nhau để sử dụng nước và kiểm soát ô nhiễm ở các luu vực sông tại hai TP này

1 INTRODUCTION

1.1 Necessity of Water Quality Zoning

Water quality zoning (zoning by quality and pollution of water sources) for a basin or a locality is extremely important not only for environmental management but also planning for use and protection of the water environment

In 2008, the Ministry of Resources and Environment (MORE) issued the National Technical Standard of Surface Water (QCVN 08:2008/BTNMT)[1] Accordingly, surface water is classified in 4 grades:

- Grade A1: for domestic water supply and for the same purposes as grades A2, B1 and B2 Grade A2: for domestic water supply with appropriate treatment technologies; for preservation of aquatic flora , and for the same purposes as grades B1 and B2

- Grade B1: For watering and irrigation or other uses that have the same requirements of water quality as grade B2

- Grade B2: for waterway and other uses that need only water of poor quality The determination that a basin or a river section in a province is of which grade, A1, B1 or A2, B2, is the responsibility of the People Committee (PC) of that province/city (from viewpoints of water use planning) The scientific and practical

background for water quality classification and zoning under QCVN 08 – 2008/BTNMT necessitate the application of a classification system based on water

quality index (WQI) in accord with characteristics of water resources in that locality or

basin

With a good zoning in hand, policy makers, governmental agencies, sectors and companies and the community can clearly determine:

- Which zones (or sections) in the river basin meeting requirements of water quality to be used for domestic water supply (water intaken for waterworks)?

- Which zones (or sections of the rivers) meeting requirement of water quality for safe and profitable aquaculture

- Which zones (or sections of the rivers) can supply safe and good water for irrigation?

- Which zones are suitable for building up qualified facilities of water sports and tourism.tourism?

- Which zones cannot be used for the purposes above and priority should be given to pollution treatment and control

In addition to adorning the landscape and the culture of Hanoi and Ho Chi Minh City, their systems of rivers, lakes and lagoons have a very important role to play in domestic water supply, irrigation, aquaculture, climate conditioning, receiving and ababolismassimilation of waste matters, and transport Nevertheless, as a result of speedy growth of population, urbanization and industrialization, water quality of rivers and lakes in these two big cities of Vietnam has and will deteriorate quickly

That circumstance urges the assessment of pollution on every river section, every lake or lagoon for proper surface water use zoning, orientation and protection of the water environment and that in turn is an incentive for studies on water quality zoning for Hanoi and Ho Chi Minh City Two projects with the similar title “Study on

water quality zoning for the rivers, canals and lakes, proposal of measures for reasonable use and protection” decided by the authorities of the cities of Ho Chi Minh and Hanoi

were implemented by Le Trinh and his colleguages in the Vietnam Environment and Sustainable Development Institute (now, the Vietnam Institute for Environmental Science and Development – VESDEC) in a durationof 2007-2010As presider [2,3]

1.2 Water Quality Model

Water environment assessment neeedsneeds a system of indexes for quantification and comprehensive description of various chemical, physical and biological components of a water source as well as the significance of every parameter

for a specific use One of those indexes is Water Quality Index (WQI) WQI is an

index computed from specific water quality parameters with a predetermined method (or mathematical formula)

The WQI model was recommended and applied the first time in the USA in

1965 – 1970 and1970 and now, it is applied widely in many states [4-6] Various WQI models have been studied and applied in many nations such as India, Canada, Chile, England, Wales, Taiwan, Australia and MalayxiaMalaysia WQI is considerdconsidered

an effective tool for environmental managers in water quality monitoring, water source management, environmental protection efficiency evaluation, water pollution control, and for communtiescommunities and policy-makers to obtain information of water pollution, etc WQI is also convenient for application of information technology in water quality management and mapping

In vietnaVietnam, WQI systems were modeled by Nguyen Van Hop (Hue University [7-8] based on the Bhavarva model (India) for applying to rivers in Quangtri, Thuathienhue (2005) Le Trinh has developed the WQI models of the NSF (USA) and Bhargava (India) for water quality zoning of rivers and canals in Ho Chi Minh City (2008) [2] and Cantho (2009) [9] Those results are valuable in water quality assessment and classification as well as pollution zoning of basins for water use planning and pollution control planning

1.3 Study area and contents of water quality zoning of Hanoi City

1.3.1 Study area

The study site is consisted of all rivers flowing over the (former) Hanoi City, i.e the Red, Duong, Cau, Calo, Nhue, Tolich – Kimnguu, - Lu and large lakes in the urban area and suburbs

13.2 Study contents

For accurate water quality zoning of Hanoi City, the project has developed the contents as follows:

- Assessment of the existing conditions and prediction of the changes in pollution levels of rivers and lakes in accordance with the development plan of Hanoi City

- Additional investigation and analyses of water pollution at 50 sites, together with measurements of water quality changes along the rivers of 300 km in total in two points of time, the rainy season (2008) and the dry season (2009)

- Selection of typical water quality parameters of Hanoi (10 selected parameters)

- Research to establish two WQI models suitable for the rivers and lakes in Hanoi: the WQI – HN1 model simulating the NSF (USA) method and the WQI – HN2 model similatingsimulating the India method

- Water quality zoning of rivers and lakes based on the obtained models and analytical data of water quality

- Preparation of digital water quality zoning maps

- Study and proposal of water use options for every river section and lake in Hanoi

- Study and proposal of measures for pollution control and water protection of rivers and lakes in Hanoi

2 OUTPUTS

2.1 WQI – HN1 model

The formula of WQI – HN1 can be expressed in two forms:

- Weighed sum:

WQI A – HN1 = ∑n qi wi

1

.

- Weighed product:

WQI M – HN1 = ∏n qi wi

1

Based on expertise, the project has seletedselected 10 parameters to put in the computation model as follows:

1 BOD 6 Suspended solid

3 T Coliform 8 Turbidity

5 Total N 10 Grease and oil

2.2 WQI – HN2 model

In order to build up the WQI – HN2 model suitable for rivers and lakes in

Hanoi city, the project has researched and developed the original model of Bhargava

[5] Accordingly, the computation of WQI for rivers and lakes at first requires

identifying:

(i) Water uses

(ii) Water quality parameters selected to accompany those uses

(iii) Sensitive function (Fi) corresponding to the paramatersparameters selected

(iv) WQI – HN2 is computed with formula:

1/n n

i i=1 WQI = ⎡ F⎤ x 100

⎣∏ ⎦ Where Fi:

- Value of the sensitive function of parameter i, in the range of 0.01 ÷ 1

- Fi is found from the sensitive function of parameter i

- n: number of selected parameters of water quality (n = 3 ÷ 5, depdendingdepending on water use)

k

i i=1

WQI WQI =

k

∑

(1)

In the computation of the general WQITQ – HN2 (water quality index for

multi-uses), it is accepted that the importance of all water uses is the same and thus the

coefficients of WQIi – HN2 for every water use in formula (1) is equal to 1 The

parameters selected based on expertise are shown in Table 1:

Table 1: Water quality parameters selected for specific uses, applicable to rivers

and lakes in Hanoi City

1 Direct contact DO, TSS, BOD5, grease and oil,

WQI – HN2

WQI i – HN2

WQI TQ – HN2

2 Domestic water supply TSS, BOD5, grease and oil, DO, Fe,

3 Aquatic organisms protection TSS, BOD5, NH4

+

, grease and oil,

4 Aquaculture DO, NH4+, grease and oil, pH 4

Note: n is the number of selected water quality parameters, n can be adjusted depending on the existing water quality of the studied rivers or lakes

2.3 Results

Through studies into the contents mentioned above, the project obtained main outputs

1 Located on both banks of the Red River, Hanoi enjoys an abundant and diverse system of rivers and lakes that are resulted for various factors such as topography, geology, climate, history and culture Their water quality of those rivers are strongly affected by natural factors as hydrological regime, topographic and geological characteristics, biological resources and water uses in the Red River basin Particularly, the water quality of rivers and lakes in Hanoi suffers perceptible impacts

of pollution due to domestic activities, industries, agriculture, irrigation, fishing and aquaculture, which are causative of significant temporal and spatial changes in pollution

2 At present, rivers and lakes in Hanoi receive millions cubic meters of wastewaters from industries, urban areas, agriculture fields and aquaculture zones According to an estimate by the project, the flow rate of sanitary wastewater in the former Hanoi will increase from 440,934 m3 per day at present to 529,050to 529,050

m3 per day in 2015in 2015 and 600,589 m3 per day in 2020 Considering the predicted wastewater flow rates and pollution loads, it is possible to indicate that in the future, the risk of water pollution in rivers and lakes in Hanoi will not decrease; in opposite, it will increase quickly, particularlparticularly the pollution due to industrial and urban wastes That is an emergency warning for activities of water quality protection and recovery in Hanoi city towards supply of safe water for living, aquaculture, tourism and agriculture

3 By means of measurements and continuous analyses of water quality along the rivers and lakes and in combination with analytical data obtained in two seasons in

2008 and 2009 at 50 representative monitoring sites, the project has clearly positioned the distribution of water zones polluted by organic matters, nutrients, grease and oil and bacteria Digital maps showing the profile of those pollutants have been prepared The curves showing the variations of dissolve oxygen (DO, representing organic pollution) and other pollutants (turbidity, pH, electric conductivity) along the Red,

Duong, Nhue, the Cau the Calo Rivers, and the West Lake have been established Those are valuable documents for evaluation of water quality changes at present and in the future, for environmental management, pollution warning and information for water use

4 By the selection of 10 typical parameters (DO, BOD, TSS, T Coliform, pH, total N, turbidity, grease and oil, Fe, total P) based on expertise from many entities and experts, and by the improvement of water quality index (WQI) models of the NSF and Bharava, the project has also set up a WQI model suitable for the water environment

of Hanoi (WQIA – HN1, WQIM – HN1, WQI – HN2)

5 Based on analytical data of water quality at 50 monitoring sites, the values of WQI at each point on the main rivers and lakes have been computed The quality of water at each point has been classified based on the point scale of WQI – HN The results obtained from the WQI – HN model show that:

- No site in the river basin in Hanoi meets Grade I (very clean , equivalent to A1 in QCVN 08:2008/BTNMT)

- A major part of points on the Red River meet Grade II (good, light-polluted, equivalent to A2 in QCVN 08:2008/BTNMT)

Some sites on the section of the Red River that flows over the urban area only meet Grade III (equivalent to B1 in QCVN 08:2008/BTNMT)

The monitoring sites on the Duong and the Cau meet Grade II in the rainy season but Grade III in the dry season

The monitoringsites on the Calo River only meet Grade III (medium, medium-polluted)

Water of the upper reaches of the Nhue River is of good quality, meeting Grade

II, but when the river flows over Conhue commune, its water quality is deteriorated, meeting only Grades III – IV (poor, heavy-polluted), and the pollution becomes serious in the section from Hadong district to the lower section, meeting only Grade V (very poor, serious-polluted)

All river sections (Tolich, Kimnguu, Lu rivers) in the urban area are heavy-polluted, meeting Grades IV – V only

All lakes fail to meet grades I and II, the most stable water quality is found at the West Lake, meeting Grade III, while heavily polluted lakes such as Yenso, Bamau and Baymau only meet grades IV – V

The results of water quality zoning for Hanoi City are indicated in some following maps

6 The results of WQI-based water quality classification are computed objectively with software and there can therefore be used as background for monitoring the water environment and evaluating water use and pollution treatment in the years to come

This is the first time the rivers and lakes in Hanoi and in the Northern Vietnam are classified by water quality with the internationally accredited WQI system

7 The WQI – HN2 model, established based on limits of QCVN 08:2008/BTNMT is also applicable The results of water quality classification with two models, namely WQI – HN1 and WQI – HN2 are consistent with some supplementary factors for each other in accurate and objective classification of the water environment in Hanoi city

8 Based on results of water quality zoning and in combination with site study opinions from questionnaires and national standards and national technical standards

of water quality, the project has also evaluated and proposed for water use in Hanoi Accordingly, the suitability (safety) for living water supply, aquaculture, tourism and irrigation for every river section is already evaluated The results reveal that water from some sections of the Red, the Duong, and the Cau can be used for waterworks, given it is treated satisfactory to standards of clean water Obviously, they can serve irrigation, fresh-water aquaculture and tourism Many sections of the Nhue River are heavily polluted and therefore cannot be used for the aforementioned purposes Water from the Duong River can be used for aquaculture and agriculture Except for the West Lake, urban rivers and lakes cannot be used for tourism (aquatic sports) and aquaculture

9 Based on the zoning, the project has studied and recommended some comprehensive solutions for water management and pollution treatment of rivers and lakes in Hanoi The solutions include: waste management at source; regulation on environmental zoning; application of appropriate measures to pollution control of

rivers and lakes; application of environmental standards and technical standards (TCVN/QCVN); water environment monitoring and water source management improvement

10 Pertaining to treatment of serious-polluted rivers and lakes (namely the Tolich, Kimnguu, Lu and urban lakes) the project has recommended the solutions such

as dredging, dilution, boosting the self-purification, etc The solutions will be studied

in details through the project

3 RECOMMENDATIONS

1 Basically, the outputs of the project have clarified the methodology of WQI-based water quality classification and zoning in accord with the conditions of rivers and lakes in Hanoi (inclusive of the expanded Hanoi City) The formulae for computing WQI are simple and easy to use Therefore, the outputs of the project should be widely applied by Hanoi City (Department of Resources and Environment, and related departments and agencies) and the General Department of Environment to monitoring and evaluation of water quality, water control and uses of rivers and lakes

in Hanoi, and extensively to the whole valley of the Red River (including the basins of the Cau and the Day - Nhue)

2 The results of water quality and pollution assessment based on the WQI –

HN model should be periodically and widely disseminated to people and leaders of the city, departments and sectors for proper use or treatment

4 WATER QUALITY ZONING FOR THE RIVERS AND CANALS IN HO CHI MINH CITY

In similar, the WQIs for the river basin in Ho Chi Minh City were set up by the authors of this paper Contents and results of the study are presented in reference [2]

REFERENCE

1 Ministry of Resources and Environment National Technical Standard of Surface Water Quality (QCVN 08:2008/BTNMT), 2008

2 Le Trinh, Nguyen The Loc et al., Water Quality Classification Based on WQIs and Water Quality Zoning for the Rivers and Canals in Ho Chi Minh, Research Report, prepared for the DOST, HCMC, 250 pp., August 2008

3 Le Trinh, Duong Thai Binh, Report on the Scientific Research “Study on Water Quality Zoning for Rivers and Lakes in Hanoi City, Proposal of Measures for Proper use and Protection”, prepared for Hanoi DOST, 210 pp., February 2010

4 NSF Consumer Information Water Quality Index, Washington, 2005

5 Wilkes University, Calculating NSF Quality Index, 2006

6 King Country, Water Quality Index for Streams and River, 2007

7 Nguyen Van Hop, Hoang Thai Long, Nguyen Hai Phong, Thuy Chau To, Use of Water Quality Indexes for Water Quality Classification and Zoning for the Huong River, Selected Works in the Second National Science and Technology Conference of Physical, Chemical and Biological Analysis, December 2005

8 Nguyen Van Hop, Thuy Chau To, Truong Quy Tung, WQI-Based Classification and Zoning of Water Quality for Three Main Rivers in Binhtri- Thien Region, Advanced in Natural Sciences, Vol 8, 2007

9 Nguyen The Loc, Le Trinh, Study to Establish a Water Quality Index (WQI) Model and its Application to Water Quality Zoning for Rivers and Canals in Cantho City, the National University in Ho Chi Minh, 2009