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Transcript of Socialist Republic of Vietnam The Study on Water Supply ... · PDF file SOCIALIST REPUBLIC OF...

  • SAIGON WATER CORPORATION (SAWACO) PEOPLE’S COMMITTEE OF HO CHI MINH CITY SOCIALIST REPUBLIC OF VIETNAM

    Socialist Republic of Vietnam

    The Study on Water Supply Improvement in Ho Chi Minh City

    Final Report

    Aug. 2013

    Japan International Cooperation Agency (JICA)

    Toyo Engineering Corporation Osaka Municipal Waterworks Bureau

    Panasonic Environmental Systems & Engineering Co., Ltd. Nihon Suido Consultants Co., Ltd. Pricewaterhousecoopers Co., Ltd.

    GE

    JR

    13-185

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    Abstract

    1. Summary of the Study The current situation of the water supply system of Ho Chi Minh City (hereinafter

    referred to as “HCMC”) is already lack of capacity to supply enough treated water to the customer. Furthermore, the demand of water will be increased with further economic growth, therefore HCMC shall face to the more challenges such as strengthening of water supply amount.

    The actual values of the water demand in HCMC is approximately 1.8 million m3 /day,

    nevertheless the capacity of water supply is, so to say “ insufficient”, only 1.55million m3/day and the coverage rate of water supply is only 85 percentages(as of September , 2010).

    In contrast, in Ho Chi Minh City, the water master Plan , that is comprised of various

    part such as new water source development , installation of new water supply related facilities, and replacement, etc., is created and approved reach a new establishment and the repair of the waterworks institution from riverhead development and get prime minister approval formally in 2012. Please input the sentence that I want to translate here. The input language is judged automatically.

    The water supply master plan seems to have much room to be improved. That is because

    it mentioned only the intake plan from the reservoir in the upstream of the river but not concretely. Furthermore, the upgrade plan of water distribution system is not only the very expensive investment, but also insufficient from the view point of water supply service level.

    For these water source development and upgrade of water distribution system,

    SAWACO requested 3 themes (New Water source Development, Optimum Water Distribution System, and Technical Transfer) for the Japan Government. And the Team was commissioned to execute the study on creating optimum solutions by utilizing the water related Japanese technologies and experiences

    2. Results of Investigation

    The Study is performed as 3 parts as follows:

     Water Source Development

    The existing water supply master plan plans the extension of the water treatment plants to increase the capacity of water supply. But the Dong Nai River and Saigon River that is the existing water source of the water treatment plant, have problems such as salty water from the sea and the water pollution from the factory and house drainage.

    Therefore the process of the existing water treatment plant will have problem and need to be considered rapid countermeasures for both quantity and quality of the water.

    For these problems, the water supply master plan suggested to take water directly from

    the 2 reservoirs located in the most upstream of the 2 rivers to secure the good quality law water, but still these suggestions are considered in detail.

    Therefore, the team conducted the study on the solutions to take water from Tri An lake

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    and Dau Tieng lake and convey to the existing water treatment plant according to the following themes

     Possibilities of taking water  Location of intake points  The way of taking water  Conveyance route  Improvement plan

    a) Possibilities of taking water

    As for the hostilities of taking water, especially, the team confirmed the amount of water to be taken from 2 reservoirs, the quality of water for taking water, rights of water, and the development plan to effect on the water source development such as urban and industry development in the upperstream and irrigation in the downstream.

     The amount of water and its rights

    The Team also studied on the Tri An reservoir and Dau Tieng reservoir from the point of the amount of water and its rights

    First, as for Tri An reservoir, almost all of discharged water (475m3/s, average of the

    year) is used for power plant. Therefore, the team calculated the effect on the amount of producing power by the development of water source. As a result, if the plant will be operated as a best performance, we concluded the decrease of power production at 6 % maximum a year. Therefore, the water source development needs to be discussed with the power production relating authorities.

    On the other hand, as for the Dau Tieng reservoir, the discussion with the government

    owns the rights of water for agricultural use (Binh Phuoc, Tay Ninh, Binh Duong, and Long An province) is still important. But from the point of the water level, the amount of taking water (990,000m3/day nearly equal to 11.5 m3/s) effects on the fluctuation of the water level (HWL – LWL) and reduce the water level by approx. 0.4 to 0.9cm/day. But these effects are not so much and we concluded that the amount of water by the water source development can be taken.

     As for water quality

    The quality of Tri An reservoir was good to satisfied with QCVN08:2008/BTNMT(A2 type). Moreover, any development plan to effect on the quality of the reservoir water doesn’t exist in the near future.

    On the other hand, as for Dau Tieng reservoir, the some pollution caused by the organic

    materials can be seen and that makes irregular values of some water quality evaluation items insufficient for QCVN08:2008/BTNMT (A2type).

    b) Consideration of intake points

    As for the study on intake points, the survey of the topographic conditions and surrounding environment, boring and trial digging will be necessary to understand geographic conditions.

    As a result of evaluation from the point of possibilities of construction, connection of

    conveyance route, depth of intake level, and water quality, there is no necessity to select

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    special intake point, therefore, the team selected the intake points according to the relation of intake methods and and conveyance routes

    c) Method of taking water

    The amounts of taking water are planned as approx. 2,500,000m3/day for Thu Duc System, and approx. 1,000,000m3/day for Tan Hiep System, in 2025.

    By setting these values as target values, and based on some evaluating items such as

    satisfaction of demand, availabilities of water amount fluctuation, availability of maintenance, and securing intake water velocity, the team studied the following 3 approaches for installation of water intake facilities

    First, as for the “Curtain Wall System”, the space for construction, depending on the

    scale of amount of water, can be prepared for any candidate water intake points, and there is no limitation for the structure caused by the amount of water.

    On the other hand, the 2nd solution “Intake Tower and Conduit” and the 3rd solution “Conduit pipes System” need pipes to convey water to the downstream, therefore, will have some restrictions for structure as the amount of taking water increase.

    Furthermore, in the “Conduit pipes System”, the intake point has 2 measure defects such

    as located in the bottom of the lake, difficult for maintenance because of the depth of water level reaching to 15m in the rainy season

    Above all, there is no merit to adopt 3rd solutions, and the Team concluded “Curtain

    Wall System” and “Intake Tower and Conduit” are as promising results

    d) Conveyance Route As for the Study on conveyance routes, the Team designed and evaluated several routes

    considering the following elements:

     Consideration of shortest routes(minimization of construction costs and depression of water pressure)

     Consideration of gravity flow as much as possible  Consideration of the routes along the public facilities such as road, river….etc.  Utilization of existing facilities(intake facilities, and conveyance pipes)

    To evaluate designed conveyance routes, the Team execute the qualitative evaluation

    such as status of traffic, road, and household), quantitative evaluation (total length of pipes, river crossing, road crossing, rail crossing, the number of pump stations, estimated construction costs, and maintenance costs).

    In the course of the Study, the qualitative evaluation is changed into quantative evaluation and prioritized 1 or 2 solutions by evaluating estimated costs and fare of power consumption. But furthermore, the Team created future upgrade plan based of the extension plan of water treatment plants.

     Study on water distribution system

    As for the Study on water distribution system, the Team reviewed the future distribution plan in the Water Supply Master Plan, and extracts the problems and issued

    Actual approach for the study is as follows:

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    a) Setting of water pressure conditions In the water distribution network model as a basis of the current future plan, it is

    planned to secure the water pressure as 10m+ G.L. at the demand points of the main 1st and 2nd grade pipes that constitutes the network