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Study area

The Study Area comprises the central part of Hanoi City (the existing urbanized area and its adjacent areas), which is surrounded by the Red River (in the north and east), the Nhue River (in the West), and the old To Lich River (in the south). The area occupies about 135 km2 (including the West Lake) while the total area of Hanoi City is 925km2.

Outline of the proposed plans

Basic policy

In the formulation of this drainage/sewerage master plan (Master Plan), primary attention shall be paid to coordination with the City Master Development Plan. A phased implementation plan of the drainage/sewerage projects shall be proposed considering the suitable scale of each project in ensuring viability of the projects proposed in the Master Plan.

From these viewpoints, the Master Plan mainly consists of two projects, the Drainage Project and the Wastewater Disposal Project. Both projects are scheduled to be implemented in stages until the year 2020.

Of the plans examined in the Master Plan, a priority project for the feasibility study was selected in consideration of the specific aspects such as needs and technical requirements for each district.

Outline of the priority project

The To Lich River Basin drainage Project (the Project) has been selected as the priority project for implementation because this project has the highest economic viability among the plans examined in the master plan study and proves to be beneficial in improving people's livelihood and hygienic conditions. The outline of the Project is shown in Table 3.17.

Table 3.17: Outline of the Project
1st Stage Construction
2nd Stage Construction
(a) Yen So Pumping Station
(Total Pumping Capacity: 90m3/s)


45 m3/s
(b) Regulating Reservoir
(Reservoir Capacity: 5.19million m3)

3.87 million m3

1.32 million m3
(c) River Improvement
(Improvement Length: 33km)


(d) Drainage Channels (Total Length:30.8km)
- Removal of sediments (as an urgent project)
- Establishment of channel sections


(e) Floodgates and Control Gates (7places) 7places -
(f) Bridges and Culverts : 125 places 96 places 29 places
(g) Lake Drainage/ Conservation
Dredging Works: 18lakes
Conservation Works: 11lakes


14 lakes
(h) Sewer Network
- Removal of sediment: Total Length 120km
(as an urgent project)
- Addition/new installation of pipes: 225km
- Addition/new installation of culverts:
 116 x 103 (spatial volume)
22 x 103m3

94 x 103 m3

Project cost

This Study aimed to prepare a master plan up until the year 2010, following the original scope of works. However, the result of a preliminary review showed that all the plans cannot be completed within 15 years due mainly to financial constraints. Accordingly, the implementation period will be extended up to the year 2020.

The implementation costs of major projects (structural measures) proposed in the master Plan were estimated at about US$ 1,162 million equivalent (Dong 12,550 billion, 1994 base price). The fund requirement for the implementation is shown in Table 3.18.

Table 3.18: Fund required for the implementation of plans
Plans 1995-2000 2001-2005 2006-2010
(Yearly Average)
2010-2015 2016-2020 Grand Total
Drainage Plan
Wastewater Disposal Plan
Total 35.3 61.9 58.2 39.4 31.9 1,162.0


The proposed drainage and wastewater disposal plans were proved to be economically, financially, technically, and environmentally viable. The To Lich River Basin Drainage Project, selected as the priority project, aims to improve flood control and drainage, and is also evaluated as improving residential environment, living standards, and urban transportation systems.

Economic evaluation

The benefits of a drainage project and a wastewater disposal project relate to each other. However, the Study assumes that the reduction in flood damage is the benefit of the drainage project, and the improvement of hygienic conditions, including the increase of land value, is the benefit of the wastewater disposal project. The economic evaluation indexes were assessed in comparison of the benefits and the costs of projects as shown in Table 3.19.

Table 3.19: Result of economic evaluation


Cost (US$ x 106 equiv.) Annual EIRR
Financial Cost Economic Cost Benefit (US$ x106 equiv.) (%)
Drainage Plan        
A) To Lich River Basin Drainage Plan   3174 285.7 12.6 11.6
  - 1st Stage 160.4 146.8 7.6 11.7
  - 2nd Stage 157.0 138.9 5.0 11.4
B) Nhue River Basin Drainage Plan 206.7 174.8 2.7 9.3
Total 524.1 460.5 15.2 10.9
Wastewater Disposal Plan        
A) Centralized Treatment System 567.1 523.4 63.4 5.2
B) On site Treatment System 70.8 66.1 6.1 -
Total 637.9 589.5 69.5 5.2

In general, the drainage plan is economically viable, taking into account its Economic Internal Rate of Return (EIRR) of more than 10%. For the on-site treatment system in the wastewater disposal plan, a negative EIRR value was obtained. However, the plan should be assessed overall in view of the necessity of improving the hygienic environment of Hanoi City as a whole. The overall EIRR of 5.2% is fairly adequate to justify the plan as viable for a sewerage project.

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