Engineering Agency,Taipei Water Department

Overview

Ⅰ. Background

　　The Phase III Construction could only sustain stable water supply until 1979. With the continual expansion of the service area, including Taipei City and parts of Taipei County such as Sanchong, Zhonghe, Yonghe, Xindian, and Hengke Borough in Xizhi, Programed water demand was expected to reach 2,130,000 CMD by 1991. The existing supply capacity would no longer suffice to meet the increasing demand. Additionally, in line with central government policies to replace groundwater with surface water, the Taipei Water Plant and the Taipei Government Water Supply and Sewerage Construction Committee initiated feasibility studies and planning for the Phase IV Preliminary Works. Following the establishment of the Taipei Water Department in 1977, the department took over and continued planning and implementing the subsequent water supply engineering works.

Ⅱ. Objectives and Benefits

　　To follow up on the Phase III construction plan and accommodate future population growth and increased water coverage, the year 1991 was set as the target year for the Program, with an aim to increase the water output by 1,740,000 CMD to meet regional supply needs. The main objectives of this expansion were:

(1) Improve existing intake facilities and construct storage facilities to meet raw water intake capacity.

(2) Construct water purification plants and enhance treatment efficiency.

(3) Construct new raw water conveyance pipelines, clear water transmission mains, distribution reservoirs, booster stations, and related distribution mains.

Ⅲ. Service Population and Water Demand

　　Upon completion of this phase, the total water output would increase to 2,741,000 CMD. Water coverage would reach 96 percent, serving a population of 3,925,000 people.

Ⅳ. Scope

　　This expansion Program consisted of two major components: water source works and water supply works. The water source works were undertaken by the Feitsui Reservoir Construction Committee and included the construction of a reservoir in the Feitsui Valley in the upper reaches of the Xindian River. The water supply works were managed by the Taipei Water Department and were divided into two stages: preliminary and subsequent works. The preliminary works served as a transition between the Phase III construction and the commencement of storage operations at the Feitsui Reservoir. These included improvements to existing intake facilities, the expansion of the Chanchu Mountain water purification Plant, the construction of two distribution reservoirs and booster stations, and the installation of new distribution pipelines. The subsequent water supply works were implemented in two stages. The first stage involved the construction of the Zhitan Intake Facility, a raw water conveyance pipeline, a 500,000-ton water purification plant, a clear water main from the Zhitan water purification Plant to the Datong Booster Station, and improvements to distribution reservoirs and related distribution facilities. The second stage included the construction of two additional 500,000-ton water purification plants, expansion of the clear water transmission system, and continued work on distribution reservoirs, booster stations, and distribution mains.

Major Program Components

(1) Water Source Infrastructure

Feitsui Reservoir: The reservoir has a catchment area of 303,000 square meters and a maximum storage capacity of 406 million tons. Construction commenced in August 1979 and was completed in June 1987.

(2) Water Supply Works – Preliminary Stage

1. Intake Structure and Raw Water Conveyance:

To accommodate the expansion of the Chanchu Mountain water purification Plant and continue the Phase III plan, the water intake level of the Chingtan Weir was raised by 1.5 meters. A gravity-flow conveyance system was adopted to increase raw water flow from 1,085,000 CMD to 1,300,000 CMD.

2. Water Purification Facilities: An additional water treatment unit was constructed in accordance with the original design of the Chanchu Mountain water purification Plant, increasing output by 240,000 CMD and bringing total capacity to 640,000 CMD.

3. Distribution Reservoirs and Booster Stations:

(A) Neihu Distribution Reservoir and Booster Station: Located behind the Army Engineering School in Neihu District, constructed with reinforced concrete, capacity of 25,000 tons, supply rate of 40,000 CMD.

(B) Xindian Distribution Reservoir and Booster Station: Located along Section 2 of Beixin Road, Xindian District, steel structure, capacity of 4,000 tons, supply rate of 30,000 CMD.

(C) Taipei Bridge Booster Station: Located beneath the Taipei Bridge on Yanping North Road, supply rate of 30,000 CMD.

(D) Guandu Booster Station: Located at the intersection of Zhongyang and Heping Roads in Beitou District, supply rate of 121,000 CMD.

4. Distribution Mains: New transmission pipelines were installed in Sanchong, Xindian, and Neihu districts, along with additional distribution pipelines in other areas, totaling 27,620 meters in length.

(3) Water Supply Works – Stage 1 of Subsequent Phase

1. Intake Structure: Located approximately 260 meters upstream of Zhitan Dam, constructed with reinforced concrete, equipped with three debris screens, two electric sluice gates, and two stilling basins. Designed capacity: 2,700,000 CMD. Construction period: May 1981 to May 1984.

2. Raw Water Conveyance Tunnel: The tunnel spans a total length of 1,600 meters and has a diameter of 4 meters, operating as a gravity-flow conduit with a water delivery capacity of 2,700,000 CMD. Construction commenced in May 1981 and was completed in May 1984.

3. Water Purification Plant: Construction of the first unit of the Zhitan water purification Plant, with a design output of 500,000 CMD and an overload capacity of 10 percent. Construction period: November 1980 to June 1984.

4. Transmission Mains: Pipelines from Zhitan Water Purification Plant to Datong Distribution Reservoir, totaling 19,569 meters in length. The Yongfu Pipeline Bridge, which spans the Xindian River, was built with exposed steel pipe structure, 400 meters in length and 2,400 mm in diameter, making it the largest steel pipeline bridge in the Far East. All works were carried out from July 1980 and completed by June 1984.

(4) Water Supply Works – Stage 2 of Subsequent Phase

1. Water Purification Plants: Construction of the second and third units of the Zhitan water purification Plant, each with a design output of 500,000 CMD and an overload capacity of 10 percent. Construction began in December 1986 and was completed in July 1988.

2. Distribution Reservoirs: Eight reservoirs were constructed at various locations, including Sanchong (37,000 metric tons), Yangming (4,000 metric tons), Ankang (4,000 metric tons), Zhonghe (30,000 metric tons), Tianmu Lowland (15,000 metric tons), Tianmu Highland (4,000 metric tons), Songshan (20,000 metric tons), and Muzha (25,000 metric tons). Construction of these facilities began in July 1984 and was completed in 1991.

3. Booster Stations: Five new booster stations were established at Gongguan (393,000 metric tons), Sanchong (246,000 metric tons), Tianmu No. 1 (40,000 metric tons), Songshan (288,000 metric tons), and Beitou (183,000 metric tons). In addition, the existing booster stations at Datong, Zhonghe, Ankang, Xindian, and Neihu were expanded. Construction began in July 1984 and was completed in 1991.

4. Transmission and Distribution Mains: The pipeline system included the Sanchong Branch Line (6,150 meters), Songshan Branch Line (3,550 meters), Beitou Main Line (2,402 meters), Shilin Branch Line (1,322 meters), and approximately 78,800 meters of distribution pipelines, totaling 92,224 meters in length. Construction of these pipelines began in 1984 and was completed in February 1991.