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  3. Outline of Regional drainage

Outline of Regional drainage

  1. Managerial sorting and quantities of regional drainage

    Regional drainage is divided by the administrative territory or the ratio of the passage of flow into central government administered, municipality administered and county/city administered regional drainage.

    • The allocations and amendments of drain and water catch and scope of facilities in central government administered regional drainage are reviewed by the Water Resources Agency, MOEA for approval and announcement by central authorities.
    • The scope of facilities in municipality and county/city administered regional drainage is reviewed by municipality or county/city governments and referred by the Water Resources Agency to central authorities for approval and announcement.

    On November 14, 2005 the Ministry of Economic Affairs announced, under Item 4, Paragraph 1 and Paragraph 2, Article 4 of “Regulations on Drainage Management”, 44 central government administered regional drainage and on 2005 February announced additionally Anshunliao Drainage as the same, whilst in 2008 January, 2012 May, 2013 April, 2014 October and 2015 February, the Ministry removed the Nantun River Drainage, Chaitougang River Drainage, Shisijhang Ditch branch, Dazhi Drainage and Xiaciaozitou Drainage from the list of central government administered regional drainage. Further in 2015 April, Tuku River Drainage, Cizhipukeng Drainage and Dazhou Drainage were announced to be taken over in 2015 July by county/city governments, leaving the number of central government administered regional drainage at the current 37.

    As to municipality administered and county/city administered regional drainage, as of 2016 April, there were 1,626 announced regional drainage distributed in counties and cities (including the governments of municipalities and other counties and cities). The statistics of the regional drainage administered by the counties and cities are shown in Table 1.

    Table 1 Statistics of distribution of municipality-administered and county/city-administered regional drainage
    Administrative region Number of county/city-administered regional drainage
    Keelung City 6
    Yilan County 50
    Taipei City 3
    New Taipei City 71
    Taoyuan City 37
    Hsinchu County 66
    Hsinchu City 14
    Miaoli County 73
    Taichung City 130
    Nantou County 166
    Changhua County 218
    Yunlin County 142
    Chiayi County 65
    Chiayi City 9
    Tainan City 162
    Kaohsiung City 116
    Pingtung County 92
    Taitung County 19
    Hualien County 78
    Penghu County 70
    Kinmen County 39
    Total 1,626
    Note: as of 2016 April
  2. History of development of regional drainage

    1. History of drainage governance

      Taiwan’s governance of flood prevention and drainage, which was derived from early river governance, can be divided in the stages of planning and survey of drainage systems from Japanese surrender of Taiwan to 1979, restoration and construction of river and sea embankments from 1979 to 2003, and creation of environment for drainage from 2004 on.

      1. Stage of planning and survey of drainage systems from Japanese surrender of Taiwan to 1979

        The reorganization of farm drainage in Taiwan started in 1895 when the Japanese occupied Taiwan, which had targeted the farmlands in plains with sound irrigation equipment. The Japanese set out a standard of drainage of “even drainage, within 3 days, of a maximum precipitation for consecutive 3 days” based on the flooding tolerance of the crop.

        Since 1969, factories have increased rapidly in areas of plain causing dense population and expanded urbanization. Runoff that was produced by factories and in urban areas was drained through agricultural drainage. But, the standard of protection that was designed specifically for allowing the drainage of waterlogging and flooding in farmland was not enough to protect factories, urban areas, clusters and transport facilities from the flood during typhoons and torrential rain; besides, it was difficult too to clearly attribute the responsibility of maintenance and management of the drainage. To respond to such development, the government amended the Enforcement Rules for Water Act in 1969, adding the “regional drainage” to the previous categories of “agricultural drainage”, “urban drainage”, “business drainage” and “other drainage” so as to incorporate drainage of more than two kinds.

        To embody the spirit of the Enforcement Rules for Water Act, the Water Resources Bureau of Taiwan embarked in 1972 on a nationwide survey and review of drainage, which task was completed in 1975.

        In 1972, simultaneously with the nationwide survey and review of drainage, a survey was conducted in the key agricultural regions like Yilan, Changhua, Yunlin, Chiayi, Tainan and Pingtung where the flood had been severe. For standard of drainage improvement, it was changed to a frequency of even drainage of a day of 2-5-year torrential rain in 1-3 days for every system of regional drainage, provided that drain channels remained earth ditches.

      2. Stage of restoration and construction of river and sea embankments from 1979 to 2003 (regarding drainage remediation)

        In 1979, the Government launched the Twelve prioritized public construction projects in response to the social transformation of businesses. Under the eighth subproject, the “Project of speeding up improvement of key agricultural drain system”, the drainage improvement works were performed in 14 counties including Yilan and Taoyuan in the period from 1979 to 1985 with a total amount of NT$3.37 billion on 847 Km of drain channel. The standard for improvement design of drainage in this period used a frequency of even drainage of a day of 2-5-year torrential rain in 1-3 days, with drain channels all in the form of earth ditches.

        It was the period of 1986 to 1991 that the Fourteen Construction Projects were implemented. And it was not until said project that “regional drainage” was dubbed--included in the 9th Item thereof, “Plan of flood prevention and drainage”. To mitigate damages from disasters, it is necessary to elevate the standards for drainage improvement design; hence the frequency of even drainage of a day of 5-year torrential rain in 1 day was used as a principle. In the case, however, of undertaking mountain drainage, it is necessary to consider the ability of the canal to discharge the peak flow occurring during a day’s torrential rain at the frequency of 25 year in mountain areas with the canal in fullbank condition.

        From 1992 to 1997, subsequent to the previous stage of project, the Government continued to make the Six-year national construction. Under the subproject of said project, the regional drainage works went on with drain channels improvement in the above mentioned 16 counties/cities as well as the review of the major drainage systems that had been improved. The standard of this stage for drainage improvement design was increased to a frequency of peak flow occurring during a day’s torrential rain at the frequency of 5-10 year, while the drain channels still took the shape of concrete embankment.

      3. Stage of regional drainage remediation and creation of environment from 2004 on

        1. The project of regional drainage remediation and creation of environment: the 4th 5-year project of regional drainage remediation and creation of environment was a continuation of a 6-year regional drainage project (1998-2003). And, it was followed by the works of another “project of regional drainage remediation and creation of environment (2009-2014)”.
        2. The project of flood management in flood-prone areas (2006-2013): to speed up the management of floods in flood-prone areas and in mountains, protect the safety of people’s life and property, increase local residents’ living quality, and conserve the quality water environment, the Executive Yuan set forth the “Special Act for Flood Management”, which was promulgated on January 27, 2006 for execution for an eight-year period. The applicability of said Act covers the county/city administered rivers, regional drainage and business sea embankments, management works of agricultural drainage and rain sewers, and related water & soil conservation works that were listed in the Executive Yuan’s approved project of flood management in flood-prone areas. It was funded with not more than NT$116 billion.
        3. Project of comprehensive management of basins (2014-2019): given the flood management not completely finished, the Ministry of Economic Affairs planned on a project of comprehensive management of basins, and the Executive Yuan set forth the “Special Statute for the Comprehensive Management of River Basins”, which was promulgated on January 29, 2014. The applicability of this Statute covers the municipality and county/city administered rivers and regional drainage, agricultural drainage, aqua farming drainage, rain sewers, water and soil conservation on upstream slopes, and flood control areas in mountain that were listed in the Executive Yuan’s approved projects of comprehensive management of river basins. NT$60 billion of budget was allocated for the required expenses for all six years.
    2. History of development of announcement on regional drainage

      1. The Water Resources Agency made a first announcement on May 20, 2002 by official letter ref. Jing-shui-zi No. 09150220950 a “Table of scope and starting & finish points of cross-county (city) regional drainage management”, where it defines the central government administered regional drainage facilities at first in the perspective of drainage channels that go through two administrative regions.
      2. To summarize the information on the all the nation’s regional drainage facilities in counties and cities, the Water Resources Agency further requested in 2005 by official letter the county/city governments and River Management Offices to verify the survey. The relevant procedures were as follows:
        1. By the “Regulations on drainage management” which was promulgated by Order Jing-shui-zi No. 09204610630 of October 1, 2003, the WRA made a recommendation for announcement of regional drainage (1st Announcement) on September 30, 2005.
        2. On November 14, 2005, the Ministry of Economic Affairs announced, by official letter ref. Jing-shou-shui-zi No. 09420219360 central government administered, municipality and county/city administered regional drainage, which resulted in 44 central government administered regional drainage and 1,464 municipality administered regional drainage.
      3. With 34 amendments from 2008 to 2016 April, the quantity of regional drainage kept increasing to a total of 1,663 county/city administered and central government administered regional drainage, described as follows:
        1. Currently there are 37 central government administered regional drainage, as Table 2 shows.
        2. Municipality administered regional drainage in the number 483 and county/city administered regional drainage in the number 1,143, as Table 2 shows.
        3. This period saw chiefly added regional drainage and changes of starting and finish points. There were few regional drainage cancelled, because the central government administered regional drainage was cancelled and added into municipality administered regional drainage as a result of the restructuring of the six cities.
  3. Central government administered regional drainage

    Table 2 Table of central government administered regional drainage (1/2)
    River Management Office SN County (city) Drainage channel Exit into Starting point of responsibility Finish point of responsibility Catchment area (km2) Flow length (km) Gradient of canal
    Tenth River Management Office 1 New Taipei City-Keelung City Shenaokeng River Drainage Keelung River Junction with Keelung River 3 of 57, Shenaokeng Rd., Keelung City 7.0 3.17 1/200
    2 New Taipei City-Keelung City Daneikeng River Drainage Keelung River Junction with Keelung River Fangsheng Pond before Lingquan Monastery 3.26 2.3 1/300
    3 New Taipei City-Taoyuan City Taliaokeng River Drainage Dahan River Junction with Dahan River Entrance of culvert on the north of Lingding Bridge on Route T1, Longshou Village, Gueishan Township, Taoyuan 29.37 10.6 1/240~
    1/900
    4 New Taipei City-Taoyuan City Yingge River (Tuzikeng River) Drainage Dahan River Junction with Dahan River Unnamed bridge on the left of Fuyuan Elem. School, Taoyuan County 21.01 8.57 1/90
    The 2nd River Management Office WRA 5 Taoyuan City-Hsinchu County Fuxing River Drainage Estuary Estuary Yuanben Bridge 42.45 12.68 1/40~
    1/120
    6 Taoyuan City-Hsinchu County Bogonggang branch Fuxing River Drainage Junction with Fuxing River Drainage Border shared by Hukou, Xinwu and Yangmei Townships 9.31 1.70 14/1000
    7 Taoyuan City-Hsinchu County liogu River Drainage Fuxing River Drainage Junction with Fuxing River Drainage Near 8th Cemetery of Yangmei Township 10.38 7.13 16/1000
    8 Taoyuan City-Hsinchu County Desheng River Drainage Xinfong River Junction with Xinfong River Shanghu Elem. School 14.76 10.02 1/47~
    1/91
    9 Taoyuan City-Hsinchu County Sihu branch Desheng River Drainage Junction with Desheng River Drainage Ruentex plant 3.5 3.38 1/44
    10 Hsinchu County-Hsinchu City-Miaoli County Yangang River Drainage Estuary Estuary Xinfong Bridge 40.20 9.83 1/520
    11 Hsinchu County-Hsinchu City Keya River Drainage Estuary Estuary Beikeng Bridge 51.31 25.89 1/50~
    1/333
    12 Hsinchu County-Hsinchu City Kezihu River Drainage Touqian River Junction with Touqian River Baoshan Dam spillway 13.383 10.63 1/420
    Third River Management Office 13 Taichung City Han River Drainage Dali River Junction with Dali River Exit of culvert for rain sewer, junction between Taichung City’s East District and Dali City 67.76 9.23 1/240
    14 Taichung City Liuchan Drainage Han River Drainage Junction with Han River Drainage Gate watershed, South Ditch of Shihgang dam 9.79 10.57 1/140
    15 Taichung City Luichan Drainage Han River Drainage Junction with Han River Drainage Jingwu Rd. 6.54 5.67 1/112
    16 Taichung City Tongancuo Drainage Wu River Drainage 1K-025 on Dinglaoshu Section embankment, north bank of Wu River Adjacent to fence of Taichung Women’s Prison 9.5 5.60 1/21~
    1/70
    17 Taichung City Gangweizi River Drainage Fazai River Junction with Fazai River Junction with Dapucuo Ditch branch and Yuanbaojhuang Ditch branch 23.5 4.50 1/120
    18 Taichung City Sikuaicuo Ditch branch Gangweizi River Drainage Junction with Gangweizi River Jhongqing Rd., Taichung City 2.03 3.17 1/100
    19 Taichung City Yuanbaojhuang Ditch branch Gangweizi River Drainage Junction with Gangweizi River #1 Freeway 10.26 8.09 1/105
    20 Taichung City Dapucuo Ditch branch Gangweizi River Drainage Junction with Gangweizi River Yatan Bridge on Yatan Rd. 7.26 4.44 1/96
    21 Changhua County-Nabtou County Ailiao River Drainage Maoluo River Junction with Maoluo River 15K+700 36.37 22.38 1/70~
    1/146
    Table 2 Table of central government administered regional drainage (2/2)
    River Management Office SN County (city) Drainage channel Exit into Starting point of responsibility Finish point of responsibility Catchment area (km2) Flow length (km) Gradient of canal
    Fifth River Management Office 22 Yunlin County-Chiayi County Xing-an Drainage Sandie River Junction with Sandie River Intersection point between Route Yun-157 and Nigu Branch line 11.61 6.6 1/426~
    1/1629
    23 Yunlin County-Chiayi County Xing-an-zhong Drainage Xing-an Drainage Junction with Xing-an Drainage Luzhu Cemetery of Dapi Township toward the west side of agricultural route Yun-108 1.13 1.9 1/545
    24 Chiayi County-Chiayi City Houzhuang (Long-en)Drainage Bazhang River Junction with Bazhang River T18 line Bridge at 11K+588 8.84 11.59 1/80
    25 Chiayi County-Chiayi City Chiayi Drainage Puzi River Junction with Puzi River Fangshuikou Bridge on Shuiyucuo Waterway of Irrigation Association 15.5 2.13 1/40~
    1/380
    26 Chiayi County-Chiayi City Mayuliao River Drainage Puzi River Junction with Puzi River Junction with Pimajiao Drainage 20.7 2.25 1/250
    27 Chiayi County-Chiayi City Pimajiao Drainage Mayuliao River Drainage Junction with Mayuliao River Drainage Downstream of Jiaxi Bridge in Daxicuo 9.66 3.19 1/430
    28 Chiayi County-Chiayi City Huzinei (Zailai) Drainage Bazhang River Side ditch by the road on Hunei embankment in Bazhang River Junction between northeastern corner of Minsheng village and the ditch behind Xiaoboshi Kindergarten 3.28 1.50 1/280~
    1/430
    Sixth River Management Office 29 Tainan City Sanye River Drainage Erren River Junction with Erren River Downstream side of Jitan Bridge (excl. Jitan Bridge) 63 12.97 1/1700
    30 Tainan City West of Airport Drainage Sanye River Drainage Junction with Sanye River Intersection between culvert and open channel at Nan-an Sec. and Jianan Sec., South Dist., Tainan City 2.3 2.2+ 1/430
    31 Tainan City Yanshui River Drainage Yanshui River Junction with Yanshui River Where Beiwujiancuo-zhong Drainage flows into 109 19.24 1/7000
    32 Tainan City Zenwen River Drainage Yanshui River Drainag Junction with Yanshui River Drainage 12K+570 31 12.57 1/5000
    33 Tainan City Anshunliao Drainage Yanshui River Drainage Junction with Yanshui River Drainage Unnamed bridge by #1 Public detention basin at Tainan Science Park (excl. bridge) 22 7.73 1/4500
    34 Kaohsiung City Dianbao River Drainage Estuary Estuary Fongshancuo Bridge 106 32.0 1/400
    Seventh River Management Office 35 Kaohsiung City-Pingtung County Wailiuliao Drainage Qishan River Junction with Qishan River Agricultural road bridge at intersection with Route Kaoping-99 9.35 7.04 1/360
    36 Kaohsiung City-Pingtung County Kaohsiung Farm Drainage Wailiuliao Drainage Junction with Wailiuliao Drainage Intersection with Route Kaoping-99 2.59 1.89 1/210
    37 Kaohsiung City-Pingtung County Jiyang Drainage Qishan River Junction with Qishan River Baonong Bridge on Route Kaoping-99 6.75 5.60 1/315