Part I: Natural Environment of Taiwan
Taiwan is an island with total area of 36,000 km2. Approximately 70% of the island is covered by mountains that mainly lying on along the central region running north to south and thus forming a ridge for the east- and west-bound rivers, and the rest 30% is the plains below the elevation of 100 m.
There are altogether 151 rivers in Taiwan, but only nine of them each possess a basin area exceeding 1,000 km2. As regards to riverbed slopes, those of the upstream reaches of most rivers exceed 1/100, and of the downstream are between 1/200 to 1/500, among them only five rivers with slope below 1/1,000. The sediment yield per unit area of the rivers in Taiwan is about 64 times of the world average and the sediment concentration is about 16 times of the world average.
Overlying both subtropical and tropical oceanic zones and situated in the Asian monsoon region, Taiwan features warm climate, the annual average temperature in the plain areas is as high as 22°C; even thelowest temperatures in a year stay above 10°C.
The rainfall in Taiwan is approximately 2,500 mm annually, which is about 2.6 times that of the world average. Owing to the dense population on this island, however, the average precipitation share per capita amounts to only 3,913 m3 per year, which is less than one eighth of the world average. Hence, it is appropriate to say that Taiwan is among the regions where the potential for water-resource is categorized as low. Statistics further show that there have been huge differences of rainfall distributions among seasons in Taiwan, with the highest annual total rainfall of 3,250 mm, and the lowest, 1,600 mm. The annual evaporation by regional amount is approximately 1,250 mm in the northeast, 1,600 mm in the west, 2,000 mm in the south, and 1,700 mm in the east, and the highest evaporation rate occurs in July.
Part II: Evolution of Irrigation and Drainage Facilities
The cultivation practice in early times in Taiwan adopted extensive farming systems such as "moving farm" and applied simple methods to divert river water into adjoining farming fields. In the course of farmland irrigation development, farmers in Taiwan gradually learned to make use of the abundant water supply from large streams and rivers for large-scale farmland irrigation. Ditching thus prevailed, making the previously moving farm into fixed farm. With the cropping system turning from extensive to intensive, the harvests of paddy rice were conducted two times in a year as compared to one time previously. The irrigation development history in Taiwan has been developed over 300 years, the major changes and evolution summarized in Fig. 3. The development of irrigation and drainage in Taiwan can be divided into three stages, namely, the Imperial Era (before 1895), the Colonial Era (1896-1945), and the Post-War Era (after 1945), as described below:
Irrigation development in Taiwan originated from around 300 years ago, that was in the era of China's Yuan Dynasty when the island remained scarcely populated. The early settlers applied simple techniques to irrigation, when large-scale irrigation and drainage facilities and irrigation management systems were both absent. The term of irrigation facilities used in Taiwan was first referred to during the Dutch occupation period (1622-1661). Adopting the mercantilism, the Dutch in the 17th century colonized Taiwan and enforced its economic policies. During this period, the bulk of the farming labor comprised the Han people from the Chinese mainland and the aborigines on the island. They cultivated the land for farm around Tainan area today. As of the year of 1659, the farming households of the Han people totaled 25,000. The total paddy lands area was about 652 ha, sugarcane fields of 184 ha, and 500 ha of other crop farms.
In view of high economic values of sugar, the Dutch in Taiwan encouraged sugarcane farming for producing sugar for export purpose. However, since the growth of sugarcane requires relatively less water, and thus there was no immediate need for water resources development. Later on, in order to achieve food self- sufficiency, the Dutch began provision with incentives for rice production and barn building in Taiwan.
The need for better agricultural irrigation facilities thus became obvious, and the first irrigation facilities in Taiwan such as "wells" and "ponds" were then constructed, which were the beginning of the development of farmland irrigation on the island. However, most of these facilities were mainly built with materials such as straws, timber, soils and stones, which were gradually replaced with soil and stone structures. To avoid destruction by floods, these structures were mainly built across the rivers where the flows were relatively steady. Major irrigation facilities at this time included ponds and water wells, mostly located in today's Danshuei and Tainan areas.
In the late Ming Dynasty (1662-1683), a dynastic officer Cheng Chen-Kung recovered Taiwan from the Dutch hands. For the purpose of supplying sufficient foods for his soldiers, he developed several irrigation projects, which included diversion works, ponds and canals, for farmland irrigation and improvement of agricultural production. He also used natural lakes and man-made ponds to store water for irrigation during drought seasons. The name "bih" and "jun" (both mean ponds and ditches) were used to refer to the water conveyance facilities. During this period, water resources development in Taiwan was politically motivated. Cheng garrisoned his troops and peasants in Taiwan to prepare for a long fight against the Ching Dynasty in the event of intrusion. When Cheng administered Taiwan, he divided the arable lands into "royal farms", "private farms", and the military controlled "garrison farms". The rice paddies area in Taiwan in those periods totaled approximately 17,900 ha, and the major irrigation ponds and canals totaled 24 units, which centered on today's areas of Tainan and Kaohsiung .
As the immigrants from Chinese mainland to Taiwan increased following the Ching Dynasty's conquering of Taiwan in 1683, the demand for agricultural water also increased. In order to meet such demand, the private sector began to develope irrigation projects, either in form of private ownership or joint venture. During this stage, the irrigation undertaking in Taiwan was mainly managed by private sector but under the government's supervision. At this stage, today's area of Tainan remained as the center for settlements, crop cultivation and administration. In addition, due to sugar was a high value product, sugarcane cultivation was much more popular than paddy rice farming. Later on, due to over production of sugar, rapid increase in population, and rise in the market prices of rice, a large-scale transformation of sugarcane fields into paddy finally took place. In the meantime, water resources development was quickly expanding to cover the entire Chianan plain area, then across the Changhua plain and eventually reaching the Taichung basin. The total area of rice paddy fields exceeded 200,000 ha, of which about 110,000 ha were irrigated by canals that conveyed water diverted from streams/rivers, water stored in man-made ponds, or groundwater from wells.
To acquire the cadastral data, the Japanese Government established the Temporary Land Survey Bureau of Taiwan after it started colonizing the island in 1896. The bureau produced maps at scale 1:20,000 of the whole island. The maps served as the basis of irrigation system survey, for gaining the knowledge of operation of private irrigation facilities and land use situations for the development of farmland irrigation undertakings. Between the years of 1902 and 1906, the emphasis of irrigation undertaking was placed on facility renovation, that was to reduce water loss or leakage in the course of irrigation water transmission and distribution. Public canals registered during this period were 181 units totally; consisting of 25 in Taipei, 67 in Hsinchu, 35 in Taichung, 20 in Tainan, 31 in Kaohsiung, 2 in Taitung, and 1 in Hualien.
Toward the development goal of "Agricultural Taiwan" set forth in the early 20th century, the Japanese Government invested heavily on irrigation projects. In reservoir construction, a total of 18 reservoirs and regulating pools were built, of which the Sun Moon Lake and the Wusantou Reservoir were among the largest. Both reservoirs were off-stream dams that store transbasin water. This phenomenon showed the sophistication of the planning concept and construction techniques at that time. As regards the irrigation projects, major systems included the Liukung, Touyuan, Papao, Shihtsuto, Houli, Tsaokung, Chiyeh, and Chianan Canals. The entire system of Touyuan Canal, for instance, then consisted of one main canal with 14 laterals and 6 sub-laterals, and also with 241 leading ditches to irrigation ponds and numerous tertiaries, totaling approximately 1,972 km in length. At that time the service area of the Taoyuan Canal was about 22,310 ha.
The Japanese Government stipulated an island-wide land improvement plan for Taiwan in 1938, including 51 new projects to benefit a total area of 600,000 ha. The plan was scheduled to first complete the 13 significant projects including the Yenpu Project. Due to the outbreak of the World War II, however, only one project was duly completed. It was also during this period that Taiwan's irrigation management started a tendency to gradually form the pattern of centralization and the introduction of new science-based technologies and application of reinforced concrete techniques. As a result, the irrigation facilities development progressed rapidly. The total irrigated area in Taiwan increased to 560,000 ha by 1942, accounting for 69% of the total arable land at that time.
After World War II, the government of Republic of China (R.O.C.) took over the sovereignty of Taiwan from Japanese occupation. At that time, the irrigation areas in Taiwan were reduced to merely 260,000 ha due to the war devastation. In order to produce food production as before, ensure social stability, and re-build national defence forces, the urgent irrigation works in the initial stage were concentrated on rehabilitation of existing facilities. And with the Government's subsidies provided, both reconstruction of war-ruined works and resumption of all unfinished pre-war projects were given first priority.
Furthermore, the Government had implemented farmland consolidation projects since 1960, aimed to improve the agricultural production environment, boost the land use efficiency, and expand farm plot scales, and therefore promote farming mechanization for enhancement of farm management efficiency. The farmland consolidation is a process consolidating the excessively small and adjacent parcels of farmland through exchanges of their ownerships and the ensuing plot-annexation, and meanwhile increasing farm roads and improving farm drainage systems. The total arable land improved reached a total of 388,774 ha as of 2002.
Till the year of 2000, the existing irrigation and drainage facilities managed by irrigation associations include, 69,293 km of large and small canals/ditches, 1,604 units of diversion dams, 17,518 units of regulating gates, 17,217 units of offtakes, 4,007 units of flumes, and 2,112 units of groundwater wells.
Part III: Evolution of Irrigation Organizations and Management
In the early stages of irrigation development in Taiwan, relevant facilities were constructed by the private sectors. However, due to the lack of effective management, disputes over water use were not unusual and water resources were used rather ineffectively. Consequently, irrigation organizations were formed and established to resolve such conflicts and improve the water management efficiency, for the purpose of effective utilization of the potential water resources. The government later on intervened and granted these irrigation organizations the status of public juridical person to advance their operation and management capabilities. The evolution of the irrigation organizational aspect in Taiwan can be divided into seven stages: Pre-Ching Dynasty Era (before 1895), Public Ponds and Canals (1895-1907), Government-owned Ponds and Canals (1908-1920), Irrigation Cooperatives (1921-1944), Irrigation Coordination Associations (1945-1947), Irrigation Committees (1948-1955), and nowadays Irrigation Associations (after 1956), as detailed below:
During the Ming and Ching Dynasties, drainage and irrigation projects were mainly invested and operated by the private sector, and thus deemed private properties so that they could be traded freely like the land. The imperial administration later promulgated irrigation supervision rules to settle water use disputes, ushering in the era of irrigation management. The imperial instructions and decrees were issued by the Ching Dynasty Government to facilitate the management of irrigation systems. For purposes of water allocation, land acquisition for the needs of facilities or works, construction approval, water levy imposition, watercourse maintenance, and banning of rights encroachment, imperial instructions/decrees were announced or posted to instruct/order the public concerned. In the meantime, to ensure normal operation of irrigation facilities, the government would also issue such imperial instructions/decrees to rule the "water share" (as so-called "water right" today) allocated to respective ponds and canals. In addition, owners of irrigation facilities were respectively issued operation licenses (the equivalent "water right certificates" and "seals" today, specifically the "Irrigation Associations' Seals").
In view of the difficulty with the maintenance of private irrigation systems, the government in this period conducted a full-scale survey on irrigation facilities and completed their registrations, and designated them as public canals, which were placed under the government's supervision. The official irrigation registers recorded full detail consisting of the items of water sources, places where each canal passed and terminated, dates of new construction completed or changes of facilities, investment methods, facility dimensions, names of beneficiaries, locations, benefited area sizes, and rights- concerned notes. Besides, the then government also specified that the stakeholders of a canal or irrigation pond were permitted to establish "Cooperatives" subject to the government's approval. And the juridical person status was granted to such cooperatives, with manager acting as the cooperative's representative. So this was the period initiating the entitlement of the institutions in charge of irrigation undertakings in Taiwan with the legal status. Although the emphasis of irrigation undertakings in this period was concentrated on facility rehabilitation, the efforts made during this period helped set a firm foundation for future outstanding irrigation development in Taiwan.
During this period, the drainage and irrigation projects were mainly funded and constructed by the government, particularly for the large projects where the private sector could not afford to construct. Hydropower development also became an important concern in order to fully exploit water resources. The "Regulation on Government-owned Ponds and Canals" and the "Organizational Regulation on Irrigation Cooperatives of Government-owned Ponds and Canals" were also enacted, which bettered the management and organizational structure of the irrigation entities.
The "Regulation on Government-owned Ponds and Canals" specified the rules on land acquisition for irrigation-use and relevant compensation; and on the applicability of imposition of national taxation to that of water use fee. The Regulation further stipulated that the land owners who used the government-owned ponds and canals may require their tenants to share all or part of water use fee. In cases where the cultivating lands were owned by the government, the tenants should be fully responsible for paying such fee. Violators of the Regulation should be subject to punishment of detention, fines, or imprisonment, depending on the severity of the violation committed.
Irrigation organizations developed on many projects during this period, including massive construction of irrigation and drainage systems as well as land consolidation, windbreak establishment for roads, and saline land and gravel land improvement. The "Taiwan Irrigation Cooperative Decree", the Enforcement Rules on Irrigation Cooperatives", and the "Guidelines for Rules to be stipulated by Irrigation Cooperatives" were also promulgated to reinforce the management of the irrigation entities. According to the Taiwan Irrigation Cooperative Decree, the chairman of a cooperative should be a government appointee, but not necessarily a cooperative member, and with each service term of four years. In addition, a cooperative' staff should be assigned from the government officials. Up to this time, the government has in fact secured its control over all the irrigation cooperatives, ensuring the Public Juridical Person status of these cooperatives while having paved a sound foundation for irrigation undertaking entities. In 1941, the "Agricultural Water Conservancy Adjustment Decree" was promulgated as a legal basis for the merging of the 108 irrigation cooperatives into 47, which were further consolidated into 38 in 1944. All of these efforts were made to make sure that water resources were fully utilized and well conserved.
The Second World War left no complete irrigation and drainage systems in its wake. Irrigation efforts during this period focused mainly on rehabilitation of the war-damaged facilities in order to promote rice production. In 1946, the original 38 irrigation cooperatives were re-organized into 39 new civil groups and renamed as "Irrigation Coordination Associations", and meanwhile re-named the 15 then existing water hazard prevention cooperatives as the "Flood Prevention Coordination Associations". The Irrigation Coordination associations also started to allow farmers to vote for the chairman and give the elected chairman the right to select and employ staff of the entity.
In 1948, the Irrigation Coordination Associations and the Flood Prevention Coordination Associations were merged and re-organized to form a total of 40 Irrigation Committees, while maintaining their civil group status. These newly established committees were mainly responsible for the water management of irrigation and drainage systems, and water hazards control for the farmlands within their respective jurisdiction. The committee's members were both elected and appointed. The elected members were voted by general members and consisted of half of landowners and half of tenant representatives. The appointed members were made by the government and came from the county-level construction bureau chiefs, township/county mayors, experts and local enthusiasts. Chairman was then elected among the committee's members themselves and served a term of four years.
The supervisory bodies of an irrigation committee consisted of two administrative levels of government: the concerned city/county governments and the Provincial Water Conservancy Bureau, depending on the sizes of irrigation areas related to the irrigation committee. However, the lack of binding regulations promulgated through legislature on clear division of rights and responsibilities for the committees' members as well as the chairmen, had often led to controversies when civil rights and obligations were involved. In 1955, the government approved the "Regulation on Taiwan's Irrigation Committees Improvement" and also the "Organizational Regulation on Taiwan's Irrigation Associations" to solve the existing organizational defects of the irrigation committees at that time.
In 1956, the 40 Irrigation Committees were again re-organized to become a total of 26 Irrigation Associations. The Water Law further stipulated that Irrigation Associations were autonomous entities entitled the status of public juridical persons.
Later in 1965, the government promulgated the General Rules Governing the Organization of Irrigation Associations as the guiding principle for the organization, operation and management, and supervision of irrigation associations at the central level. Irrigation Associations have then undergone a series of consolidation and re-organization into 17 Irrigation Associations, of which 15 are scattered around the Province of Taiwan and two in the city of Taipei. The chairman of each Irrigation Associations was elected by the member- representatives, which were elected by the farmers.
Due to recent socio-economic change, the General Rules that promulgated in 1965 was revised in 1993 for the purpose of promoting irrigation efficiency and improving farmer service. The chairman was government appointee; the member-representatives were suspended and replaced by the so-called "Association Committees" who were also appointed by the government. However, this General Rules was revised again by the congress in 2001, with both chairman and association committees been elected by the members.
Part IV: Taiwan's Irrigation Situation Today
In Taiwan, the following crop patterns were established and carried out to adapt to the local farmland production environments including climatic and hydraulic conditions, the kinds of crops to be grown, and the production techniques applicable:
The various cropping patterns commonly practiced in Taiwan are illustratively shown in Fig.4.
According to the statistics conducted in 1999, the total area of arable land in the plains and agricultural and domestic animal-raising lands on the slope lands in Taiwan amounted to 854,205 ha, 24.01% of the total area of the island. Most of the arable lands are rice paddies and uplands, of 448,698 ha and 405,507 ha in area respectively. And there were a total of 374,451 ha serviced by the Irrigation Associations.
With warm climate, Taiwan's cropping lands require large quantities of irrigation water; per unit demand on the time scale is rather uniform. Fig. 5 shows the water use variation with time in the Kaoping Creek Irrigation District in a typical year.
Presently, 81.14% of irrigation water in Taiwan was diverted from rivers, 10.89% from reservoirs and various ponds, 5.42% pumped from groundwater, and 2.55% from other sources.
The Irrigation Associations in Taiwan have been generally established in accordance with local geographical conditions and economic benefits. And their official titles were given according to the major regions they are servicing, or the river/canal systems. Currently in Taiwan, the 17 Irrigation Associations have been entitled the public juridical persons as already mentioned previously.
They are obliged to help the Government carry out the irrigation undertakings, under the supervision of the Council of Agriculture, the central-level competent authority.
According to the General Rules Governing in Organization of Irrigation Associations, these Associations should take the following six major responsibilities:
In order to perform their legally prescribed duties, the Irrigation Associations have typical organizational structure as schematically shown in Fig. 7. The Association Committee is responsible for supervising the performance of the chairman. And under the Chairman, there are a general manager and a chief engineer assisting him with the general and technical affairs. The association's responsibilities and activities are carried out by eight divisions and offices designated respective functions, while field activities including operation and maintenance (O&M) in the fields of the service areas and association-owned facilities, are carried out by the work stations assisted by irrigation groups, in their respective service areas.
Part V: Prospects
With the ROC's entry to the World Trade Organization (WTO) in January 2002, both the quality and added value of domestic agricultural products and the flexibility in production will have to be enhanced in order to boost their marketing competitiveness and to reduce the impact of an open market and lowered tariff to imported agricultural products. Therefore, being the foundation for agricultural development, the irrigation undertakings in Taiwan also require to be further improved on their effectiveness and efficiencies to better support the goals set by the agricultural policies. Accordingly, the key areas of focus for irrigation development in Taiwan are summarized as follows: