Water transfer from agriculture to urban domestic users: a case study of the Tone River Basin, Japan

Agricultural water reorganization measures (AWRM) is an approach that has been adopted in Japan for more than 30 years to capture excess water from agriculture for other uses by relying on the modernization of existing irrigation infrastructures. This paper reviews the history and processes of four such permanent water transfers by AWRM in the Tone River Basin, specifically those conducted in the Saitama Prefecture, Japan. The benefit of AWRM for the agricultural sector is the lowering of rehabilitation costs by sharing part of it with the city sector. AWRM does not require saving water at the on-farm level. Instead, the labor requirement of farmers is reduced by the rehabilitation and installation of pipelines. The benefit to the city is the lower cost, when compared with costs for the development of new water resources, and the relatively short duration of the project, which are important factors in an environment of the rapid increase in domestic water demand.

Transferring water from irrigation to higher valued uses: a case study of the Zhanghe irrigation system in China

The Zhanghe irrigation system (ZIS) is located in the Yangtze River Basin approximately 200 km west of Wuhan in Hubei Province. The reservoir was designed for multiple uses—irrigation, flood control, domestic water supply, industrial use, aquaculture, and hydropower. Over a period of more than 30 years a steadily increasing amount of water has been transferred from irrigation to other uses. Activities on the part of government, irrigation system managers, and farmers made this transfer possible with only modest decline in rice production. Most important factor was the steady increase in rice yields. The water pricing system provided an incentive for ZIS to reduce irrigation releases. With the steady decline in releases, farmers were forced to find ways to save water. Farmers improved existing ponds and built new ones to store water (improved infrastructure). Access to pond water on demand facilitated the adoption of alternate wetting and drying (technology) particularly in dry years. The establishment of volumetric pricing (price policy) and water user associations (institutions) may also have provided incentives for adoption of AWD, but more research is needed to establish their impact. These activities taken together can be seen as potentially complementary measures. Farmers received no direct compensation for the transfer of water, but recently farm taxes have been reduced or altogether abolished. Further reduction in water releases from the ZIS reservoir could adversely affect rice production in normal or dry years.     

Experiences of water transfer from the agricultural to the non-agricultural sector in Taiwan

Two type of water transfer have occurred in Taiwan, namely, regular and emergency transfers. According to the prevailing Water Law, water is permitted to transfer among water rights holders whenever they need and agree upon relevant compensation. As for the emergency transfer, in the event of extensive drought, every water user sector will suffer serious water shortages resulting in unavoidable economic losses. The Government should step in to perform emergency water transfer by suspending agricultural water rights a course of action considered to cause smaller losses even when an entire rice crop is abandoned, to minimize overall losses to the national macro economy. This study has examined two typical water transfer cases that were implemented in Taiwan. The first one involved the regular transfer of agricultural water from the Changhwa and Yunlin Irrigation Associations (IAs) to the industrial user Formosa Petrochemical Corporation (FPC). The second one involved the transfer of agricultural water from the Taoyuan, Shimen and Shinchu IAs to domestic and industrial uses during the period from 2002 to 2006 as an emergency transfer. From the perspective of water transfer options, Taiwanese case studies have demonstrated that an officially recognized marketing oriented water transfer mechanism has yet to be established. However, water transfer is still undertaken whenever necessary. In this respect, regardless of the type of water transfer undertaken, water rights can only be suspended but not terminated. In spite of the types of water transfer, it is inevitable to affect the ecological and environmental functions. Therefore, further investigations with related topics should be broadly taken into account. Ecosystem services of paddy fields have attracted increasing recognition in the monsoon Asian countries. Currently, there is a research program collaborating with the International Water Management Institute (IWMI) on the impact and influence induced by water transfer with a major concern on the ecosystem services of paddy fields in Taiwan.     

Appropriation of Río San Juan water by Monterrey City, Mexico: implications for agriculture and basin water sharing

Monterrey metropolitan area’s growth has resulted in water transfers from the Río San Juan basin with significant impacts for downstream water users, especially farmers in the Bajo Río San Juan (BRSJ) irrigation district. El Cuchillo dam is the centerpiece of the basin’s water management infrastructure and has become the flashpoint of a multi-faceted water dispute between the states of Nuevo León and Tamaulipas as well as between urban and agricultural water interests in the basin. Subsequent to El Cuchillo’s implementation in 1994, the BRSJ irrigation district has been modifying its irrigation operations to adjust to the new water availability scenario. Compensation arrangements for farmers have been established, including crop loss payments on the order of US$ 100 per hectare un-irrigable due to the diversion of water to Monterrey plus 60% of the water diverted to be returned to farmers as treated effluent via the Ayancual Creek and Pesquería River, a process with its own water competition and environmental implications. The Mexican irrigation sector will continue to face intense competition for water given: (a) low water productivity in agriculture leading decision-makers to allocate water to higher productivity uses particularly in cities, (b) priority accorded to the domestic use component of municipal water supply, and in the BRSJ case, (c) Mexico’s national interests in meeting its water sharing obligations with the United States.     

Unveiling a voluntary farmland registration program to secure open space for risk reduction and post-disaster restoration from earthquakes: lessons learned from practices in Chukyo and Kinki,Japan

Paddy and Water Environment - Because of rapid urbanization, urban agriculture’s capacity to reduce the risks associated with natural disasters has been receiving broad attention. Asian...     

Pest resistance to Cry1Ab Bt maize: Field resistance,contributing factors and lessons from South Africa

This paper documents the historical development of resistance of the African maize stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae) to Bt maize (Zea mays L.). This pest was one of the first to evolve resistance to Bt maize expressing Cry1Ab protein. A time-line of events and contributing factors are presented, from the commencement of efficacy testing through to the present situation, where the Cry1Ab toxin has lost its efficacy against B. fusca at many localities throughout the maize producing region, and single-gene Bt maize events often require insecticide treatments for which farmers are compensated. Significant levels of pest survival on Bt maize was observed in the first season after commercial release in 1998 and confirmed seven years later. Reduced selection pressure on the target pest is the objective of insect resistance management (IRM), and strategies to accomplish this should receive highest priority. Where resistance is prevalent, the only viable options to reduce selection pressure are withdrawal of the product and/or enforcement of high-dose/refuge requirements. The latter action may however be of no value under conditions where resistance is prevalent, since the value of refugia to an IRM strategy may be compromised. Remedial actions taken in South Africa included the propagation and enforcement of refuge compliance followed by the release of pyramided maize hybrids in 2011. These pyramids combine Cry1A.105 and Cry2Ab2 toxin-producing transgenes, replacing the ineffective single-transgene. However, it remains uncertain if cross-resistance occurs between Cry1A.105/Cry2Ab2 and the closely related Cry1Ab toxin, and for how long this pyramided event will endure. Cultivation of Cry1Ab-expressing hybrids continues in areas where resistance levels have been confirmed to be high. In retrospect, this case provides lessons regarding IRM, not only in South Africa, but wherever Bt crops are being introduced.