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1.
Experiences of water transfer from the agricultural to the non-agricultural sector in Taiwan 总被引:2,自引:0,他引:2
C. C. Huang M. H. Tsai W. T. Lin Y. F. Ho C. H. Tan Y. L. Sung 《Paddy and Water Environment》2007,5(4):271-277
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. 相似文献
2.
Hyderabad is one of the fastest growing cities in India. To meet its rapidly expanding water needs, it constructed and began
withdrawals from the Singur reservoir, located on a tributary of the Godavari River, in 1991. Administrative rules define
allocation of water from the reservoir but prioritize Hyderabad urban needs over much longer established agricultural uses.
Furthermore, the agricultural sector receives less water than even these rules allow, and urban withdrawals have changed the
quantity and the timing of the water, which is available to agriculture. An increase in groundwater use by farmers may have
been one response to these changes, with possible implications for surface and groundwater users further downstream. While
proposals have been put forth to compensate the agricultural sector in general and the farmers directly affected by reallocation,
for example by improving access to wastewater for irrigation downstream from Hyderabad or by conveying wastewater for irrigation
purposes downstream Singur reservoir, compensation has not been implemented to date. The Hyderabad case study clearly highlights
the advantages for devising and implementing arrangements to regulate the transfer of water from agriculture to cities, allowing
a move from sectoral competition for water to efficient management of a scarce resource.
相似文献
Mattia CelioEmail: |
3.
R. Loeve B. Dong L. Hong C. D. Chen S. Zhang R. Barker 《Paddy and Water Environment》2007,5(4):263-269
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. 相似文献
4.
G. Levine 《Paddy and Water Environment》2007,5(4):279-284
The Lower Rio Grande Valley is a sub-tropical area with a productive irrigated agriculture, but with an over-committed single
water resource. It is experiencing a rapidly growing population that is placing increasing pressure on the water resource.
This, combined with expanding urban areas and land moving out of agriculture, has resulted in a vigorous water market, with
transfers from agriculture to municipal uses. For the US portion of the valley, transfers from agriculture to municipalities
are either short-term (usually 1 year) or permanent. Prices vary depending upon the location and timing, and result from negotiations
between the parties. Over time, and not without difficulty, the water market has been facilitated by appropriate enabling
legislation, water rights that have been validated judicially, and an efficient transfer mechanism that has a minimum of transaction
cost. Government involvement is primarily for protection of the public, and to facilitate the transfer process.
相似文献
G. LevineEmail: |
5.
Yasushi Ishigooka Tsuneo Kuwagata Shinkichi Goto Hitoshi Toritani Hiroyuki Ohno Shin-ichi Urano 《Paddy and Water Environment》2008,6(1):55-71
The relationship between agricultural water demand and supply has been of interest to government decision makers and scientists
because of its importance in water resources management. We developed a water cycle model for eastern Eurasia that can estimate
water requirements for crop growth and evaluate the demand–supply relationships of agricultural water use on a continental
scale. To produce an appropriate water cycle, the model was constructed based on small drainage basins. To validate the model
performance with respect to simulated runoff, which is here considered as the available water resource, we compared our outputs
with those of other models and with observed river discharges. The results show that this model is comparable to other models
and that it is applicable for the evaluation of water cycles at continental scale. We defined two types of crop water deficits
(CWDs) as indicators of agricultural water demand. These were formulated by considering the physical processes of crop water
use; we did not include water consumption that is dependent on cultivation management practices, such as water losses in irrigation
systems. We assessed the reliability of our indicators by comparison with indicators from other studies and with published
statistics related to agricultural water use. These comparisons suggest that our indicators are consistent with independent
data and can provide a reasonable representation of water requirements for crop growth. 相似文献
6.
Water markets as a mechanism for intersectoral water transfers: the Elqui Basin in Chile 总被引:2,自引:0,他引:2
Robert R. Hearne 《Paddy and Water Environment》2007,5(4):223-227
The Elqui River in north-central Chile provides water for a medium-sized urban area and a small but thriving irrigated agriculture
sector. A number of factors combined to provide incentive for the municipal water company servicing the coastal urban area
to purchase water-use rights from irrigators in the early 1990s. This transfer was a well-recorded example of Chilean water
markets functioning as proponents had expected. And despite the elapsed time, and Chile’s favorable system of transferable
water-use rights, these trades remain among the very few recorded cases of intersectoral trading in the country. By purchasing
water rights this water supply company was able to reduce its cost of raw water provision. Economic analysis of this transfer
showed relatively modest economic gains from trade. Although, the value of water in municipal water supply is high, the value
of water to profitable farmers is also high. The construction of the Puclaro Dam on the Elqui River demonstrates that the
intersectoral water transfer that occurred in the early 1990s will not be the ultimate solution to the urban water supply
needs of this urban area. 相似文献
7.
Christopher A. Scott Francisco Flores-López Jesús R. Gastélum 《Paddy and Water Environment》2007,5(4):253-262
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. 相似文献
8.
While studying water quality in the Tatara river, we realized that the river has various hydraulic and topographic characteristics
when flowing through different regions. Because of these specific characteristics, the application of the existing models
for simulation of its water quality may not be appropriate due to limitations in the models themselves. Therefore, we developed
a mathematical model that is suitable for short-term simulations of water quality in rivers with characteristics similar to
the Tatara river. The main foundation of the model is the one-dimensional transport equation established on the basis of the
mass conservation law. To solve this equation numerically, it was discretized by the method of finite-difference approximations,
and an algorithm has been programmed in Fortran 90. To verify the model, the Tatara river was chosen as a case study. Water
temperature, dissolved oxygen, hydraulic parameters in four typical blocks of the river, and meteorological data of the study
area, have been observed and used to test the model. By calibrating the model with different series of data collected from
the designated blocks, all results have shown a good fit between simulated data and the observed one. Therefore, the model
could be a reliable tool for simulating water quality in medium- and small-sized rivers over a short-term period. This research
has also indicated the changing tendencies of water temperature and dissolved oxygen in Tatara river in response to different
meteorological patterns over a daily 24-h period. Besides, the model could be improved to simulate other water quality variables,
which would be studied further. 相似文献
9.
为给裸燕麦(Avena nuda L.)高效节水生产提供理论和技术支持,在温室盆栽条件下,研究了裸燕麦持续性干旱胁迫后不同生育时期复水的生理响应。结果表明,拔节-抽穗期内复水较正常供水处理显著(P<0.05)提高株高6.57%~7.67%,其他时期复水株高与正常供水处理差异不显著(P>0.05);拔节-孕穗期和抽穗-灌浆期内复水,裸燕麦功能叶片净光合速率(Pn)、气孔导度(Ci)、胞间CO2浓度(Gs)和蒸腾速率(Tr)等光合参数均表现出补偿或超补偿效应,灌浆期后复水无法恢复叶片正常光合能力;拔节期、孕穗期、抽穗期和灌浆期复水,较持续干旱胁迫处理显著提高裸燕麦籽粒产量,产量增幅分别为14.29%、152.38%、66.67%和32.80%;孕穗-灌浆期复水有利于提高灌溉水利用效率。说明裸燕麦持续干旱胁迫后孕穗期和抽穗期复水对植株生长、功能叶片光合能力和产量的补偿效应明显,有利于灌溉水高效利用。 相似文献
10.
《Journal of Crop Improvement》2013,27(2):421-470
Summary Nitrogen (N) availability for crop uptake is dependent on various factors that influence the transformation of N sources and transport of N forms in soils. The fate and transport of N is site specific. Therefore evaluation of N dynamics under each condition is neither practical nor feasible. Simulation models which are adequately calibrated and tested can be used to estimate the fate and transport of N as well as crop responses under different production systems. These evaluations provide some guidelines as how to manage N and water efficiently to maximize the N uptake efficiency and minimize the losses. Thus, they contribute to the development of N and water best management practices. In this chapter, we discuss recent information on experimentally measuring the water and nutrient transport in soils as well as performing estimations using simulation models. The development and application of different simulation models for different production systems have been summarized. Some case studies on nitrogen and water best management practices are also discussed. 相似文献
11.
水氮胁迫对玉米产量和氮素吸收和运移的影响 总被引:2,自引:0,他引:2
2011~2012年在吉林公主岭试验区可移动防雨棚内进行两年微区试验,探讨水氮胁迫对玉米产量及氮素的吸收和分配的影响。结果表明,全生育期灌水300 mm情况下,玉米产量随施氮量的增加而增加;水分胁迫(灌水100 mm)情况下,玉米产量随施氮量的增加而减少。植株氮积累总量成熟期最高,氮素在营养器官中的比例最高时期是拔节期,生殖器官含氮比例最高在吐丝期,子粒的含氮百分比最高时期是吐丝后15 d。水氮胁迫条件下,氮素转运率、贡献率均下降,仅氮胁迫转运率和贡献率增加。相同灌水量情况下,子粒吸收氮素量与施氮量显著正相关;水分胁迫条件下,表观土壤水分利用效率随施氮量的增加而下降,正常供水则相反;水分胁迫下的土壤水分利用效率极显著高于正常供水。 相似文献
12.
Soil erosion in agricultural fields affects not only land productivity but also water environment down stream. Many investigations
have been made for the prediction of soil erosion processes. The Universal Soil Loss Equation (USLE) has been applied broadly
for the prediction of average annual soil loss from upland fields. However, there are few reports concerning the prediction
of nutrient (N, P) losses based on the USLE. Thus, the objective of this study is to propose the prediction equation of nitrogen
and phosphorus losses during soil erosion processes on the basis of the USLE. In order to predict total nitrogen and phosphorus
losses, the coefficients for total nitrogen or phosphorus transfer are derived on the basis of results from experimental field
plots. Three bare-cover USLE plots with different amounts of granular chemical fertilizer were installed in an experimental
upland field. There was a tendency for the coefficient of total nitrogen or phosphorus transfer to increase with the average
concentration of total nitrogen or phosphorus in the soils. It follows that the more granular chemical fertilizer applied
caused a higher coefficient of total nitrogen or phosphorus transfer in the calculations. Moreover, the coefficients in heavily
fertilized plots were higher than 1.0. Through this investigation, it became clear that the nutrient losses during soil erosion
could be predicted on the basis of the coefficient of total nitrogen or phosphorus transfer along with other soil erosion
parameters. 相似文献
13.
Crispness is among the most important factors that the consumer uses to assess the quality of crispy bread. However, this quality attribute is rapidly lost after baking. It is known that crispness retention can be increased more than eight times by enhancing the water vapor permeability of the crust. Current methods to achieve this, i.e., puncturing the bread before baking, require an extra process step. We hypothesize that cracks that appear spontaneously on the crust surface after baking can also enhance water vapor permeability and therefore improve crispness retention. We were able to confirm this hypothesis by preparing composite breads containing the same crumb but different crusts, with crust recipes of varying starch/protein ratios. Crusts systems that were generally high in gelatinized starch content and poor in evenly distributed gluten were more prone to crack after the whole process of part-baking, freezing, and baking off. These cracks led to an increased water vapor permeability of the crust and an eight times longer instrumental crispness retention compared to standard bread. In this paper we also discuss possible causes for crack formation in the crust. We hypothesize that effective cracks are caused by thermal shock in materials with a low ability to dissipate energy. 相似文献
14.
We investigated the applicability of a dredged pool formed at the inlet of a reservoir for pollution control. To quantify
the effect of a dredged pool on the water quality of a reservoir, we monitored the water quality of the Masan Reservoir, located
in the city of Asan, Choongnam Province, Korea, before and after dredging. In addition, a completely mixed box model was applied
to simulate the water quality of the dredged pool and reservoir. The model included a water balance equation and chemical
mass balance equation, into which several interactions among water quality components, such as phytoplankton, total nitrogen
(T-N), total phosphorus (T-P), dissolved oxygen, and chemical oxygen demand (COD), were incorporated. The water quality monitoring
and modeling results indicated that reservoir water quality was greatly affected by the dredged pool. The loads of T-N and
T-P into the reservoir were reduced by the dredged pool, which may have induced the removal of nutrients by settling. However,
the dredged pool may have had a negative effect on the reservoir in terms of COD and chlorophyll-a because of the internal production of organic matter and/or algae with water detention. Therefore, a dredged pool may be
used for pollution control in a reservoir, as long as it is combined with measures to reduce concentrations of organic matter
and/or algae. 相似文献
15.
River water and groundwater are used to irrigate paddy fields and are also principal sources of drinking water for humans.
It is important to understand the transport characteristics of water (e.g., direction and intensity of water flow), when grasping
a pollution situation in the soil. Endo and Hara (Soc Inst Contr Eng Trans Ind App 2:88–95, 2003) developed the Quintuple-Probe Heat-Pulse (QPHP) sensor to identify water flux density vectors and thermal properties under
saturated and steady state conditions. However, there has not yet been any investigation of moisture transfer under transient
conditions such as during internal drainage and mid-summer drainage of paddy fields. Only Sand has been used in previous experiments,
and examinations with Loamy and Clayey soils have not yet led to done. Simultaneous measurements of the water flux density
vectors and thermal properties of soil texture of three types under drainage conditions as well as the soil moisture transfer
analysis with Finite Element Method (FEM), were done. The representative drainage flow was indicated as downward, except in
the Sandy-Clayey Loam, in which the rightward flux exceeded the downward flux owing to anisotropy of the soil-pore structure
and hydraulic conductivity. The apparent horizontal/vertical advanced distance was introduced in order to know about how water
moved through the soil column. The estimated volumetric water content was in good agreement with the measured value. Thus,
this measurement method was shown to be valid under transient water flow conditions. 相似文献
16.
17.
Increasing water productivity for paddy irrigation in China 总被引:4,自引:0,他引:4
This paper introduces the research on practices to increase water productivity for paddy irrigation in China and summarizes the experience on implementation of the alternate wetting and drying (AWD) irrigation technique. The widespread adoption of the AWD practice on 40% of the rice growing area provides an opportunity for China to produce more food in the water-surplus south where it is wet and the traditional based paddy field agriculture is dominant. Physical and institutional measures leading to increasing water and land productivity in rice-based systems are discussed. Research studies show that AWD practice does not reduce rice yield, but does increase the productivity of water. Water use and thus water charges can be reduced. However, experience shows that demonstrations and training are needed to encourage farmer adoption. Furthermore, there are a range of complementary policies and practices, such as volumetric pricing or farm pond development, which provide incentives for adoption of AWD. Finally, there remain many scientific issues to be addressed. Application of the AWD technique in some regions is still very difficult because of both bio-physical and socio-economic problems. In conclusion, the widespread adoption of AWD is only a first step in the continuing effort to find practices that will increase water productivity for paddy irrigation in China.Dr. Yuanhua Li was a Professor and Dean in Wuhan University of Hydraulic and Electric Engineering from 1996 to 2000. After that, he has been a Professor and Deputy Director General of the National Centre for Irrigation and Drainage Development, Ministry of Water Resources, China. He has been doing research on irrigation principally for paddy since 1982.Dr. Randolph Barker is an agricultural economist and Professor Emeritus Cornell University. From 1966 to 1978 he served as head of the Economics Department, International Rice Research Institute, Los Banos, Philippines and from 1995 to 2004 was principal researcher, International Water Management Institute, Colombo, Sri Lanka. 相似文献
18.
Wheat gluten is an inexpensive protein derived from mill industries with good film forming properties, which allows producing semipermeable membranes able to slow down water migration in foods.The first objective of this study was to evaluate the effects of the incorporation of a lipid phase (25 wt%, dry basis) in wheat gluten on the functional properties of the film, such water sorption, surface hydrophilicity, water barrier properties, mechanical properties and thermal properties. The second one was to asses if such incorporation was able to reduce the water sensitivity of film mechanical properties.Findings clearly showed that the incorporation of a lipid phase was able to decrease the water sorption, water affinity (hydrophilicity) and water transfer (≈2 times) of wheat gluten films. Moreover, mechanical properties are also affected by the lipid addition with a decrease in rigidity and, at high aw, an increase in extensibility. However, the sensitivity of the mechanical properties to water was not modified. Lastly, DSC (Differential Scanning Calorimetry) analysis proved that changes in mechanical properties of films as a function of hydration state were the consequence of glass transition depletion, which allowed them to turn from a glassy-like behavior to a rubber-like behavior. 相似文献
19.
The OECD has introduced a water pricing mechanism and listed eight categories gleaned from experience in OECD countries. However, in the Asian humid tropics, it is too early to apply water pricing because there is seldom a concept of water right, or practical organization of water management. In almost all irrigation projects in Japan, area charge has been applied, and collected fees have recovered entire operation and maintenance costs. Although effective volumetric charge is employed in several regions in Japan, most farmers pay area-based annual charges at several times of the year via Land Improvement Districts. In the Asian humid tropics, it is important to facilitate the establishment of sound management organizations of irrigation water before introducing a strict water pricing mechanism to levy the charge. 相似文献
20.
Bread loses crispness rapidly after baking because water originating from the wet crumb accumulates in the dry crust. This water accumulation might be increased by the dense and low permeable character of the bread crust. Our objective was to investigate the influence of permeability of the crust on water uptake in the crust and on crispness retention. To achieve this objective, we increased the permeability of the control bread crust by creating small channels through the crust. The water vapour permeability of the crust with and without channels was measured using a newly developed method for brittle materials. Two further properties were measured over time: crispness of bread by analysing acoustic properties and water content of the crust. Control bread crust had low water vapour permeability and functioned as a barrier, leading to increased uptake of water in the crust. Water uptake was halved, however, if the water vapour permeability of the crust was doubled. As a consequence, crispness retention increased eight-fold; breads stored for four hours were as crispy as control breads stored for 30 min. We can conclude, therefore, that permeability of crust is key to crispness retention. 相似文献