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1.
Realistic estimation of irrigation volume applied to any crop at farm level generally requires information on event based discharge rates and corresponding periods of irrigation application. Use of mean seasonal discharge rates leads to erroneous estimation of volume due to unaccounted seasonal fluctuations in the water table, upon which the discharge rate of tube well is dependent. In the absence of such information, an alternative approach of estimating farm level water application based upon water table fluctuation data has been adopted in this study. The total actual water extracted during each irrigation event from the watershed was distributed among the farms irrigating crops in proportion to the product of irrigation time and the pump capacity (hp). Volume of water withdrawal concurrent to an irrigation event was computed based on the water level fluctuations in the wells in conjunction with potential recharge contribution from the surface storage structures to the groundwater aquifer. A production function approach was used to estimate the marginal productivity of water for selected crops at various stages of plant growth. Water, as an input in the production function, encompassed either in-situ soil moisture storage from rainfall or irrigation from groundwater or both. The inter-season as well as intra-season groundwater use, and the consequent groundwater withdrawals were analyzed based on the marginal value and output elasticity of water at different crop growth stages during the season. The cotton crop realized marginal value product of water, ranging from Rs. 1.03/m3 to Rs. 10.43/m3 at different crop growth stages in cotton. Castor crop had the marginal value product ranging from Rs. 2.89/m3 to Rs. 6.81/m3. The availability and use of water, including soil moisture, in the two seasons, coupled with the local harvest prices received, yielded the differential marginal values of water.  相似文献   

2.
Conjunctive Water Use Planning in an Irrigation Command Area   总被引:6,自引:4,他引:2  
In the present study, an integrated soil water balance algorithm was coupled to a non-linear optimization model in order to carry out water allocation planning in complex deficit agricultural water resources systems based on an economic efficiency criterion. The LINGO 10.0, optimization package has been used to evolve at optimal allocation plan of surface and ground water for irrigation of multiple crops. The proposed model was applied for Qazvin Irrigation Command Area, a semi-arid region in Iran. Various scenarios of conjunctive use of surface and ground water along-with current and proposed cropping pattern have been explored. Some deficit irrigation practices were also investigated. The results indicate that conjunctive use practices are feasible and can be easily implemented in the study area, which would enhance the overall benefits from cropping activities. The study provides various possible operational scenarios of the branch canals of the command area in the common and dry condition, which can help managers in decision making for the optimum allocation plans of water resources within the different irrigation districts. The findings demonstrate that for deficit irrigation options, the mining allowance of ground water value of the command area is greatly reduced and ground water withdrawal may be also restricted to the recharge to maintain the river–aquifer equilibrium.  相似文献   

3.
This study highlights the methodological challenges in determining the value of water in informal water markets. As the decision to participate in water markets is unlikely to be random, self-selectivity is an important issue for an unbiased estimation of the participating farmers’ revealed willingness to pay. The relevance of these issues is illustrated for an informal irrigation water market in Iran. A two-stage random sampling was carried out in pistachio-growing farms which are irrigated by water from the Rafsanjan aquifer in Iran during 2008–2009. A Heckman sample selection model shows that the real willingness to pay can be less than the observed prices in an informal water market.  相似文献   

4.
Dependency of reservoir operation on the climate variation occurs especially in regions, where agricultural demand has a significant share of the total water demands. The variability between demands that are based on annual climate conditions may be larger than the uncertainty associated with other explanatory variables in long-term operation of an irrigation dam. This paper proposed a rule curves to the water managers of the Zayandeh-rud reservoir in Iran in long-lead reservoir operation. A regional optimal allocation of water among different crops and irrigation units is developed. The optimal allocation model is coupled with a reservoir operating model, which is developed based on the certain hedging that deals with the available water and the water demands mutually. This coupled model is able to activate restrictions on allocating water to agricultural demands considering variation of inflow to the reservoir, variation of demands and the economic value of allocating water among different crops and irrigation units. The resulted rule curve is presented with a number of tables for more details and accuracy and a simple curve, which is more useful for operational purpose.  相似文献   

5.
Virtual water is the water required to produce food or a commodity, and includes rainwater in addition to irrigation and the water required to grow feed in livestock systems. Measuring virtual water is a useful concept in assessing water management as it permits the comparison of crops and livestock from the perspective of embedded water. To evaluate trade-offs in water allocation in countries like Canada with large regional variability in climate, virtual water should be calculated on a watershed scale. Two watersheds in Canada were selected representing wet and dry regions, and virtual water requirements for crop and livestock products were evaluated. For both the Lower Fraser Valley and the Okanagan basins, the results indicate that the most water demanding agricultural activities are livestock and fodder production. In the Lower Fraser basin, berry crops require 32 Mm3 of virtual water per year and have a potential value of $95 million. In contrast, the major fruit crops in the Okanagan require 63 Mm3 of virtual water per year and have a potential value of $95 million. In contrast, the major fruit crops in the Okanagan require 63 Mm3 of virtual water per year and have a potential value of 68 million. Blueberries and grapes which have moderately high virtual water contents have been expanding in the Lower Fraser and Okanagan basins respectively. Water to grow feed dominates overall animal virtual water requirements. Livestock requires nearly 4.5 times more virtual water per year than crops in the Lower Fraser, poultry and dairy having the largest virtual water requirements. In the dry Okanagan basin the total virtual water requirements for crops and livestock are similar. To accommodate future growth, decisions on water management will need to be made, particularly in dry basins such as the Okanagan. Virtual water calculations provide information that can assist decision makers in the strategic choices of reallocation and conservation water use.  相似文献   

6.
The upper Ewaso Ng’iro basin, which starts from the central highlands of Kenya and stretches northwards transcending different climatic zones, has experienced decreasing river flows for the last two decades. The Naro Moru sub-basin is used to demonstrate the looming water crisis in this water scarce river basin. The objective of the study was to show the extent of dry seasons’ irrigation water abstractions on river flows, and to assess the hydrological impact of flood storage on temporal water distribution and irrigation water management. Decreasing river flows are attributed to over-abstraction mainly for irrigating horticultural crops. The number of abstractors has increased four times over a period of 10 years. The amount of water abstracted has also increased by 64% over the last 5 years. Moreover, the proportion of unauthorized abstractions has been increasing over the years, currently at about 80% and 95% during high and low flows respectively. This has resulted in alarming conflicts among various water users. The situation is aggravated by low irrigation efficiency (25–40%) and inadequate flood storage facilities. The paper analyzes over 40 years’ observed river flow data and 5-year interval water abstraction monitoring records for 15 years. It assesses whether flood storage and management, can reduce dry seasons’ irrigation water abstractions without significantly reducing river flows to affect the sustenance of natural ecosystems downstream. The results demonstrate that flood storage and management can reduce water abstraction and increase river flows during the dry seasons, without significantly reducing high flows to affect the downstream water users. However, socio-economic, hydrological and environmental implications should be considered if a sustainable river basin water resources management strategy is to be developed and implemented. The case study of Naro Moru sub-basin is representative of the situation in the other sub-basins, and hence can be taken as a pilot basin for developing an integrated water resources management strategy that will foster socio-economic development with minimal negative hydrological impacts in the water scarce upper Ewaso Ng’iro river basin.  相似文献   

7.
Egypt produces approximately 2.4 million m3 of secondary treated wastewater (TWW) annually, used for irrigation directly or indirectly by blending with agricultural drainage water (BDW). The annual re-use of (BDW) is approximately 4 million m3. The safe and efficient use of marginal water (BDW and TWW) is a core objective of this study which has been operating from 1997 to date. After six growing seasons the main results can be summarized as follows: MAXIMIZING CROP PRODUCTION: TWW can be used for high production of oil crops (canola, soybean sunflower or maize) compared to fresh water, while BDW can be used for high production of tolerant crops (cotton and sugar beet). CROP QUALITY: using marginal water increases the concentration of elements (Pb, B, Ni, Co) in all crops but these elements were under critical levels (there were no toxicity hazards). It is better to use alternative irrigation with fresh water under a drip irrigation system to maximise crop production and minimise the adverse effects of such water in field crops quality. SOIL POLLUTION AND SALINITY BUILD UP: A drip irrigation system under alternative irrigation by fresh with TWW or BDW reduces salinity build up risks and the levels of elements (Pb, B, Ni, Co) in soil compared to re-use marginal water. SOIL PATHOGENS: Using marginal water slightly contaminated the soil with total faecal coliform (TFC), mites, shigella and salmonella. PLANT ANATOMY: No great changes in anatomical disturbance where induced in different structures of plants which were reduced at maturity stage. PRIMARY GUIDELINES FOR RE-USING MARGINAL WATER: From obtained results it can be recommended to use marginal water with salinity content ranged between 1.1 to 3.64dS/m, and elemental contents (Pb 3.0-3.51 ppm), (B 0.05-1.67 ppm), (Co 0.04-0.07 ppm), (Ni 0.08-0.15 ppm) for safe (field, vegetable and medicinal) crops production. REUSE BIO SOLIDS FOR CROP PRODUCTION: Sewage sludge produced from treated wastewater can be safely used by mixing with rice straw (1:1 w/w) for economic crop production and saving mineral fertilisers. GENERAL CONCLUSION: In the North Nile Delta, marginal water (especially BDW) can be safely used without significant negative impact on the environment, but there is a need for multi-disciplinary, long-term research to investigate irrigation with marginal water in terms of the environment, public health and agricultural productivity.  相似文献   

8.
In this paper, a new methodology based on interval optimization and game theory is developed for optimal operation of an inter-basin water transfer system considering efficiency, equity and sustainability criteria. A linear version of the agricultural water production function is proposed and used for incorporating deficit irrigation. The interval programming and cooperative game theory are utilized for equitable reallocation of benefits to water users in both water donor and receiving basins. To assess the sustainability of water allocation policies, water quality and environmental flow in the donor basin and groundwater table drawdown in the receiving basin are taken into consideration. The effectiveness of this methodology is examined by applying it to a large scale case study of water transfer from the Karoon river basin in south-west to the Rafsanjan plain in the central part of Iran.  相似文献   

9.
A great challenge of the current European water policy is the implementation of volumetric water pricing in the agricultural sector, especially of Mediterranean countries, where irrigation is a necessary precondition of agricultural production and farmers’ income, but also the major consumer of water. The overall aim of the present work is to develop a methodology that will be suitable for the estimation of the potential environmental, economic and social impacts of irrigation water pricing. For this purpose, Multi-Attribute Utility Theory is implemented in order to simulate agricultural decision making at various water pricing scenarios. Water demand functions are then elicited, by means of the best crop and water allocation (farmers’ decisions) in each scenario. The European Water Framework Directive recommends that any issue concerning water resources management (including water pricing policies) should be developed at the river basin level. In this framework, a cluster analysis is performed to partition the river basin area (namely, Loudias River Basin, located in Northern Greece) into a small number of homogeneous sub-regions. The differential impact of water pricing in each region is then analyzed, and finally, an average water demand function is formulated for the whole river basin.  相似文献   

10.
ABSTRACT

This article evaluates profitability of irrigated versus non-irrigated agricultural production of major crops (corn, cotton, wheat, soybeans, sorghum) in 2010 (a wet year) and 2011 (an exceptional drought year) in Oklahoma and Texas. It also estimates the economic value of water for agricultural production in both states to answer the question of added value generated with irrigation. Answering those questions is critical in the face of exceptional and severe droughts affecting Oklahoma and Texas in the past decade, in addition to steeply declining groundwater resources in the Ogalalla Aquifer. The results can help with designing mitigation and adaptation measures to water scarcity.  相似文献   

11.
Water use patterns are not distributed evenly over space and time. Determining the amount of water used within a region, as well as the various ways in which water is used is important for making adequate and sustainable water management policies and determining future water availability. We examined differences in spatial trends in Oregon freshwater use (total, municipal, and agricultural water withdrawals), by county, between the years 1985 and 2005. We also explored biophysical and socioeconomic factors that explain spatial patterns using Moran’s I, local index of spatial autocorrelation (LISA), and spatial regression models. There was a moderate positive spatial autocorrelation among counties that had similar total and irrigation withdrawals. LISA analysis identified hot spots between certain arid agricultural counties in the southeastern Oregon and cold spots between certain humid northwestern counties, including within the Portland metro area. Annual precipitation and income are negatively associated with total water withdrawals. Summer temperature and farm size is positively associated with irrigation water withdrawals, while net cash return and income are negatively associated with irrigation water withdrawals. When compared to ordinary least square regression models, spatial error models that take into account spatial dependence provide a more comprehensive explanation of the variations of water use, suggesting that water resource planning and management should incorporate spatial and neighborhood effects to effective manage limited natural resources.  相似文献   

12.
将广东省分为6个灌溉用水定额分区,并选定20个典型县,通过对各分区主要粮食作物、蔬菜、果树等灌溉用水定额进行调查,统计分析得出了各分区以水稻、薯类等为主的粮食作物,以叶菜、瓜果、椒类等为主的蔬菜和以香蕉、荔枝、龙眼等为主的果树等的农业灌溉用水定额。  相似文献   

13.
灌排一体化工程是提高农业水肥利用效率、减小旱涝灾害影响、提高作物产量的重要方式之一,近年来人们逐渐认识到灌溉与排水是紧密相连的两部分,对于农田灌溉排水工程的研究与相关建设也在不断增加。灌排系统从早期提高排水效率,到注重环境影响,逐渐发展为节水灌溉与新型排水技术相结合的灌排一体化工程。灌排一体化工程通过控制灌溉与排水过程,会对土壤含水率和地下水位、地下水矿化度产生一定的影响,改变作物根系土壤水分条件,从而影响作物的水分吸收和生理生长过程,合理的灌排工程可以促进作物的生长,提高产量。我国南北方灌排系统功能存在一定差异,南方以除涝防渗为主,北方则以提高抗旱能力、治理土壤盐渍化为主。同时,我国灌排系统还存在前期投入成本高、运行维护管理不完善、系统操作技术难度高等问题急需解决。未来,灌排一体化工程应朝着管网化、信息化和自动化方向发展,进一步提高田间水肥利用效率,实现灌排现代化。  相似文献   

14.
While extending irrigated areas to augment agricultural production, irrigation efficiency should be increased not only to improve the agricultural production but also to obtain the sustainable use of valuable and limited water resources. Through the use of Data Envelopment Analysis (DEA), which is a linear programming technique to determine the relative efficiency of a decision-making unit, it is possible to decide whether the use of water in an irrigation district is efficient or not. In this study, an input oriented DEA model is constituted to focus on the efficient use of inputs, and the method is applied to the irrigation districts having similar types of agriculture in the Buyuk Menderes Basin, Turkey. This paper aims to determine the efficient irrigation district(s), in other words where the application of water is the most profitable, considering two inputs; water volume supplied and the total irrigated area, and one output, the total value of agricultural production. The weight restrictions consistent with decision makers’ value judgements are added as constraints into the DEA models to prevent excessive weight flexibility assigned to inputs and outputs. The results have provided the efficiency scores of the irrigation districts and numerically delineated desired features of the irrigation districts for maximum efficiency. The analyses for three study years have inferred the robustness of the results. It is concluded that DEA is a practical tool for detecting local inefficiencies and proposing possible improvements for irrigation districts that could offer the greatest potential for growth.  相似文献   

15.
Numerous uncertainties and complexities exist in the agricultural irrigation water allocation system, that must be considered in the optimization of water resources allocation. In this paper, an agricultural multi-water source allocation model, consisting of stochastic robust programming and two-stage random programming and introducing interval numbers and random variables to represent the uncertainties, was proposed for the optimization of irrigation water allocation in Jiamusi City of Heilongjiang Province, China. The model could optimize the water allocaton to different crops of groundwater and surface water. Then, the optimal target value and the optimal water allocation of different water sources distributed to different crops could be obtained. The model optimized the economic benefits and stability of the agricultural irrigation water allocation system via the introduction of a the penalty cost variable measurement to the objective function. The results revealed that the total water shortage changed from [18.6, 32.3]?×?108 m3 to [15.7, 26.2]?×?108 m3 at a risk level ω from zero to five, indicating that the water shortage decreased and the reliability improved in the agricultural irrigation water allocation system. Additionally, the net economic benefits of irrigation changed from [287.21, 357.86]?×?108 yuan to [253.23, 301.32]?×?108 yuan, indicating that the economic benefit difference was reduced. Therefore, the model can be used by decision makers to develop appropriate water distribution schemes based on the rational consideration of the economic benefit, stability and risk of the agricultural irrigation water allocation system.  相似文献   

16.
An alternative solution of the water shortage problem in Libya   总被引:3,自引:2,他引:1  
In Libya there is a growing awareness of increasing demand for fresh water while fossil groundwater supply is limited. This situation of water supply has become more problematic with rapidly increasing population and low rainfall. Hence soon after the discovery of fresh groundwater in the deserts of southern Libya, the local authority has made huge efforts to address its water deficit problems, mainly through the implementation of “The Great Manmade River Project” to sustain its economy. Especially the agriculture sector exceeds its traditional supplies. The Libyan authority began to design and install the hydraulic infrastructure needed to withdraw and transport this fossil water to various demand sites along its Mediterranean coast where most of the population lives and where the water is used. There is an over-exploitation of fossil groundwater resources to meet the irrigation demands as a result of adapting a self-sufficing policy in food. Rapid development of agricultural activity, expansion of irrigated areas and over irrigation practices will lead to more depletion of water resources since most of the country's groundwater resources are non-renewable. The supply-driven approach for water management has demonstrated its inability to deliver a substantial degree of water sustainability on the national Libyan level. Despite the strenuous efforts made by the country, it still faces serious water deficits due to continuously increasing water demands beyond the limits of its available water resources. As pressure on water converges on the country's fossil water resources, an immediate reconsideration of agricultural water extractions is needed and appropriate actions have to be implemented in response to its huge consumption. This policy aims at rescuing the present water situation and at avoiding serious environmental and economical crises. Reorganisation of the water consumption pattern, to maintain the country's standard of living and to ensure the economical security for the future generation is drastically needed. This paper considers the country's water management that requires water policy reforms, with emphasis on supply and demand management measures and improvement of the legal and institutional provisions. This could be achieved by reviewing agricultural water policies in order to minimise some local deficits in water resources and to avoid water quality deterioration in the coastal areas. Developing additional non-conventional sources of water supply needs to be considered. This should be supported by creating authorised water institutions lead by a high-professional staff and enabling them in making the appropriate legislation and decisive measurements to allocate water among consumptive sectors as well as to ensure the protection of the environment.  相似文献   

17.
Debate about irrigation development of water resources in northern Australia has been hampered by a lack of quantitative information to enable accurate assessment of the volume of water that could potentially be regulated in the ‘North’ (north of the tropic of Capricorn). Too often the debate focuses solely on streamflow volumes and quantities of runoff. In this paper we present simple calculations to estimate a representative irrigation requirement and the potential exploitable yield in each of the 12 drainage divisions of Australia in order to more fully inform this on-going debate. Environmental, social, cultural and economic considerations are not examined. The results indicate that, despite northern Australia generating approximately 64% of the continent’s runoff, only 45% of Australia’s potentially exploitable yield is located in that portion of Australia, due to unfavourable streamflow characteristics, storage constraints and large evaporation losses. If exploitable yield and irrigation requirement were the sole factors constraining sustainable irrigation, under a full development scenario, southern Australia could hypothetically support an area of irrigation about 60% greater than that of northern Australia (based on only 36% of the country’s runoff). Using ‘best estimates’ of rainfall and evapotranspiration projected under changes in climate resulting from a moderate emissions scenario, the percentage of Australia’s exploitable yield located in northern Australia is estimated to increase from 45% to 47% by the year 2050, which equates to a 2% increase to the percentage of Australia’s hypothetical area of irrigation that could be located in northern Australia. These results suggest that efforts towards achieving and developing sustainable irrigation practices in the South will remain most important in achieving Australia’s long term irrigation potential. This study also highlights the need for better regional scale information on the potential to regulate streamflow in Australia, under current and future climates. Such information is essential to guide policy and planning, future Government and private investment, and to manage community expectations of Australia’s water resources.  相似文献   

18.
A tank cum open dug well system suitable for plateau region of eastern India has been developed for providing reliable irrigation to croplands. The system comprises of a series of tanks with open dug wells in the recharge zone of the tank that reharvest back the seepage water. Thus, the rainwater remaining in the tank as well as partial seeped water is used for providing round the year full irrigation. This system was evaluated in field in Keonjhar district of Orissa of eastern India with six tanks and five wells in two drainage lines. The total command area of the system of six tanks and five wells in both drainage lines is 23 ha and the total irrigation potential is 44.5 ha. The total cost of the system is US $19,180 making the cost of irrigation resource creation as US $426 per ha which is much less than about $2,220 per ha for major and medium irrigation projects in the last decade of 20th century. The system increased the rice yields from 1.92 t ha − 1 to a range of 2.25 to 3.8 t ha − 1 depending upon the package of practices or the amount of inputs. The farmers went for crops in post-monsoon and summer season and the cropping intensity rose to 112% in the first year, 126% in the second year and 132% in the third year. The internal rate of return from the system was 13.4% at the present level of utilization, which is about 2.4% more than the prime-lending rate of Indian banks, and 3.4% more than the lending rate for agricultural purposes.  相似文献   

19.
Water Productivity in a Rigid Irrigation Delivery System   总被引:4,自引:2,他引:2  
The rotational irrigation water delivery (warabandi) system practiced in the Indus river basin of Pakistan has continued for 100 years. Irrigation water allocated to the farmers under the warabandi system is proportional to farm size and is fixed. This rigid allocation system has been partly justified by its contribution to social equity though this may have been at the cost of economic gains. In order to assess the operation of warabandi’s basic rules, a farmers’ survey was completed from 124 farmers located on five watercourses. A questionnaire was administered to each farmer and farm management data were gathered. As fresh water resources are under stress and becoming scarce their efficient use in all applications should be assured in water allocations. It is shown from the survey results that water allocation based on very limited criteria does not maximize the socio-economic benefits gained from the use of scarce water. Thus, it is suggested that the existence or non-existence of fresh groundwater resources along with other critical variables should be taken into consideration when making canal water allocation decisions. Missed water deliveries due to failure of the canal system appear to be the largest cause of losses. Water charges need to be increased to fund large improvements in canal maintenance programs. It is pointed out that a framework should be developed as a tool to improve water productivity for Pakistan. This should include: consideration of the gross area of a tertiary canal, sensitivity of crop growth stage to water shortage, crop value, bias of allocation towards most water use efficient areas and water use efficient crops, the potential losses from water deficiency.  相似文献   

20.
The Egyptian Ministry of Water Resources and Irrigation (MWRI) has expressed concern about the current high cost of the Irrigation Improvement Project (IIP) implemented in the “old lands” of the lower reaches of the Nile River. Because the IIP is financed through fees paid by the direct beneficiaries of the project, i.e., irrigation water users, these same Egyptian agricultural producers are especially sensitive to the higher than expected costs that the project has incurred to date. The objective of the current study is to evaluate whether this cost reduction is associated with any deficiency in irrigation performance. This Monitoring and Evaluation (M&;E) study aims to answer questions such as: Does reducing pump capacity and increased pump operation affect the farmers negatively? And, does the use of electricity instead of diesel fuel affect the farmers positively? Six indicators were used to compare new design criteria in the W10 and the IIP1 irrigation system designs, water savings, irrigation cost, irrigation time, night irrigation, and land savings. The W10 project design achieved the minimum actual operating cost per unit of area and per unit of water compared to the IIP1 project design on both Meet Yazied and El-Mesk Canals. The total cost per unit of area in the W10 project design is lower than IIP1 by 19.33% and 24.92% on the Meet Yazied and El-Mesk Canals, respectively. The total cost per unit of water in the W10 design is also lower than IIP1 on the Meet Yazied and El-Mesk Canals. Average irrigation time for rice and cotton crops cultivated in the W10 area are higher than average irrigation time for these crops cultivated in the IIP1 area for all locations on the Mesqa (head, middle and tail), because of increased pump operation in the W10 area (16 to 20 h d???1). The number of irrigation events at the head of the Sefsafa Canal in the W10 area is higher than on the Meet Yazied and El-Mesk Canals in the IIP1 areas because of the increased pump operation in the W10 area.  相似文献   

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