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  • Articles  (9)
  • Other Sources
  • irrigation  (9)
  • Springer  (9)
  • MDPI Publishing
  • Architecture, Civil Engineering, Surveying  (9)
  • 1
    Electronic Resource
    Electronic Resource
    Simulating Reservoir Management under the Threat of Sedimentation: The Case of Tarbela Dam on the River Indus (2000)
    Springer
    Water resources management 14 (2000), S. 191-208 
    Details
    ISSN: 1573-1650
    Keywords: flushing ; hydropower ; irrigation ; operating rule curves ; reservoir sedimentation ; reservoir simulation model ; River Indus ; Tarbela Dam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract The useful life of Tarbela reservoir, on the River Indus, is threatened by a sediment delta which is approaching the dam'sintake tunnels; these lead to a hydroelectric power station and are used for irrigation releases. This article describes thesimulated system, involving Tarbela Dam, with Ghazi Barotha hydropower scheme downstream, and the planned construction of Basha Dam upstream. This study formed an innovative approachwhich enabled the relationship between demands and supply in the basin to be studied, under a range of development and operating scenarios, and to different time horizons. A computer software package, 'Hydro', was used to perform systemsimulation modelling of Tarbela Dam and the Upper Indus Basin,Pakistan. The results enabled estimation of the economic benefits of several potential future operating strategies forTarbela to be tested and compared. Employing the results of associated sediment modelling, projected storage/elevation curves were used to predict the irrigation and power benefitsavailable to Pakistan over the coming sixty years. It wassubsequently demonstrated that the most beneficial remedial measures are an underwater dike or dam to protect the intakes,and low-level flushing facilities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026579230560
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  • 2
    Electronic Resource
    Electronic Resource
    Wastewater Irrigation-Economic Concerns Regarding Beneficiary and Hazardous Effects of Nutrients (1999)
    Springer
    Water resources management 13 (1999), S. 303-314 
    Details
    ISSN: 1573-1650
    Keywords: economics ; irrigation ; nitrogen ; nutrients ; wastewater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract The optimal wastewater treatment level is affected by costs, hazards and benefits. Lowering the wastewater treatment level decreases fertilization costs because of the increased levels of available nutrients left in the water, and irrigation costs decrease if water prices reflect the lower treatment costs. Agricultural yields and/or prices may decrease according to differences between levels of nutrients needed by crops and those available in wastewater. The present article focuses on determination of monthly optimal treatment levels and of the mix of crops calculated to maximize agricultural incomes, according to farmers' point of view. It does not reflect the national point-view focusing on maximization of net national benefits considering also environmental hazards. The methodology appears in Haruvy (1994) and application will be presented in another article (Haruvy et al., 1999).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008114225469
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  • 3
    Electronic Resource
    Electronic Resource
    Sorghum Water Loss in Relation to Irrigation Treatment (1999)
    Springer
    Water resources management 13 (1999), S. 39-57 
    Details
    ISSN: 1573-1650
    Keywords: crop coefficient ; evapotranspiration ; irrigation ; resistance ; sorghum ; yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract Aiming towards rational irrigation water management in a seasonally dry climate, sorghum water losses via evapotranspiration were studied during a two-year experiment in relation to irrigation treatments in Central Greece. Relative to high irrigation (IH), that provided the root depth with 458 mm of water in 1994 and 512 mm in 1995, 56 and 64% of the water was supplied by the medium (IM) and 34 and 46% by the low (IL) treatments, respectively, during the two years. A fourth treatment (IHA) was performed like (IH) until the end of anthesis, when irrigation stopped. Gravimetric soil moisture was measured, biometric measurements were taken and all meteorological parameters required to estimate evapotranspiration by the Penman–Monteith equation were logged. A model estimating sorghum actual water loss was first run with the 1994 data. During the model-establishment year, it was found that (a) surface resistance rs, consisting of a canopy rsc and a soil rss resistance acting in parallel, was almost exclusively dependent on soil water shortage, (b) under the IM and IL irrigation treatments, the lowest possible (immediately after water application) canopy resistance r'sc, higher than the (IH) minimum canopy resistance rsc (min) = 40 sm-1, was irrigation-deficit dependent and (c) the rss (min) was as high as 1200 sm-1, common to all treatments. The model established was then verified with the 1995 data and used to calculate the crop coefficient kc values for sorghum. The model, although tending to underestimate actual evapotranspiration by 4–10%, depending on the treatment, may be considered as reliable. The kc values calculated are considerably higher than the kc values suggested for sorghum by the Food and Agriculture Organization (FAO). Therefore, taking also into account that any additional mm of water supplied results in an increase of 0.052 t of dry biomass per hectare, higher irrigation water applications could be recommended, although the low irrigation treatment made slightly better use of water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008026119228
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  • 4
    Electronic Resource
    Electronic Resource
    Irrigation development and environmental degradation in developing countries — a dynamic model of investment decisions and policy options (1996)
    Springer
    Water resources management 10 (1996), S. 129-146 
    Details
    ISSN: 1573-1650
    Keywords: irrigation ; environmental degradation ; dynamic optimization ; policy analysis ; developing countries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract In the wake of increased environmental and sustainability concerns associated with agricultural development, developing countries are faced with the dilemma of choice between the short-run technological gains and the long-run environmental conservation. A dynamic investment decision model is developed to optimize the use of scarce public investment funds in the magagement of irrigation water supply, depth to water table and soil salinity. Four major classes of investments with different impacts on the hydrological balance within the Indus basin are considered: (a) expansion of the surface irrigation network, (b) public drainage projects, (c) tax and subsidy policies designed to influence the rate of private groundwater exploitation and (d) investment in improving the efficiency of the existing canal system by reducing conveyance losses. The crop area lost due to water logging and salt accumulation is treated as a damage cost of increasing the application of surface irrigation water. The resulting optimality conditions from the model are used to assess the development and operation of public drainage projects. The model results are compared for areas underlain by fresh and saline groundwater. The model is also used to analyze recent policy debate which has focused on the use of incentives such as subsidized credit, energy subsidies, and electrical grid expansion to accomplish the transfer of tubewell operation from the public to the private sector. Optimal switching conditions for such transfers are derived. The results show that a private farmer's optimal decision will diverge more from the societal optimal decision as more externalities from surface irrigation are accounted for.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429683
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  • 5
    Electronic Resource
    Electronic Resource
    Stochastic sketching of infiltration-advance isochrones (1996)
    Springer
    Stochastic environmental research and risk assessment 10 (1996), S. 209-229 
    Details
    ISSN: 1436-3259
    Keywords: Infiltration-advance equation ; water spreading ; cellular automata ; irrigation ; surface hydrology ; hydrodynamics ; stochastic processes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Energy, Environment Protection, Nuclear Power Engineering , Geography , Geosciences
    Notes: Abstract A technique has been developed for predicting the irregular advance pattern often observed as water spreads on the surface of the ground. The technique is a combination of stochastic sketching, potential theory, probability theory, and a mass balance equation in the form of an advance equation. The technique can be used on flat as well as sloping terrain and addresses any form of obstructions or constraints to the flow of the water. The stochastic sketching portion of the technique uses cellular automata with transition probability movement rules to sketch the dynamics of small volume water elements in the defined environment. Randomly selected small volume flow path segments are computed and plotted. The envelope of these segments defines the wetted area and the advance front. Several examples are presented showing the patterns produced for various situations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01581464
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  • 6
    Electronic Resource
    Electronic Resource
    Appraisal and optimization of agricultural water use in large irrigation schemes: II. Applications (1992)
    Springer
    Water resources management 6 (1992), S. 201-221 
    Details
    ISSN: 1573-1650
    Keywords: Argentina ; groundwater ; irrigation ; simulation model ; surface water ; water use
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract In this paper, the theoretical approach presented in Part I is demonstrated by means of case studies on the irrigation schemes of Rio Mendoza and Rio Tunuyán in the Province of Mendoza, Argentina. The object of the case studies was the determination of optimal allocation of surface water to reduce the use of groundwater. Current and optimal conjunctive allocation of ground and surface water is studied by means of the developed simulation and optimization models. The second case study was designed on the basis of the experience gathered during the first one: each step of the case studies is compared. The comparison between the two case studies illustrates how to apply the proposed approach when the amount and quality of available data are different. For the more detailed Rio Tunuyán study, we determined the following physical characteristics of all terminal nodes: on-farm rotational intervals, mean water application depth, actual soil water storage capacity, crop water requirements, depth of groundwater table, aquifer transmissivity, and efficiency of groundwater use. The performance of the entire system is sensitive to changes in the water application depth, as it was shown by a simulation study. The application of our optimization approach to the conjunctive use of ground- and surface water showed that the total water requirements over a year can be met by a reassignment of water that reduces the total costs of a great amount.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00872356
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  • 7
    Electronic Resource
    Electronic Resource
    A numerical model of a saturated-unsaturated porous flow system (1988)
    Springer
    Water resources management 2 (1988), S. 183-190 
    Details
    ISSN: 1573-1650
    Keywords: Unsaturated flow ; numerical model ; irrigation ; drainage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract The paper presents a numerical model of transient, saturated-unsaturated water flow through a porous medium. The model solves Richards' equation, which is assumed to present water flow in both unsaturated and saturated zones. The equation is solved by the implicit iterative finite difference method, using the over-relaxation technique. The model is tested by comparison with published laboratory experiments. The agreement between measured and computed values is very good for both infiltration and drainage experiments. The purpose of the model is the prediction of a soil-water regime either in natural conditions or under the influence of an irrigation or drainage system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429900
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  • 8
    Electronic Resource
    Electronic Resource
    Screening model for assessing ‘cost’ of minimum flow requirements in the Svartå River, Sweden (1988)
    Springer
    Water resources management 2 (1988), S. 35-55 
    Details
    ISSN: 1573-1650
    Keywords: Hydroelectricity ; irrigation ; minimum flows ; mixed-integer ; multi-objective ; optimisation ; Svartå River ; urban water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract The minimum flow requirements in the Svartå River in Sweden are directed at maintaining fishlife and providing suitable dilution for waste flows. The implications of varying the minimum flow requirements in the river are examined using a mixed integer optimisation model. The model is formulated as a modified method-of-weights technique with the economic issues of hydro-electricity generation, irrigation and urban water supply placed in the objective function and the minimum flows specified within the constraint set. The integer component of the model is required to model the operating policy at the major flow regulation facility in the system and the ‘restricted’ validity of the irrigation permits. Application of the model shows that in dry years where competition between minimum flow levels and the other economic uses, is most intense, the levels achieved by the various economic objectives are only slightly reduced even with significant increases in the minimum flow requirements. Variations in minimum flow requirements of up to 45% only produce changes of 10% or less in the economic objectives. The lack of sensitivity of the objective levels is due primarily to the level of control exerted indirectly on the whole system in dry years by the release regulation policy and the restricted validity of the irrigation permits. In normal to wet years these policies are not as restrictive and more choice is available. In such years, however, there is generally sufficient water to satisfy all requirements and allocation is not a critical issue. The model itself is formulated generally so that a range of scenarios beyond those examined specifically in the paper can be considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00421929
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  • 9
    Electronic Resource
    Electronic Resource
    Development and testing of soil water regime simulation models (1987)
    Springer
    Water resources management 1 (1987), S. 293-303 
    Details
    ISSN: 1573-1650
    Keywords: Soil water regime ; modelling ; simulation ; evapotranspiration ; drainage ; soil water resources ; irrigation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: Abstract Four soil water balance simulation models corresponding to specific soil-crop relations were developed for application to irrigation planning and management. The forms of the models were inferred from 18 months of weekly and bi-weekly soil water data and daily meteorological data. Soil water change is computed by budgeting of the water inputs and outputs, namely precipitation, evapotranspiration, drainage, and runoff. Actual evapotranspiration was found to be dependent on both potential evapotranspiration and soil water content. Empirical drainage functions were developed, but semi-empirical ones inferred from theoretical knowledge of soil hydraulic properties performed at least as well. Runoff functions were required to explain only exceptional conditions of very heavy rainfall. A quantitative assessment of each model's prediction accuracy was performed. The uncertainty that can be expected for any predicted value with a cumulative probability of 0.95 is in all cases within an interval of 1% of the soil water content in average conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00421881
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