Optimal Water Allocation for Irrigation Planning

The aim of this study was to assess the effect of applying different irrigation levels and soil mulches on vegetative growth, yield and water use efficiency (WUE) of potato (Solanum tuberosum L.) valor cultivar. The experiment was carried out during two successive seasons of 2010/2011 and 2011/2012 under open field conditions in El-Bossily farm, Agricultural Research Center, El-Beheira Governorate, Egypt. The experimental design was split plot and consisted of three irrigation levels as main plots and three soil mulches as sub-plots with three replicates. Drip irrigation was practiced at 50, 75 and 100% of irrigation requirements (IR). The soil mulches consisted of black (PE-B) and transparent (PET) polyethylene as well as rice straw (RS). In both seasons, the application of different irrigation levels and mulch treatments affected significantly potato vegetative growth, tuber yield and nutrients content (N, P and K). The use of PE-B mulch resulted in significantly higher values of plant height, number of leaves, canopy fresh and dry weight per potato plant. Increasing IR of potato from 50% to 100% enhanced total and marketable yield. The highest WUE was obtained under PE-B mulch followed by RS and both of them were superior compared to the PET and bare soil. Regarding the interaction between irrigation and mulching treatments, the highest vegetative and tuber yield were obtained by PE-B treatment combined with 100% IR. However, the highest WUE was obtained by 75% IR combined with PE-B mulch.

The allocation of groundwater resources has been a challenge for many years due to its unforeseen side effect and lag time issues, which are often overlooked. The full impact of groundwater utilization/abstraction takes time to realize its effect at its full. In this paper, long‐term effects and groundwater dynamics were assessed using a water balance model and a time series analysis, respectively. Undeveloped groundwater systems are commonly found in a state of equilibrium, where, on average, equal amounts of water are recharged and discharged. A water budget is a static accounting of the state of the system at a given time, often before the system is developed. Water balance analysis was carried out together with the groundwater through flow, hydrograph, and surface‐groundwater interaction analysis (base flow index) to develop a conceptual water balance model, which is a very basic representation of a complex natural aquifer system and is instrumental to constrain and build a robust numerical model that can be readily justified and updated. A noble approach was employed to assess and constrain the discharge coming out of the model area to sustain the lake level, located to the north of the study area, using the whole lake catchment and lake water balance analysis. Based on the lake water balance, there is a deficit between input and output computation, and hence there should be a groundwater input to sustain the historical lake area. The analysis showed that the model area contributes 40% of the lake catchment, and hence the portion of the groundwater inflow feeding the lake was computed. This is one of the means to constrain the discharge, which adds more confidence to the recharge estimation. This is very important because the size of a sustainable groundwater development usually depends on how much of the discharge from the system can be captured by the development. Capture is independent of the recharge. Instead, it depends on the dynamic response of the aquifer system to the development. The idea that knowing the recharge is important in determining the size of a sustainable groundwater development is a myth and has no basis. The important entity in determining how a groundwater system reaches a new equilibrium is capture. How capture occurs in an aquifer system is a dynamic process. Following this study, lake water balance assessment was indirectly considered as prior information for the numerical model calibration of the discharge from the model area using a conductance parameter. Conductance is a key parameter to estimate the discharge volume together with the change in the simulated hydraulic head between time steps. The water balance error highlights which one is more sensitive, and this could help to assist in planning for future data collection/field work and where to invest the money. The water balance computation helps to figure out the degree of surface‐groundwater interaction, uncertainty, sensitive parameter, helps in the decision to invest time and money, and operates as a cross check with other analytical or numerical modelling.

In order to optimize the usage of water in agriculture, it is necessary to increase the efficiency of irrigation systems, especially those of surface irrigation. One of the steps to be made to achieve this goal is the optimal design of surface irrigation. It this article the design variables of furrow irrigation, that includes length of furrow, inflow rate and irrigation time (time of cutoff), were calculated to minimize the irrigation costs, the objective function, and to obtain a maximum application efficiency. The objective function encompasses water, labor, head ditch and furrow digging (ditch constructions) costs. Labor cost is irrigation time's function and the latter is dependent on water advance period in the furrows. Therefore, it is necessary for the objective function to apply explicit and accurate equation in order to calculate time of advance. Because in none of the accurate methods for furrow irrigation design, such as zero-inertia modeling, the advance time is explicitly calculated, therefore in this research the equation obtained by Valiantzas, which he extracted from the results of zero-inertia modeling, was used. In the objective function in addition to the design variables the specifications of soil, furrow and net irrigation requirement also exist. Therefore, it is possible to calculate design variables and afterwards the irrigation efficiency for different soil types and plant types. In this article this task was performed with different soil types and in accordance with different requirements for irrigation and the results are presented in the tables.

Optimal operation of water resources in multiple and multipurpose reservoirs is very complicated. This is because of the number of dams, each dam's location (Series and parallel), conflict in objectives and the stochastic nature of the inflow of water in the system. In this paper, performance optimization of the system of Karun and Dez reservoir dams have been studied and investigated with the purposes of hydroelectric energy generation and providing water demand in 6 dams. On the Karun River, 5 dams have been built in the series arrangements, and the Dez dam has been built parallel to those 5 dams. One of the main achievements in this research is the implementation of the structure of production of hydroelectric energy as a function of matrix in MATLAB software. The results show that the role of objective function structure for generating hydroelectric energy in weighting method algorithm is more important than water supply. Nonetheless by implementing ε-constraint method algorithm, we can both increase hydroelectric power generation and supply around 85% of agricultural and industrial demands.

In order to optimize the usage of water in agriculture, it is necessary to increase the efficiency of irrigation systems, especially those of surface irrigation. One of the steps to be made to achieve this goal is the optimal design of surface irrigation. It this article the design variables of furrow irrigation, that includes length of furrow, inflow rate and irrigation time (time of cutoff), were calculated to minimize the irrigation costs, the objective function, and to obtain a maximum application efficiency. The objective function encompasses water, labor, head ditch and furrow digging (ditch constructions) costs. Labor cost is irrigation time's function and the latter is dependent on water advance period in the furrows. Therefore, it is necessary for the objective function to apply explicit and accurate equation in order to calculate time of advance. Because in none of the accurate methods for furrow irrigation design, such as zero-inertia modeling, the advance time is explicitly calculated, therefore in this research the equation obtained by Valiantzas, which he extracted from the results of zero-inertia modeling, was used. In the objective function in addition to the design variables the specifications of soil, furrow and net irrigation requirement also exist. Therefore, it is possible to calculate design variables and afterwards the irrigation efficiency for different soil types and plant types. In this article this task was performed with different soil types and in accordance with different requirements for irrigation and the results are presented in the tables.

A mathematical model involving inverse optimization theory and data en-velopment analysis (DEA) as an efficiency measurement tool has recently been developed to handle the reallocation of resources in the context of Mergers & Acquisitions (Gattoufi et al. [8]). This paper highlights the practical importance of these concepts through an application in the farming sector, using a sample of 45 farms from the Batinah region, in the sultanate of Oman. Through a random selection of potential merging farms, the proposed InvDEA method is shown to enable not only reallocating resources but also reversing the merger's decision if the contribution of one of the merging entities is found to be poor. In order to gauge the practical importance of the InvDEA model, its application scope can be expanded to other sectors, like banking, insurance, education, healthcare, etc.