Irrigation
F. Hayatgheibi; N. Shahnoushi; B. Ghahreman; H. Samadi; M. Ghorbani; Mahmood Sabouhi
Abstract
Introduction: The development of water resources in many cases has led to increased economic welfare, improved living and health standards, food production, etc. However, in some cases due to the insufficient attention to all aspects of these projects, the irreparable environmental effects and subsequent ...
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Introduction: The development of water resources in many cases has led to increased economic welfare, improved living and health standards, food production, etc. However, in some cases due to the insufficient attention to all aspects of these projects, the irreparable environmental effects and subsequent social and economic effects have been imposed on society. Paying attention to environmental water requirements is one of the most important issues in decision making in water resources development plans. The objective of this study is to assess river environmental water requirements in upstream and downstream of Beheshtabad Dam. Beheshtabad Dam has designed to build on the Karun River for water transfer from Karun to Zayanderood basin. But it has not been implemented due to the various problems and challenges. Materials and Methods: Protecting and restoring river flow regimes and hence, the ecosystems they support by providing environmental flows has become a major aspect of river basin management. Environmental flows describe the quantity, timing, and quality of water flows required to sustain freshwater,estuarine ecosystems,the human livelihoods, and well-being that depend on these ecosystems. Over 200 approaches for determining environmental flows now exist and used or proposed for use in more than 50 countries worldwide. In the present study, hydrological methods have been used. These methodes include Tennant and modified Tennant, Flow Duration Curve (FDC) and FDC shifting (for different environmental management classes). For this purpose, four hydrometric stations (three stations upstream and one station downstream of the dam) have been selected. Results and Discussion: The results of the study showed that the river water flow had not been sufficient to meet environmental water requirements in several cases, especially in years when the region was experiencing mild to moderate drought conditions. According to the Tennant method, the minimum environmental flow requirement averages based on Beheshtabad, DezakAbad, Kaj, and Armand stations data were 3.80, 5.06, 6.99, 22.01 m3/s, respectively. Using the mentioned stations data, , the minimum environmental flow requirement averages were 3.62, 6.07, 7.91, 23.67 m3/s based on the modified Tennant method. According to the flow duration curve method, minimum environmental flow requirements (Q95) were 1.96, 5.1, 8.32, 30.62 m3/s, using data collected from Beheshtabad, DezakAbad, Kaj, and Armand stations, respectively. The results of the flow duration curve shifting method indicated that the river water flow did not meet the river environmental water requirements in different environmental management classes in some months and years. Comparative results of different methods revealed that the minimum environmental flow requirement of Beheshtabad River upstream of Beheshtabad Dam was 1.22-16.75 m3/s from September to April (based on FDC shifting method, class C). The estimated minimum environmental flow for Koohrang River was 3.69-16.81 m3/s from September to April. The downstream of the dam, Karun River requires a minimum flow rate of 20.8-73.29 m3/s from September and October to April (based on FDC shifting method, class E). Conclusion: According to the results of various methods used in this study, the Karun River flow is not enough to meet the minimum river environmental water requirements in some years and months. Therefore, decision-makers must pay attention to the environmental water requirements in decisions related to the development plans and water transfer from this river. It should be noted that the river environmental water requirements have not been met completely when the region has experienced moderate or mild drought, which would be more acute in cases of more severe drought conditions. Therefore, the current surplus water of this basin may not be a sustainable source to transfer to another basin.
elham kalbali; Mahmood Sabouhi; mahmoud ahmadpour
Abstract
Introduction: In the present study, dealing with water deficit challenges for Gorgan River Basin has been considered. Golestan province's economy is dependent on agriculture but the occurrence of drought periods reduced the agricultural production and consequently the region's economy is in crisis. Therefore, ...
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Introduction: In the present study, dealing with water deficit challenges for Gorgan River Basin has been considered. Golestan province's economy is dependent on agriculture but the occurrence of drought periods reduced the agricultural production and consequently the region's economy is in crisis. Therefore, performing studies for programming and management of the water resources of the province and the water allocation in the margin of Voshmgir dam in Gorganrood basin has a great deal of importance. The issue of the allocation of water resources is proposed in order to maximize the expected profit of the water system. According to the regional water organization policy, one of the main goals of Voshmgir dam water management is the allocation of water between the competing consumers. If the amount of promised water is released in the future, the expected net profit of the system will be realized and if it is not released, the system will experience losses.
Materials and Methods: In this studyWater supply is considered stochasticand objective function of the model is to maximize the system (Agriculture, Aquaculture and Environment) profit and optimal allocation of water during the programming period using a two-stage stochastic model as follows:
Constraint of the available land:
Constraint of the available water in each of the main canals:
Constraint of the available water:
Constraint of the amount of inflow water
Reservoir capacity constraint
Constraint on the maximum and minimum water demand for environmental sector
Constraint on the maximum and minimum water demand for crops
Constraint on the maximum and minimum water demand for warm-water fish
Constraint on non-negativity of the decision variables in the model
Results and Discussion: The length of the right main canal of this network is about 17.76 km and the length of the left main canal is about 21.338 km. In this study, is considered for the right main canal and is considered for left main canal. Lands under irrigation network are considered in three regions. Right bank regions and sample farm are covered by the network in the right part of the network and the left bank regions are covered by the network on the left. Thus, there is one region in the left side of the network and there are two regions on the right. The major crops cultivated in the agricultural lands of the network include wheat, barley, canola, cotton, alfalfa, sunflower, rice, cotton-melon, and maize. Due to the random nature of the river flow to the dam, fixed and determined data cannot be used to calculate the volume of water entering the irrigation system, for this reason, using simulation techniques, we can predict the future behavior of the system for each reservoir. The results of the study showed that only agriculturalsector suffers from water deficit and target water demand of the other sectors is supplied and there is no deficit of water for these sectors and target water demand, lack of water and the final allocation of water in the agricultural sector are declined under different efficiencies of irrigation. If other sectors are remained unchanged and irrigation efficiency did not affect them, it is because irrigation efficiency has a direct impact on the water use in agriculture and decreases by increasing the efficiency of the allocated water to this sector and the amount of water stored in the reservoir for the coming year is added. By increasing the efficiency of irrigation which has a direct impact on water use in agriculture sector, the amount of water deficit reduced as a result of the increased system profit.
Conclusion: The results showed that there is no water deficit for aquaculture and environmental sectors in the scenarios of dry, wet and normal years and the target water demand of these sectors is supplied. However, the amount of water deficit in agricultural sector in dry year with the probability of 18% and under the efficiencies of 37, 45 and 51 percent would be 40.98, 23.67 and 14.07, respectively. With the increase in efficiency, water demand in agriculture, water deficit and ultimate allocation of water to this sector are decreased and system profit under different efficiencies is increased. Based on the obtained results, highlighting the irrigation efficiency and allocating the minimum water demand of the sectors is recommended.
A.A. Keikha; M. Mosannan Mozafari; M. Sabouhi; Gh. Soltani
Abstract
River flow modeling has special importance in water resources management. Since the actual river flow data are often low and they correlate and depend yearly and monthly, making the data similar to historical data is so difficult and complex. In this study, 50 year data and Seasonal Auto Regressive Moving ...
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River flow modeling has special importance in water resources management. Since the actual river flow data are often low and they correlate and depend yearly and monthly, making the data similar to historical data is so difficult and complex. In this study, 50 year data and Seasonal Auto Regressive Moving Average (SARMA) and Clayton and Frank Copulas which are the prediction and simulation methods of the river flow molding, were used to generate random flow data of Helmand River. Results show, SARMA model forecasts minimum river flow data very good, but the generated data hasn’t correlation of historical data and usually the maximum river flow is greater than real data. Otherwise, Copula preserved concordance of real data and make the data that are similar to real river flow. Therefore it is proposed that Copula is used for Helmand river flow modeling. Also this method use for simulating other river flows and also using other Copulas for river flow modeling could have the subject of future researches.
