نشریه تحقیقات مهندسی سازه های آبیاری و زهکشی
سال بیست و سوم شماره 89 (زمستان 1401)

Walnut is one of the most valuable garden products of the country, which will be very profitable for gardeners if the water and food needs are met on time. During the growth period, the walnut tree goes through different stages, during these stages, the lack of sufficient and timely irrigation will affect not only the crop of the same year, but also the quantitative and qualitative production of the next years. The results of various researches have shown that the walnut tree is sensitive to the lack of water and the lack of soil moisture leads to a decrease in yield and the quality of the product in terms of color and size. Researches in the country are mainly focused on determining the water requirements of walnut trees, the effects of low irrigation and the quality of irrigation water on the quantitative and qualitative performance of walnuts, and not many researches have been done on determining the amount of water used by walnut trees in the country. The review of the articles shows that walnut is one of the water-bearing products among garden products, and due to the severe limitation of water resources in the centers of production of this product in the world, many researches focused on determining the amount of water used for walnut trees and low management. It has been irrigated. On the other hand, the researches carried out in the country have mainly been carried out either in limited areas or in the form of research projects on the scale of experimental plots. Therefore, there is almost no comprehensive report on measuring and estimating the volume of water used for this water-bearing product in the country. Based on this, in the current research, the amount of water consumed by walnut gardeners in the country has been measured.

Considering that the main purpose of the research was to measure the volume of water used for walnut production in different regions of the country, the water given by gardeners for walnut production during two cropping seasons was measured without interfering in irrigation management and at the level of users' gardens. Is. In this research, due to the fact that the yield of walnut is affected by the age and climatic factors such as frosts, the measurements were made during two consecutive crop years 1396-1397 and 1397-1398. Based on this, the provinces of Hamedan, Kerman, Lorestan, East Azerbaijan, Kermanshah, Chaharmahal and Bakhtiari, Kohgiluyeh and Boyerahmad, Zanjan, Fars, Markazi and Qazvin, where the area under cultivation and the amount of walnut production in them are about 70 and 75% of the whole country, respectively. include, were selected as pilot areas for the implementation of the current research. After that, in each province, city or cities, the top producers of the mentioned product were determined in terms of the level of cultivation and production, and finally, the desired gardens were selected in the cities. In this regard, we tried to select the gardens in such a way that they cover most of the conditions such as climate, garden area, planting intervals, soil texture, water and soil salinity, irrigation methods and different managements, etc. The volume of water supplied was measured with the WSC flume or ultrasonic flow meter without interfering with the irrigation program.

The results of the research showed that the volume of applied water of walnut orchards in the studied areas varied from 3050 to 14800 m3/ha and its weighted average in the country was about 7000 m3/ha. Also, the amount of water used in the selected gardens in two methods of surface and drip irrigation was obtained as 7675 and 5709 m3/ha, respectively. The two-year average yield of walnuts in the production areas varied from 520 to 3280 kg/ha and its weight average was 1235 kg/ha. Based on this, the productivity index of irrigation water varies from 0.04 to 0.71 kg/m3 and its average weight in the country is about 0.20 kg/m3. The general results of the research indicate that in the investigated provinces, the amount of water used in walnut orchards is less than the gross water requirement of this product and there is a kind of forced under-irrigation in walnut orchards.

The study of fish habitats is important for us to better understand the impact of reservoir construction on river ecosystems. Hydropeaking hydropower plants are the main source of renewable energy, meeting sub-daily peaks in electricity demand. Dam reservoir that regulates river water to supply different sectors demands such as drinking water municipal, agricultural, and hydropower generation and this ignores the need for water in the river as the first beneficiary. The development of a rational watershed planning and management plan (develop a suitable ecological flow scenarios) is significant for the survival, reproduction, and development of fish. Recently, several classical approaches were used to estimate ecological flow, including hydrologic, hydraulic, and a habitat suitability modeling approach. The hydrological approach determines ecological flow based on historical hydrological data, of which one representative method is the Tennant method. The hydraulic approach determines the ecological flow according to the wetted perimeter of the cross section of the river. Hydrological and hydraulic approaches are favored because of their simplicity and ease of calculation, but both of them lack the biological mechanisms and biological requirements. Fortunately, the habitat suitability modeling approach combines the knowledge of hydraulics and biology to establish the relationship between habitat and hydraulic factors. It has certain advantages in the evaluation of ecological flow and has attracted more and more researchers’ attention. The most classical habitat suitability modeling approach is the instream flow incremental methodology (IFIM) and its physical habitat simulation component (PHABSIM), which includes the suitability of habitat target species to a series of hydraulic factors such as flow velocity and water depth to build a habitat suitability index model. The habitat suitability modeling approach provides the best range of hydraulic factors such as flow for habitat target species, which has certain reference significance for guiding reservoir operation. The Physical Habitat Simulation Model (PHABSIM) is proposed to simulate the relationship between streamflow and physical habitat for various life stages of target fish species, and thus to determine the optimal ecological flow of the representative river reach.The classical PHABSIM includes two components, namely hydraulic simulation and habitat modeling. On the basis of that, one-dimension hydraulic simulation model is proposed to determine characteristics of the stream in terms of depth and velocity as a function of discharge. As for habitat modelling, the river sectors and aquatic species most vulnerable to the variation of streamflow should be identified initially. Then, the Habitat Suitability Index (HSI) is introduced to reflect the preferences of target fish species with regards to the flow velocity, depth, and channel properties. Basically, HSI was determined according to the number of fish population appearing at the target point. The maximum value of HSI is set at 1.0, and the rest of the HSI values are determined in terms of relative ratio to the maximum value. Then, the Weighted Usable Areas (WUA) is employed to reflect the amount of physical habitat that available for fish species at different flow condition, which can be calculated as an aggregate of the product of a composite HSI. In terms of ecological constraint, maintaining at least 75% of largest WUA is set as an example in optimization modelling, to describe the detailed process to incorporate the ecological demand into reservoirs operation under one certain recovery level.Based on the results, the environmental flow in the range of 2.5-18.55 m3/s was calculated as the amount of release flow needed to stabilize the fish species and habitat of Jajrood River. Also, the low flow months (July to November) compared to the high flow months (March to June), need to consider a higher proportion of the average monthly flow than the mean annual flow as the minimum required environmental flow. The reservoir operation makes flow series flat and the duration of a single pulse increases compared with flow series before construction. Overall, it is obvious that the hydrological parameters of natural flow have a lager alteration due to the construction and operation of reservoir, which may change the downstream riverine structure and threaten freshwater biodiversity. The combination of eco-flow indicators and hydrological regime alteration, which is capable of mirroring the key hydrological information and related ecological connotation, is prove to be an effective method to evaluate the eco-hydrological regimes. It was demonstrated that the operation of the hydroelectric power plant in the hydropeaking system is the cause of a large flow alteration in respect of the frequency and duration of low- and high-flow pulses and the rate and frequency of change in the flow. The change in the manner of operation of the hydroelectric power plant affected the reduction in the degree of transformation of most features of the flow. Trend of maximum and mean flow ratio and maximum and minimum flow ratio has attenuated in reservoir after condition.

Extension activities to improve irrigation and farm management will have an effective role in increasing yield and optimal use of water and soil resources. Yield gap is considered as one of the important issues in farm management, and it is very important to know the factors affecting it. One of the problems of farmers is their little knowledge in the field of water and soil. If they have access to modern knowledge and farm management, they can make an effective contribution in managing water use and increasing production. One of the solutions that can be effective in the field of optimal management of water consumption and other production inputs is to increase the knowledge, attitude and skills of farmers. The main goal of this research was to investigate and analyze the role of extension activities implemented in model sites located in the northern region of Khuzestan province in increasing yield and improving water productivity.

The intended extension method in this research was a model site based on which each model site has a main user and between 20 and 25 functional users. Functional units included farmers who, while visiting the main site, applied all or part of the recommendations used in the main site in their own farm.In order to transfer knowledge, increase yield and water productivity at on-farm scale, 52 extension model sites in the regions of Dezful, Shush, Shushtar and Andimshek located in the north of Khuzestan, Iran, (2017-2019) and in the technical packages (balanced nutrition, cultivation, optimal length of border irrigation, cultivar, low tillage methods, modified irrigation method) were done according to different crops. The crops were included wheat, corn, canola, sugarbeet, mung bean, onion, cabbage, lettuce, eggplant, beans and citrus fruits. In addition to model sites, control farms under traditional management were also investigated and evaluated. The result of comparing the average values of advanved management treatment (main site) and traditional management (control) was with t-test indicates the existence of a significant difference in yield and water productivity. Water productivity was obtained from the ratio of yield (kg/ha) to irrigation water. The guaranteed selling price of wheat, canola and sugar (beet) was 115 thousand rials, 235 thousand rials and 230 thousand rials, respectively. All measures in two parts of the farm were carried out by the operator under technical supervision and all measurements were carried out by the researcher.

The results of extension activities conducted by researchers and agricultural experts in the faremer condition and with the participation of 1201 of them, showed that if the results are widespread, the total amount of crop production will increase despite the reduction in irrigation water consumption. The amount of expected increase in the production of wheat, Canola, sugar beet, corn, mung bean and citrus fruits in Shush region was 14857 tons, 13347 tons, 8303 tons, 6225 tons, 221 tons and 870 tons respectively; The expected increase in the production of wheat, Canola and beans in Shushtar region was 19750 tons, 2028 tons and 83 tons, respectively; The expected increase in the production of wheat, Canola and beans in Shushtar region was 19750 tons, 2028 tons and 83 tons, respectively; The expected increase in wheat, corn and eggplant production in Andimshek region was 21966 tons, 3792 tons and 71 tons respectively and The expected increase in the production of wheat, Canola, sugar beet, corn, onion, lettuce, cabbage and citrus in Dezful region was 9447 tons, 20107 tons, 717 tons, 1594 tons, 2478 tons, 3610 tons, 5749 tons and 19232 tons respectively. The increase in water productivity by using specific technical packages for each crops compared to the control for wheat, canola, sugar beet, corn, vegetables, beans, mung bean, and citrus fruits is 10, 35, 9.6, 21.4, 42.5, 11.1, 50 and 168 percent respectively.

Considering the nature of the model sites, which is accompanied by the participation of the users in the processes of learning and applying techniques, the continuation of these activities can help the development and sustainability of the aforementioned achievements.

Razavi Khorasan province is one of Khorasan provinces in northeastern Iran, centered on Mashhad. The area of this province is 118854 square kilometers. Due to having high evaporation potential and low rainfall, which is mostly associated with inappropriate distribution, this region is among the dry and semi-arid regions of our country, so that water is considered the most important factor limiting the growth and development of agriculture. Nowadays, the existence of limitations in water resources has made it necessary to create ways to increase water productivity. This is a proof of the importance of careful planning and finding the use of different irrigation methods to increase the water productivity of agricultural and garden crops. By examining the sources, it was found that the amount of water used in the tomato crop varies in different regions and with different irrigation systems. This research aims to measure the volume of applied water, the yield and productivity of tomato juice under the management of farmers in Razavi Khorasan province (Torbetjam, Chenaran and Mashhad cities) and compare the amount of applied water with the water requirement of tomatoes in these three plains (city) with the national document and It was also calculated by Penman-Monteith method with meteorological data.

This project was carried out in the field in order to determine the useful water of tomatoes in the fields under the management of farmers during one cropping season (2019). Three cities of Torbat Jam, Chenaran and Mashhad were selected in Razavi Khorasan province, which have the largest area under tomato cultivation. At first, based on the data required by the project, a questionnaire containing necessary information for investigation and logical conclusion was prepared. The required data of the selected farms in each city were either measured or through face-to-face interviews with the farmer or were calculated and completed according to the data of the previous two stages. The measurements were carried out in type of water source, irrigation network and method and water source discharge, total level The field and area under cultivation of tomato crop, variety, planting arrangement, planting date, soil texture, electrical conductivity of irrigation water and soil saturation extract, date of first irrigation, irrigation cycle and different irrigation methods, etc. The Measured Applied water were compared with the net irrigation water requirement estimated by the Penman-Monteith method using the last 10 years meteorological data (2010 to 2019) and also with the national water document values. Crop yield was recorded at the end of the growing season and water productivity was calculated as the ratio of yield to total water (irrigation applied water and effective rainfall).

The results showed that the amount of applied water, the amount of tomato yield and the water productivity in Torbat Jam region were 13424 m3/ha, 50629 kg/ha and 3.825 kg/m3, respectively. The amount of applied water, the amount of tomato yield and the water productivity in Chenaran region were determined as 10782 m3/ha, 67700 kg/ha and 6.266 kg/m3, respectively and The amount of applied water, the amount of tomato yield and the water productivity in Mashhad region were determined as 12262 m3/ha, 63686 kg/ha and 4.410 kg/m3, respectively. The average amount of applied water, the amount of tomato yield and the water productivity in above three regions were determined as 12245 m3/ha, 60219 kg/ha and 5.096 kg/m3, respectively. Also, the average volume of irrigation water, yield and productivity of water in the surface irrigation method were 13379 m3/ha, 52682 kg/ha and 4.042 kg/m3respectively, and in the drip irrigation method are 11621 m3/ha 64365 kg/ha and 5.656 kg/m3 was obtained.

In Razavi Khorasan province, underground water sources are facing a reservoir deficit. Therefore, efforts towards better use of extracted water and reducing exploitation of underground water resources are inevitable. In this project, the water given by the farmers for tomato production during one cropping season and without expert intervention in the irrigation management of the farmer was measured in the three plains of Torbat Jam, Chenaran and Mashhad, which had the largest area under tomato cultivation in Razavi Khorasan province. The method of irrigation of the fields was surface and drip irrigation (type). The results showed that the average applied water, yield and water productivity in all investigated tomato fields were 12245 cubic meters per hectare, 60219 kg per hectare and 5.096 kg per cubic meter of water, respectively. The difference between the volume of applied water, performance and water efficiency in two methods of surface and drip irrigation was significant. Under the drip irrigation system, the amount of applied water is 15% less (11,621 cubic meters per hectare versus 13,379), the yield is 22% higher (64,365 kg/hectare versus 52,682) and the water efficiency is about 40% higher (5.676 kg/cubic meter in vs. 4/042) was from the surface irrigation method.

Labyrinth weirs reduce the flood height compared to linear weirs. Labyrinth weirs have a longer length than linear weirs and therefore the flood will pass over it with a lower height. But different forms of Labyrinth weirs have different efficiency. Considering the many effective parameters in the discharge coefficient of Labyrinth weirs, in this research, semi-circular and triangular homologous labyrinth weirs are investigated. Therefore, only changes in the angle of the weir head and the angle with the channel wall will be compared and investigated.

Experiments were performed in a channel with a width of 0.8 meters and a flow rate of up to 70 liters per second. 10 weir models with a thickness of 4 mm were made, five of which are triangular weirs and 5 of which are semi-circular weirs. The height of the weirs is 15 cm and the ratio of the length of the weirs to the width of the channel (L/W) is equal to 1.26. Each triangular labyrinth weir was compared with its homologous semi-circular weir. This means that the single-cycle semi-circular Labyrinth weir with the upward apex will be compared with the triangular single-cycle Labyrinth weir with the upward apex. Other Labyrinth weirs will also be compared with their corresponding triangular Labyrinth weirs. This causes the angle of the head of the weir as well as the angle of the weir with the wall of the downstream channel to be investigated and other parameters effective in the discharge coefficient are constant in this investigation. Finally, according to the measured data, a relation for the discharge coefficient will be presented.

The comparison of the triangular labyrinth weir with the identical semi-circular weir showed that the discharge coefficient of the triangular weirs is generally higher. The maximum reduction of the discharge coefficient of the semi-circular labyrinth weir was 9%, which is for the single-cycle labyrinth weir with the with downward apex. With the increase of cycles and the placement of the weirs apex towards the upstream, the distance between the discharge coefficient of the identical semi-circular and triangular labyrinth weirs decreases and their efficiency becomes almost the same. The smaller angle of the semi-circular labyrinth weir with downward apex with channel wall causes more interference of Nappe with the channel wall and cause more local submergence and reduce its efficiency. Also, the angle of impact of the flow jets at the apex of the semi-circular labyrinth weir with downward apex is greater than that of the triangular labyrinth weir, which causes more turbulence and as a result reduces the efficiency more at the apex of the semi-circular labyrinth weir. By placing the apex of the labyrinth weir towards the upstream, the impact of the flow jets at the apex is eliminated and the angle of the weir with the wall of the downstream channel increases, which ultimately increases the efficiency of the weir. The increase in efficiency in a semi-circular weir with the apex towards the upstream is more than in a similar triangular weir, and as a result, the discharge coefficient of the two weirs is close to each other. For triangular labyrinth weir, the discharge coefficient is equal to -0.146Ln(HT/P)+0.4959 with a regression of 0.94 and for semicircular labyrinth weir, the discharge coefficient is equal to -0.158Ln(HT /P)+ 0.4731 with a regression of 0.9, which indicates that these relationships fit the data well.

The results showed that the labyrinth weirs with the upward apex have a better performance than the labyrinth weirs with the downward apex. Also, semi-circular labyrinth weirs had lower efficiency than triangular labyrinth weirs. Of course, with the placement of the apex of the labyrinth weirs upstream, the performance of the semi-circular labyrinth weirs increases and they approach the triangular labyrinth weirs. Therefore, in labyrinth weirs with upward apex, which have better performance, the use of each of semi-circular and triangular labyrinth weirs will not make much difference.

The cost of implementing spillways includes a large part of the dam construction budget. Optimizing these structures can significantly reduce the cost of building dams. So far, many studies have been done on optimizing the dimensions of spillways in order to reduce the amount of materials used. Among the used optimization methods, the methods based on meta-heuristic algorithms have had stunning results. The review of the studies conducted in the field of stepped and labyrinth spillways shows that the goals of all studies in stepped spillways have been to provide an acceptable plan for energy dissipation and in labyrinth spillways to reach a the largest amount of water passing. The purpose of this study is to combine stepped spillways with labyrinth spillways and optimization in order to increase the water passage coefficient and energy consumption at the same time. For this purpose, the multi-objective optimization approach has been used.

In the present study, the redesign of the spillway of the Sarouk rockfill dam located in West Azarbaijan province has been studied. In the case of labyrinth-stepped spillway, the decision variables, constraints and objective functions of the two spillways are combined and analyzed as a multi-objective optimization problem. In this study, a dynamic coefficient is used to improve the performance of the dragonfly algorithm in the search and exploitation stage. After determining the optimal values of the regulatory parameters of the MODA, NSGA-II, MOPSO and MOIDA algorithms, four benchmark examples were solved with each of them 20 times with an initial population of 50 and a maximum number of iterations equal to 100.

After validating the improved dragonfly algorithm on benchmark functions and evaluating its performance in solving multi-objective problems, this algorithm was used to design a combined spillway on the introduced dam. In multi-objective problems, there is a set of optimal solutions rather than a single optimal solution, which appear as a Pareto front. The implementation of the improved dragonfly algorithm with 200 initial population and 500 repetitions has resulted in providing 200 optimal answers on the Pareto chart. After performing the calculations related to the fuzzy decision-making method, a design with the values of the objective functions of concreting volume: 59795.54 cubic meters, dissipated energy: 75.18%, flow rate: 1255.19 cubic meters per second was selected as the optimal answer. In addition, the design with the highest and lowest cost of concrete consumption was selected as two other answers. The flow rate passing over the spillway has increased by 120% in plans A and B, and by 25% in plan C compared to the initial design flow rate. The amount of energy dissipation of plans A and B is about 76 and 75%, respectively. In plan C, where the flow rate has not increased significantly (25%), energy dissipation has reached about 81%, which is more than the other two cases.

Among the available answers, according to the priority of the cost, the plans with the lowest (C) and the highest (A) implementation cost based on the volume of concrete were selected. Also, by using the fuzzy decision-making approach, an optimal plan (B) that has a suitable balance between the three objectives was selected. Based on the results, it was found that each of the plans A, B and C can be used based on the needs of the employer. From the economic point of view, according to the project conditions and the needs of the employer, all the proposed plans are suitable options for replacing the actual spillway and reduce the implementation costs. Also, the comparison of plan C with the stepped spillway plan presented by previous researchers showed that with almost the same volume of concrete, using a multi-objective approach in comparison with a single-objective optimization approach, in addition to increasing flow energy consumption, also led to an increase in flow through the spillway.