مجله سامانه های سطوح آبگیر باران
سال یازدهم شماره 1 (پیاپی 36، بهار 1402)

This research has been carried out with the aim of investigating the use of gravelly filters in rainfed gardens on sloping lands in order to optimize infiltration and increase soil moisture storage in the conditions of using micro catchment systems during the years 2013-2018 in Chaharmahal and Bakhtiari province. The research rejoin has an average annual rainfall of 300 mm, soil with silty clay loam texture, and an average slope of 15%. Towards this attempt, micro catchments were made with five different treatments including a removed surface with and without using a gravelly filter, an isolated surface with and without using a gravelly filter, and the control treatment(natural surface), along with three cultivars of almond(Rabie, Mamaei, and Shahroud 21) and were constructed in 5 repetitions. The soil moisture at the depths of 25, 50, and 75 cm of the seedling hole in each of the systems was accurately measured and recorded using a TDR device. In order to determine the role of filters and to determine the difference between similar treatments with the different presence or absence of gravelly filters in them, Paired-Samples T-Test was used in SPSS software. The results showed that there is a significant difference between the treatments with filter and without filter in terms of soil moisture percentage. In other words, using the gravelly filter in the seedling pit will optimize the infiltration of extracted runoff into the soil, increase humidity in the place of tree root development, and increase its growth. Therefore, it is recommended to use the gravelly filter in the seedling pit in the conditions of using rainwater catchment systems.

The lack of surface water resources has caused the indiscriminate extraction of groundwater in many parts of the world. The sharp drop in the level of groundwater tables, and the investigation of changes in groundwater resources are very important in the planning and sustainable management of water resources in each region. The purpose of this research is to investigate the changes in the level of the groundwater table Ghorveh-Dehgolan plain, which is one of the most important and largest plains of the province. To this end, the statistics of 104 observation wells during three time periods (2001-2008, 2008-2013, and 2013-2018) were analyzed. At first, statistical data was collected, and after entering the data into the Geographical Information System (GIS) with the interpolation method, maps of lines of equal depth, and zoning of decreasing the level of groundwater table were prepared. To investigate the long-term changes and fluctuations of the groundwater level, the representative water table of the aquifer was also drawn in the Excel software. The results obtained from the maps of the same area of the fall showed that the highest level of groundwater in the third time period (2013-2018) in the southern part of the aquifer was 7.3 m, in the second time period (2008-2013) in the central part of the aquifer has dropped by 5.7 m, and in the first period (2008-2001) in the northern and central parts has dropped by 3.3 m. The hydrographs of the groundwater level show that the water level has decreased by 13.8 m in the 20-year period, and the average water level has decreased by 0.7 m every year. The results of the reservoir volume changes showed that the volume deficit of the alluvial reservoir is equal to 56.2 million m3. In addition, the temporal monitoring of drought of the groundwater resources of Ghorveh-Dehgolan plain with the Groundwater Resource Index (GRI) has a downward trend towards drought during the 20-year statistical period.

Reservoir dams are important structures for surface water harvesting and flood control. Before construction, various studies are carried out in multiple phases to calculate the input to their reservoirs and the volume of stored water. The non-optimal operation of a reservoir dam occurs when the volume of the inflow during operation does not match the volume of the calculated inflow. The water intake systems of dams and their volumes can be measured with different criteria and options. Using the opinions of expert experts and the realism of different technical, economic, and social conditions with different multi-criteria decision-making models in identifying factors affecting the correct inflow forecasting of water harvesting by dams is a common method in water resources management research. In this study, using different multi-criteria decision-making methods including ElectreIII, Entropy, Topsis, SAW, VIKOR, PROMETEE and Fuzzy TOPSIS, the inflow to the reservoirs of 17 dams in Kermanshah province has been investigated. This research is the first research work in the field of evaluating the inflow forecasting to the reservoirs of the dams of Kermanshah province, which, with a comprehensive approach, expresses and examines the most important factors influencing the failure to estimate the optimal inflows to the dam. According to the findings of the research, the option that has more frequency than other options is the proportionality of water allocation in each dam reservoir, in fact, the inadequacy of the amount of water allocation with the objectives of the dam reservoir studies, the time-consuming studies and implementation of the dam cause deviation from the right path. Water harvesting is done in reservoir dams, and the trustees inevitably change the goals of the plan by making interim decisions and even during implementation. Such a process without economic analysis leads to a loss of opportunities and a waste of investments.

Identifying the appropriate places for implementing various management actions in the watershed is a challenging issue. Multi-Criteria Analysis (MCA) is an approach to assist managers in solving this problem. This study aimed to determine appropriate places for gabion check dams, earth embankments, and stone and mortar dams using the MCA technique in the Dorahan watershed in Chaharmahal and Bakhtiari province. First, a criteria tree was developed to integrate some ecological maps (flooding, erosion, channel number, slope, and geomorphology) with economic variables (distance to villages and roads) and spatial restriction variables (stream order, slope, geomorphology, and elevation). Analytical Hierarchical Process (AHP) was used to compare and weight the variables and management options. The eigenvalue vectors were measured for all criteria used in AHP. According to the AHP, the eigenvalues of flooding and erosion as the most important variables were 0.36 and 0.32, respectively. The management options against all criteria were then compared and earth embankment with an eigenvalue of 0.494 was recognized as the best management option in the watershed. Stone and mortar dams and gabion check dams were the two later management options with eigenvectors of 0.316 and 0.126, respectively.  All criteria maps were produced in a raster format by ILWIS software and were then imported into the Spatial Multi-Criteria Evaluation (SMCE) model. The appropriate areas for the construction of these management options (different kinds of small dams) were then mapped in the watershed. Sub-watersheds 6 and 7 were identified as the most suitable area for implementing these management options. A similar approach can be used to identify the best management practices for suggesting other bio-mechanical projects.

Considering the successive droughts and the importance of water in the agricultural sector, as well as the spending of government credits in construction projects, the importance of investigating the efficiency of water transfer in irrigation canals is determined. In this research, the transfer efficiency and water losses in 20 cases of concrete and stone and mortar canals in different areas of Khorramabad city were evaluated. For this purpose, the amount of water loss was determined by the field method and calculating the input-output flow. Based on the obtained results, the values of water transfer efficiency in the canals have been determined between 51% and 89.9% and on average 77.3% in the total length. The lowest and highest amount of total losses in the canals respectively equal to 13.7 and 168.7 with an average of 74.8 l/s per kilometer has been measured. Also, the lowest and highest efficiency are 31.5% and 89.1% per kilometer respectively related to Badeh Abestan and Tagh and Togh canals and the amount of loss is calculated from 1.4 to 6.3 m3/m2 per day. The very low efficiency in two cases of the canals shows the large volume of water loss. According to the results of this research, special arrangements should be made to increase the quality of implementation in water supply canals and training of users by the relevant institutions and organizations, including the Ministry of Agricultural Jihad, which is in charge of the implementation of water supply canals in this research.

Protection, restoration, development, and optimal use of soil, especially in natural areas such as forests, pastures, deserts, and natural groves, for sustainable development, are possible through scientific and comprehensive management. In the present research, some physical and chemical properties of soil were investigated in two locations reclaimed wetlands through flood spreading operations and the control area (degraded wetlands). In both places, 16 profiles were dug and due to two sampling depths of 0-25 and 25-50 cm, 32 soil samples were collected. In the samples, the percentage of silt, clay, sand, permeability, electrical conductivity (EC), soil acidity, absorbable iron, manganese, zinc, phosphorus, potassium, percentage of carbon and organic matter were measured. Then, the average of mentioned characteristics was compared using the T-test between the two restoration areas and the degraded control area at the level of 5% and 1%. According to the results the difference between the two places in the first depth of 0-25 cm, was more evident, so in the first depth between the two places in terms of silt, clay, sand, permeability, apparent specific gravity, electrical conductivity and cation exchange capacity and percentage of organic matter, soil carbon, absorbable phosphorus, iron, zinc, and manganese there is a statically significant difference at the 95% level (P≤0.05). It was also found that the percentage of soil organic matter and carbon increased significantly and the permeability of the soil decreased significantly at the level of 95% with the implementation of flood spreading restoration operations. Also, the results showed that in the control the rain-fed amount of soil phosphorus was higher which can be explained by the continuous fertilization of phosphate fertilizers by the farmers in the degraded rain-fed lands.