yazdan yarahmadi

Improvement of the natural tourism industry is considered as an important way for sustainable development of watersheds. Ecotourism should increase watershed income and consequently reduce the pressure caused by harvesting of natural resources. Sangtarashan watershed located in Khorramabad city, is a suitable area for tourism development. The main aim of this study was to identify the internal (strengths and weaknesses) and external factors (opportunities and threats) of the study area available for the development of regional tourism and present appropriate strategies. To conduct this study, first, based on the basic information available in the region and with the opinion of managers and stakeholders, a list of strengths and weaknesses as well as opportunities, opportunities and threats of the region was prepared and provided to experts and watershed residents to determine the importance and rank of each case to be determined. Then, internal and external factors were analyzed using SWOT model. The Quantitative Strategic Planning Matrix (QSPM) was used to select the best strategy for tourism development in the region. According to the results conservative strategies (WO) are the most appropriate strategies for development of Sangtarashan tourism.

Urban watersheds have become important due to the problems related to water resources management, including floods and pollution control. Therefore, the approach of engineers in recent years is toward computer software for estimating and simulating runoff. So far, many rainfall-runoff software with different capabilities and complexity have been developed and used for flood forecasting. The approach of the current research is to simulate the surface runoff and to identify the flood and critical nodes under the influence of climate change and to determine the efficiency of the surface drainage network in the west of six districts of Tehran municipality.

This research includes two parts of hydrology and water flow. In the hydrological department, after calculating the concentration time, in order to extract the rainfall intensity of the plan and to analyze the maximum rainfall for different durations of the base period (1980-2020), the near future period (2021-2050) and the far future (2051-2100) and preparing the IDF curve at different times and durations, based on the RCP2.6 and RCP8.5 scenarios, the Abkhezer-Qahraman method was used. In the water flow section, the assessment of the drainage network and flood control nodes in the western part of the six municipalities of Tehran in the base period (1980-2020) and under the influence of climate change (2021-2050), (2051-2100) in the RCP 2.6 and RCP8.5 scenarios for the period 25 and 50 year returns were made.

The results showed that the values ​​of rainfall intensity in the duration of rainfall and different return periods in all three scenarios have increased compared to the frequency intensity curve of the base period, and the maximum rainfall intensity has increased in the short-term time base, and with the passage of time, the maximum rainfall intensity has decreased. and IDF curves are affected by short-term rainfall. The results of the model calibration showed that there is a good agreement between the observed and simulated data in the simulation of water runoff in the five investigated rainfall events. The results of the sensitivity analysis showed that the impervious areas have the greatest impact on the change of peak water discharge. The results of the evaluation of flood nodes showed that, for example, the number of flood nodes in the base period (1980-2020) and under the influence of climate change in the RCP2.6 and RCP8.5 scenarios (2021-2050) for the 25-year return period are 7, 10, and 12, respectively. The number of flood nodes in the base period (1980-2020) and under the influence of climate change scenario RCP2.6 and RCP8.5 (2051-2100) for the return period of 50 years are 9, 14 and 17, respectively.

Conclusion and Suggestions :

The results of this research showed that the number of flood catchment nodes in the basin increased in the 25-year return period compared to the 50-year return period in each period. According to the identification of critical nodes in the research area, by applying modern methods of urban runoff control, such as creating permeable surfaces and gardens, absorption wells and reservoirs and storage ponds, the runoff can be controlled at the source to reduce the volume and peak water in the downstream, so that the probability of occurrence Minimize flooding and flooding. Since the percentage of impervious areas in the study area is high, it is recommended to increase the dimensions of the channels in terms of the passage of flood during rains and to have the ability to direct more amount of runoff and reduce the amount of peak flow of runoff in the location of super critical nodes.

The aim of the current research is to evaluate the performance of the drainage network and flood control nodes in the base period and under the influence of climate change for the 25 and 50-year return periods in the east of Tehran's sixth district using the SWMM and LARS-WG models. After calibrating the SWMM model based on observed rainfall-runoff events, the calibrating and validation results confirmed the agreement between the observed and simulated data. So that the value of the coefficient(KGE)in the calibration stage for the first, second and third event is 0.70,0.66 and 0.74 respectively and this coefficient in the validation stage for the two measured events is 0.71 and 0.65 respectively. The model simulation for the base period and under the influence of climate change was carried out with a return period of 25 and 50 years and the results showed that the number of flood nodes in the base period(1980-2020)and under the influence of climate change scenario RCP2.6 and RCP8.5(2021 - 2050)for the return period of 25 years, respectively 16,18 and 20 and the number of flood nodes in the base period(1980 - 2020)and under the influence of climate change scenario RCP2.6 and RCP8.5(2051 - 2100) for the return period of 50 years is 20,26 and 28 respectively. Therefore, the modeling results show that the surface runoff collection system of the research area needs to improve and modify the slope of the passages and the dimensions of the channels to transfer the runoff caused by the flood.

In this research, the changes in the frequency intensity curve for the Zone No. 6 of Tehran municipality (Mehrabad synoptic station) under the influence of climate change were investigated by using the Abkhezr-Ghahreman relationship. The information related to the current research includes two categories: First category includes hourly rainfall data measured in order to derive IDF curves for the base period (1980-2020). The second category includes the predicted daily rainfall data for the near future (2021-2050) and the far future (2051-2100), which were obtained from the output of the LARS model. First, using EasyFit software, statistical analysis was done on the observational data and the best distribution (Gamble distribution) was selected and the corresponding IDF curves were extracted for different return periods. To extract the IDF curves under the influence of climate change, the general circulation model of the atmosphere HadGEM - ES from the series of CMIP5 models under RCP2.6, RCP4.5 and RCP8.5 emission scenarios was used. The results showed that the rainfall intensity in all rainfall interval duration and different return periods in all three scenarios have increased compared to the intensity duration frequency curve of the base period, and only for the near future (2021-2050) under the RCP 8.5 scenario, there is a decreasing trend compared to the base period will have. For example, interval duration of 4 and 24 hours for the return period of 10 years, the amount of precipitation intensity for the scenario RCP 2.6 and RCP 8.5 for the distant future (2051 -2100) is 7.05, 7.1 and 2.56, 2.58, respectively, while which for the base period (1980-2020) is 6.71 and 2.44, respectively, which indicates the increase in the intensity of maximum rainfall with the increase of the return period. It can be concluded that the maximum intensity of rainfall has increased in short-term time base and with the passage of time, the intensity of the maximum rainfall has decreased, and the IDF curves are affected by short-term rainfall.

Identification of groundwater potential areas as one of the important sources for drinking water supply, agriculture, ecological diversity and various industries is one of the important and necessary issues in the management of water resources of any country, especially developing countries. In this study, a groundwater zoning map was presented to manage and plan groundwater resources using WOE, SI and Shannon models in ArcGIS10.5 in this area. For this purpose, the geographical location of 624 wells with a flow rate of more than 10 cubic meters per second in the region were divided into two groups: calibration (70%) and validation (30%). In implementing all three models, the effective parameters in groundwater potential identification include: height, slope, slope direction, land curvature, geology, land use, soil science, topographic moisture index, distance from fault, fault density, waterway density and Distance from the area waterway was used. Also, the ROC curve in SPSS software was used to validate the results of the models. The highest accuracy for this region was assigned to the statistical index model, the AUC value for this model is 84.5%, followed by evidence weight models with 81.6% and Shannon entropy with 80.6%, respectively. More than 60% of the area has moderate to very high groundwater potential. The statistical index model is more appropriate and accurate for this region. Determining areas with high groundwater potential using these methods is appropriate for implementing management programs.

Identifying groundwater potential is a key requirement in groundwater conservation and management and is especially useful for engineers and designers looking for suitable locations for the exploitation of these resources. GIS-based methods have increased the accuracy and speed of groundwater surveys. Many researchers have focused on the use of GIS-based methods, remote sensing and machine learning, and statistical methods. These methods identified latent patterns in groundwater and obtain a nonlinear relationship between affecting variables. In this regard, the final groundwater potential map is determined using 12 effective variables based on ArcGIS and Weight-Of-Evidence (WOE) model for Lenjanat area, Isfahan Province.

Lenjanat study area is located in the southwest of Isfahan Province. It has a variable climate that is always affected by the central semi-arid and semi-humid areas of Chaharmahal and Bakhtiari Province. WOE model is based on standard deviation and used to predict the occurrence of accidents when there is enough data available to assess the relative importance of the layers using the statistical average. The Receiver Operating Characteristic (ROC) curve related to the groundwater potential mapping in the Lenjanat study area was prepared using SPSS software. The Area Under Curve (AUC) indicates the accuracy degree of the final map. The extent area of each curve indicates the model’s prediction ability. The value below the graph would be equal to unity in the best case and ideal scenario. This index is a suitable criterion to evaluate the model accuracy.

The areas with low elevation and low slope due to the high level of infiltration and water movement in the soil had a higher potential of groundwater, which is consistent with the results of the previous researchers. These areas had a higher groundwater potential in the east and flat terrains than in other directions. From the land use point of view, arable lands and areas with dense vegetation had the highest groundwater potential. The shorter the distance from the waterway and the higher the drainage density leads to the greater the groundwater potential. Areas with Aridsols soil have higher groundwater potential compared to the Entisol and Inceptisols categories. Soft alluvial sediments have a higher potential than other sediments. It is expected that the areas with high groundwater potential will be more in the eastern part of the region due to the high concentration of factors affecting the creation of potential groundwater conditions. The final groundwater potential map also determined these areas as high groundwater potential regions.

The results showed a higher sensitivity to land use and slope variables, which play an important role in water penetration. More than 60% of Lenjanat has moderate to very high groundwater potential. Identifying areas with high groundwater potential is important in determining areas for implementing management programs. It is suggested to use the WOE model with more input variables and other models to prepare a high accuracy potential map should be evaluated in future studies.

Studying and evaluating changes in snow cover as one of the important sources of water supply is very important. Due to the conditions of the hard-to-reach areas of The Mountains, it is not possible to permanently measure the land for estimating the snow resources and forming databases. Therefore, the use of satellite images is very important in identifying snow-affected areas and evaluating its changes. In this study, MODIS satellite images of Marber basin located in the south of Isfahan province during the 20-2000-2019 period were used. It is note that in this study, Google Earth Engine (GEE) system was used, which has been highly regarded by researchers in recent years and has been recognized as a new and highly functional system. Gets. In the present study, more than 7,000 images related to daily snow cover were used, which are available in GEE in the shortest time. TFPW-MK test was used to evaluate the trend of changes in snow cover. ArcGIS software was used in this study. The results showed that the trend of changes in snow cover over a period of 20 years has been decreasing, which can have different causes such as rising temperatures. Long-term changes were also examined monthly and daily and always showed a decrease in snow cover levels. Water from snow melting in this region as an important source of water supply should be considered, protected as well as further investigations with different methods and also to investigate the causes in future studies.

Lorestan province, especially the Kashkan basin, is very flooded and has suffered flood damage many times, and in April 2019, it experienced the biggest flood in the last 200 years. In this study, an attempt has been made to map flood zonation to reduce flood hazards in Kashkan watershed using FR, SI and Shannon models and also using ArcGIS techniques to improve flood decision-making and management in Provide this area. For this purpose, the geographical location of 123 flood-catching points in the region were divided into two groups: calibration and validation. In the implementation of all three models of effective parameters in floods including: slope, slope direction, land curvature, geology, land use, soil science, topographic moisture index, precipitation, waterway density, distance from waterway and digital elevation model of the area used Were. The ROC curve is also used to validate the results of the models. The highest accuracy for this region was attributed to Shannon entropy model, followed by frequency ratio models and statistical index, respectively. Due to the fact that surface water management is very important in order to prevent the recurrence of high flood damage in this area, so the use of flood sensitivity maps to improve management and decision-making in flood management is essential.

Estimation of runoff from atmospheric rainfall has a special importance in hydrology studies, watershed management and soil science water conservation. In order to efficiently manage the watershed, the need to investigate the efficiency of hydrological models is more effective. The software package RRL is designed to simulate the runoff relationships of the basin and consists of five sub-conceptual models. In this study, conceptual models of AWBM, SACRAMENTO, SIMHYD, SMAR and TANK were used for Silakhor plain watershed (Rahim Abad station). The daily data of precipitation, evaporation and discharge were used in the statistical period of 1998 to 2018. For all conceptual models, from 1998 to 2000, as a balance period, from 2001 to 2013 as calibration and from 2014 to 2018, it was selected as the verification period. In the SIMHYD model, the Nash-Sutcliffe coefficient in the Multi Pattern Search Start method in the calibration and validation stages were 0.70 and 0.68, respectively, which indicates the relative ability of this model to simulate runoff among other models. In the TANK model, calibration and validation using Genetic Algorithm were 0.47 and 0.44, respectively, which had the lowest efficiency among the models. The results showed that in the different optimization methods, the Multi Pattern Search Start method provides better results.

Snow and snow melt runoff have a major role to play in supplying water. In this study the impact of climate change on runoff caused by snowmelt was studied in Sarab Seyed Ali watershed in north of Lorestan province. In this study, using snow cover level extracted from Landsat 5 and 7 satellite images and climatic data predicted by general circulation model using Lars-WG software snowmelt runoff under three scenarios A1B, A2 and B2 in the year 2010 to 2013 was simulated using the SRM model. The simulation results were evaluated using two statistic including coefficient of determination and volume difference. The value of 0.87 for the coefficient of explanation and -3.62 for the volume difference indicates the accuracy of the model. Then, using these three scenarios, the climate parameters for 2020 to 2060 were predicted through general circulation model, then using the predicted climate parameters, the rate of snow cover was estimated through multivariate regression equations and was into to SRM model. the simulation was done for 2020 to 2060. The results showed that the average runoff in November to May for the three scenarios was 4.3, 4.4 and 4.2 m3/s respectively, while the long-time mean runoff from 1980 to 2013 was 6.07 m3. However, this decrease in future runoff volume can be justified by the reduction of snow cover.

Locating suitable areas for the construction of flood spreading structures and infiltration into underground aquifers for the purpose of storing runoff and increasing groundwater reserves to supply the water needed for various purposes and to control flood damage, Highlights the importance and necessity of these studies in protecting natural and human resources. In this study, it has been attempted to provide suitable locations for flood spreading in Khorramabad watershed. For this purpose, parameters: land use, elevation, drainage density, geology, distance from residential areas, river distance, distance from road, slope, soil classes, soil texture, electrical conductivity and unsaturated thickness were measured in ArcGIS10.5. . At first the parameters were fuzzy-fuzzy between zero and one, and then, using hierarchical analysis, pairwise comparison of the variables was quantitatively classified, and then using Expert Choice software based on AHP method, Weight of each criterion was obtained. The most effective criteria in this study were the parameters of distance from residential areas, land use and unsaturated thickness. Finally, using ArcGIS10.5 techniques and linear-weight combination, the location for flood propagation was determined. The results showed that according to the final map of flood spreading, 13.99% of Khorramabad watershed has appropriate utility and 26.04% of moderate utility for constructing flood spreading structures. These areas can be considered in planning the actions needed for flooding in the area.

Identifying areas susceptible to landslide through risk zoning is one of the most effective and necessary measures to reduce potential hazards and manage risk. In order to zoning the risk of landslide in Salavat Abad basin, slope, gradient, geology, land use, rainfall, distance from the river, distance from the fault, distance from the road were used for landslide risk zoning. The standard fuzzy layers are overlapped and organized in the GIS environment, and then the weight of effective factors is calculated by the ANP model and applied to the information layers for the GIS environment. By overlapping them, the landslide landslide zoning map in 5 floors is very sensitive, High, medium, low, and very low. The results of this assessment showed that the total area of the Salavat Abad Basin with an average risk area of 804.77 ha (32.18%). Among the eight factors surveyed, the incidence of landslide was the gradient with weight (0.224) and the geological criterion with weight (0.194), the highest weight, and the distance from the fault with weight (0.036), the criterion of distance from The river with weight (0.058) and precipitation with weight (0.056) had the lowest weight for zoning the risk of landslide. The greatest risk of landslide is towards the slopes of the south, south east and east. Also, slopes higher than 10% had the highest risk of landslide.