Mohammadjafar Soltani; Amir Sarreshtehdari; Samad Shadfar
Abstract
Inadequate temporal and spatial distribution of precipitation in arid and semi-arid regions, cause destructive floods in addition to loss of surface runoff. Therefore, controlling surface runoff and its proper utilization through the construction of rainwater catchment systems can be a good way to prevent ...
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Inadequate temporal and spatial distribution of precipitation in arid and semi-arid regions, cause destructive floods in addition to loss of surface runoff. Therefore, controlling surface runoff and its proper utilization through the construction of rainwater catchment systems can be a good way to prevent water loss. Traditional methods may be time wasting and concise. Geographic information systems provide new methods and models of using huge number of maps and data for analysis in a short time with best results and conciseness. This project was implemented in Kan Basin as a pilot which covers an area about 197 km2. Different maps including slope, land use, precipitation, vegetation cover, soil hydrologic groups and geology were overlayed. Land use maps were extracted from ETM+ 8 satellite images of 2014 along with field controls. Then layers were weighted according to their importance and role of each map. Suitable areas for establishing rainwater catchment systems in each model were determined by overlaying in the frameworks of different models including Boolean logic, Index overlay and Fuzzy logic and compared with control points which were implemented with Ministry of Jihad Agriculture. The results showed that the operators gamma=0.2, gamma=0.3 and Product from Fuzzy logic model had the most overlap with the control areas, the best integrated model for determining the appropriate locations for the construction of rainwater catchment systems in the study region.
Jamal Mosaffaie; Amin Salehpour Jam
Abstract
Evaluation of the impacts of past watershed projects provides useful insights for future projects. In this study, the hydrology and water resources status of Akujan Catchment of Qazvin Province has been the object of the study in which the effects of various measures of watershed managements were evaluated. ...
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Evaluation of the impacts of past watershed projects provides useful insights for future projects. In this study, the hydrology and water resources status of Akujan Catchment of Qazvin Province has been the object of the study in which the effects of various measures of watershed managements were evaluated. For this purpose, the changes of water resources discharge, increased infiltration, water storage, peaks and volumes of catchment floods, were compared before and after the implementation of watershed management projects. Results showed that 114000 m3 more runoff storage has been carried out by watershed management operations that 20.1% of this volume was related to the structural operations and 79.9% of it was due to biological and biomechanical projects of the catchment. Results of the flood analysis indicated that the role of structural measures in the change of time of concentration is low and even negative. Therefore the reduction of the peak flow and flood volume at the outlet of the catchment is due to the implementation of biological and biomechanical measures which reduces the peak flows by 42.7, 25.4, 20.8, 17.1, 15.3 and 13.8% and flood volumes by 41.8, 24.8, 20.2, 16.5, 14.8 and 13.3% respectively for the return periods of two, five, 10, 25, 50 and 100 years. Another observation is that the effect of watershed management practices on the reduction of flood peak and volume decreases when the return period of flood is increased.
Ali Talebi; Zahra Eslami; Abdolhossein Abbasi
Abstract
Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. ...
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Identification of areas with high potential for flooding in the basin is one of the most important activities in flood control and reducing its damages. In this research, the possibility of prioritizing nine sub-basins from flooding point of view has been studied in Eskandari Watershed, using HEC-HMS. Also, the priorities of sub-basins were studied using flooding coefficient and peak discharge per unit area experimental methods. In order to run HEC-HMS model, plan rainfall with two, five, 10 and 50 years return periods were used. Flood hydrographs associated with each precipitation were calculated for each sub-basin, using the sequential removal method of sub-basins and removing CN in each sub-basin in each run of the model and their effect were computed in flood generation. Results showed that sub-basin I has the first priority is flooding potential, considering independent and depended sub-basins. Prioritization of sub-basins with two experimental methods had different results that are independent from a particular process. As E sub-basin had sixth priority in flooding coefficient method and third priority in the peak discharge estimating method. By comparing the prioritization of sub-basins in HEC-HMS model in different return periods, results showed that sub-basins prioritization in different return periods has specific process. Therefore, HEC-HMS model is more efficient compared to experimental methods in sub-basins prioritization in flooding.
Reza Chamanpira; Mohammad Roughani
Abstract
Evaluation is a fundamental tool for implementation of projects, and is used as a tool to assess their effectiveness. In areas with no evaluation, assessment is difficult. A practical method for overcoming to this problem is basin simulation using mathematical models. This research was implemented in ...
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Evaluation is a fundamental tool for implementation of projects, and is used as a tool to assess their effectiveness. In areas with no evaluation, assessment is difficult. A practical method for overcoming to this problem is basin simulation using mathematical models. This research was implemented in Dadabad Watershed in Lorestan, followed by impact assessment of watershed management operations on basin behavior change on reducing watershed area floods. Mapping and determining the volume of the built structures and their number, status, and characteristics constituted the first step of the research. The HEC-HMS mathematical model was then employed to estimate flood volumes. Results of simulations and comparison of the observed and simulated hydrographs indicated that the model had the required efficiency for simulating the Dadabad Watershed and was very sensitive to the parameters of curve number and initial loss. The capability of the storage ponds in storing runoff was then determined through calculating their volumes. The behavior of floodwater for the various return periods was simulated to determine the response of the watershed to design storms by applying the changes that had happened in the input part of the model. Results indicated that the water storage ponds could collect and store more than 80 percent of the runoff resulting from rainfalls with return periods of 2 and 5 years. In return periods of 10, 25, 50 and 100 years, 63.4, 54.3, 38.8 and 28.6 percent of the runoff stored in the ponds respectively, and the rest left the watershed from its outlet. In general, the water harvesting systems in the Dadabad Watershed could store 236645 m3 of runoff.
Jafar Rezaei; Heydar Seydzadeh; Alireza Shadmani
Abstract
Flood control, artifcial feeding of ground water aquifers and effort to optimize the productivity of natural resources are component the most results that have gotten from implementation of spreading project in spreading statious of country. One of the most important goals of spreading is the creation ...
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Flood control, artifcial feeding of ground water aquifers and effort to optimize the productivity of natural resources are component the most results that have gotten from implementation of spreading project in spreading statious of country. One of the most important goals of spreading is the creation of positive changes in economical variables of area including agricultural and rangeland productionsand their development. In other words, each of spreading projects implemented in different stations have specific economical effects in desired area. The goal of this project is determination of economical effects of floodwater spreading project on Dehloran aquifer through monitoring and surveying its behavior and recording relevant data steadily. For this purpose, profit ability and economical justification of the project have been determined through economical indicator evaluation of projects. Results demonstrated that irrigated lands of downstream villages have been inceased 3.5 times in 2010 compared to the year1995. The added value of the injected floodwater was estimated to be 14.6 billionRial. The added value of rangeland products was about 1353.96 billion Rial. The added value of wood production was estimated about 13.38 billion Rial. The added value of agricultual products was about 657.05 billion Rial. NPV, ROR and B/C of the project were 1398.61 billion Rial, 0.38 and 2.87, respectively that show economical justification of the project.
Abolghasem Dadrasi Sabzevar; Ali Ghazanchian; Mohammad Namaki
Abstract
Social and economical evaluation of watershed management activities, is an important criterion for its validation. The main objective of present study was, identification and analysis of socio-economic impacts of watershed management operations implimented in Gosh village wich is located in 60 km north ...
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Social and economical evaluation of watershed management activities, is an important criterion for its validation. The main objective of present study was, identification and analysis of socio-economic impacts of watershed management operations implimented in Gosh village wich is located in 60 km north of Mashhad. The sample data of this study was consisted of 38 extension workers were randomly selected from the study area based on Cochran’s sampling methodology. The research instrument consisted of three parts in Likert scale. The validity of the questionnaire was analyzed and reliability coefficient was calculated for the questionnaire using Cronbach's alpha ratio of 0.745. These amounts showed that questionnaire has an acceptable ability for data gathering. Factor analysis was the major statistical method. The results offactor analysis indicated that socio-economic effective parameters are increasing garden and farm area, increasing qanats water discharge, increasing rangeland area, and preventing lands flood damages. These four factors, in general, had more than 60 percent of the total variance. Final results indicated that watershed management activities have improved qanats water discharge by flood control and aquifer rechrge and increased the area of Agricultural and garden lands. Also, conseving activities in rangelands caused improving of vegetation cover density and the area of rangelands.
Raouf Mostafazadeh; Amir Sadoddin; Abdolreza Bahremand; Vahedbordi Sheikh; Habib Nazarnejad
Volume 2, Issue 2 , July 2010, , Pages 83-93
Abstract
Assessment of flood control projects in the same conditions is essential in order to improve decision making that assist us in watershed management purposes. Focus of this study is on assessing hydrological effects of the Jafar-Abad watershed management project. The study area (109 km2) located in north ...
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Assessment of flood control projects in the same conditions is essential in order to improve decision making that assist us in watershed management purposes. Focus of this study is on assessing hydrological effects of the Jafar-Abad watershed management project. The study area (109 km2) located in north of Iran in the Golestan province. Paired t-tests were performed for Indicators of Hydrologic Alteration (IHA) in Taghi-Abad gauging station, located in the outlet of the catchment, before and after construction of 58 check dams. HEC-HMS model was calibrated using 12 storm events and validated for study area. Calibrated HEC-HMS model was applied to rainfall-runoff modeling in sub-catchments and Level-pool method used for reservoir elements. Design flood hydrographs for 2-100 year return periods were simulated for both before and after check dams construction periods. The results of statistical analysis indicate that existing flood control measures had no significant impact on the hydrologic characteristics measured by IHA in 95% confidence level. The results indicated that constructed structures do not have important effect on IHAs and the amount of these effects was less than 1.5 percent in all cases. Also, by increasing in return period, the effects of structures on peak discharge and flood volume were reduced.
