جستجوی مقالات مرتبط با کلیدواژه "فرسایش آبراهه ای" در نشریات گروه "جغرافیا"

river erosion is always one of the main factors in the risk of energy transmission lines and oil and gas pipelines. In this paper, using the Pipeline Risk Screening Matrix (PRSM) and the ANP model, stream pipelines in the Iran gas trunk – line 9 (IGAT 9), in the province of Khuzestan with a length of 170 km were investigated. For this purpose, using the ANP model, four main categories of criteria were included: the criteria "pipeline situation to the streams", "Hydrogeomorphology", "geomorphology" and "other environmental factors", with 36 sub-criteria, then using the PRSM model and the questionnaire were sub-criteria scoring in the Super decision software, as well as a pipeline hazard risk classification map. The results showed that the "pipeline situation to the streams" criterion has the highest risk and response to pipeline hazards among the four criteria. The most important sub-criteria with the highest risk profile are construction method, mountain, drainage and geology. Risk map is also in the range of Shushtar and km 150+ to 170+ in east of Dezful. The 9th gas pipeline has the highest risk situation and increased stream and rivers response in mountain geomorphology unit.

In recent years, valuable experiences have been gained in relation to environmental challenges, as well as pipeline risk management in the United States and Europe, in relation to the design and stabilization of pipelines, including the knowledge of geomorphological hazards, in particular the erosion hazards of the stream. It has helped to reduce the risk, and identify the response and response of the stream and rivers. In this paper, Pipeline Risk Screening Matrix studies the hazards of the geomorphology of the stream pipelines in the Iran gas trunk – line 9 (IGAT 9), in Khuzestan province. For this purpose, seven hydro-geomorphological data including scale, landscape sensitivity, stream type, riparian corridor, bank characteristics, bed characteristics and hydrologic regime were used. In the pipeline risk axis, three nominal scales include:

Low risk, medium risk, and high risk were used to estimate the risk profile of the pipeline in relation to the increase or decrease of response and river responses. The results of this study showed that from the seven classes of the studied, the type stream is low-intermediate risk stream response and three classes, the riparian corridor, bed characteristics and hydrological regime are Medium risk. Bed characteristics and scale are medium-high risk and the landscape sensitivity high risk stream response. Overall, the class of risk stream response in IGAT 9, is medium – high risk stream response class.

In the world, most of the research work on the hazards of pipelines (oil and gas pipelines) is in the United States, Canada and Russia, respectively. Also Western European countries, in particular the UK, have had research in this field. In Iran, pipeline failure or damage to the pipeline is eroded annually, for example, Rafsanjan-Naein-Esfahan oil pipeline (2013), Ray-Tabriz (2017). In Iran, there is no comprehensive study in which the geomorphological impact of the erosion damages to the pipelines unlike the long history (over 110 year records) of the oil and gas industry. In this paper, the purpose is to identify and assess of the risk stream response by using of pipeline risk screening axis relation to IGAT 9. Method and result In this paper we use of pipeline risk screening axis for estimate and identify of stream response risk class. This axis has seven criteria such as: scale, landscape sensitivity, stream type, riparian corridor, bank characteristics, bed characteristics and hydrologic regime. Pipeline risk screening axis classified into three categories, low risk, medium risk and high risk based on field data from seven criteria:

1) 50 river have point scale, 2 river reach scale, 4 rivers multi-reach and 4 rivers have watershed.

2) Landscape sensitivity have high risk reaction groups.

3) Stream type are two class include alluvial and bed rock.

4) Riparian corridor is 3 type of continuous – wide, semi continuous – wide and discontinuous – narrow.

5) bank characteristics have 3 type naturally non erodible, erosion resistant and highly erodible.

6) bed characteristics have 3 types boulder/cobble/clay bed, gravel /silt bed (dominate in case study) and sand bed.

7) hydrologic regime in our case study is rain and thunderstorm.

The results of this study showed that from the seven classes of the studied, the type stream is low-intermediate risk stream response and three classes, the riparian corridor, bed characteristics and hydrological regime are Medium risk. Bed characteristics and scale are medium-high risk, and the landscape sensitivity high risk stream response. Overall, the class of risk stream response in IGAT 9, is medium – high risk stream response class. For decrease of stream response risk, and improvement Iran gas trunk – line 9, it needs to tight management – engineering measurements, and Geomorphologically in case of erosion stream and restoration and review of project of rout line.

Flooding is a natural hazard events and Survey data from the annual losses due to flood in Iran and the world show the extent of the flood damage caused on natural and human resources. To estimate height of the runoff and discharge maximum in basins and stream erosion، there are various experimental methods and mathematical models that one of these models، SCS model is. Thus، the aim of this study was to estimate the Runoff coefficient and Maximum discharge by Curve Number method with different units forming the Fyruzkla Kojoor basin and zoning maps of potential runoff and stream erosion in the drainage basin is. After mapping the watershed CN and S، to calculate the volume of runoff produced in the region، short-term rainfall for different return periods were calculated using Pearson distribution of type III. According to the map of potential runoff in the basin، forest land has the lowest runoff potential and pasture lands have the greatest potential to generate runoff and erosion is occurring and also has the lowest penetration. The middle part of the basin، the most prone to runoff and erosion and gully formation in the region are. After determining the height of the basin surface runoff، peak discharge was calculated for various hydrological. The highest values of maximum flow rate are based on rangeland with hydrologic group D.