The Presentation of Environmental Risk Assessment Pattern for Gas Pipeline Project by Using of Indexing System and AHP Methods (Case Study: Transportation Pipelines 24 inches, Tasuj-Salmas Project)

Gas transportation pipelines production plans, unlike technical and economical justification in the field of energy supplying for societies, by having danger on environment, needs the continuous studies of assessment and environmental risk management in manufacturing and benefiting stage. In this study, for purpose of environmental risk assessment for gas transportation pipelines the indexing system method and Analytical Hierarchy Process were combined. Indexing System is a compulsive and applicable method that was based at the basis of characterizing index effect and ranking. By using this method, we can classify, quantify and prefering types of environmental risk in pipelines according to the determined criteria’s and typical. In the mentioned method, typical of dangers, show the possibility of danger occurrence and effects of typical show the effect intensity. Final grade for environmental risk in this method produce via possibility of danger occurrence multiply with effect intensity. According to that efficiency scale for whole of criteria are not equal in the final level of risk. In addition for the purpose of weighting the criteria’s, the Analytical Hierarchy Process was used and for the purpose of weighting the digital layers of information related to the criteria Ordered Weight Analysis method was used. For the purpose of examination results of this research, environmental risk assessment of gas transportation pipelines 24 inches for Tasuj-Salmas with approximate length about42 kilometer as a case study was exerted. Via usage of Geographic Information Systems abilities, the identified risks and risk zonation in the path of pipelines were considered. Results showed that 46% of gas pipeline path of Tasuj-Salmas, has a high risk level (5467- 6054 grade), 48% of it, has a medium risk level (6055- 6641 grade), 2% of it, has a low level of risk (6642-7228 grade) and 4% of it, has a little risk (7228< grade). Adjacency of southern zone of pipelines path with Orumieh lake national park, is an important ecological sensitivity that is under investigation. 15 kilometer of pipeline path (kilometer 18+220 to 33+220) is aligned with 5 kilometer of biosphere reserved.