Evaluation of Highways in the River Environmental Geomorphologic and Design Considerations (Case Study: Semnan - Garmsar Road, Iran)

摘要

Garmsar - Semnan road and railway is a part of Tehran-Mashhad way also a part of the Hableh-Rood and Semnan rivers basin. The area of study is located: E 52° 45' to E 53° 30 and N 35° 21' 30" to 35° 45' 30" (Iran). The arid and semi-arid regions influence to this area. The important characteristics for semnan water shed are Low and high fluctuation of precipitation and in some years it may exceed annual average. Since there is no control over climate element it is very important to know those change to assment and study method of safety railway. Linear structures (such as high ways, railway, ...) have main and common effects on geomorpholclimatic and rivers hydrologic system and on houses and structures establishment in geomorphology unit in the region which were studied (Hableh-rood and Semnan river basin). This region has relative morphologic stability. Without studying and planning ae this leads to unpleasant results and in turn these results change natural units equation and have effects on people in many ways. On the other hand it has main effects on region economic balance in future and it causes that environmental and safety index will be decreased. So in this paper ae according to the reaction of Hableh-rood, Semnan and its subrivers and the effects on environmental elements ae it is necessary to study the following activities: at first organizing a systematic and exact study to change the effect of different selective plans on structures and the way of using them on environment and finally ae the selection of structural projects measurements and linear structures so that they have minimum effects on environment. For these purposes ae continuous researches neccessarities for improvement of the rivers and city zones linking with rivers also application of their results in urban and regional levels ae it is necessary to systematic studies with comprehensive geographic views which based on different subjective sciences such as geomorphology ae climatology ae hydrology and so on. To distinguish of geomorphologic features and units ae at first aerial photographs and different geomorphologic units have been showed on topographic maps. These units have been reviewed in field study and finally comparised features and units has been reviewed in field study.