A study Of Surface Water Hydrodynamic And It's role In The Haraz Road Stability

Drainage network have main role in destruction and washout of trench of the roads which these inflict main damage to the road way. This effects include two factors: 1- climatical factors like rain and snow melt which affect directly on road and road components. 2- effect of river on road that consist of Road – Stream Proximity and Road – Stream Crossing.The aim of this study is surveying effects of haraz river and subbasins on the haraz road,which this study distinguish critical routes and sections. in this regard, we studied 85 km of haraz road. Determining the limits of road haraz river perform with topographic map and air photo and complate with field works. The result show from 85 km road under examination, 33 percents (27 km) placed in 50 meters of river limits. The studies and observations indicated that river and stream affected on the road in 50 meters distance due to effects of stream water on fillslope of road which that undercutting the road, also infiltrate water in fillslope of road which cause of dippig the road in some places. And 67 percents (58km) 100 meters and more of river limits. Also The study of crossings show that there are 7 point including diversion, 9 main subbasin are having main crossing, 119 minor subbasin have side crossing, and among of these 119 minor subbasin, 62 intersection strike to trenchs.