Investigation of Culverts According to Fish-Passage and Geometric Design of Forest Road

摘要

This study was conducted to investigate and compare the existence cross drainage with its standards in forest regions of Savad kooh, Iran. Research was done according to the importance of the planning issue of technical structures in forest roads based on wildlife habitat. In order to assess the characteristics of considered ravine different analysis was respectively carried out to achieve flow direction, flow length, cumulate center and flow rate. The Roadeng software, which has been produced for road construction project, was used to design existent road, streams and culvert in our study area. In this software the level of water depth in culvert is determined with combination of topographic layers, ravine properties (length, direction, flow intensity and catchment area) and status of culvert installation. A result of investigations in study area showed that skew of mounted culverts is not accordance to flow direction. So that, when the culverts causes to skew water flow from its main route it can be a barrier against aquatic migration. In this study the culvert had suitable status in viewpoint of gradient and water level (suitable depth for fish passage). So that, this issue causes to even level flow and balance along culvert. According to the results of this study it can be concluded that the correct installation of culverts in forest roads need accurate scientific studies in field of road engineering, forest and fishing.