Estimating sediment yield from a forest road network using SEDMODEL and GIS technique (case study Arasbaran forests)

Aims :

This study has been done to investigate the effects of access road network of Arasbaran forest areas on erosion in order to achieve appropriate criteria for sustainable development in forest areas while protecting forest soil.

Materials & Methods :

This research was carried out to introduce the SEDMODEL and its capabilities in estimating the production of sediment from road construction Sutanchay watershed in Arasbaran forest, located in the northwest of Iran. From road networks, 10km selected for research. Initially, the maps of geology, slope, rainfall, and drainage density, were prepared in the GIS system. Then, excavation trenches, road surface coverage, and traffic volume were examined in 34 stations through field surveys. The statistical method of Fisher distribution was used to compare the model estimation and observation values.

Findings:

 Statistical analysis of the data showed that there was no significant difference between sediment delivery and Metric method in the erosion assessment resulting from access roads. Standard Error of the metric method and the SEDMODEL was calculated to be 1.34×10-3 and 1.37×10-3, respectively. The results showed that sedimentation caused by road surface was more than 19,000tons, of which 240ton are related to 3km of asphalt road and the rest are related to 7km of dirt road. Total sedimentation of the watershed was estimated to be 46,000ton.

 Conclusion:

 The application of sediment delivery model provides a realistic estimate of forest soil erosion caused by the road network. This model can be considered as a planning criterion in the sustainable development of forest areas.