Evaluation of Roads Effects on Flooding in Madarsoo Watershed, Golestan Province

Flood as a disaster in the Madarsoo Watershed of Golestan Province has caused many socio-economic and environmental consequences in the last decades. In this study, analytical hierarchy process (AHP) and sensitivity analysis were used to assess the effects of road infrastructures on flooding of Madarsoo Watershed, Golestan Province. First, the effective thematic layers on the flood occurrence including slope, rainfall, distance from bridges, drainage density, and altitude were prepared in ArcGIS10.2. The final weights of factors were determined in Expert Choice software using pairwise comparison and questionnaires filled by experts. Furthermore, a flood susceptibility map was created based on these weighted-layers, and then validation was carried out by ROC curve method in SPSS 21 software. Results indicated that the distance from bridges and altitude have received the highest and lowest weights, respectively. Validation of results showed that our analysis performed fairly good in flood predication with an accuracy of 88%. Moreover, results of sensitivity analysis demonstrated that distance from bridge has a great effect on the flood susceptibility of study area. Therefore, non-standard bridges, road infrastructures on river and flow discharge regime are considered as the most important factors in flood occurrences in Madarsoo Watershed of the Golestan Province.