1- AREEO
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Extended Abstract
Introduction and objectives: Improper road construction, by disrupting the integrity of nature, collapsing the mountain life cycle, and involving large volumes of excavation, leads to the destruction of animal and plant habitats, a reduction in aesthetic values, and damage to sensitive areas. One of the biggest problems arising from road construction is the creation and increase of various forms of erosion, such as gully and mass erosion around roads. During the road construction process, a significant portion of natural covers (including forests and pastures along and beside the road) is are typically destroyed. The displacement of large volumes of soil and rock during civil operations also causes changes in land structure and disruption of the natural environmental balance. Some of these materials may enter waterways and rivers, subsequently settling as sediment in reservoirs, wetlands, and lakes. This phenomenon not only reduces the capacity of these water resources but can also alter their natural shape through sedimentation in river beds and exacerbate erosion. Therefore, in the design and implementation of road networks, in addition to economic considerations, special attention must be paid to proper water and soil management to minimize negative environmental impacts.
Materials and methods:
In this study, the SEDMODL model and Geographic Information System (GIS) were used to estimate sediment resulting from the forest road network in the oak forests of western Chaharmahal and Bakhtiari Province, Kohrang County. The study area included 5,643 meters of dirt roads constructed for access to various areas. Required maps such as those of geology, slope, rainfall, and roads were prepared and digitized in the GIS environment. Field data, including road material, age, and traffic, were also collected. The SEDMODL model calculates sedimentation based on three main sources: the road surface, excavation trenches, and side ditches. These factors are influenced by parameters such as road length and width, surface material, slope, rainfall, traffic, and geological type. Data were analyzed statistically using the Pearson correlation test. For field measurement of erosion, 36 measurement points were installed and examined over one year with precise instruments. Additionally, using Hotspot statistical analysis in the GIS environment, points with high erosion (hot-spots) were identified. The analysis results were presented as a map of areas with high erosion.
Findings:
The results from field measurements indicated an average soil erosion of 4.5 millimeters per year. On the other hand, the erosion amount calculated based on the SEDMODL model for the Tabark road was 2,360 tons per year along the studied road. Regarding the estimation of road sediment yield, the sediment contribution was separately determined for the road surface (TS) and excavation trench (CS) as 153 and 19 tons per year, respectively, in the mentioned model. Ultimately, the total sediment yield of the studied road based on the SEDMODL model, from the sum of sediment yield from the road surface and side ditches plus sediment yield from the excavation trench, was determined to be 344 tons per year. The results from hot spot analysis for identifying areas with high erosion amounts, with a confidence level greater than 95% (Confidence level >95%) for the Tabark road, showed 22.6% (1,276 meters) of the road as areas with very high erosion production and as hot spots. Based on the produced maps, it was found that in areas with steep slopes and geologically sensitive conditions, soil erosion is higher, and these parts play the greatest role in regional sediment production. On the other hand, the results from the statistical correlation test show that the strongest significant correlation for the total road erosion is with geological factors, road width, and rainfall factors.
Results:
The analysis of the results of this research indicates that the SEDMODL model has high capability in identifying erosion-sensitive areas and estimating sediment yield rates resulting from forest roads. It can be stated that forest roads cover a small percentage of the watershed area but produce a much higher amount of sediment. Therefore, attention to adhering to proper principles in road construction, designing appropriate networks such as protecting excavation slopes with netting and planting shrubs, minimizing road lengths, and implementing proper road management to minimize soil erosion and sedimentation in these areas is of great importance. Additionally, based on the model results, the highest road vulnerability in slope destruction relates to areas with steep slopes and destroyed vegetation cover, which highlights the importance of implementing watershed management measures to restore vegetation cover and stablize slopes in the area. Furthermore, it can be seen that geological conditions and formations sensitive to erosion play the greatest role in sediment production from forest roads, which is consistent with the findings of other studies. Therefore, the precise implementation of management programs in areas with steep slopes, after examining geological factors, road width, and rainfall, is essential.
Introduction and objectives: Improper road construction, by disrupting the integrity of nature, collapsing the mountain life cycle, and involving large volumes of excavation, leads to the destruction of animal and plant habitats, a reduction in aesthetic values, and damage to sensitive areas. One of the biggest problems arising from road construction is the creation and increase of various forms of erosion, such as gully and mass erosion around roads. During the road construction process, a significant portion of natural covers (including forests and pastures along and beside the road) is are typically destroyed. The displacement of large volumes of soil and rock during civil operations also causes changes in land structure and disruption of the natural environmental balance. Some of these materials may enter waterways and rivers, subsequently settling as sediment in reservoirs, wetlands, and lakes. This phenomenon not only reduces the capacity of these water resources but can also alter their natural shape through sedimentation in river beds and exacerbate erosion. Therefore, in the design and implementation of road networks, in addition to economic considerations, special attention must be paid to proper water and soil management to minimize negative environmental impacts.
Materials and methods:
In this study, the SEDMODL model and Geographic Information System (GIS) were used to estimate sediment resulting from the forest road network in the oak forests of western Chaharmahal and Bakhtiari Province, Kohrang County. The study area included 5,643 meters of dirt roads constructed for access to various areas. Required maps such as those of geology, slope, rainfall, and roads were prepared and digitized in the GIS environment. Field data, including road material, age, and traffic, were also collected. The SEDMODL model calculates sedimentation based on three main sources: the road surface, excavation trenches, and side ditches. These factors are influenced by parameters such as road length and width, surface material, slope, rainfall, traffic, and geological type. Data were analyzed statistically using the Pearson correlation test. For field measurement of erosion, 36 measurement points were installed and examined over one year with precise instruments. Additionally, using Hotspot statistical analysis in the GIS environment, points with high erosion (hot-spots) were identified. The analysis results were presented as a map of areas with high erosion.
Findings:
The results from field measurements indicated an average soil erosion of 4.5 millimeters per year. On the other hand, the erosion amount calculated based on the SEDMODL model for the Tabark road was 2,360 tons per year along the studied road. Regarding the estimation of road sediment yield, the sediment contribution was separately determined for the road surface (TS) and excavation trench (CS) as 153 and 19 tons per year, respectively, in the mentioned model. Ultimately, the total sediment yield of the studied road based on the SEDMODL model, from the sum of sediment yield from the road surface and side ditches plus sediment yield from the excavation trench, was determined to be 344 tons per year. The results from hot spot analysis for identifying areas with high erosion amounts, with a confidence level greater than 95% (Confidence level >95%) for the Tabark road, showed 22.6% (1,276 meters) of the road as areas with very high erosion production and as hot spots. Based on the produced maps, it was found that in areas with steep slopes and geologically sensitive conditions, soil erosion is higher, and these parts play the greatest role in regional sediment production. On the other hand, the results from the statistical correlation test show that the strongest significant correlation for the total road erosion is with geological factors, road width, and rainfall factors.
Results:
The analysis of the results of this research indicates that the SEDMODL model has high capability in identifying erosion-sensitive areas and estimating sediment yield rates resulting from forest roads. It can be stated that forest roads cover a small percentage of the watershed area but produce a much higher amount of sediment. Therefore, attention to adhering to proper principles in road construction, designing appropriate networks such as protecting excavation slopes with netting and planting shrubs, minimizing road lengths, and implementing proper road management to minimize soil erosion and sedimentation in these areas is of great importance. Additionally, based on the model results, the highest road vulnerability in slope destruction relates to areas with steep slopes and destroyed vegetation cover, which highlights the importance of implementing watershed management measures to restore vegetation cover and stablize slopes in the area. Furthermore, it can be seen that geological conditions and formations sensitive to erosion play the greatest role in sediment production from forest roads, which is consistent with the findings of other studies. Therefore, the precise implementation of management programs in areas with steep slopes, after examining geological factors, road width, and rainfall, is essential.
Type of Study: Research |
Subject:
فرسايش خاک و توليد رسوب
Received: 2023/04/26 | Accepted: 2026/02/24
Received: 2023/04/26 | Accepted: 2026/02/24
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