Predicting Forest Road Surface Erosion and Storm Runoff from High-Elevation Sites

2017 ◽  
Vol 60 (3) ◽  
pp. 705-719 ◽  
Author(s):  
Johnny McFero Grace III

Abstract. Forest roads are a concern in management because they represent areas of elevated risks associated with soil erosion and storm runoff connectivity to stream systems. Storm runoff emanating from forest roads and their connectivity to downslope resources can be influenced by a myriad of factors, including storm characteristics, management practices, and the interaction of management practices and successive storm events. Mitigating sediment export and ensuring that storm runoff has negligible impacts on downstream resources requires a more complete understanding of forest road erosion and sediment delivery dynamics. Progress in the area of road and stream connectivity issues hinges on reliable prediction tools to inform broader-scale modeling of watershed-scale effects of forest roads and management practices. In this study, the Water Erosion Prediction Project (WEPP) model was evaluated based on the results from 156 runoff-generating storm events during a continuous five-year study of nine high-elevation road sections in the Appalachian Mountains. The model adequately predicted sediment yield from the road sections with an overall Nash-Sutcliffe model efficiency (E) of 0.76, Willmott refined index of agreement (dr) of 0.56, percent error of 5%, and average storm difference (ASD) of 1.2 kg. In contrast, WEPP predictions of storm runoff were not as good, and the poor agreement was attributed to an inability to determine the source area for runoff from some of the larger runoff events. In general, the WEPP model for these high-elevation sites adequately described the sediment yield for the road sections. Keywords: Forest roads, Long-term simulation, Runoff, Sediment, Water Erosion Modeling, WEPP.

Author(s):  
Rebecca Teasley

Since the late 1970’s the U.S. Geologic Survey (USGS) has led a program to remove abandoned logging roads in Redwood National Park. Because abandoned logging roads contribute large amounts of sediment to local fish bearing streams, the ecosystem health of these waterways suffer. Recent research has identified the effectiveness of preventing sediment from reaching the streams for different road treatments after significant storm events. However, road removal is expensive and time consuming. This research reported in this paper was part of that pilot study, and specifically reviews the feasibility of the optimization algorithm Dynamic Programming (DP), using data from recent research on road removal effectiveness. The DP sought to determine the road removal treatment that maximizes the amount of sediment saved from erosion, while meeting a budgetary constraint. The results indicate that DP is an effective tool for developing a road removal management plan. However, the order in which roads and stream crossings are treated has a large effect on the solution, indicating that the DP formulation has room for improvement. The USGS is supporting further research to reformulate the DP.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1805
Author(s):  
Saeid Rahbarisisakht ◽  
Mohammad Hadi Moayeri ◽  
Elyas Hayati ◽  
Seyed Mohammad Moein Sadeghi ◽  
Sebastian Kepfer-Rojas ◽  
...  

Forest roads play an important role in providing access to forest resources. However, they can significantly impact the adjacent soil and vegetation. This study aimed to evaluate the effects of road geometry (RG) on the chemical and biochemical properties of adjacent soils to assist in environmentally friendly forest road planning in mountainous areas. Litter layer, canopy cover, soil organic carbon (SOC) stock, total nitrogen (TN), the activity of dehydrogenase (DHA), and urease (UA) enzymes at a 0–20 cm soil depth were measured by sampling at various distances from the road edge to 100 m into the forest interior. The measurements were done for three road geometries (RG), namely straight, curved, and bent roads, to ensure data heterogeneity and to reflect the main geometric features of the forest roads. Analysis of variance (ANOVA) showed that the effects of RG on the measured variables were statistically significant. Spearman’s correlation test clearly showed a strong positive correlation between environmental conditions, SOC, TN, DHA, and UA for given RGs. Based on piecewise linear regression analysis, the down slope direction of the straight and the inside direction of bent roads accounted for the lowest and highest ranges of ecological effects, respectively. The results of this study contribute to our understanding of the environmental effects brought about by road geometry, which can be important for forest road managers when applying the best management practices.


2017 ◽  
Vol 36 (1) ◽  
pp. 25-39 ◽  
Author(s):  
Tomáš Orfánus ◽  
Marián Jenčo ◽  
Juraj Bebej ◽  
Martin Benko

Abstract There was a destructive flood on Gidra river on June induced by 104-mm rainfall during 3 h on 7 June 2011. The total flood discharge was estimated to be 531,000 m3. The upper part of the Gidra river catchment is forested by more than 95%, but the forest floor has been disrupted to a large extent by intensive logging activities in the basin. Forest road density is up to 10 km/km2 in the catchment. The field inspections in the catchments revealed that approximately 25% of forest roads have been deepened down to the less permeable subsoil directly during their construction or by subsequent traffic and soil erosion. Forest roads affect runoff generation via two mechanisms: (1) generation of infiltration-excess runoff on road surfaces and (2) capturing of hillslope surface and subsurface water by road incisions. Infiltration-excess water runoff from all compacted surfaces was estimated to be about 54,000 m3 by simply multiplying the compacted area by the difference between the precipitation and infiltration. More challenging was to quantify the transformation of hillslope water to the road-surface runoff. We have suggested the methodological approach that combines the GIS analyses of the terrain with mathematical simulations of the subsurface water exfiltration from hillslopes to the road surfaces using HYDRUS 2D model. Simulations based on the variability of slope inclinations and slope lengths within catchment revealed that drainage of the upward hillslopes by forest roads and deeper logging lines increased the forest road runoff by another 6,000-15,000 m3 of water.


1999 ◽  
Vol 26 (3) ◽  
pp. 262-269 ◽  
Author(s):  
C T Gnanendran ◽  
C Beaulieu

A new resurfacing method has been proposed recently for rehabilitating low-cost unpaved resource access (forest) roads using a mobile crusher. The quality and performance of the road rehabilitated using this new method have been a concern for some forestry companies and a study was initiated to compare it with the traditional resurfacing method where pit-run material is used. Two selected forest roads in New Brunswick, Canada, one resurfaced with the mobile crusher and the other resurfaced with pit-run material from a stationary crusher, were examined to assess the relative merits and deficiencies of the two methods. The particle-size distribution, maximum dry unit weight, and optimum water content for standard Proctor compaction were similar for the resurfacing materials derived from each method. The Benkelman beam deflection data suggest that the resulting roads from the two resurfacing methods were of similar structural capacity but the thickness of the gravel added and the level of compaction applied during resurfacing were different. Moreover, the materials from both methods contained a significant proportion of larger size particles exceeding 25.4 mm (1 in.) and failed to contain the required cohesive (binder) component.Key words: road rehabilitation, road resurfacing, mobile crusher, Benkelman beam, unpaved low volume road, forest road.


2021 ◽  
Vol 42 (2) ◽  
Author(s):  
Abdullah E. Akay ◽  
Hasan Serin ◽  
John Sessions ◽  
Ebru Bilici ◽  
Mehmet Pak

Forest roads are the key infrastructures that provide access to forest areas for sustainable management, protection, and utilization of forest resources. In order to benefit from the important functions of forest roads, they should be built in with adequate technical road standards. The road network with low technical standards require more frequent major repairs to ensure continues access to forest resources. In addition, only small trucks with low load capacity can move on the low standard roads. Furthermore, the low road standards limit the truck speed that increases vehicle travel time. These negative effects increase the transportation costs which are an important part of the timber production costs in Turkey. Thus, improving the road standards and developing forest transportation planning should be evaluated together in the most appropriate way. Large logging trucks with high load capacity are generally preferred for efficient transportation of wood-based forest products. In Turkey, large logging trucks, however, cannot operate on the most of the forest roads because insufficient technical road standards (road width, curve radius, surface materials, road structures) limit the maneuverability of large logging trucks. In this study, the objective is to determine the effects of improving forest road standards on total net profit of forest products by using the NETWORK 2000 program, a heuristic approach for solving forest transportation problems. Three Forest Enterprise Chiefs (FECs) located in Mustafakemalpaşa Forest Enterprise Directorate (FED) in Bursa Forest Regional Directorate were selected as the study area. The digital data layers for forest road network was generated by using ArcGIS 10.4 software. In the solution process, firstly, the optimum routes that minimize the transportation cost and maximize the total net profit of forest products on existing forest road networks were investigated for a truck type (15 ton) currently used in the region. In the second case, forest transportation was planned for the high load capacity truck (29 ton) moving on the forest roads with improved standards. In the first case, the transportation costs and annual major repair costs were considered in the calculation of the net profit of forest products, while one time cost of road improvement activities (i.e. road improvement construction, road structure installation, road surface construction) and annual maintenance costs were considered along with transportation costs in the second case. In both cases, the costs of other forest operations (i.e. felling, logging, etc.) were not considered since it was assumed that they do not vary with the forest transportation alternatives. As a result of the transportation plan developed for high load capacity truck, the annual transportation cost decreased by 46.85% comparing to the local logging trucks with low load capacity. Using improved road standards, the total road costs computed for the time period of 30 years (i.e. the average expected life cycle of forest roads) were reduced by 4.64%. The total net profit of forest products transported by using a high load capacity truck was 473,340 Euro more than that of using low load capacity truck on the existing forest road network. Thus, improving road standards might result in some additional costs in the road construction stage, but total net profit of forest products increase since transportation costs along with maintenance and repair costs considerably decrease in the long term.


Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1201
Author(s):  
Aristeidis Kastridis

The current review summarizes the knowledge generated by the recently published studies of the last twenty years, in the field of forest road networks, concerning the impact of forest road construction on hydrological processes. The currently applied methodology techniques/practices are discussed, the findings are highlighted and effective mitigation measures to mitigate the impact of forest roads are proposed. Critical for the minimization of the impact of forest roads on overland flow is the significant decrease in road surface runoff and overland flow velocity. The decrease in runoff energy reduces the detachment of soil particles and transportation in streams. The disturbances of forest roads in logging areas should be limited to decrease soil erosion. Additionally, aiming to minimize sediment transportation into the streams, it is very important to reduce the connectivity between the forest roads (or skid trails) and streams. The positive role of vegetation and organic matter on the road prism, naturally/technically established riparian buffers along the streams, and the use of appropriate bioengineering designs for each area significantly decrease the runoff generation and sedimentation. From a construction point of view, the decrease in short and long-term forest road-related impact could be achieved by reducing the depth of excavations and the use of soil compaction limiting technology during forest works. The road network design should be more efficient, avoiding hydrologically active zero-order basins. Techniques that minimize the length and connectivity among skid trails, unpaved roads and streams are highly crucial. Broad-based dips, immediate revegetation and outsloping of the road base are considered good road construction practices. Research should be focused on the hydrologic behavior of forest road networks and on the impact at the watershed scale, the degree of connectivity, utilizing plenty of qualitative field data, especially during intense rainfall events, which has been proven to exacerbate the runoff and sediment generation and transportation into the stream networks.


2009 ◽  
Vol 24 (2) ◽  
pp. 83-87 ◽  
Author(s):  
Kevin Boston ◽  
Robert Robek ◽  
Jesse Rathom

Abstract Improving subgrade strength can reduce a road's construction and maintenance costs. Additionally, it may lessen some of the environmental impacts from forest roads. However, most forest roads receive little effort to establish or control compaction because of the perceived increase in construction costs and potential delays in the flow of wood from the area. A light drop-weight deflectometer was tested on two forest roads in western Oregon to determine if this tool could aid with improving forest road construction by improving the quality of the road's subgrade. One road was built on a fine sand-silt soil and the other was constructed on a silt-clay soil. The goal was to correlate the easily collected subgrade values produced from the light drop-weight deflectometer and wet unit weight to the soaked and nonsoaked California bearing ratio (CBR) values for the subgrade, which are common design variables used to determine the minimum thickness of the aggregate surface. The light drop-weight deflectometer showed mixed results with regards to its ability to predict the values from the more expensive CBR laboratory test. The results from site 1, sand-silt soils, showed the potential of the light drop-weight deflectometer to aid in construction control as the values from light drop-weight deflectometer, when combined with the wet unit weight, explained a statistically significant amount of the variability in the soaked and nonsoaked laboratory CBR values. These variables explain approximately 60% of the variation in CBR values. The data from site 2, the silt-clay soils, were not able to significantly predict the subgrade strength variables, and the road will need to continue to use the traditional methods for establishing and controlling compaction.


2015 ◽  
Vol 45 (11) ◽  
pp. 1636-1642 ◽  
Author(s):  
Katalin Kiss ◽  
Jukka Malinen ◽  
Timo Tokola

Good road conditions are necessary for the smooth transportation of forest machines and products. High-density airborne laser scanning data were used here to determine the quality of road surfaces and ditching systems. Forest roads in Kiihtelysvaara, Finland, were assessed in August 2013. Eight categories (structural condition, seasonal damage, drying, bridges, surface wear, visibility, coppicing, and flatness) have been inventoried and divided into three quality classes: poor, satisfactory, and good. The topographic position index, standardize elevation index, and hydrology tools were used on digital elevation models with different resolutions to test which categories could be derived. The road surface quality was most clearly related to surface wearing and flatness, and the topographic position index described the road surface best at resolutions of 0.20 m and 0.25 m; however, the standardized elevation index was superior at a 0.50 m resolution. The ditching system plays an important role in the drying of roads, and the hydrological tools and land facet analysis were most suitable for identifying the location of ditches and assessing their quality at 0.20 m and 0.25 m resolutions, respectively. The road surface was classified in all resolutions at least 66% correctly, whereas the ditches were classified in all resolutions at least 60% correctly. The results confirm that airborne laser scanning data can be used for obtaining quality information on forest roads.


2012 ◽  
Vol 58 (No. 4) ◽  
pp. 165-169 ◽  
Author(s):  
M. Akbarimehr ◽  
R. Naghdi

A road network in forest lands provides easy access to forest resources for extraction, regeneration, protection and recreation activities. Erosion from forest roads and skid trails is a major concern in forest management due to the capability to cause adverse environmental effects. The objective of this paper is to introduce two methods for reducing erosion on forest roads and skid trails: water diversion and vegetation cover. Factors affecting erosion on forest roads and skid trails are climate, quality of forest road surfacing material, traffic, slope and vegetation cover. There are several management practices to mitigate the impact of logging and forest road and skid trail construction on stream water quality. Sediments delivered to streams from roads and skid trails lead to a number of dramatic effects on water quality and aquatic life. These management practices were found to be effective in controlling and reducing the runoff volume and soil erosion. Therefore, management and maintenance of forest roads and skid trails are essential elements to mitigate erosion.  


2010 ◽  
Vol 34 (4) ◽  
pp. 577-586
Author(s):  
Samuel Rivera ◽  
Jeffrey L Kershner ◽  
James P Dobrowolski

Surface runoff and sediment production from different timber yarding practices, some using Best Management Practices (BMPs) recommended for Honduras, were monitored in experimental plots during the rainy seasons of two consecutive years in pine forest highlands of central Honduras. Different timber yarding systems were applied to pseudo-replicated plots during the rainy seasons of 1999 and 2000. In 1999, two treatments were studied: tractor yarding and skyline cable (a recommended BMP). In 2000, four treatments were evaluated: tractor skidding, skyline cable, animal skidding (another recommended BMP), and undisturbed forest (reference). During the rainy seasons of these years, surface runoff volumes and sediment yield were measured at five 1.5m x 10m erosion plots in each treated area. The results showed significant differences between traditional tractor yarding and the recommended skyline cable and animal skidding methods. Tractor yarding produced six to ten times more erosion during the rainy seasons than cable and animal yarding. The improved soil retention of cable and animal yarding was especially important during September when the highest rainfall occurred in this climate.


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