Road maintenance is essential in order to (1) preserve the road in its originally constructed condition, (2) protect adjacent resources and user safety, and (3) provide efficient, convenient travel along the route. Unfortunately, maintenance is often neglected or improperly performed resulting in rapid deterioration of the road and eventual failure from both climatic and vehicle use impacts. It follows that it is impossible to build and use a road that requires no maintenance.
In order to plan for road maintenance needs, it is important to keep a complete set of "as built" plans and records of all maintenance operations and observations. The as built plan should contain the following:
Probably the most valuable tool for any maintenance program is the knowledge and experience gained by individuals performing the maintenance. Every effort should be made to retain competent, knowledgeable, and experienced individuals in these positions not only from the standpoint of instituting and executing a good maintenance program, but for future road planning needs as well.
In deciding on an appropriate level of maintenance for a particular road or road segment, consideration must be given to the amount and type of vehicle use and physiographic and climatic variables which may impact drainage structures. A useful guide to the types and frequency of maintenance activities appropriate for a given road is shown in Table 43.
Drainage structures must be kept free of debris and obstructions. On newly constructed roads, or in upstream areas where heavy earth moving is taking place (e.g., urban development, logging, mining, etc.), cleaning may have to be more frequent.
Grass growing in ditches, unless it is dense enough to cause a major impediment to flow, should not be removed during cleaning. Likewise, shoulder and cut banks must not be undercut.
Table 44. Typical road maintenance activities appropriate for a given road use level.
The objective in "pulling a ditch" is to grade the ditch so as to clean it of debris that could divert flow from the ditch on to the road surface. Hand clearing with a shovel is effective when the work load is light or the presence of structures (e.g. cross drains or culvert inlets) make it impractical to use heavy equipment. With a grader, the following procedure is followed:
1. Flag all culverts and cross drains
2. Remove snags, rocks, and other hazards before grading begins
3. Cut only the ditch bottom and shoulder; avoid undercutting the cut slope; do not redress the cut slope
4. Spread fines into the road with surface reworking
5. Avoid working around culverts or other channel crossing structures so as to minimize damage to inlets
Debris in and around culverts should be removed by hand or by grapples or tongs rather than by heavy equipment working directly in the stream. Stream channels should be completely free of floatable debris (branches, leaves, small logs, construction material, garbage, etc.) for at least 30 m (100 feet) upstream. If plugging of a particular culvert occurs frequently and a debris deflector or "trash rack" was not included in the original design, one should be installed as part of the maintenance program.
Road surfaces should be reworked only as necessary to provide a smooth running surface and a good crown or slope for drainage. All-season roads will require continual monitoring for surface and subgrade wear or deterioration. Rutting and loss of ballast often occur during rainy season use. Snow removal equipment can also destroy the road surface by removing or altering the crown and removing ballast. A plan should be in place to provide ballast when necessary to maintain continued use of the road.
On non-surfaced roads, a grader on the first pass should move material from the shoulder to a windrow in the center of the roadway. On the second pass, the blade should be centered on the windrow and continue working along the roadway. The blade should be adjusted so as to provide a slight slope or crown and should avoid cutting too deep into the road surface. Any excess material should be stored in the berm--not sidecast over the edge of the fill.
A wide variety of chemicals are commonly used to treat road surfaces to minimize wear, reduce dust, or de-ice. However, many of these products provide only minimal benefit and represent a potential hazard to water quality (US Environmental Protection Agency, 1975). Oil based dust palliatives must be used very carefully where the potential for entering surface or groundwater exists. Likewise, salts such as sodium chloride (NaCI) and calcium chloride (CaCl2), along with additives to prevent caking, rust, and corrosion, can cause acute and chronic toxicity in aquatic organisms and fish, contamination of groundwater supplying public and domestic water users, and death to vegetation adjacent to the road. Maximum salt concentrations can be found at soil surfaces nearest the road, but because they can be readily leached, salts can easily enter groundwater. High concentrations of salts have been found in streams during dry season low flows when the major component contributing to stream flow consists of groundwater.
Sulfite waste liquor from pulping operations is used extensively for dust abatement, however, it too has a potential for adversely impacting water quality through its high biochemical oxygen demand. Fortunately, though, the BOD-containing agents in pulping liquors will oxidize rapidly on the road surface. Controlled application during dry weather to prevent runoff will minimize impacts.
Herbicides used to control roadside vegetation represent the final class of road maintenance compounds that present a potential health or water pollution hazard if used incorrectly. Compounds such as dioxin, contained in 2,4-D and 2,4,5-T, are extremely toxic even in minute quantities.
Practices and methods to help minimize impacts from road chemicals include:
An effective way of dealing with storm damage to roads and property is to provide for an emergency response program in which personnel and equipment can be mobilized as needed on short notice. This concept is similar in practice to that dealing with emergency measures used in fire control. The purpose of the plan is to:
1. Prevent loss of life or injury
2. Prevent damage to soils, streams, fisheries, and other resources
3. Prevent and/or minimize damage to capital improvements, private property, roads, and other features
4. Provide for efficient, economical, and necessary use of available finances, equipment, and personnel
5. Evaluate structural and resource damage when it occurs and determine needs for corrective measures to prevent further damage
Necessary items to include in a storm response action plan are:
1. A system to collect and analyze weather, soil, and road conditions
2. A communication system between personnel responsible for activating the storm action plan
3. Establishment of organizational plans and responsibilities for prevention and control of storm damage
4. Methods of financing and documenting costs of personnel and equipment; outline of individuals authorized to use finances, personnel, and equipment
5. Telephone numbers for providing public information and communication with law enforcement and other public agencies
6. Provisions for monitoring the effects of storms and efforts to prevent damage; reconnaissance and estimates of extent of damage to structures and resources; preliminary cost estimates
7. Storm damage reporting procedures
Weather data should be collected daily and should include daily amounts of precipitation, cumulative precipitation per storm, total per season, month, etc. Any information indicating run-off amounts, snow pack accumulation/melt rates, temperature, temperature changes, wind and barometric pressure should be noted. Additional or more frequent information updates can be requested as conditions warrant. A rating system for storms, such as that used for fires, can be developed based on historical data and/or local knowledge. For each condition, a specific set of activities ranging from observation to full region-wide patrols and work teams will be identified.
Forest roads are often designed for temporary or intermittent use in which two situations may exist: (1) the road is planned for closure with the intent of reconstructing at some point in the future, or (2) the road is planned for permanent closure. In the first instance, if the interval of non-use is relatively short, a physical barricade blocking all entrances to the road may be all that is required provided that periodic checks are made throughout the non-use period to ensure that road drainage structures, erosion control measures, and other slope protection measures are functioning properly. A barricade may consist of a locked gate or a variety of crude barriers constructed of native materials--rock, slash, cull logs, etc.
If periodic checks and maintenance cannot be performed (e.g. during heavy snow pack conditions) other measures in addition to barricading need to be taken. These measures might include installing a system of rolling dips or water bars, outsloping, and stabilizing all cut and fill slopes (see Chapter 4). Scarification and revegetation of exposed surfaces, including the roadway itself, may be appropriate depending on the type of road surface, the potential for erosion, and the non-use period.
When an extended non-use period is planned and the risk of environmental damage from failure is significant, a partial restoration of the original ground profile may be considered. The objective here is to convert a portion of surface water flow back to subsurface flow and to provide more efficient surface runoff capacity. An effective method, called "Kanisku" closure, can be used on sideslopes less than 60 percent and is illustrated in Figure 121. If terrain and road conditions permit the use of this technique without significant loss of soil over the edge of the fill, this procedure can be accomplished with an angle-blade bulldozer. This technique is not appropriate on end haul constructed roads, on ballasted or surfaced roads, on some soil types, or in regions with high precipitation.
Figure 121. "Kanisku" closure is effective on side cast constructed roads on slopes up to 60 percent in areas with low to moderate precipitation.
Stream crossings on intermittent-use roads require special attention. In addition to guidelines presented elsewhere in this book, design, construction, and maintenance considerations for intermittent-use roads include:
Temporary log stringer bridges can be used when a stream crossing installation would require a large amount of fill. With short non-use periods, it may be more economical to design a "longer life" temporary bridge and leave it in place. With longer non-use periods, it is advisable to use a minimal cost structure and remove it after use.
For channel crossing structures that have functioned satisfactorily for years, the best solution, in most cases, is to leave it in place and restore it to its original condition (remove debris, clean ditches, revegetate side slopes, reshape road surface crown). For those crossings having a high failure risk, continued maintenance or partial or entire removal are the only choices, difficult as they may be. If removal is chosen, the use of proper equipment and attention to timing can aid in reducing the severity of water quality impacts. If total removal cannot be accomplished for technical or economic reasons, a possible solution is a relief dip in the culvert fill (Figure 122). A relief dip does not preclude the need for stabilization, but, rather, reduces the water quality impact upon failure by directing the course of overflow water and reducing the amount of available sediment.
In the case of permanent closure, methods described above may be appropriate, making sure that all culverts and bridges are removed and excess fill is hauled to a safe disposal area. Additionally, it is also desirable to break up the road surface with deep penetrating hydraulic ripper teeth. This aids in restoring soil permeability and enhancing revegetation.
For esthetic reasons, it may be desirable to completely restore the original ground profile, or "deconstruct" the road. One way to accomplish this is to temporarily store excavated material and then pack it back into the roadway following use. More commonly, excavated material is side cast, and following use, pulled back up into the road prism with hydraulic shovel or dragline. On slopes greater than 60 percent, it is highly recommended that excavation and side cast pullback be accomplished during the same dry season. After deconstruction, the site is revegetated including tree establishment where appropriate. Follow-up planting or fertilizing may be necessary for several years following restoration.
Figure 122. Relief dip reduces the potential impact of culvert failure by reducing the amount of potential sediment.
U. S. Environmental Protection Agency. 1975. Logging roads and protection of water quality. EPA 910/9-75-007, NTIS, Springfield, VA 22161. 312 pp.