Soil Rehabilitation Guidebook

[Soil Rehabilitation Guidebook Table of Contents]

Planning considerations and treatment options for soil rehabilitation1

This section describes some of the special concerns that are associated with particular types of access structures and disturbance. Successful rehabilitation requires an evaluation of soil and site conditions to determine the goals of rehabilitation and the techniques to be used. The ideas presented in this section should not be interpreted as ready-made prescriptions, but rather as an indication of problems that may be encountered, and solutions that may be useful for achieving successful rehabilitation.

Soil rehabilitation treatments are expensive. Whenever the construction of temporary access is being considered, every attempt should be made to limit the amount of soil disturbance and the area that will require rehabilitation. In addition, consideration should be given to all future access requirements to avoid rehabilitating areas that will be required for access before the next harvest.

Rehabilitation of landings

Planning for landing rehabilitation

Drainage control

Tillage

Revegetation

Rehabilitation of roadsides

Rehabilitation of roadside cuts and fills is aimed at controlling erosion and restoring productive tree growth. The following methods relate to both cuts and fills although the emphasis is on fill slopes because they typically occupy a larger area than cuts and often support productive tree growth.

Planning for roadside rehabilitation

Drainage and erosion control

Minimize the need for rehabilitation by carefully managing water during construction and active use. When the road is no longer in use, follow proper deactivation procedures: See Chatwin et al. (1994) for specific techniques.

Restoring soil productivity

A slope must be mechanically stable before seeding and planting:

Vegetation

Revegetate fill slopes and cut slopes as soon as possible after construction. A delay in seeding can lead to erosion of the fine soil particles from the surface leaving a "pavement" of coarser material that is more difficult to revegetate. Figure 1. Preparing slopes for roadside seeding.

Rehabilitation of roads

Rehabilitation of roads involves removal of the road and restoration of the original slope. The objectives are to prevent erosion and to establish a productive growing site for trees.

Planning for road rehabilitation

Drainage and erosion control

Tillage

Revegetation

Excavated and bladed trails

Planning for rehabilitation of excavated and bladed trails

Drainage and erosion control

Restoring soil productivity

Mulching

Revegetation

Compacted logging trails

Planning for rehabilitation of compacted logging trails

Drainage and erosion control

Tillage

Mulching

Revegetation

Rehabilitation of ruts and areas of dispersed disturbance

Drainage control

Restoring soil productivity

Revegetation

Rehabilitation of severely burned areas

Broadcast burns

Slash accumulation burns

Rehabilitation of gravel and rock pits

Planning for rehabilitation of gravel and rock pits

Drainage and erosion control

Soil productivity

Revegetation

Rehabilitation of landslides

Landslides can take many forms, including deep-seated rotational failures, channelized debris flows, open-slope debris avalanches, bedrock failures and rock falls. Because these different types of failures can be initiated by a variety of circumstances and because they result in a wide range of soil damage, each situation should be carefully analyzed to determine what rehabilitation techniques are needed.

Conditions on landslides may be hazardous to other resources, to people and property in the vicinity and to those who will do the rehabilitation work. Seek advice from experienced terrain and soil specialists and/or engineers to develop rehabilitation plans for major landslides or where issues of public safety arise.

Figure 2 shows a typical landslide profile for an open-slope debris avalanche.

Planning for landslide rehabilitation

Slope stability and drainage control

Soil

When clearing a slide from a roadway, prepare the ground for seeding. Re-sloping is usually required for slides that initiate at roads, oversteepened slopes, where mid-slope roads have been rendered unusable by slides, and where roads are buried under landslide debris.

Figure 3 recommends approaches to the following situations:

Revegetation

Figure 3. Slope preparation and drainage restoration associated with landslides and road systems.


TOP OF PAGE PREVIOUS PAGE NEXT PAGE