Vegetation Effects on Sub Base Drainage Relating to Pavement Preservation
Construction and Maintenance Practices
Environmental Process, Natural Resources
Research Idea Scope
Winter materials, such as aggregate and sand, can accumulate along the roadside impeding surface drainage and requiring periodic maintenance operations to remove it. Grass along the edge of pavement causes increased winter material accumulation and greater surface drainage problems. Maintenance operations that remove the winter material also remove or severely damage the grass in the process causing new erosion concerns.
Research is needed to identify sound roadside maintenance practices that satisfy the environmental requirements and the sub base drainage functions of the roadway. These practices should address maintenance operations from the edge of roadway to the bottom of the ditch or to extent of the sub base exposure on the slope, and should focus on the effects of the presents or absence of vegetation, proper types of vegetation, and the use topsoil in these operations.
Certain vegetation, notably shrub willow species are often used to dewater wet slopes. This is an effective technique especially in the spring when the shrubs are actively growing. While willows are not appropriate on shoulders or on many slopes, it is possible that specific grasses may perform a similar function of removing water through evapotranspiration.
Urgency and Payoff
The research would impact several roadway characteristics such as longer pavement life, reduction in shoulder drop offs, safer roadways, and reduction in surface runoff problems
TRB Research Needs Database, AHD50, Roadside Maintenance Operations