Evaluation of Urban Soils for Green Infrastructure or Urban Agriculture

In Evapotranspiration Covers for Landfills, you'll learn ...

• How evapotranspiration (ET) landfill cover systems differ from conventional cover systems
• Permeability limitations for landfill cover systems
• Differences between a monolithic ET cover and a capillary barrier ET cover
• Considerations involved in the design of ET covers, including climate, soil type/thickness, soil fertility and vegetation types
• Percolation monitoring methods for ET cover systems

Overview

Credit: 2 PDH

Length: 21 pages

Final cover systems are frequently used at a variety of different waste disposal sites, including landfills, abandoned dumps, hazardous waste containment facilities, and sites with surface contamination, as well as some hazardous, low-level, and mixed low-level waste sites with conducive environmental conditions. Final covers serve multiple purposes: to control moisture and percolation, manage surface water runoff, minimize erosion, prevent direct exposure to waste, control gas emissions and odors, prevent occurrence of disease vectors and other nuisances, and meet aesthetic and other end-use purposes. Final cover systems are intended to remain in place and maintain their functions for periods of many decades to hundreds of years.

To minimize percolation, conventional cover systems typically use low-conductivity barrier layers. These barrier layers are often constructed of compacted clay, geomembranes, geosynthetic clay liners, or combinations of these materials.

First appearing in the mid-1990’s, evapotranspiration (ET) covers may be a cost-effective alternative to conventional ones. ET covers are designed to rely on the ability of a soil layer to store the precipitation until it is naturally evaporated or is transpired by the vegetative cover. In this respect they differ from more conventional cover designs in that they rely on obtaining an appropriate water storage capacity in the soil rather than an as-built engineered low hydraulic conductivity. ET cover system designs are based on using the hydrological processes (water balance components) at a site, which include the water storage capacity of the soil, precipitation, surface runoff, evapotranspiration, and infiltration.

This course is intended primarily for civil and environmental engineers interested in learning how ET covers can provide a cost-effective alternative to conventional final cover systems found at many waste disposal sites.