Municipal Solid Waste Water Balance Cover Guidance
Subtitle D municipal solid waste landfills are required to install final covers that are no less permeable than the bottom liners. This is typically achieved through the use of compacted low-permeability soils and geomembrane liners. Alternative final covers may also be approved if the alternative cover achieves an equivalent reduction in infiltration and equivalent protection from wind and water erosion as the prescriptive cover. A water balance cover (also known as evapotranspiration or ET cover) is a type of alternative final cover. A water balance cover utilizes temporary storage of precipitation infiltration within the cover soil layer(s) while the mechanisms of evaporation and plant transpiration return the stored water back to the atmosphere.
- Guidance for Requesting a Water Balance Alternative Final Cover for a Municipal Solid Waste Landfill (RG-494, in PDF; help with PDF)
The TCEQ Waste Permits Division developed the water balance cover guidance with input from landfill owners and operators, academia, and the public. A workshop was held in Austin on January 5, 2011, to present an overview of the guidance and offer technical presentations by experts on water balance cover design and monitoring. The presentations are listed below. (Please see the More Information section of this page for contact information to request a copy of a presentation).
- Field-Scale Evaluation of Lysimeters Versus Actual Caps: Effect on Percolation
Milind V. Khire, Ph.D., P.E., Professor, Department of Civil and Environmental Engineering, Michigan State University
- The USEPA's Alternative Cover Assessment Program (ACAP): Lessons Learned From the Field
William H. Albright, Ph.D., Hydrogeologist, Desert Research Institute in Reno, Nevada
- Moisture Monitoring of Water Balance Test Plots
Jorge G. Zornberg, Ph.D., P.E., Associate Professor, Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin
For More Information
To request PDF versions of the workshop presentations or for additional information on water balance covers, contact Dwight C. Russell, P.E., at 512-239-5282 or through our main Waste Permits Division line at 512-239-2334.