Free-Flow Leakage from Landfill Geomembrane Defects
Installation defects in landfill geomembranes (GM) result in leakages. Free-flow leakage is a special worst-case scenario in which the controlling layers surrounding the GM are assumed to be hydraulically conductive. A specialized form of Bernoulli's principle can be used to describe the relationship among defect density, average hydraulic head and free-flow leakage rate, assuming that the head loss coefficient for sharp-edged landfill orifices is 0.6 and the defect area is 0.0001 for the time step of 1 day.
 P. R. Schroeder, T. S. Dozier, P. A. Zappi, B. M. McEnroe, J. W. Sjostrom and R. L. Peyton, The Hydrologic Evaluation of Landfill Performance (HELP) Model: Engineering Documentation for Version 3, EPA/600/R-94/168b, Cincinnati, OH: U.S. Environmental Protection Agency Office of Research and Development, September 1994. www.nrc.gov/docs/ML1015/ML101590183.pdf.