The FGI Pond Leakage Calculator Geomembranes v. Compacted Clay Liners
Fresh water is a precious resource with demands rising daily and supply greatly fluctuating. Only two (2) percent of all water on Earth is fresh water with the other 98% being salt water. This 2% of fresh water is comprised of: 87% ice, 12% groundwater, and 1% rivers and lakes. Thus, only 13% of the available freshwater is readily accessible. Therefore, it is imperative that we capture and hold these limited water resources for agriculture, domestic use, and industry and also protect valuable groundwater from surface or subsurface contamination.
The FGI’s Pond Leakage Calculator is a Microsoft EXCEL spreadsheet based on Darcy's Law of Seepage and provides a comparison between leakage rates from a canal, pond, or reservoir constructed with compacted fine-grained soils and a geomembrane liner system. The Leakage Calculator allows the user to input the size of the containment basin (including length, width, depth, side slope angle and freeboard), the anticipated level of hydraulic conductivity of the compacted soil or geomembrane liner, and the relative cost of water in dollars per acre-foot of water.
The Calculator then calculates the volume of the basin in gallons, a comparison of leakage rates between the compacted soil and geomembrane liner systems in gallons, and the cost of the leakage based on the cost of water per acre-foot to replace it. This Calculator is designed to help consultants, engineers, architects, and end users decide how to line their canals, ponds, reservoirs, and basins to capture and/or protect valuable fresh water. The Calculator does not consider variances in construction quality and operational techniques on the long-term effectiveness of the chosen liner system. The FGI has additional research and publications to help with other aspects of successful water containment applications.
Types of Geomembranes Four (4) popular types of geomembranes are available for pond liner systems. These four (4) geomembranes in ALPHABETICAL order are: (1) EPDM, (2) reinforced polyethylene (RPE), (3) Polypropylene (PP), and (4) Polyvinyl Chloride (PVC). EPDM (Ethylene Propylene Diene Monomer) geomembranes are unreinforced and have been used for the construction of ponds of varying kinds. EPDM geomembranes are made from rubber and can be welded together with tape and primer. EPDM can be reinforced or unreinforced. RPE geomembranes have a high tensile strength and puncture resistance because they are reinforced. RPE geomembranes also can be welded with heat. PP geomembranes can be unreinforced or reinforced depending on the application. Reinforced PP geomembranes also have a high tensile strength and puncture resistance because they are reinforced. PVC geomembranes are also unreinforced and have been used successfully for decades in water canals, ponds, and reservoirs. PVC geomembranes can be welded with heat and/or solvents.
Please click below to access FGI’s Pond Leakage Calculator.
FGI Publishes Article on Elvaloy Nomenclature in Geosythetics
Clarifying the Nomenclature of Elvaloy-based Geomembranes: EIA, EIP or KEE
By E. Silva and T. D. Stark
Since the first flexible membrane liner (FML) was used as part of an environmental liner system, the geomembrane industry has always looked for innovative solutions to environmental containment applications. Although there have been many innovations over the last fifty (50) years, one of the most significant is the introduction of ketone ethylene ester (KEE), which is a solid plasticizer. KEE is available under the Elvaloy® trade or product name and is used to plasticize PVC geomembranes as discussed in detail below.
The Fabricated Geomembrane Institute (FGI) at the University of Illinois at Urbana-Champaign has created a library of Geomembrane Test Method Videos that explain various factory and field test methods. Testing videos available to view/download include demonstrations on how to measure the following: thickness, tensile strength, dimensional stability, seam shear and peel strength, and brittleness.
The FGI has recently recorded two new testing videos, as part of the Geomembrane Test Method Library on the FGI website: ASTM D1204 Dimensional Stability and ASTM D1790 Brittleness Temperature of Plastic Sheeting by Impact.
In addition to these two testing videos, the FGI has recorded the following testing videos available to view/download:
ASTM D7408 Seam Peel Strength
ASTM D882 Tensile Properties Geomembranes
ASTM D7408 Seam Shear Strength
ASTM D5994 Thickness Textured Geomembrane
ASTM D5199 Procedure B Thickness Smooth Geomembrane