DOWNLOAD NOW! GCL Shear Strength Webinar - Presented by Dr. Chris Bareither of Colorado State University - Recorded THURS - 2/28/2019

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Factory fabrication reduces field welding, reduces installation time and costs, allows modular construction and provides consistent seam and liner quality.

GCL Shear Strength

Presented by Dr. Chris Bareither of Colorado State University
Presented on February 28, 2019


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New: Design and Installation Detail Drawings

Details available for constructing a containment facility including pipe boots, concrete attachments, penetrations, and vent details.  Both PDF and DWG available.

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Geomembrane Test Method Videos Now Available

FGI has created videos on the following Test Methods:

ASTM D5994 Thickness (Textured), D5119 Procedure B Thickness (Smooth), ASTM D7408 Seam Peel Strength, ASTM D882 Tensile Properties & D7408 Seam Shear Strength 

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Geomembrane Guide

An interactive list of geomembrane products for various applications. Read more

The FGI Equipment Guide

An interactive list of welding equipment and products for fabricated geomembranes. Read more

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.
GCL Shear Strength
Presented by Christopher A. Bareither, PhD, PE of Colorado State University
Recorded on February 28, 2019



The Fabricated Geomembrane Institute (FGI) at the University of Illinois at Urbana-Champaign presented two (2) Fabricated Geomembrane Engineering Innovation Awards during its biennial membership meeting in Houston, Texas on 12 February, 2019 during the 2019 Geosynthetics  Conference. The 2019 Engineering Innovation Award for Specifying Fabricated Geomembranes was presented to J.C. York of J& T Consulting, Inc. (see Figure 1) for the Fort Lupton Terminal Reservoir and the Taproot Water Storage Pond Projects.


The Fort Lupton Terminal Reservoir is a raw water storage facility that was built to serve North Denver and surrounding cities. The Northern Colorado Water Conservancy delivers source water to the city of Fort Lupton and Tri-State through a pipeline that terminates at Fort Lupton’s Water Treatment Facility. The pipeline requires general maintenance annually, which results in temporarily closing the pipeline. During pipeline maintenance or shutdown, no source water can be provided to the City or Tri-State. As a result, a water storage storage reservoir with a two (2) to six (6) week capacity had to be created and lined with a geomembrane to limit leakage. This reservoir liner system also had to be designed for a rapid drawdown (larger water discharge volumes) due to demand or operational reasons. This proved challenging because there are few geomembranes that can withstand the design rapid drawdown and provide the factors of safety required by the State of Colorado Dam Safety Rules and Regulations. The challenging water storage reservoir was designed by J&T Consulting with civil operations performed by Sema Construction.  The geosynthetics portion of the project is comprised of a 12 inch thick (0.3 m) gravel layer and the following liner system from bottom to top:  an 8 ounce nonwoven geotextile underlayment, 36 mil thick double sided textured reinforced polyethylene (RPE) geomembrane, and an 8 ounce cushion nonwoven geotextile that served as protection from the 18 inches of cover soil.


To accelerate construction, increase quality, and make construction more modular and predictable, the RPE geomembrane was pre-fabricated, which reduced field welding by approximately 80%. Figure 2 shows some of the pre-fabricated panels being deployed.  The project involved considerable creative details due to the inflow and outflow structures and requirements,as well as spillway (see Figure 3).  The nonwoven geotextiles were also pre-fabricated to accelerate construction.  In addition to the standard quality assurance(QA) procedures for a bottom liner system, a third party leak location survey was performed aftercover soil placement (see Figure 4) to minimize leakage.  This survey found nomajor defects to the liner system even after cover soil placement. This was confirmation of the success of the project by J & T Consulting, Raven Industries (manufacturer, fabricator, and installer), and Sema Construction.


The Taproot Storage Pond is a fresh water storage pond intended to service oil fields in Northeastern Colorado.  This pond also had a rapid drawdown design issue because the drilling process utilizes a large volume of water for the oil/gas well development.  The bottom liner system consists of a geomembrane placed on the existing fine-grained soils that had to be ballasted to prevent failure during rapid drawdown. Also designed by J & T Consulting, with civil operations performed by Northern Colorado Constructors, this project posed many challenges from a design and construction standpoint.  A geomembrane that could not only withstand the harsh chemical and windy conditions of the eastern Colorado plains, but also could be installed in a short installation window, was needed.  Raven Industries’ 45 mil thick RPE geomembrane (see Figure 5) was used because of its durability and longevity in harsh conditions, as well as designing of an integrated ballast system for the slopes that would ensure that the high winds and rapid drawdown would not affect liner system integrity.


The FGI Engineering Innovation Award provides recognition for engineer(s) who have creatively used fabricated geomembranes to successfully fulfill a client/owner’s needs including, technical requirements, scheduling, and budget.  

FGI Welcomes Hilts Consulting Group

The Fabricated Geomembrane Institute (FGI) is pleased to welcome its newest associate member, Hilts Consulting Group, Inc.  Hilts Consulting Group (HCG) is a civil engineering firm founded in 2003 and is located in Yorba Linda, California.  Engineering services range from project inception through construction including feasibility studies, peer reviews, value engineering, preliminary design reports, final designs, construction documents, construction administration support, construction management, construction observations and inspections, field investigations, owner’s representative, constructability reviews, forensic investigations, and expert witness.  HCG specializes in geomembrane floating covers, liners, and baffles for potable water, wastewater, biogas, recreational, industrial, and oil & gas facilities.  Their FGI liaison is Doug Hilts, President of HCG, who can be reached at  Please help us welcome HCG to the FGI!!!!

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Pond Leakage Calculator

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