Design of Geomembranes for Surface Impoundments

*Open only to Central Ohio Section Members
*Seating is limited to the first 25 people
*Bring your own lunch

Surface impoundments are used to contain (either temporarily or permanently) all types of liquids and quasi-liquids. In addition to the obvious (potable water, industrial waters, grey waters, various sludges) there are 206,000 hazardous liquid impoundments in America. Quasi-liquids like sewage sludge, dredged sediments, and coal combustion residuals are also necessarily contained materials. For all of these materials, geomembranes as a single or double-lined barrier system hold the key toward a successful containment system. After a brief background, this webinar progresses step-by-step through the design process of surface impoundments. The progression begins with geometric considerations and then deciding upon a preferred cross-section. Regulations, where appropriate, will be mentioned. The all-important choice of geomembrane type is addressed using a benefit-to-cost analysis for resin type and this is then followed by an analytic design for thickness. Details regarding subgrade stability and cover soil stability are then presented. The termination of the geomembrane insofar as runout and anchor trench design, are presented. Lastly, allowable leakage values and details of the relatively new “electrical leak location survey” are presented.

RSVP to JDRoss@smeinc.com by Monday, January 13, 2014.

Webinar Outline

• Background
• Geometric considerations
• Typical cross sections
• Geomembrane selection
• Thickness considerations
• Subgrade and cover soil stability
• Runout and anchor trench considerations
• Leakage through geomembrane holes
• Summary and conclusion

Learning Outcomes / Benefits

• Recognize the scope and range of lined surface impoundments
• Understand the appropriate design methodology geomembranes for surface impoundments
• Learn appropriate site selection methods; various optional geosynthetic cross-sections; idiosyncrasies of different geomembrane types; various design details (thickness, soil stability, anchor trenches); as well as leakage scenarios
• Understand the various regulatory agency allowable leakage rates
• Know the “electrical leak location survey” method will be described and discussed
• Understanding the scope and range of lined surface impoundments
• Discuss the various optional cross-sections vis-à-vis different geosynthetic materials, including geomembranes, geosynthetic clay liners, geotextiles, geonets, and geocomposites
• Present design models (with numeric examples), for geomembrane thickness, subgrade stability, cover and stability, runout and anchor trench design
• Learn various regulatory agency allowable leakage rates and most importantly describe the relatively recent method of leak location, which is conducted before the surface impoundment is put into service

See the ASCE website for more info.

The Central Ohio Section of ASCE sponsors free continuing education webinars as a service to our members. These webinars are produced by ASCE and normally cost $250 or $300 for ASCE members. However, the Central Ohio Section is paying the registration fee and inviting any interested section members to attend for free. Just RSVP to JDRoss@smeinc.com by the deadline. Seating is limited, so do not delay.

You can see the complete list of webinars available from ASCE National on their website. If you see one you like, let us know. If you and your company would like to host one, let us know that too. If you open it up to any interested Central Ohio ASCE section members to come, we will pay the registration fee.