Each month Tim Stark introduces a new technical topic for discussion and possible action. This month’s topic is: “Determining Lining/Floating Cover Systems for Critical and Non-Critical Applications”. This topic generated significant discussion with the main “take-aways” being listed below:

 Non-Critical Applications

·        Relevant Factors/Questions:
‍-            Site Specific Determination – Activate ancient landslide or fault system? If so, critical application
-            Does the owner accept some leakage?
-            Regulations don’t require zero leakage?
-            What is the cost of a leak (environmentally or economically)?
-            What is allowable (regulation)/acceptable (owner) leakage rate?
-            What is subgrade condition? Soft, hard, existing asphalt, existing concrete, does it need remediation? If so, may be critical application
-            What is geomembrane being selected?
-            Site specific CQA/CQC requirements – depends on GM selected but usually less than critical applications
-            Is site specific Leak Location Testing necessary? – depends on site
-            Choice of material depends on availability, e.g., available soil v. GM

 ·        Non-Critical Applications:
‍-            Canal liners
-            Temporary remediation
-            Decorative ponds
-            Landscape ponds
-            Detention basins – control flow
-            Stormwater collection – depends on level of contamination – natural and man-made
-            Wetland mitigation
-            Dewatering
-            Freshwater containment if water is readily available
-            Final cover systems
-            Floating cover system for non-potable water – site specific

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