Background Information and Challenges
The Poway Clearwell Rehabilitation project was a separate part of an extensive water treatment plant upgrade. The design-build project delivery system was chosen as the most practical and effective way to provide the unique combination of requirements that the City desired. The Water Treatment Supervisor and an experienced staff operating and maintaining their existing floating cover provided valuable input to the design of the new cover. The project entailed the removal of the existing floating cover, demolishing a large concrete surge tower, replacing a section of an 80 mil HDPE liner as a result of the demolition activities and installing a new HypaFlex™ CSPE mechanically tensioned cover. The existing HypaFlex™ CSPE tensioned cable system floating cover installed in 1982 was removed and discarded due to the extensive retrofitting costs due to the tower demolition, the age of the cover, and the City’s desire to make significant upgrades in the floating cover.
The tower demolition required the replacement of the entire northwest corner section of the existing 80 mil liner and 12 oz non-woven geotextile buffer sheet.
Solution
A new 45 mil HypaFlex™ CSPE tensioned cable system floating cover was designed, fabricated, and installed. The 45 mil CSPE cover was retrofitted with a new low-profile CW Neal Revoc® patented tensioning assembly system. Improvements were made in the cover to decrease maintenance while improving operational efficiencies. Major operational concerns were met with the design and installation of an automated rainwater removal system and unique protective sump fold cover. The low profile Revoc® Tensioning Assemblies improved the appearance and control of the peripheral fold.
The rainwater removal system efficiently drains the top surfaces of the cover. The protective skirt fold cover eliminates nearly all debris and rainwater from entering the peripheral folds. The HypaFlex™ cover was made with a slate gray top color that matches the surrounding earthen surfaces, improving the appearance.
Results
The City’s Water Treatment Supervisor and his staff are pleased with their new floating cover system and the continuing service supplied by CW Neal.
