3301 SEAWAY BLVD WHOLE SITE 2025-10-30

6. Equivalent methods of protection for the geomembrane liner will be considered. Equivalency will be judged on the basis of the ability of the alternate method to protect the geomembrane from puncture, tearing, and abrasion. 7. The manufacturer's recommendations for bedding and installation of the geomembrane liner must be included on the plans and followed by the installer. 8. Geomembrane liners must be covered with 12 inches of top dressing on the bottom and sides of the detention pond. Top dressing shall consist of 6 inches of crushed rock covered with 6 inches of native soil. The rock layer is to mark the location of the liner for future maintenance operations. As an alternative to crushed rock, 12 inches of native soil may be used if orange plastic "safety fencing" or another highly visible, continuous marker is embedded 6 inches above the membrane. If possible, the pond liner should be of a contrasting color so that maintenance workers are aware of any areas where a liner may have become exposed when maintaining the facility. 9. Geomembrane liners are generally not allowed on slopes steeper than 5H:1V to prevent the top dressing material from slipping. Textured liners may be used on slopes up to 3H:1V provided the geotechnical engineer indicates, in writing, that the top dressing will be stable for all site conditions, including maintenance. 10. Special details must be given on the plans for any pipe or catch basin penetrations of the liner as well as for the temporary sediment pond outlet control structure shown on sheet C9/13. The structural plans for the pond walls shall also include special details regarding the liner. Construction Plans: 1. Construction runoff must be tightlined to the bottom of the pond with down drains to prevent scouring the top dressing off the liner and to prevent erosion and channeling that would undermine the liner. 2. The lower invert elevations shown in the storm drain structure table do not match those shown on sheet C10/13 for CB#28. 3. The upper overflow pipe coming into CB#28 should have an invert elevation in the pond of 425' and should be brought into CB#28 at an elevation low enough to provide adequate clearance between the crown of the overflow pipe and the underside of the catch basin lid. 4. A detail of CB#30 showing the "jail house overflow" must be provided, and the invert elevation of the overflow specified. 5. CB#30 must be labeled on the plans on both C5/13 and C6/13. r-51- q/ _Page-4f4.-