Opening of Quotes - Laurel Woods Drainage Improvements Proj No. 121-007 - Selge Construction Co., Inc.

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Version 2/14/2020 Page - 16 Public Works Quote reporting information shall be included in the cost of Sewer Televising and no additional compensation will be allowed. b. Payment will be made under: Pay Item Pay Unit Clean Storm Sewer, 12”-24” Dia LFT Televise Storm Sewer, 12”-24” Dia LFT XXXI. CONSTRUCTION DEWATERING A. Prevailing Specifications: None B. Additions: 1. The work consists of providing all labor, equipment, including pumps, and materials necessary to dewater the site to maintain suitable working conditions. 2. The Contractor shall design, install, and maintain a construction dewatering system with adequate pumping capacity to lower and maintain a maximum free water surface elevation of 693.0 ft across the existing fenced pond area, on the same vertical datum benchmarks shown on the Plans. This measurement shall be the standard measurement for suitable Construction Dewatering conditions at the existing detention pond area. 3. The equipment used to dewater the pond area shall include the use of a movable dam downstream of the existing detention pond and shall be constructed in such a way that a portion of the dam may be collapsed at any time during the cleaning operation to protect against flooding of the sewer. If sewer cleaning balls or other equipment, which cannot be collapsed, is used, special precautions to prevent flooding of the sewers and public or private property shall be taken. The use of a suitable temporary dam within the storm sewer downstream of the existing pond is intended to prevent backflow of groundwater and Kiefer Ditch into the pond area during dewatering operations. 4. Construction dewatering measures shall be in place and active during all sewer cleaning and video operations, and during all earthwork operations within the existing pond area. 5. Adequate construction dewatering operations shall be in place during the project punch list walkthrough with the Owner. 6. By submitting a Bid/Quote, the Contractor is certifying that high groundwater elevations, on the order of elevation 695.0 feet, are an anticipated component of the project which have been considered in the Construction Dewatering component of the Bid/Quote. As shown on the Plans, this groundwater elevation may be above the crown of certain pipes within the Work area and above the ground surface within the existing fenced pond area. 7. All work required for maintaining the project work site in suitable working conditions is included in this Pay Item. 8. Dewatering measures for pipe cleaning operations, such as removal of water and debris from storm lines is to be included in this Pay Item. 9. The acceptable outlet for the Construction Dewatering process from the pond is shown on the Plans. The outlet for temporary pipe dewatering operations is the back to the pond or directly to a vacuum truck operated by the Contractor. 10. The dewatering Plan to be submitted by the Contractor shall include and indicate the use of water filtering and stabilized outlets as part of this Pay Item. Direct release of dewatering discharge lines without the use of a filter is prohibited. 11. Release of discharge from the Construction Dewatering process at the acceptable outlet shall be accomplished by the Contractor at a rate that limits erosion by the use of a stabilized outlet, such as temporary rock filter berm downstream of the filter bags. 12. The Contractor shall construct a rock filter berm near the outlet, as a secondary containment Best Management Practice. The approximate height of the rock filter berm shall be approximately one-foot high by four feet wide by 20 feet long. 13. Filter bags shall be placed on a relatively flat surface behind/upstream of the secondary containment BMP.