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HomeMy WebLinkAboutSDP 16-12; HARDING VETERANS HOUSING; BMP CERTIFICATION BIOFILTRATION BASINS; 2022-06-27 June 27, 2022 Subject: Permanent BMP As-built Verification Report Harding Veterans Housing Project Drawing No. 523-4A Summary: This project includes the construction of seven biolfiltration basins designed in accordance with the City of Carlsbad BMP Design Manual. As shown on sheets 3 and 4 of the approved grading plans, Drawing No. 523-4A, the required treatment areas are: BMP 1 107 SF BMP 2 84 SF BMP 3 107 SF BMP 4 71 SF BMP 5 31 SF BMP 6 75 SF BMP 7 15 SF Details for the biofiltration basin are shown on sheet 4 of the grading plans. Additional information can be found in the project’s approved Storm Water Quality Management Plan (SWQMP) prepared by Chang Consultants, dated June 5, 2020. Site Visits: Onsite reviews of the construction of the basins occurred on the following dates; 4/20/22 6/15/22 The purpose of the site visits was to document the construction of the basins and to ensure compliance with the approved grading plans and SWQMP. Additional Observations: The basins were constructed in substantial conformance with the plans. The depths of the aggregate and engineered fill placed in the basin is consistent with what is KETTLER♦LEWECK ENGINEERING 1620 Fifth Avenue, Suite 675 I San Diego, CA 92101 Tel: 619 269-3444 I Fax: 619 269-3459 I www.kettlerleweck.com required per the approved plans. The ponding and freeboard depths are also consistent with the approved plans. Slight modifications were made in the field to the shapes of the basins due to conflicts with the building footings. In all cases the minimum treatment area provided is as shown in the BMP Treatment Area Table on sheet 4 of the approved grading plans. Additional Information: 1. The impermeable liner was installed over the entire bottom and sides of the basin as per plan. 2. Landscaping appears to be consistent with landscape plans in the approved grading permit plan set. The amount of pervious and impervious areas within the project limits is consistent with the approved plans. See the attached letter from form/work Landscape Architecture. 3. The contractor provided written confirmation that they constructed the basins in substantial conformance to the plans. See the attached letter from HA Builder. Conclusion: Based on the above information, KLE believes all BMPs have been constructed in substantial conformance with the project’s approved grading plans, SWQMP, and the City’s BMP Design Manual. Lisa Leweck, PE Principal Attachments -Construction substantial conformance letter from form/work landscape Architecture -Construction substantial conformance letter from HA Builder -Construction photos by Kettler Leweck (4/20/22, 6/15/22) -Construction photos by Contractor KETTLER♦LEWECK ENGINEERING 1620 Fifth Avenue, Suite 675 I San Diego, CA 92101 Tel: 619 269-3444 I Fax: 619 269-3459 I www.kettlerleweck.com