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HomeMy WebLinkAboutTract 7044_Revision COBd oft BAKERSFIELD THE SOUND OF 1Mtet1j Regex February 7, 2020 McIntosh & Associates 2001 Wheelan Court Bakersfield, CA 93309 RE: Drainage Study for Tract 70" - Additional drainage from Berkshire Road Dear Mr. Neptune: We have completed review of the revised drainage study for TR 7044 dated Feb b, 2420. As a result of our review, we approve the study with the following comments: 1. A new stormdrain line was added to handle additional flow east of Chetco River Street at Berkshire Road as portion of Berkshire Road was not included in the original report. 2. Per the recommendations in the soils report by Krazon and Associates dated February 8, 2008, the sump shall be overexcavated to at least 35 feet below existing ground level, to approximate elevation 308.00, and backfilled with free draining sand to sump bottom elevation 328.00. Prior to sump acceptance a letter from the soils engineer will be required verifying that the sump has been constructed in accordance with the recommendations in the soils report. 3. Soil permeability testing shall be performed at the 30 - 35 foot depth to confirm existing soil layer at that depth will drain the basin in accordance with City standards. If this permeability test is satisfactory to the City Engineer at the overexcavated depth, the developer will not need to perform the sump -water -fill test. The City agrees with proposed methods to use 1.5:1 temporary excavation slope to maximize the removal of basin bottom area soils. At the 30 -foot excavation depth, the developer shall confirm sands exist for an additional 5 feet. Permeability tests may be performed. If favorable sands do not exist at this level, then the developer shall continue to excavate to the 35 -foot level where an additional permeability testing will be accomplished to determine favorable drainage characteristics. Permeability test results shall be forwarded to the City Engineer for confirmation. 4. This study sizes a shared drainage basin for both Tracts 7043 and 7044, but hydrology and hydraulics only for Tract 7044. A future study will determine hydrology and hydraulics for the Tract 7043 storm drain system. 0 Public Works Department 1501 Truxtun Avenue, Bakersfield, CA 93301 661-326-3724 FAX: 661-852-2120 W 4 .W r 2 5, As the portion of the sump located within Tract 7043 is also required to be constructed in order to provide drainage for Tract 7044, all necessary easements and dedications for the complete sump shall be obtained prier to approval of the grading plan for Tract 7044. 6, Please provide an electronic copy of the calculations. As a back up to the hard copy submitted, the City is asking all the engineering firms to submit a digital PDF copy. Should you have any questions, please contact Alerik Hoeh at (661) 326-3576.. Very truly yours, NICK FIDLER Public Works Director By: j� �f Manpreet Behl Civil Engineer III Subdivision cc: Project files: Tract 7044 Reading File \ah S:\LETERS\DRAINAGE\202CAMC DS Tract 7044-REV2.docx Public Works Department 1501 Truxtun Avenue, Bakersfield, CA 93341 661-326-3724 FAX: 661-852-2120 rw°�A �#I V ry t"P-W r