HomeMy WebLinkAboutCUP 2020-0003; RECYCLED WATER PHASE III D-4; ADDENDUM 1 - REVISED REMOVE AND RECOMPACTION RECOMMENDATIONS; 2021-05-25NV 5
Carlsbad Municipal Water District
5950 El Camino Real
Carlsbad, California 92009-8802
Attention :
Project:
Mr. Dave Padilla, PE, QSD
Recycled Water Phase Ill: D-4 Reservoir
Carlsbad Municipal Water District
Carlsbad, California
May 25, 2021
Project Number 226816-000011.00
EVE
OCT 18 2022
LA O DEVELOPMENT
ENGINEERING
Subject: Addendum No. 1 -Revised Remove and Recompaction Recommendations
References: "Geotechnical Investigation Report, Carlsbad Municipal Water District, Phase Ill Recycled
Water Project, Carlsbad, California", prepared by NV5 West, Inc. (NV5), dated April 24,
2019
Dear Mr. Padilla,
Introduction
Civil Plan Sheet C-01, "Improvement Plans for: Recylced Water Phase Ill: 0-4 Reservoir,
Tank Site Grading", 100% Submittal (Not for construction), prepared by NV5
As requested, this letter addendum provides NV5 West, Inc. (NV5) revised recommendations for removal and
recompaction of "topsoil" material within the footprint of the subject project's proposed water tank. Reference
is made to the geotechnical report and civil plan Sheet C-01 prepared for the project. Per our correspondence
with the City the following revisions are provided to our geotechnical recommendations for consideration.
• Recomm.endations presented in Sections 9.1 (General) and 9.2 (Earthwork) of the referenced report
should be revised to indicate "topsoil" within the footprint of the proposed water tank pad should be
removed to a project elevation (as indicated on referenced Civil Plan Sheet C-01) of 372.0 feet. The
removal should extend at least 5 feet outside of the perimeter of the water tank pad footprint.
• The base of the excavation noted above should be scarified in place to a depth of at least 8 inches,
moisture conditioned within 2 percent above optimum moisture content (unless otherwise directed by
the geotechnical engineer) and compacted to at least 95 percent relative compaction based on
laboratory standard ASTM D1557.
• Excavated "topsoil" noted above can be placed back in the excavation in approximately 8 inches lifts
(loose thickness). The loose lifts should be moisture conditioned within 2 percent above optimum
moisture content (unless otherwise directed by the geotechnical engineer) and compacted to at least
95 percent relative compaction based on laboratory standard ASTM D1557.
OFFICES IJATIONl'llDf
15092 AVENUE OF SCIENCE, STE 200 SAN DIEGO, CA 92128 I www.NV5.COM OFFICE 858.715.5800 I FAX 858.715.5810
CONSTRUCTION QUALITY ASSURANCE -INFRASTRUCTURE -ENERGY -PROGRAM MANAGEMENT -ENVIRONMENTAL
Addendum No. 1 -Revised Remove and Recompaction Recommendations
Recycled Water Phase 111:D-4 Reservoir
Carlsbad Municipal Water District
Carlsbad, California
Closing and Limitation
May 25, 2021
226816-0000111.00
Page 2
NV5 appreciates the opportunity to be of service. We have prepared this letter in substanfial accordance with
the generally accepted geotechnical engineering practice as it exists in the site area at the time of our study.
No warranty is expressed or implied. The limitations discussed in the referenced report apply to the
recommendations contained in this letter. If you have any questions regarding this letter or need further
assistance, please contact us at your convenience.
Respectfully Submitted,
NV5 Inc.
Gene Custenborder, CEG No. 1319
Senior Engineering Geologist
Distribution (1) Addressee, via e-mail
NIVl5
OFFlCES NATIONWIDE
CONSTRUCTION QUALITY ASSURANCE · INFRASTRUCTURE ENGINEERING -MUNICIPAL OUTSOURCING -ASSET MAtiAGEMENT • ENVIAOl-4ME.ITTA.L SERVICES