Addendum 2 Letter for 2023 Storm Damage Repairs.pdf

Addendum No.2

2023 Storm Damage Repairs Project (LOP 5, 13, & 14)

Debris Removal S202300A & Permanent Repair Project S202300P

CITY OF LIVERMORE

COMMUNITY DEVELOPMENT DEPARTMENT

ADDENDUM NO. 2

TO THE

2023 STORM DAMAGE REPAIR PROJECT (LOP 5, 13, & 14)

PROJECT S202300A & S202300P

IN THE CITY OF LIVERMORE

July 2, 2024

This addendum consists of 3 pages: this 1 sheet, 1 page Sheet C6 of bid plans, and 1 page of responses to bidder questions. All prospective bidders for the above referenced project are to be aware that the following changes, additions, and/or clarifications shall be included as an integral part of the contract drawings and specifications for the above referenced project and that they are bound by all conditions set forth therein. This Addendum does not change the Bid Opening date which remains Tuesday, July 9, 2024, at 2:30p.m.

THE BIDDER SHALL SIGN AND INCLUDE THIS FORM IN HIS SEALED BID PACKAGE

AND/OR FILL IN THE ADDENDUM NUMBER ON PAGE 14 OF THE BID PROPOSAL AS

ACKNOWLEDGMENT OF RECEIPT. FAILURE TO INCLUDE THIS FORM AND/OR FILL

IN THE ADDENDUM NUMBER IN THE BID PROPOSAL MAY BE CAUSE FOR THE

DISQUALIFICATION OF HIS BID.

Leo Sum, P.E.

Project Engineer

Company Name

Date Representative

Addendum No.2

2023 Storm Damage Repairs Project (LOP 5, 13, & 14)

Debris Removal S202300A & Permanent Repair Project S202300P

RESPONSE TO BIDDER QUESTIONS

1. Question: Per Plan Sheet C3 of Page 5, Note 3: “HYDROSEEDING SHALL BE INSTALLED ON

THE STAGING AREA, THE ACCESS PATH, AND DISTURBED SLOPES AT THE

COMPLETION OF CONSTRUCTION; AVOID PLACEMENT IN LOW FLOW CHANNEL.

COORDINATE WITH THE CITY TO DEFINE LIMITS OF HYDROSEEDING PRIOR TO

PLACEMENT.” Please define the access path that needs hydroseeding. Does this include the entire route from College Avenue or does this refer to the immediate work area?

Response: Hydroseeding is only necessary at the immediate work area, which is any work along the Arroyo Bike Trail from the start of the pedestrian detour route to the end of the pedestrian detour route as specified in the plans.

2. Question: Per Plan Sheet C6 of Page 8, Note 9: “CONTRACTOR SHALL REMOVE SEDIMENT, DEBRIS, AND TRASH UPSTREAM OF ROAD CROSSING, WITHIN CULVERTS, AND

DOWNSTREAM OF ROAD CROSSING. ALL MATERIAL REMOVED FROM THE SITE SHALL

BE TRANSPORTED AND DISPOSED OF AT AN APPROPRIATE LANDFILL/DISPOSAL SITE.”

Clarify if additional debris removal outside of the depicted work zone is required or remove conflicting notes.

Response: The scope of work for sediment, debris, and trash removal is only at the downstream portion depicted by the hatching on Plan Sheet C6. Note 9 on Plan Sheet C6 has been revised and is issued along with this addendum.

3. Question: Will the City be providing pre-construction staking and final topo survey to quantify excavation and fill quantities? If not, how will the quantities be established?

Response: The City will not be providing pre-construction staking, only control benchmarks. Bid quantities are based on neat-line estimates. The City in the past has measured quantities based on topo survey, truckloads, or by the bid quantities, which is left for the inspector of the project to decide.

4. Question: Can Zone 7 cut off and pause the flow at LOP 5?

Response: No, Zone 7 does not release water into the Arroyo Las Positas. The City is coordinating with Zone 7 to shut off water release into the Arroyo Mocho; this only affects LOP

14 by Creek Road. LOP 5 at Airway Blvd. will not be affected because the site is part of the

Arroyo Las Positas, which is a different creek.

5. Question: Specifications Section 32 91 00, 2.7A shows the construction fence will have mesh size

1.5” x 1.5”. Construction fence is also detailed on Sheet D-1 of the drawings. Is wildlife exclusion fencing (WEF) for biological compliance required as well? If so, provide additional specifications and locations required.

Response: The wildlife exclusion fencing is not required, only construction fencing will be required. No additional specifications are needed.

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DWV

REMOVE 17"Ø BLACK WALNUT

TREE & WILLOW AT BASE OF TREE

REMOVE 16"Ø BLACK WALNUT TREE (FALLEN)

(E) TOE OF CHANNEL

(E) TOP OF BANK

COFFERDAM IN CHANNEL AS

NECESSARY FOR CONSTRUCTION

NOTE 12

ARROYO LAS POSITAS

(N) CONSTRUCTION FENCE

SEE NOTE 5 AND DETAIL

D1

TEMPORARY STAGING & STOCKPILE AREA

SEE NOTE 3 & 13

CP27

200'

(N) TOP OF BANK

CP25

C

7DC

7C

C7B

C7A

LIMB (E) WILLOWS

ON NORTH BANK

MATCH GRADE OF (E) CHANNEL TO

CREATE SMOOTH TRANSITION FROM

SEDIMENT REMOVAL AREA TO (E)

CHANNEL, TYP OF UPSTREAM AND

DOWNSTREAM LIMITS OF WORK

(N) TOE OF SLOPE

REMOVE 18"Ø BLACK WALNUT TREE

REMOVE EXISTING SEDIMENT, DEBRIS, AND SELECT

TREES. CREATE SMOOTH TRANSITION FROM CULVERTS.

REMOVE, STOCKPILE, AND REPLACE TOPSOIL

SEE NOTE 19

COFFERDAM IN CHANNEL AS

NECESSARY FOR CONSTRUCTION

NOTE 12

33'±

(E) ORDINARY HIGH WATER MARK

LIMB (E) 22"Ø VALLEY OAK TREE,

SEE NOTE 18

2023 STORM DAMAGE REPAIR PROJECT (LOP 5, 13, & 14)

City Project No. S202300A & S202300P

CITY OF

COMMUNITY DEVELOPMENT DEPARTMENT-ENGINEERING DIVISION

A L I F O R N I AC

BE

NJAMIN L.

No. 68813

C I LIV

STATE OF

AINROFILAC

RE

GI

ST

ER

ED

PROF

RE

EN

IG

NE

LANOISSE

SHICK

(707) 528-4848

SANTA ROSA, CA 95405

2200 RANGE AVENUE, STE 201

CONSULTING CIVIL ENGINEERS

Schaaf Wheeler

NTS

LOP 5 - AIRWAY CULVERT -

PLAN VIEW

NOTES:

1. ALL WORK BELOW TOP OF BANK SHALL BE COMPLETED PRIOR TO OCTOBER 15, 2024.

2. ACCESS SITE VIA AIRWAY BOULEVARD.

3. TEMPORARY STOCKPILE AND STAGING AREA MAY BE USED FOR TEMPORARY STOCKPILE OF MATERIALS

AND STAGING OF EQUIPMENT AS NECESSARY DURING CONSTRUCTION. STAGING AREA SHALL BE

RESTORED TO ITS ORIGINAL CONDITION AT COMPLETION OF CONSTRUCTION.

4. BIODEGRADABLE EROSION CONTROL BLANKET AND BROADCAST SEEDING SHALL BE INSTALLED ON DISTURBED SLOPES STEEPER THAN 4H:1V, AND HYDROSEEDING SHALL BE PLACED ON ALL OTHER DISTURBED AREAS AT THE COMPLETION OF CONSTRUCTION. AVOID PLACEMENT IN LOW FLOW CHANNEL.

5. CONSTRUCTION FENCE SHALL BE INSTALLED PRIOR TO PLACEMENT OF ANY EQUIPMENT OR MATERIALS ON SITE. WORKSITE SHALL BE COMPLETELY ENCLOSED BY SUCH FENCING. THE LOCATION AND LENGTH OF FENCING IS APPROXIMATE AND SHALL BE CONFIRMED AND ADJUSTED AS DIRECTED BY THE CITY'S

REPRESENTATIVES IN THE FIELD DURING CONSTRUCTION.

6. CONTRACTOR SHALL EXCAVATE, OFF-HAUL, AND DISPOSE OF ALL SEDIMENT, DEBRIS AND VEGETATION

AS DETAILED ON THE PLANS AND SPECIFICATIONS.

7. CONTRACTOR SHALL ATTEND STREAM MAINTENANCE PROGRAM (SMP) ENVIRONMENTAL TRAINING PRIOR

TO BEGINNING WORK.

8. CONTRACTOR SHALL IMPLEMENT ALL SMP BMPs AND CONSERVATION MEASURE IN COMPLIANCE WITH

RESOURCE REGULATORY PERMITS.

9. CONTRACTOR SHALL REMOVE SEDIMENT, DEBRIS, AND TRASH DOWNSTREAM OF ROAD CROSSING. ALL MATERIAL REMOVED FROM THE SITE SHALL BE TRANSPORTED AND DISPOSED OF AT AN APPROPRIATE

LANDFILL/DISPOSAL SITE.

10. THE EXTENT, ELEVATIONS, AND QUANTITIES OF GRADING AND SEDIMENT REMOVAL IS APPROXIMATE AND SHALL BE CONFIRMED AND ADJUSTED AS DIRECTED BY THE CITY'S REPRESENTATIVES IN THE FIELD

DURING CONSTRUCTION.

11. THE LOCATIONS AND LIMITS OF TREE REMOVAL AND TRIMMING IS APPROXIMATE AND SHALL BE CONFIRMED AND ADJUSTED AS DIRECTED BY THE CITY'S REPRESENTATIVES IN THE FIELD DURING

CONSTRUCTION.

12. CONTRACTOR SHALL BYPASS ALL CHANNEL FLOWS. CONTRACTOR SHALL VISIT SITE PRIOR TO BIDDING TO ESTIMATE THE FLOW DIVERSION AND BYPASS REQUIREMENTS. CONTRACTOR SHALL BE RESPONSIBLE FOR DESIGNING THE EXACT LOCATIONS OF THE COFFERDAMS AND THE SIZE AND LENGTHS OF THE

BYPASS SYSTEMS REQUIRED FOR FLOW DIVERSION.

13. MATERIAL REMOVED FROM THE DRAINAGE CHANNEL SHALL BE STOCKPILED AND DRAINED AT THE TEMPORARY STOCKPILE LOCATION SHOWN ON THIS SHEET, PRIOR TO BEING TRANSPORTED TO THE

PERMANENT SEDIMENT FILL AREA SHOWN ON SHEET C8.

14. THE CITY'S BIOLOGIST SHALL BE ON-SITE DURING ALL CONSTRUCTION ACTIVITIES. THE CITY'S BIOLOGIST

HAS THE AUTHORITY TO STOP WORK AT ANY TIME DURING CONSTRUCTION.

15. TYPICAL AVERAGE DRY WEATHER FLOW IN ARROYO LOS POSITAS IS 4 CUBIC FEET PER SECOND (CFS).

POTENTIAL PEAK DRY WEATHER FLOW IS 10 CFS. CONTRACTOR SHALL ADEQUATELY CONTROL AND BYPASS ANY AND ALL FLOWS THAT OCCUR DURING CONSTRUCTION AS SHOWN HEREIN AND DETAILED IN

THE SPECIFICATIONS. CONTRACTOR IS RESPONSIBLE FOR MONITORING CHANNEL FLOW RATES,

MONITORING THE WEATHER, AND PROTECTING THE SITE FROM CHANNEL FLOWS AND EROSION.

16. NO WORK SHALL COMMENCE PRIOR TO THE COMPLETION OF THE QUALIFIED BIOLOGIST SURVEY TO BE

COMPLETED BY THE CITY.

17. CONTRACTOR SHALL REMOVE AND DISPOSE OF TRASH, SOIL, SILT, MUD, EXCESSIVE ORGANIC MATERIAL

AND DEBRIS.

18. SEDIMENT REMOVAL SHALL NOT OCCUR WITHIN THE LIMITS OF THE EXISTING 22-INCH VALLEY OAK TREE

ROOT SYSTEM.

19. TOPSOIL WITHIN THE SEDIMENT REMOVAL AREA SHALL BE TEMPORARILY STOCKPILED AND REPLACED WITHIN THE SEDIMENT REMOVAL AREA UPON COMPLETION OF SEDIMENT REMOVAL AND GRADING.

20. EQUIPMENT SHALL NOT ENTER THE CHANNEL BELOW THE OHWM AS DIRECTED BY THE CITY'S BIOLOGIST.

ALL EXCAVATIONS SHALL BE SHALL BE PERFORMED WITH AN EXCAVATOR, A DOZER SHALL NOT BE USED

TO GRADE OR REMOVE MATERIAL FROM THE SITE.

SCALE: 1" = 30'

PLAN

SCALE: 1 INCH = 30 FEET

C6

LOCAL BENCHMARKS

CP#

NORTHING

(FT)

EASTING

(FT)

ELEVATION

(FT)

25 2079501.08 6180309.78 384.51

27 2079507.37 6180388.95 390.39

QUANTITY TABLE

DESCRIPTION UNIT QUANTITY

CONSTRUCTION FENCE LF 1090

SEDIMENT, DEBRIS AND TRASH

REMOVAL, OFF-HAUL, AND DISPOSAL CY 10

SEDIMENT EXCAVATION, PLACEMENT,

AND COMPACTION AT STOCKPILE AREA

CY 860

1 07/02/23 JFO PLAN REVISION

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