HomeMy WebLinkAbout09. Authorize an agreement for Class 2 Encroachment at 5050 Imhoff Pl, Martinez re: RV Storage over the Outfall Page 1 of 29
Item 9.
CENTRAL SAN BOARD OF DIRECTORS
POSITION PAPER
MEETING DATE: MARCH 3, 2022
SUBJECT: ADOPT RESOLUTION NO. 2022-015 AUTHORIZING EXECUTION OF AN
AGREEMENT FOR A CLASS 2 ENCROACHMENT AT 5050 I MHOFF PLACE,
MARTI NEZ
SUBMITTED BY: INITIATING DEPARTMENT:
DANA LAWSON, SENIOR ENGINEER ENGINEERING AND TECHNICAL SERVICES -
PDS - DEVELOPMENT SERVICES - RIGHT OF
WAY
REVIEWED BY: DANEA GEMMELL, PLANNING AND DEVELOPMENT SERVICES DIVISION
MANAGER
JEAN-MARC PETIT, DIRECTOR OF ENGINEERING AND TECHNICAL
SERVICES
Roger S. Bailey Kenton L. Alm
General Manager District Counsel
ISSUE
Although a resolution of the Board of Directors (Board) is not required for encroachment agreement, staff
is requesting Board direction on this development request since the proposed use is categorized as a
Class 2 encroachment over critical infrastructure.
BACKGROUND
Conco is interested in paving a portion of the area on their property to create storage space for
recreational vehicles (RVs) and install shade canopies for their long-term storage. However, this proposed
paved area is located within the 30-foot easement for Central San's 72-inch sanitary sewer("Outfall")
located across Conco's property, north of the treatment plant and wet weather holding basins (see
March 3, 2022 Regular Board Meeting Agenda Packet- Page 42 of 165
Page 2 of 29
Attachment 1). Preliminary computations evaluated the potential impacts of the additional loading to the
Outfall and proposed mitigation measures.
To protect the pipeline and mitigate the additional loading from fill placed within 50 feet of the existing
Central San Outfall, Conco proposes the use of a proprietary material, ConFoamTM, which is a composite
lightweight fill material. The mitigation plan proposes to excavate 1.5 feet of existing material and replace it
with a combination of 6-inch Portland cement concrete (PCC)over 2 feet of ConFoamTM material to offset
the vehicle weights, such that there would be no net increase in pipe load stress.
The PCC pavement would have construction joints at predetermined locations to create weakened planes
where the concrete can crack in a straight line and will result in removal of concrete portions when
maintenance or a repair operation is required for the underground utilities. RV parking will be placed to
facilitate access to all manholes, access structures, settlement markers, or other Central San facilities as
deemed necessary.
Overhead canopies will be proposed at discrete locations within the development footprint. The canopy
columns can be easily installed within the ConFoamTm 2-foot section and will be placed at locations which
would not interfere with Central San's maintenance/repair operations. The location of proposed canopies
will be subject to approval by Central San. Conco understands that any damage to RV facilities due to
Central San maintenance or emergency repair operations will be Conco's responsibility to repair.
Central San engaged DCM Consulting, I nc. for a geotechnical peer review of the proposal. I n general, the
ConFoamTM is a good solution to meet the project objective of no new long-term loading on the Outfall
pipeline and the input parameters and calculations in the Milani &Associates evaluation are appropriate.
Additional recommendations, which Conco included in a resubmittal on November 11, 2021, clarified the
loading calculations, agreed to submit canopy foundation plans, grading plans, and construction/earthwork
plans for Central San review and approval.
The agreement may include, but not be limited to, the following conditions:
• agreement fees including reimbursement of staff costs;
• no loss revenue if/when Central San needs access to the Outfall or its structures;
• submit canopy foundation plans, grading plans, and construction/earthwork plans to Central San for
review and approval;
• emergency contacts and response times;
• agreement is non-transferrable;
• ability to terminate agreement after providing an agreed-upon and reasonable notification period;
• RV parking will be placed to facilitate access to all manholes, access structures, settlement markers,
or other Central San facilities as deemed necessary; and
• any damage to RV facilities due to Central San maintenance or emergency repair operations will be
Conco's responsibility to repair.
ALTERNATIVES/CONSIDERATIONS
1. Reject the request for a new Class 2 encroachment.
2. Authorize the request for a new Class 2 encroachment and execution of an encroachment
agreement, once the General Manager is satisfied with the terms of the document. Instead of a Real
Property Agreement, a license/encroachment agreement was chosen because it can be revoked if
there are adverse impacts due to the additional loading and is not recorded to run with the property.
Final conditions for the agreement will be determined, subject to review and approval of the
improvement plans.
3. Provide other direction to staff.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 43 of 165
Page 3 of 29
FINANCIAL IMPACTS
None. The Applicant will pay the applicable Environmental and Development-Related Fees, per the
current ordinance, including reimbursement for staff and related costs.
COMMITTEE RECOMMENDATION
The Real Estate, Environmental and Planning Committee reviewed this matter at its meeting on February
23, 2022 and recommended approval.
RECOMMENDED BOARD ACTION
Adopt the proposed resolution authorizing execution of an encroachment agreement to allow the new
Class 2 encroachment for RV storage over the Outfall at 5050 1 mhoff Place, Martinez (APN 159-250-
018), once the General Manager is satisfied with the terms of the document.
Strategic Plan Tie-In
GOAL ONE: Customer and Community
Strategy 2—Maintain a positive reputation
GOAL FIVE:Infrastructure Reliability
Strategy 1—Manage assets optimally to prolong their useful life
ATTACHMENTS:
1. GeoPortal Map
2. Proposal and Plan
3. Geotech Peer Review
4. Proposal - Resubmittal 11-11-21
5. Proposal - Emergency Access Letter
6. Proposed Resolution
March 3, 2022 Regular Board Meeting Agenda Packet- Page 44 of 165
ATTACHMENT 1
Manholes-Outfall
O Manhole
Metering Manhole
— Main-Outfall
,c a Manholes-Outfall-Abandoned
Main-Outfall-Abandoned
3 � x- Fence
.. k, Storage Tank
Structure
Furnace
Building
f:' f
Channel
` jai rt Tunnel
t i ® Basin
Recycled Water Main
'.
A ��: � .� ,. — Active
•.• Tentative
Inactive(Water only)
Abandoned
Network Structures
A
. �•• � _ L� `� � Access Vault
i _ h p {p• ,� Influent Structure
L' Lift Station
Metering Station
Open Inlet(Holding Basins Only)
Pump Station
c` !s• l Valve Structure
Sewer Mains
Active
W'ct.
- j, ,•.Y i �c� Renovation Scheduled
Tentative
NOteS l -r B85ir' :i Abandonment Scheduled
4; r .
Proposed Encroachment of RV Storage _ ` .y �f ''' - • Inactive or Future Use
over Outfall on Conco Property ti' r,! V- Force Main
f Basin C Recycled Water-Other Utility
\ Sewer-Other Utility
Water Line-Other Utility
'4..
This map is a user generated static output from Central San's
,efCENTRAL SAN 0 400 800 Feet Geoportal and is for reference only.Data layers that appear on this
map may or may not be accurate,current,or otherwise reliable.
N Map Created On:11/12/2021 Map Projection:WGS84 Central San Map
ATTACT22
W6F&*A�
MILANI
Date:August 26,2021
Project No: 727
Dana Lawson, P.E.
Senior Engineer- Development Services Section
Central Contra Costa Sanitary District (CCCSD)
5019 Imhoff Place
Martinez, CA 94553
Jonathan Largent, P.E.
Senior Engineer
Contra Costa Water District(CCCWD)
1331 Concord Avenue
Concord, Ca 94520
Attention: Mr.Jonathan Largent
Dana Lawson
RV Storage Report
Conco Construction and Storage Yard
Contra costa County, California
Dear Dana and Jonathan,
This report presents discussion of civil engineering considerations for storage of recreational vehicles
(RV) in the site area within the Central Contra Costa Sanitary District (CCCSD) easement and Contra
Costa Water District (CCWD) utilities. We understand that Conco is interested in considering this area as
an RV storage lot. Preliminary evaluation computations were conducted to evaluate potential impacts to
the CCCSD 72" sanitary sewer and CCWD 42" recycled water from the placement of fill.
To protect the existing pipelines, Conco will be using a proprietary material, ConFoam"', which is a
composite lightweight fill material, proposed to be utilized to mitigate any increase in pipe load from fill
placed within 50 feet of existing District pipelines.The mitigation plan proposal is to excavate 2 feet of
existing material and replace with 7" Portland cement concrete and 3.5 feet of confoam material.The
site could be raised with a combination of confoam and pavement and vehicle weights such that the
existing pipe load stress will not be increased.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 46 of 165
Page 6 of 29
The ConFoam material maintains a unit weight of 27 pounds per cubic foot(pcf) or less.The existing fill
weighs 125 pcf.The removal of 2 feet of soil removes 250 pounds per square foot (psf)weight.The 3.5
ft of confoam and then a 7-inch-thick Portland cement concrete (PCC) pavement will be added thereby
raising the existing grade by 2 feet.The weight of the ConFoam and PCC would be 189.5 psf leaving 60.5
psf for RV vehicle storage. Please see attached calculations sheets.
The PCC pavement shall be placed in such a way that the construction joints will be placed in the
concrete surface at predetermined locations to create weakened planes where the concrete can crack in
a straight line and will result in removal of concrete portions when maintenance or a repair operation is
required for the underground utilities.The RV storage vehicles shall be relocated by Conco to an
alternate location to facilitate District maintenance operations or emergency repair operations. RV
parking will be placed to facilitate access to all district manholes, access structures, settlement markers
or other District facilities as deemed necessary.
Overhead canopies will be proposed at discrete locations within development footprint. The canopy
columns can be easily installed within the ConFoamT"' installation and will be placed at locations which
would not interfere with District pipeline maintenance/repair operations. Location of proposed
canopies will be subject to final District approval. Conco understands that any damage to RV facilities
due to District maintenance or emergency repair operations will be Conco's responsibility to repair.
I trust this provides you with the information that you require. If you have any questions, please feel
free to contact our office.
Sincerely,
r
*6c" �•
Michael Milani, P.E.
President
ESS1
a No.35121 -
S EXP. 09/30/23 V
CIV1 Z�
�41F OF Cp01O4
MEM:
Cc: Joe Sostaric-Conco
Enclosures:
1. RV storage Calculations
2. RV storage Exhibit- Baja Site Plan (5 copies)
3. ConFoamTm Brochure
March 3, 2022 Regular Board Meeting Agenda Packet- Page 47 of 165
Page 7 of 29
ATTACHMENT-1 8/17/2021
727-CONCO RV VEHICLE STORAGE CALCULATIONS
Abbreviations
1 Confoam Material Weight 27 pcf pcf pounds per cubic feet
2 Portland Cement Concrete(PCC)weight 150 pcf lbs pounds per cubic feet
3 Class II Aggregate Base(AB)weight 140 pcf Psf pounds per square feet
4 One RV Vehicle Weight 12,000 lbs sf square feet
5 Existing Material Weight 125 pcf PCC Portland Cement Concrete
6 Available space for RV vehicle storage 101,768 sf AB Aggregate Base
7 Total available spaces for RV 183 spaces RV Recreational Vehicle
8 Total weight of RVs in the available space 22 psf
9 Pavement sections is 7" PCC/10"AB
The plan is to remove 2 feet of existing material and replace it with 3.5 feet of light weight material called Confoam.
Weight of the existing material fill= 125 pcf
Weight of removal of 2 feet of existing material= 2x125= 250 psf
Weight of confoam+Weight of 7"PCC= 3.5x27+0.58x150= 182 psf
Therefore,weight left for the vehicle storage= 250-181.5= 68.5 psf
Page 1
March 3, 2022 Regular Board Meeting Agenda Packet- Page 48 of 165
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March 3, 2022 Regular Board Meeting Agenda Packet- Page 51 of 165
ATTA4HMENT 3
DCM Consulting, Inc. Technical Memorandum
P.O.Box 225,Lafayette,CA 94549,Telephone: 925.322.9590 mm.dcmconsults.com
To: Dana Lawson Date: October 4, 2021
CCCSD
From: Dave Mathy File: No. 108ZC
DCM Consulting, Inc.
Subject: Conco RV Storage Yard Development
over CCCSD's 72-inch RCP Outfall Pipeline
Approximate Manhole 14 (Station 107+44)
to Manhole 16 (Station 119+36
Martinez, California
1.0 INTRODUCTION
This Technical Memorandum (TM) summarizes DCM Consulting, Inc.'s (DCM) geotechnical review of
proposed development of an RV Storage Yard in an expanded Conco Companies property in Martinez,
California. The proposed RV Storage Yard is located north of Central Contra County Sanitation District's
(CCCSD)waste water treatment plant along the east side of Pacheco Creek and just north of the existing
Conco Cement yard off of Waterbird Way.The area for RV storage will be approximately 2.3 acres in size
with storage for up to 183 RVs. Site development will span over approximately 1,200 feet of CCCSD's
easement for the waste water treatment plant's 72-inch RCP Outfall pipeline.The CCCSD Outfall pipeline,
constructed in the late 1950's is approximately 4 miles long extending from the CCCSD waste water
treatment plant to Suisun Bay. Milani & Associates has provided a civil engineering analysis of the
proposed RV storage development with specific recommendations to protect the 72-inch RCP Outfall
pipeline from any new long-term pipeline loading. The project objective is for the proposed RV Storage
Yard to impose no new loading on the underlying 72-inch Outfall pipeline.CCCSD has requested that DCM
review the Milani &Associates analysis, specifically:
• does the Milani &Associates proposal mitigate impacts on the 72-inch RCP Outfall pipeline; and
• does Milani &Associates need to provide any additional information or mitigation measures.
DCM's project review is limited to the 72-inch RCP Outfall pipeline only and does not address any other
utilities in the proposed RV storage development area.
The following project documents have been provided by CCCSD for DCM's review and reference:
• RV Storage Report
Conco Construction and Storage Yard
Contra Costa County,California
By: Milani &Associates
To: CCCSD
March 3, 2022 Regular Board Meeting Agenda Packet- Page 52 of 165
Page 12 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 2
Dated:August 26, 2021
6 Pages
• RV Storage Exhibit—Preliminary Site Plan
Sheet 1 of 1
By: Milani &Associates
Dated:8/11/21
• Central San Map
Recycled Water Main
Dated:9/24/21
1 page
• Central San Map
Manholes—Outfall
Dated:9/24/21
1 page
• Project Area 3—Existing 72" Outfall Line
Plan and Profile
Station 94+00 to 108+00
Drawing No. 133-8
By: CCCSD
Dated: 3/16/12
• Project Area 3—Existing 72" Outfall Line
Plan and Profile
Station 108+00 to 122+00
Drawing No. P3-9
By: CCCSD
Dated: 3/16/12
This technical memorandum has been completed in conformance with the scope of engineering services
described in Release No. 24 to Contract Agreement No.044811 between CCCSD and DCM.
2.0 PROJECT DESCRIPTION
The proposed RV Storage Yard along the east side of Pacheco Creek is approximately 2.3 acres in size and
will encroach onto and span over CCCSD's easement for the waste water treatment plant's 72-inch RCP
Outfall pipeline.The length of Outfall pipeline underlying the proposed RV Storage Yard is approximately
1,200 feet and spans from about Outfall pipeline Manhole 16 to Manhole 14 (see Figure 1). Grading,
specifically finished surface elevations over the CCCSD easement,will raise the finished RV parking surface
elevations by 2 feet above existing ground surfaces.
File No.108ZI DCM Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 53 of 165
Page 13 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 3
The existing 72-inch RCP Outfall pipeline, constructed in the late 1950's has relatively shallow cover
ranging from about 6 feet to 12 feet and averaging 8 feet (see Figure 2, cover depths rounded to the
nearest lesser foot).As shown in Figure 3—Geologic Setting,the section of Outfall pipeline from Manhole
16 to Manhole 14 is underlain by alluvial soils. In this area the alluvium is predominantly clays and silts
with lesser sands and gravels. The alluvial clays and silts are typically medium stiff in place. (This is a
significantly better pipeline subgrade condition than the very soft Young Bay Mud in the northern reach
of the Outfall pipeline alignment.) The lesser sand strata within the alluvium are subject to liquefaction
during seismic shaking and therefor are sensitive to vibrations.
In order to protect the 72-inch RCP pipeline from any increase in long-term loading, Milani &Associates'
August 26, 2021 RV Storage Report letter to the CCCSD outlines the following:
• Development of the RV Storage Yard will raise grades over the CCCSD easement by 2 feet;
• In a 100-foot-wide strip, over the 72-inch Outfall pipeline, remove 2 feet of existing soil over a
length of approximately 1,200 feet.
• In the 100-foot-wide strip over the 72-inch Outfall pipeline place 3.5 feet of ConFoam. ConFoam
is a proprietary material of Conco Companies that is a lightweight, low density cellular concrete
consisting of cement, water and foam. The ConFoam mix design for this project will have a
finished unit weight of 27 pcf. The total volume of ConFoam will be 100' x 1,200' x 3.5' / 27 =
15,500 cubic yards.
• Place 7 inches of Portland cement concrete directly on the ConFoam for the RV storage
pavement.
With this pavement section and 3.5 feet of ConFoam the Milani calculations show that there will be no
net increase in long-term loading(i.e., dead loads) on the 72-inch Outfall pipeline, even with the storage
yard full of RVs. Future live loading(i.e.,H2O vehicle loads)with a minimum of 8 feet of final cover(original
6 foot minimum plus 2 feet of raised grade)will be nominal at less than 1 psi.
3.0 CONCLUSIONS
The following conclusions assume that:
• the current ground surface elevations as shown on the 2012 CCCSD Outfall pipeline drawings
(see Figure 2)are accurate and have not been changed by grading since 2012;
• the 72-inch RCP pipeline is of consistent wall thickness and reinforcing (i.e., same design) over
the 1,200-foot project area length;
• this 1,200-foot-long reach of the 72-inch RCP Outfall pipeline has not required any extraordinary
repairs over the past 60+years. CCCSD should review historic records for any repairs to the 72-
inch RCP Outfall pipeline over the 1,200-foot length of the RV Storage Yard for any indications of
pipeline instability(e.g., pipeline differential settlement and pipe joint deflections). Pipeline joint
File No.108ZI DCIVI Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 54 of 165
Page 14 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 4
repairs are not uncommon over the 4-mile length of the Outfall pipeline, particularly in the
northern reach underlain by soft Bay Mud.; and
• the 72-inch RCP pipeline is in good structural condition including pipe joints/joint deflection.
Given these assumptions the following conclusions are outlined:
• The August 26, 2021 Milani & Associates report proposes the use of ConFoam (at 27 pcf) to
replace 2 feet of existing soil cover (at 125 pcf) to ensure no new net long-term loading on the
existing 72-inch RCP Outfall pipeline. This is a good solution to meet the project objective of no
new long-term loading on the Outfall pipeline. The input parameters in the Milani &Associates
calculations as well as the calculations are appropriate.
• The August 26, 2021 Milani &Associates report has some conflicting information regarding the
RV storage pavement section. Two different pavement sections are referenced, 7 inches of
concrete placed directly on the ConFoam and of 7 inches of concrete over 10 inches of aggregate
base rock placed directly on the ConFoam (see points 3 and 9 in Milani &Associates Attachment-
1). A pavement section of 7 inches of concrete over 10" aggregate base rock with 2 feet of
overexcavation will add long-term load to the 72-inch Outfall pipeline(see Figure 4)and does not
meet the project objective of no new long-term loading.
• The August 26, 2021 Milani & Associates report does not include an analysis of short-term
construction period live loading on the 72-inch Outfall pipeline.A construction/grading work plan
needs to be provided, for example with a 100-foot wide overexcavation zone over the 72-inch
Outfall pipeline, how will construction equipment pass over the Outfall pipeline. With 2 feet of
overexcavation the cover thickness on the Outfall pipeline may locally be as little as 4 to 5 feet.
What equipment limitations will be placed on earthmoving equipment passing over the 72-inch
Outfall pipeline to limit construction period live loading?
• Current external loading on the 72-inch RCP pipeline is a maximum at about Station 108+20. At
this location the depth of cover is about 12 feet.Current earth prism dead load on the pipeline is
then 12 ft x 125 pcf= 1,500 psf or 10.4 psi.
During construction,the total load(i.e.,dead load plus live load)on the Outfall pipeline should
not exceed 10 psi.That is,cover thickness dead load plus construction equipment live load stress
distribution should not exceed 10 psi. Live load stress distribution should be based on the
minimum depth of existing cover at 6 feet minus the depth of overexcavation at 2 feet.
4.0 RECOMMENDATIONS
• Milani & Associates should confirm that the RV storage pavement section will be 7 inches of
concrete place directly on ConFoam,that is,the pavement section will not include aggregate base
rock.
File No.108ZI DCM Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 55 of 165
Page 15 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 5
If aggregate base rock is to be used in the pavement section, then the depth of overexcavation
and thickness of light weight concrete will have to be recalculated and increased to ensure no
new net long-term load on the 72-inch Outfall pipeline.
• Milani &Associates should confirm that the actual area of RV storage/parking is 101,768 sf(i.e.,
the 101,768 sf does not include storage yard aisles and driveways).
• The August 26,2021 Milani&Associates report references canopies to be constructed within the
RV Storage Yard with canopy foundations constructed within the ConFoam (presumably spread
footings). Milani &Associates should submit canopy foundation plans to CCCSD with foundation
dead plus live loads for analysis of footing stress distribution down to the 72-inch Outfall pipeline
and any additional long-term loading to be considered and added to the current calculations.
• Milani &Associates should submit a project grading plan and grading specifications to CCCSD for
review.Specifications should include a QA/QC testing program for the approximate 15,500 cubic
yards of ConFoam to ensure a uniform finished unit weight of no more than 27 pcf.
• Milani & Associates and CCCSD need to work out details for raising manholes within the RV
storage area (e.g., MH 14, 15 and 16).
• Milani &Associates should submit a construction/earthwork work plan for CCCDs review with:
o A description of the specific construction equipment that will be allowed over the 72-
inch Outfall pipeline and any limitations on construction equipment wheel and track
contact pressures(e.g., scrapers, excavators, dozers,water trucks,etc.)
o Clarify overexcavation subgrade treatment, specifically will the exposed subgrade at 2
feet deep in the 100-foot wide by 1,200-foot long overexcavation zone be scarified,
moisture conditioned and compacted in place or cut to grade and not reworked. If
scarified, moisture conditioned and compacted specify limitations on compaction
equipment and vibratory compactors (vibratory compactors should not be used over
the 72-inch Outfall pipeline).
• CCCSD should have an on-site inspector during grading to ensure that the approved construction
work plan is followed,the 72-inch outfall pipeline is protected and manholes are properly raised.
5.0 LIMITATIONS
This Technical Memorandum has been prepared for the exclusive use of CCCSD for geotechnical analysis
of Milani&Associates August 26,2021 letter submittal to CCCSD regarding development of an RV Storage
Yard over CCCSD's Outfall pipeline easement as described herein. This Technical Memorandum addresses
potential geotechnical impacts of site development on CCCSD's 72-inch RCP Outfall pipeline only and does
not address any other utilities in the project area.This Technical Memorandum may not be used for any
File No.108ZI DCIVI Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 56 of 165
Page 16 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 6
other purpose or for any other project. Within the limitations of scope, schedule and budget, DCM
Consulting, Inc.'s services have been provided in accordance with generally accepted practices in the field
of geotechnical engineering in Northern California at the time this Technical Memorandum was
completed. All opinions, conclusions and recommendations presented in this Technical Memorandum
are based on the author's professional knowledge, judgment and experience. No warranty or other
conditions express or implied should be understood.
9�C>r soot, e�ESSrp
0 j2
David C. Mathy * � 69Z 4
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C.E. 28082
GE 569 POFCALtF
File No.108ZI DCM Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 57 of 165
Page 17 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 7
Man-.oles-Ouftl
p
- � tn�laq ravrore
— Main-Outfall
G Manholes-Outfall-Abandoned
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Figure 1—CCCSD 72-inch RCP Outfall Pipeline in purple. Manholes 14 to 16 represent
the length of easement encroached by the proposed Conco RV Storage Yard project.
Total length of encroachment is approximately 1,200 feet.
File No.108ZI DCM Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 58 of 165
Page 18 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 8
I I I
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0»411
o.m.r
MH 16
Figure 2-CCCSD Record Drawings P3-8 and P3-9
- dated 3/16/12, Profile of 72-inch RCP Outfall
pipeline from Manhole 14 at Station 107+43 to
Manhole 16 at Station 119+38.
LU
- The maximum depth of cover is approximately 12
feet at Station 108+20.
-4 The minimum depth of cover is approximately 6
feet at Station 119+00.
The average depth of cover is approximately 8
feet.
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File No.108ZI DClllfl Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 59 of 165
Page 19 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 9
a1
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Figure 3—Geologic Setting, the project area is underlain by Qa, alluvial soils consisting of pebble
gravel, sand and clay. Bay Mud, Qbm is to the north.
Source: Geologic Map of Vine Hill and Honker Bay Quadrangle,Thomas Dibblee, DF 191, 2006
File No.108ZI DCM Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 60 of 165
Page 20 of 29
Memorandum to CCCSD for Conco RV Storage
October 4,2021
Page 10
t)C-,A-
+fi e a+-1 LOAtAP f-A A-0%T A A4, o-aAI C ?az
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Figure 4—Calculation of increased net long-term loading on the 72-inch Outfall pipeline with an
RV Storage Yard pavement section of 7" concrete over 10" aggregate base rock.
File No.108ZI ❑CM Consulting, Inc.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 61 of 165
ATTACHINMr 2F
00
['SL.Associates
MILANI
Date: November 11,2021
Project No: 727
Dana Lawson, P.E.
Senior Engineer- Development Services Section
Central Contra Costa Sanitary District(CCCSD)
5019 Imhoff Place
Martinez, CA 94553
Jonathan Largent, P.E.
Senior Engineer
Contra Costa Water District (CCCWD)
1331 Concord Avenue
Concord, Ca 94520
Attention: Mr.Jonathan Largent
Dana Lawson
RV Storage Report
Conco Construction and Storage Yard
Contra costa County, California
Dear Dana and Jonathan,
This report presents discussion of civil engineering considerations for storage of recreational vehicles
(RV) in the site area within the Central Contra Costa Sanitary District (CCCSD) easement and Contra
Costa Water District (CCWD) utilities. We understand that Conco is interested in considering this area as
an RV storage lot. Preliminary evaluation computations were conducted to evaluate potential impacts to
the CCCSD 72" sanitary sewer and CCWD 42" recycled water from the placement of fill.
To protect the existing pipelines, Conco will be using a proprietary material, ConFoam'11' which is a
composite lightweight fill material, proposed to be utilized to mitigate any increase in pipe load from fill
placed within 50 feet of existing District pipelines.To address prior concerns contained within the
District Peer review dated October 4, 2021, prepare by DCM Consulting,the mitigation plan proposal
has been modified to excavate 1.5 feet of existing material and replace with 6" Portland cement
March 3, 2022 Regular Board Meeting Agenda Packet- Page 62 of 165
Page 22 of 29
concrete and replace with 2 feet of confoam material.The site could be raised with a combination of
confoam and pavement and vehicle weights such that the existing pipe load stress will not be increased.
The ConFoam material maintains a unit weight of 27 pounds per cubic foot (pcf) or less.The existing in-
situ soil to be removed has a unit weight of 125 pcf.The removal of 1.5 feet of soil removes 187.5
pounds per square foot(psf) of overburden weight.The replacement of 2 ft of Confoam together with 6-
inch-thick Portland cement concrete (PCC) pavement will add 129 psf of overburden weight and will
result in raising the existing grade by 1 foot.The weight of the ConFoam and PCC would be 129 psf
leaving 58.5 psf for RV vehicle storage. Please see attached calculations sheets.
The PCC pavement shall be placed in such a way that the construction joints will be placed in the
concrete surface at predetermined locations to create weakened planes where the concrete can crack in
a straight line and will result in removal of concrete portions when maintenance or a repair operation is
required for the underground utilities.The RV storage vehicles shall be relocated by Conco to an
alternate location to facilitate District maintenance operations or emergency repair operations. RV
parking will be placed to facilitate access to all district manholes, access structures, settlement markers
or other District facilities as deemed necessary.
Overhead canopies will be proposed at discrete locations within development footprint. The canopy
columns can be easily installed within the ConFoam"' installation and will be placed at locations which
would not interfere with District pipeline maintenance/repair operations. Location of proposed
canopies will be subject to final District approval. Conco understands that any damage to RV facilities
due to District maintenance or emergency repair operations will be Conco's responsibility to repair.
Construction Considerations:
The DCM Technical Memorandum noted that the initial August 26 submittal package did not address
construction activities to be conducted over the District's outfall pipeline. A full grading permit
application package will need to be submitted to Contra Costa County for final permitting. District
Engineering staff will be provided with all permitting documents for their review and comment during
the permitting process. The proposed RV Storage facility will require a Use Permit application to be
submitted and approved by the County Development of Conservation and Development. The Use
Permit approval process with precede any formal construction documents permitted by County
Planning/Grading departments.
The Use Permit application will provide a more detailed grading analysis and will provide a more robust
narrative as to how grading/construction activities will be conducted over and near the District outfall
pipe.
For purposes of this initial review the following construction limitations/recommended construction
BMP's would be included in any interim or final proposed grading permit application:
• Prior to any construction activities the centerline alignment of the existing District outfall
pipeline would be staked in the field and maintained during all phased of construction activities.
• Any grading operations conducted within a 100-foot-wide construction zone, (centered over
the District outfall pipeline)would utilize smaller grading equipment to reduce interim dead
loads, ie., 613 self-loading scrapers.
• A work zone, 50 feet in width, centered over the District pipeline would limit construction
activity to small loaders and articulated blades only. With small depts of cut, articulated blades
would be able to push cut material outside the 50'work zone to be picked up by smaller self-
loading 613 scrapers.
March 3, 2022 Regular Board Meeting Agenda Packet- Page 63 of 165
Page 23 of 29
• Any interim/final grading plan would require the final selected grading contractor to provide
written means and methods to address the contractor's final proposed construction operations,
compliant with the final approved plan set. The contractor can offer alternative means and
method,to be approved by District staff, prior to start of construction. Any contractor
submitted alternative means and methods would need to provide safety mechanism or
construction methods that would provide additional safety measures to protect the District
outfall pipeline during all stages of construction activity.
I trust this provides you with the information that you require. If you have any questions, please feel
free to contact our office.
Sincerely,
Michael Milani, P.E.
President
Qat ESS/q�,
m
0 No.35121 z
EXP. 09/30/23
ClV1
qTF OF CA \1
MEM:
Cc: Joe Sostaric-Conco
Enclosures:
1. RV storage Calculations
2. RV storage Exhibit- Baja Site Plan (5 copies)
3. ConFoaMTm Brochure
March 3, 2022 Regular Board Meeting Agenda Packet- Page 64 of 165
Page 24 of 29
ATTACHMENT-1 11/11/2021
727-CONCO RV VEHICLE STORAGE CALCULATIONS
Abbreviations
1 Confoam Material Weight 27 pcf pcf pounds per cubic feet
2 Portland Cement Concrete(PCC)weight 150 pcf lbs pounds per cubic feet
3 Class II Aggregate Base(AB)weight 140 pcf psf pounds per square feet
4 One RV Vehicle Weight 14,000 lbs sf square feet
5 Existing Material Weight 125 pcf PCC Portland Cement Concrete
6 Available space for RV vehicle storage 101,768 sf AB Aggregate Base
7 Total available spaces for RV 183 spaces RV Recreational Vehicle
8 Total weight of RVs in the available space 35 psf RV 40'Gross Vehicle Weight=14,000 lbs
9 Pavement sections is 6"PCC(no AB) RV pressure load 14,000/10 x 40'=35 psf
The plan is to remove 1.5 feet of existing material and replace it with 2 feet of light weight"Confoam"material.
Weight of the existing material fill= 125 pcf
Weight of removal of 1.5 feet of existing material= 1.5x125= 187.5 psf
Weight of confoam+Weight of 6"PCC= 2x27+0.50x150= 129 psf
Therefore,weight left for the vehicle storage= 187.5-129= 58.5 psf
Total weight in=129+35= 164 psf
Total weight out=187.5 psf
Therefore total weight in is less than total weight out.
Page 1
March 3, 2022 Regular Board Meeting Agenda Packet- Page 65 of 165
ATTACHMENT19
Corporate Office
5141 Com m ercial Circle
O N C O Con cord,CA 94520
Ph:925.685.6799
info@conconow.com
CA LIC.#199902
January 14, 2022
Dana Lawson
Senior Engineer
Central San
5019 Imhoff Place
Martinez, CA 94553
Dear Dana,
I want to address the concerns Central San has regarding Conco's plans to have recreational vehicle
(RV) storage over the Central San outfall pipeline easement that runs through the Conco Martinez
property. As I understand it, the concern is that should access be required to perform emergency
repairs on the pipeline, the presence of RV's may impede Central San's ability to perform the work
needed. I believe that Conco can address these concerns in a manner that satisfies Central San. Here
would be our strategy to do so.
This is not a new issue for Conco. Conco operates a self and RV storage facility less than two miles
from the proposed site call Abba Self& RV Storage (see the attached map for location). The Abba site
has some of the same issues as there is a Kinder Morgan pipeline that traverses underneath the
property. Here is how we were able to address the same concerns expressed by Kinder Morgan.
1. The contract we have with our clients allows us to move their rigs in case of an emergency. This
is standard in all our contracts as we need the ability to do so for other disasters such as a fire
at the facility.
2. The nature of RV storage means most of your clients live within ten miles of the site as people
do not want to travel long distances to access their rigs. More than 80% of the RV owners live
very close to the site. We have called customers in the past to move or address issues with
their vehicles (for example, a client may leave a window open on their unit) and the response
time is very fast.
3. Conco is well equipped to move their rigs if needed. We contract with several tow companies
that specialize in moving large trucks and RV's. We have these relationships because we
operate large concrete pumps (up to 115,000 pounds) that sometimes require these services.
Our heavy-duty repairmen also have equipment at our Martinez facility should they need to
www.conconow.com
Southern California Oregon Washington Colorado
13502 Dahlia St 838 SW 1st Ave.#400 18644 72nd Ave 2045 W Union Ave,
Fontana,CA 92337 Portland,OP 97204 Kent,WA 98032 Bldg A
Ph:909.350.0474 Ph:971.808.5954 Ph:425.251.1684 Englewood,CO 80110
CA LIC.#199902 OP LIC.#110962 WA LIC.#CONCOCC044L5 Ph:303.996.9841
March 3, 2022 Regular Board Meeting Agenda Packet- Page 66 of 165
Page 26 of 29
move immobile equipment. Conco has had to move clients' rigs in the past (client is out of
town at the time) and we have done so with no issues.
4. The Abba facility has a manager that lives onsite. This makes it easy to respond immediately to
any emergency that may take place. Because of the proximity to the new site, the same
manager will be able to respond there also. The nature of Conco's business (we send
equipment out all hours of the day) means we have additional people that are capable of
responding quickly to provide any additional support or assistance needed.
5. We have done this in the past. Right now, Kinder Morgan has scheduled for work to be done
on their pipeline the week of January 17t". We have already vacated the spots where the work
is being done so as not to impede their ability to perform repairs.
Conco will have the same protocols for handling any issues that may come up with the outfall pipeline
for Central San. In addition, to these protocols, Conco:
1. Will lay out the site providing Central San constant access to their manholes. RV's will not be
parked on top of the manholes.
2. Has designed the spaces above the outfall pipeline easement for drive through access. This
makes it even easier to move any RV's parked in this area as there is access to the RVs from
both ends.
The Conco business values the relationship it has with Central San. We find that our businesses are
very compatible and are seeking uses for our property that will also fit in with the business activities
that we both do. We believe RV storage is a business that can coexist with what we both do.
I hope this letter addresses any concerns you might have. This is a very important project for us, and I
hope it meets with your approval. Please call me if you have any questions. I am also available to
meet if you would like to discuss in greater detail.
Sincerely,
Joe Sostaric
The Conco Companies
Enclosures:
The Conco Com panies I Page 2
March 3, 2022 Regular Board Meeting Agenda Packet- Page 67 of 165
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The Conco Com panies Page 4
March 3, 2022 Regular Board Meeting Agenda Packet- Page 69 of 165
Page 29 of 29
ATTACHMENT 6
RESOLUTION NO. 2022-015
A RESOLUTION OF THE CENTRAL CONTRA COSTA SANITARY DISTRICT
EXECUTING AN ENCROACHMENT AGREEMENT
5050 IMHOFF PLACE IN MARTINEZ
(APN: 159-250-018)
BE IT RESOLVED by the Board of Directors of Central Contra Costa Sanitary District
(Central San) as follows:
THAT Central San hereby authorized to execute an Encroachment Agreement with the
following property owner(s) related to the indicated property:
Assessors' Parcel No.: 159-250-018
Property Owner(s): Gonsalves & Santucci, Inc.
Site Address: 5050 Imhoff Place, Martinez
THAT the President of the Board of Directors and the Secretary of the District are hereby
authorized to execute said documents for and on behalf of Central San.
PASSED AND ADOPTED this 3rd day of March 2022 by the Board of Directors of Central San
by the following vote:
AYES: Members:
NOES: Members:
ABSENT: Members:
David Williams
President of the Board of Directors
Central Contra Costa Sanitary District
County of Contra Costa, State of California
COUNTERSIGNED:
Katie Young
Secretary of the District
Central Contra Costa Sanitary District
County of Contra Costa, State of California
Approved as to form:
Kenton L. Alm, Esq.
Counsel for the District
March 3, 2022 Regular Board Meeting Agenda Packet- Page 70 of 165