Contract - AECOM Technical Services - 8/14/2025 , -
STATE OF TEXAS §
COUNTY OF WILLIAMSON §
SUPPLEMENTAL CONTRACT NO. 1
TO CONTRACT FOR ENGINEERING SERVICES
FIRM: AECOM TECHNICAL SERVICES ("Engineer")
ADDRESS: 13640 Briarwick Drive, Suite 200, Austin, TX 78729
PROJECT: BCRWWS East WWTP Floodwall Study
This Supplemental Contract No. 1 to Contract for Engineering Services is made by and between
the City of Round Rock, Texas, hereinafter called the "City" and AECOM Technical Services,
hereinafter called the"Engineer."
WHEREAS, the City and Engineer executed a Contract for Engineering Services, hereinafter
called the "Contract," on the 27th day of September, 2024 for the BCRWWS East WWTP
Floodwall Study Project in the amount of$93,640.00; and
WHEREAS,it has become necessary to amend the Contract to modify the provisions for the scope
of services and to increase the compensation by $51,270.00 to a total of$144,910.00;
NOW THEREFORE,premises considered, the City and the Engineer agree that said Contract is
amended as follows:
Article 1, City Services and Exhibit A, City Services shall be amended as set forth in the attached
Addendum To Exhibit A.
II.
Article 2, Engineering Services and Exhibit B, Engineering Services shall be amended as set forth
in the attached Addendum to Exhibit B. Exhibit C, Work Schedule shall be amended as set forth
in the attached Addendum to Exhibit C.
III.
Article 4, Compensation and Exhibit D, Fee Schedule shall be amended by increasing by
$51,270.00 the maximum amount payable under the Contract for a total of$144,910.00, as shown
by the attached Addendum to Exhibit D.
IN WITNESS WHEREOF,the City and the Engineer have executed this Supplemental Contract
in duplicate.
Supplemental Contract Rev.06/l6
0199.202435;4933-7861-8449 84275
1
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AECOM TECHNICAL SERVICES
Digitally signed by Fischer,Cada
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Fischer, Carla O mn°oC U�rs
By: Date:2025.07.09 10:47:40-05'00'
7/9/2025
Date
Supplemental Contract Rev.06/16
0199.202435;4933-7861-8449 84275
2
CITY OF ROUND ROCK APPROVED AS TO FORM:
By:
Craig gMayor a ep anie L. San re, City Attorney
// /2c25
Date
Supplemental Contract Rev.06/16
0199.202435;4933-7861-8449 84275
3
AECOM I it
Delivered.magne AECOM
13640 Briarwick Drive,Suite 200
Austin,TX 78729
aecom.com
ADDENDUM TO EXHIBIT A
City Services
City of Round Rock services for the BCER WWTP Amendment 1 study will include:
• Photogrammetric or other aerial mapping,as available.
• Existing digital 2D/3D terrain and facility data from Civil 3D or other software.
• Data for any projects adjacent to the subject project.
• Existing hydrologic and hydraulic studies associated with the project and project area.
• Proposed hydrologic and hydraulic studies associated with the project and project area.
• Coordination and assistance, for the Engineer, in acquiring information from other local,
regional,state and federal agencies,as needed.
• Provide timely reviews and decisions necessary to maintain the project work schedule.
• Design criteria for drainage and hydraulics.
• Available supplemental Federal Emergency Management Agency (FEMA) Hydrologic &
Hydraulic(H&H)data that may have previously been acquired by the City.
AECOM
Imagine it.
/�� Delivered. AECOM
13640 Briarwick Drive,Suite 200
Austin,TX 78729
aecom.com
ADDENDUM TO EXHIBIT B
Engineering Services
June 15,2025
Federico Sanchez,P.E.,CFM
Stormwater Engineer,Public Works-Utilities
City of Round Rock
3400 Sunrise Road
Round Rock,Texas 78665
Reference: Proposal for Professional Engineering Services, BCER WWTP Floodwall Study,
Supplement 1
Dear Mr. Sanchez:
AECOM Technical Services, Inc. (AECOM)is pleased to submit this supplementary proposal to the
City of Round Rock (CoRR). This proposal is for professional engineering services to develop a
conceptual Opinion of Probable Cost(OPC)for preliminary engineering,design and construction of the
proposed Brushy Creek East Regional(BCER)Wastewater Treatment Plant(WWTP)floodwall and
associated site items.
AECOM recently performed preliminary hydrologic and hydraulic analysis to assess the floodplain
impacts of a floodwall installation to protect the expanding BCER WWTP. The approximate length
and height of the wall was identified,but no further studies have been performed to advance preliminary
design or construction of the floodwall. This evaluation aims to provide the CoRR with an estimate of
the expected range of planning,design,and construction costs for planning budgetary purposes only.
SCOPE OF WORK
This scope of work will identify field work,analyses, and project components that will be needed to
advance to final design, construction, and permitting of a floodwall. AECOM will draw upon our
extensive knowledge of both WWTPs and flood defense design both locally and throughout the United
States to complete the OPC. Supplement 1 will include Task 5 — Prepare Conceptual Opinion of
Probably Cost,described in further detail below.
Task 5—Prepare Conceptual Opinion of Probable Cost
Task 5.1—Additional Project Management
This subtask includes time for general management,team coordination,conducting team meetings
necessary for successful task completion, and invoicing. AECOM will host two virtual meetings with
the CoRR.The first meeting is aimed to review initial assumptions and clarify any questions that arise.
The second meeting will discuss draft memorandum prior to completion of Supplement 1.
BCER WWTP Floodwall Study Supplement 1 June 15,2025
Task 5.2—Develop Final Design Cost Estimate and Assumptions
This task includes time for reviewing available BCER WWTP data and prior studies,comparing these
site conditions to similar projects, and developing high-level costs for fmal floodwall and onsite
drainage design to protect the BCER WWTP from 1%Annual Exceedance Probability(AEP)flood.
The Final Design estimate will consist of conceptual cost estimates for the following preliminary
engineering,and all phases of final design.
Preliminary Engineering Phase
• Topographic Survey
• Subsurface Utility Engineering(SUE)Survey
• Geotechnical Investigation
• Geotechnical Analysis and Reporting(GIR/SMR)
• Utility Conflict Assessment
• Structural Design Considerations
• Floodwall Closure Structure(e.g. Gate)or Pond Pump Station Electrical
Considerations
• Interior/On site Drainage Analysis and Concept Design
• Environmental Studies. The need for a CLOMR/LOMR on the floodwall project
requires compliance with federal regulations including,but not limited to,the
Endangered Species Act,Clean Water Act, and National Historical Preservation
Act. Studies that may be required include a Waters of the US delineation,habitat
assessment, and cultural resources evaluations.
• Preliminary Engineering Report—will summarize the above investigation and
studies. Where appropriate this report will present multiple design options when
certain components have several possible configurations needing client input.
This report will set the final design components for the subsequent design phases.
30% Design
• Includes plans,specification,and estimates(PS&E)development conceptual cost
estimate to the 30%level of design. The level of effort for this item will be based
on a percentage of total construction cost and/or comparison and scaling to a
similar floodwall design effort for a WWTP in the central Texas area.
60% Design
• Includes PS&E development conceptual cost estimate to the 60%level of design.
The level of effort for this item will be based on a percentage of total construction
cost and/or comparison and scaling to a similar floodwall design effort for a
WWTP in the central Texas area.
90% Design
• Includes PS&E development conceptual cost estimate to the 90%level of design
The level of effort for this item will be based on a percentage of total construction
cost and/or comparison and scaling to a similar floodwall design effort for a
WWTP in the central Texas area.
CLOMR Preparation
• Includes preparation of the Conditional Letter of Map Revision(CLOMR)
application package(MT-2 application and report)for FEMA review and
approval
Page 2
BCER WWTP Floodwall Study Supplement 1 June 15,2025
Final Design
• Includes PS&E development conceptual cost estimate to the 100%level of
design. The level of effort for this item will be based on a percentage of total
construction cost and/or comparison and scaling to a similar floodwall design
effort for a WWTP in the central Texas area.
Task 5.3—Develop Construction Cost Estimate and Assumptions
This task includes time for reviewing the following:
• Available BCER WWTP data and prior studies,
• Comparing these site conditions to similar projects AECOM has successfully
delivered,
• Developing high-level costs for floodwall construction to protect the BCER WWTP
from 1%AEP flood event.
The items to be considered in the cost estimate include but are not limited to the following:
Floodwall Construction
• Construction oversight
• Site preparation
• Surveying and layout,including but not limited to construction staking,baseline and
control point establishment,and as-built surveys.
• Environmental and safety compliance,including but not limited to erosion and
sediment control, dust and noise mitigation, spill prevention and response.
• Excavation and earthwork for floodwall installation
• Installation of temporary flood barriers to protect both the contractor and BCER
WWTP during construction
• Drainage and underseepage control
• Floodwall—the results of the preliminary floodwall H&H evaluation will be used to
conceptually size the wall height needed along the alignment with consideration of
FEMA freeboard requirements.These wall heights will then be used estimate an
approximate bedding depth(s)along the alignment after a cursory review of available
geotechnical data. Conceptual construction costs will be developed for wall type(s)
best suited to the geologic conditions at the site(i.e. earthen levee, T-Type concrete
floodwall, I-Type sheetpile floodwall). These costs could include as applicable:
formwork,reinforcing steel placement, concrete placement, expansion and control
joints,water stops and sealants.
• Closure structures, including floodwall gate installation(s)
• Quality control and testing,including but not limited to concrete testing,soil
compaction testing,pile load testing.
• Site restoration
Interior Drainage/Site Stormwater(collection system to onsite pond(s)with gravity outfall)
• Collection system.Cost will be based on a percentage of ditch versus storm drain
needed to collect and convey water..
• Onsite pond.The available H&H models will be used to estimate the 100-year storage
volume. The pond will be sized accordingly with appropriate gravity outlet works.
The City of Round Rock Design and Construction Standards Drainage Criteria
Manual will be reviewed.
Page 3
BCER WWTP Floodwall Study Supplement 1 June 15,2025
• Pump station. At this time,pumped discharge to either Brushy Creek or Chandler
Branch will be considered as an optional item. It is not known whether this will be
needed as part of final design.
• Structural components.These could include concrete walls for pond interior or outlet
pipes and structures.
• A high-level review of site drainage patterns and any assumptions on conveyance to
the ponds will be stated,
Permitting
• City of Round Rock Development Permit(s)
• Letter of Map Revision(LOMR)—Includes preparation of the LOMR application
package(MT-2 application and report) for FEMA review and approval.
• Levee accreditation—preparation of the levee accreditation package for compliance
with 44 CFR 65.10. This package includes an overall summary report plus a series of
attachments and exhibits to highlight that the design meets all required FEMA items.
This includes updating the interior drainage modeling from the PER phase for
inclusion in the submittal package.
• USACE 404 Permit/TCEQ Section 401 Certification
• Stormwater Pollution Prevention Plan
Task 5.4—Memorandum
The only deliverable associated with Supplement 1 (Task 5)will be the provision of a memorandum
documenting the OPCC and necessary assumption used to generate it,will be submitted to the CoRR.
The cost associated with this task includes an initial draft submittal, one round of consolidated
comments from CoRR and resolution,and a final submittal.
Notes and Other Assumptions:
- The approximate length and height of the flood wall has been determined from initial hydraulic
modeling,this is subject to change as the design develops.
- This OPC represents a high-level estimate of planning, design, and construction costs for
budgetary purposes only based on best available information at the time of preparation.As
additional information,such as geotechnical investigation,becomes available,the cost of design
and construction will change.
- While three flood wall types were previously discussed as construction options,earthen levee,
T-Type concrete floodwall and I-Type sheetpile floodwall,high level construction costs will
be based on the type best suited to the geological conditions.
- Geological conditions assessment used to inform the OPC will be based on best available
information and may be subject to change following site investigation.
- Optimism bias will be applied to costing of scope items detailed under Task 5.CoRR should
determine whether additional contingency should be applied given the uncertainty given the
preliminary design phase has not been undertaken. The location of utilities is not fully
understood.Utility relocation to accommodate the design or design refinements associated with
the wall may be required.This could impact design and construction costs.
- When preparing cost associated with the collection system it is assumed that flow will be
conveyed to no more than two onsite ponds via gravity drainage.
- Temporary flood protection measures will be designed based on government-furnished criteria
and must accommodate hurricane season constraints.
Page 4
BCER WWTP Floodwall Study Supplement 1 June 15,2025
- The standard of protection for the flood wall is assumed to be the 1%AEP.
- Detailed drainage calculations will not be performed as part of the OPC scope.
- Drainage patterns and assumptions on conveyance are subject to change based on site
investigation.
- Construction sequencing will need to consider hurricane season restrictions and an allowance
for weather delays will need to be made during cost of the construction once a preferred flood
wall solution has been designed.
- This scope of work represents a costing exercise only,all design elements including preliminary,
30%, 60%and 90%design are excluded from the proposed scope of work.The OPC is the only
deliverable.
- Only two virtual meetings have been allowed: one to review initial assumptions and a second
meeting to discuss draft deliverables associated with Supplement 1 prior to issuing for CoRR
review.
- AECOM will assume a streamlined approach to costing permitting approvals as part of the
OPC. However, timing of permit issuance by regulatory agencies is outside of AECOM's
control.
- AECOM will list all assumptions in pricing out each phase of study,design,and construction
based on best available information at the time of preparation.Assumptions in the OPC are
subject to change as the design develops.
COST
AECOM proposes to perform this study for a total estimated cost of$51,270. The cost per task
summary is provided in Table 1.A detailed cost estimate is provided in Exhibit D.
Table 1.Brushy Creek East Regional WWTP Floodwall Study Supplement 1 Fee Summary
Task Task Cost
Task 5 Prepare Conceptual Opinion of Probable Cost $51,270
Total $51,270
SCHEDULE
Upon notice to proceed, AECOM proposes the deliverable schedule provided in Table 2. If an
extension to the schedule is required,then AECOM will coordinate with CoRR staff on the additional
time only needed to complete the cost estimate and accompanying memo.
Table 2.Brushy Creek East Regional WWTP Floodwall Study Schedule
Task Start Date End Date
Notice to Proceed 7/15/2025 —
Task 5 Prepare Conceptual Opinion of Probable Cost 7/15/2025 10/14/2025
TERMS AND CONDITIONS
The fee will be effective if this proposal is accepted by the CoRR within 90 days of the date of this
proposal.The scope of services will be performed in accordance with the terms and conditions in our
Time and Materials Engineering Services Contract CM-2024-251 dated September 27, 2024. Please
indicate your acceptance of this proposal by issuing a Supplement referencing this proposal.
Page 5
BCER WWTP Floodwall Study Supplement 1 June 15,2025
Thank you for selecting our firm for providing the above services.Ms.Monica Wedo will be the project
manager and AECOM contact for this work. If you have questions or would like additional information,
please feel free to contact Ms.Monica Wedo at 512-779-0880 or email listed below or Carla Fischer,at
the contact information listed below.
Sincerely,
t2/14161" 64,14, adeAt/L
Monica Wedo,P.E. Carla Fischer,P.E.(WI),CFM
Project Manager Vice President Business Line Director,
Surface Water, Central US Surface Water, Central US
AECOM Technical Services,Inc. AECOM Technical Services,Inc.
monica.wedo@aecom.com carla.fischer@aecom.com
Page 6
A=COM wed AECOM
13840 Briarwick Drive,Suite 200
Austin,TX 78729
aecom.com
ADDENDUM TO EXHIBIT C
Work Schedule
The proposed work schedule for the Brushy Creek East Regional WWTP Floodwall Study Supplement
1 is provided below.The schedule assumes a NTP date of 7/15/2025.
Task Start Date End Date
Notice to Proceed 7/15/2025 —
Task 5 Prepare Conceptual Opinion of Probable Cost 7/15/2025 10/14/2025
ADDENDUM TO EXHIBIT D
Fee Schedule
Attached Behind This Page
Exhibit D: Fee Schedule
Brushy Creek East Regional WWTP Floodwall Study Supplement 1
City of Round Rock
Brushy Creek East(BCE)Regional Wastewater Treatment Plant(WWTP)Floodplain Program Project Senior Cost Senior Senior Project Staff Contract TOTAL TASK LEVEL
Study Supplement 1 Principal Principal Engineer Ill Estimator Engineer I Scientist Engineer II Engineer I Geologist Admin Admin. HOURS FEE
(TASK I $265.00 I $245.00 I $220.00 I $245.00 I $17500 I $220.00 I $120.00 I $105.00 I $110.00 I $95.00 I $13500 II $0.00 I $0.00
Task 5-Prepare Conceptual Opinion of Probable Cost
Task 5.1-Additional Project Management 3 11 3 0 0 1 0 0 0 0 7 25 $5,315
Task 5.2-Develop Final Design Cost Estimate and Assumptions 6 19 9 0 3 6 3 0 10 0 0 56 $11,530
Topographic Survey 2 2
SUE Survey 2 2
Geotechnical Investigation 2 6 8
Geotechnical Analysis and Reporting(GIR/SMR) 4 4 8
Utility Conflict Assessment 2 2
Floodwall Structrual Design Considerations 3 3
Floodwall Closure Structure or Pond Pump Station Electrical Considerations 3 3
Interior/On site Drainage Analysis and Concept Design 4 3 7
Environmental Studies 6 6
Preliminary Engineering Report(PER) 4 4
30%Design PS&E 2 2
60%Design PS&E 2 2
90%Design PS&E 2 2
CLOMR 3 3
100%Design PS&E 2 2
Task 5.3-Develop Construction Cost Estimate and Assumptions 5 30 5 40 9 2 14 0 0 0 0 105 $23,270
Develop Floodwall Assumptions and Cost Estimate 1 10 5 40 6 5 67
Develop Interior Drainge/Site Stormwater Assumptions and Cost Estimate 4 17 9 30
Permitting Assumptions and Cost Estimate 3 3 2 8
Task 5.4-Memorandum 6 24 6 0 2 6 6 0 6 0 56 $11,150
I TOTAL HOURS I 20 I 84 I 23 I 40 I 12 11 23 I 6 I 10 I 6 I 7 II 242 I
I TOTAL LABOR COSTS' $5,300 I $20.580 I $5,060 I $9,800 I $2.100 I $2,420 I $2,760 I $630 I $1,100 I $570 I $945 II • I $51,265 I
I S51,270 I
6/15/2025