HomeMy WebLinkAboutAECOM_Supp_Agmnt__1_Virden_Creek_-_3.2.2026Docusign Envelope ID: 2BA02A85-E195-4590-93B8-E23065DB8755
AECOM
AECOM 319-232-6531 tel
501 Sycamore Street 319-439-3089 fax
Suite 222
Waterloo, Iowa 50703
www.aecom.com
VIRDEN CREEK DAM AND FLETCHER AVENUE
FLOOD CLOSURE REPAIR ANALYSES AND
CONCEPTUAL DESIGN REPORT (PHASE I)
CITY OF WATERLOO
SUPPLEMENTAL AGREEMENT NO. 1
WHEREAS, a Professional Services Agreement was entered into between the City of Waterloo (Client),
715 Mulberry Street, Waterloo, Iowa, and AECOM Technical Services, Inc. (ATS), 501 Sycamore Street,
Suite 222, Waterloo, Iowa, dated August 5, 2024, for Virden Creek Dam and Fletcher Avenue Flood Closure
Repair Analysis and Conceptual Design Report (Phase 1); and
WHEREAS, the Client and ATS now desire to enter into Supplemental Agreement No. 1 for Virden Creek
Dam Auxiliary Spillway Replacement and Fletcher Avenue Flood Closure Repair Plan Development.
NOW THEREFORE, it is mutually agreed to amend the original Professional Service Agreement as follows:
I. PROJECT DESCRIPTION
This project consists of field survey, preliminary and final design for the replacement of the
emergency concrete spillway for the Virden Creek Dam, repair of the existing main outfall reinforced
concrete box culvert (RCB) outlet through the earthen dam, and associated underdrain system
repairs. This project also includes the removal and repair of the existing Fletcher Avenue Floodgate
System for Black Hawk Creek. The repairs will include full removal and replacement of the four (4)
existing floodgates, sand blasting, structural repair, painting, gate hardware replacement, addition
of a toe wheel (4), addition of a hinge (4), addition of anchor points for closure operations and
structural concrete wall and roadway repair. The replacement and repair recommendations were
detailed in the conceptual report completed by AECOM dated November 2025 as well as in the
scoping coordination meeting with City staff in December 2025. These projects will also require
Section 408 review and coordination with the USAGE during design and construction along with
updates to the existing O&M manuals for Virden and Fletcher. Preliminary coordination with the
United States Army Corps of Engineers (USACE) was started during the conceptual report
development of the project and they are aware of the upcoming replacement/repair projects.
The Virden Creek Dam is located NE of the intersection of Moline Road and E. Airline Highway,
and the Fletcher Avenue floodgates are located at the roadway crossings of the Black Hawk Creek
Levee System.
The Virden Creek Dam received a satisfactory rating during the last Iowa DNR inspection in August
2023; however, concrete deterioration within the emergency spillway and primary spillway was
noted. Erosion and undermining of the existing concrete matting protecting the earthen dam along
the emergency spillway was also noted during the inspection. The DNR has recommended
developing repair recommendations to address the concerns which may require a rating reduction
if not addressed. Construction of the dam was completed in 1979 and is part of the City of Waterloo
Flood Protection Works designed by the USACE. The dam is maintained and operated by the City
of Waterloo.
The Fletcher Avenue floodgates were also constructed as part of the Waterloo Flood Protection
Works designed by the USACE. Construction of the north gates (near University Avenue) was
completed in 1975, and construction of the south gates (near US Highway 63) was completed in
1977. A repair was completed on the north gates as part of the University Avenue Reconstruction
project in 2022 which included concrete repair at some of the hinge/gate anchor locations.
Docusign Envelope ID: 2BA02A85-E195-4590-93B8-E23065DB8755
AECOM
II. SCOPE OF SERVICES
Page 2
The Scope of Services will encompass and include work, services, materials, equipment, personnel
and supplies necessary to complete field survey, preliminary and final design, geotechnical
foundation analysis, preparation of regulatory permitting and coordination (Section 408 and Iowa
DNR Floodplain) and project administration.
The Scope of Services is further defined by the following tasks:
Design Survey (Tasks 1-7)
The following tasks lead to the completion of the topographical survey required for project
completion. This task also includes review and development of a boundary survey within the project
area.
Task 1 - Survey Planning, Coordination, One -Call
Task 2 - Horizontal Control (GPS)
Task 3 - Vertical Control (Level/Total Station)
Task 4 - Generate Control File
Task 5 - Topographic Survey (Spillway, Outfall Structure and 12 CMP Toe Drains Outlets)
Task 6 - Utility Survey
Task 7 - Boundary Survey (Limited — No Platting)
Preliminary Design (Tasks 8-22)
These tasks include developing preliminary removal, grading, and structural design plans for the
auxiliary spillway replacement and associated dam repairs. Structural calculations meeting USACE
requirements will also be developed during the preliminary design phase of the project. These
calculations will be summarized in a draft design documentation report (DDR) which will be included
in the Section 408 submittal to the USACE. The Section 408 submittal will also include a Flood
Contingency Plan per EC 1165-2-220, Appendix E, Section E-5.h.(5) of USACE documentation.
Preliminary plans will be submitted to the City of Waterloo for review at the approximate 60% level.
The following specific tasks are part of the preliminary design:
Task 8 - Title and Legend Sheets
Task 9 - Typical Section and Details
Task 10 - Plan and Profile Sheets
Task 11 - Grading Sheets
Task 12 - Removal Sheets
Task 13 - ROW Sheets
Task 14 - Structural Design - Virden Creek Spillway
Task 15 - Structural Design - Fletcher Avenue Flood Closure
Task 16 - Draft DDR Development
Task 17 - Draft Flood Contingency Plan Development
Task 18 - Draft Section 408 and Iowa DNR Floodplain Permit Development
Task 19 - O&M Plan Review and Update
Task 20 - Quality Control Review
Task 21 - 60% Plan Submittal
Task 22 - Construction Cost Estimate
Docusign Envelope ID: 2BA02A85-E195-4590-93B8-E23065DB8755
AECOM
Final Design, Construction Plans and Specifications (Tasks 23-44)
Page 3
These tasks include developing final removal, grading, and structural design plans and
specifications in a format suitable for City of Waterloo project letting format for the Virden Creek
Auxiliary Spillway Replacement and Fletcher Avenue Flood Closure Repair Project. Included in
these tasks will be typical sections and details, tabulations and quantities, plan and profile sheets,
grading sheets, removal sheets, cross section sheets, structural sheets and erosion control and
stabilization plan. Final plans will be submitted for City staff review at a pre -bid 90% interval. The
final DDR, Flood Contingency Plan and Section 408 documents will be completed during this phase
as well. The following specific tasks lead to the completion of the final construction plans and
specifications:
Task 23 - Title and Legend Sheets
Task 24 - Typical Section and Detail
Task 25 - Bid Items, General Notes and Tabulations
a. Bid Item and Quantity Listing
b. Estimate Reference Information
c. General Notes and Tabulations
Task 26 - Tabulations and Quantities
Task 27 - Plan and Profile Sheets
Task 28 - Grading Sheets
Task 29 - Removal Sheets
Task 30 - Structural Sheets
Task 31 - Geometric Layout Sheets
Task 32 - Earthwork Tabulation
Task 33 - Design Cross Sections
Task 34 - Erosion Control and SWPPP Plan Sheets
Task 35 - Quality Control Review
Task 36 - Final DDR Plan Development and Submittal
Task 37 - Final Flood Contingency Plan Development and Submittal
Task 38 - Final Section 408 and Iowa DNR Floodplain Development and Submittal
Task 39 - Final O&M Plan Development
Task 40 - Pre -Bid Plan Submittal (90% Plans)
Task 41 - Final Revisions
Task 42 - Construction Cost Estimate
Task 43 - Specifications
Task 44 - Printing and Submittals
Geotechnical Services (Task 45)
These tasks include completing three (3) borings at the auxiliary spillway location (2 within the
paved portion of the spillway and one (1) north of the spillway in the earthen portion of the grading).
These tasks will be completed by Terracon Consultants, Inc. (Terracon) and will include a
foundation recommendation summary report to be utilized in the spillway design.
Task 45 - Geotechnical Review (Terracon)
Project Administration, Regulatory Coordination and Meetings (Tasks 46-48)
These tasks include project administration, regulatory coordination, and design coordination
throughout the project development. The following tasks are included:
Task 46 - Project Design Meetings with City of Waterloo (3)
Task 47 - Regulatory Agency Coordination (Iowa DNR and USACE)
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AECOM
Task 48 - Project Administration
Exclusions
Page 4
The following items are not included in this scope, but could be added in a supplemental agreement
if needed:
• Seepage Analysis
• Independent Peer Review (Structural Calculations)
• Hydrologic and Hydraulic Modeling of Virden Creek or Black Hawk Creek
Construction -Related Services
The scope of construction -related services will be determined at the time the services are needed
and defined under a future amendment.
III. COMPENSATION
Compensation for the above services will be on an hourly basis in accordance with Part VI of the
original agreement and shall be integrated with the fees in the original agreement. The total
compensation for these services is a not -to -exceed fee of Two Hundred Seventy -Three Thousand
Seven Hundred Dollars ($273,700.00) and will not be exceeded without authorization from the
Client.
IV. In all other respects, the obligations of the Client and the Consultant shall remain as specified in
the Professional Services Agreement dated August 5, 2024.
IN WITNESS WHEREOF, the parties hereto have executed this Supplemental Agreement No. 1 as of the
dates shown below:
APPROVED FOR CITY OF WATERLOO APPROVED FOR AECOM TECHNICAL SERVICES, INC.
,—Signed by:
NWU4, jj�t,StM By: e, .e sizi(.ez&er
▪ -\-393E8397B3D3421...
Printed Name: David Boesen Printed Name: Michelle M. Sweeney, PE, PTOE
Title: Mayor Title: Associate Vice President
03/02/2026
Date: Date: 03/02/2026
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