CM-2025-213 - 8/22/2025 STATE OF TEXAS §
COUNTY OF WILLIAMSON §
SUPPLEMENTAL CONTRACT NO. 1
TO CONTRACT FOR ENGINEERING SERVICES
FIRM: PLUMMER ASSOCIATES,INC. ("Engineer")
ADDRESS: 6300 La Calma Drive, Suite 400, Austin,TX 78752
PROJECT: BCRWWS West WWTP TPDES Permit Renewal
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 Plummer Associates, Inc.,
hereinafter called the"Engineer."
WHEREAS, the City and Engineer executed a Contract for Engineering Services, hereinafter
called the"Contract,"on the 5th day of April,2024 for the BCRWWS West WWTP TPDES Permit
Renewal Project in the amount of$25,000.00; 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$3,000.00 to a total of$28,000.00;
NOW THEREFORE,premises considered,the City and the Engineer agree that said Contract is
amended as follows:
I.
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$3,000.00
the maximum amount payable under the Contract for a total of $28,000.00, 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.06/1 6
0199.202412;4907-9079-6380 84275
C Y1 ,22-5 - 213
PLUMMER ASSOCIATES,INC.
8/11/2025
Date
Supplemental Contract Rev.06/16
0199.202412;4907-9079-6380 84275
2
CITY OF ROUND ROCK APPROVED AS TO FORM:
/ 7-J
By:
I,s r Q��/�,, Stephanie L. Sandre, City Attorney
Printed Name: brooks C 1
Title: 3
Date Signed: 5c 122-l2S
Supplemental Contract Rev.06/16
0199.202412,4907-9079-6380 84275
3
ADDENDUM TO EXHIBIT A
City Services
CITY OF ROUND ROCK
BRUSHY CREEK REGIONAL WASTEWATER SYSTEM—WEST PLANT
TEXAS POLLUTANT DISCHARGE ELIMINATION SYSTEM
DISCHARGE PERMIT MODEL REVIEW
CITY SERVICES
Per the scope of work documented in Exhibit B—Consulting Services, the City of Round Rock
(CITY) responsibilities will include the following:
• Provide Plummer Associates, Inc. (PLUMMER)with requested information as needed.
• Provide PLUMMER with access to the CITY's facilities as needed to complete the work.
• Review model results provided by PLUMMER and provide authorization to communicate
results to the Texas Commission on Environmental Quality (TCEQ).
https-.//apaienv.sharepoint.com/sites/WQPermitting_Team/Shared Documents/General/Proposals and Scopes/0982-021-0-1887 City of Round Rock Brushy Creek West Permit
App/2025 Amendment/EXHIBIT A-City Services.dacx A-o 1
ADDENDUM TO EXHIBIT B
Engineering Services
CITY OF ROUND ROCK
BRUSHY CREEK REGIONAL WASTEWATER SYSTEM —WEST PLANT
TEXAS POLLUTANT DISCHARGE ELIMINATION SYSTEM
DISCHARGE PERMIT MODEL REVIEW
SCOPE OF WORK
The CITY has requested the assistance of PLUMMER in reviewing Texas Commission on
Environmental Quality (TCEQ)'s updated and recalibrated water quality discharge model to
evaluate proposed changes to the ammonia-nitrogen limits of the Texas Pollutant Discharge
Elimination System (TPDES) permit for the Brushy Creek Regional Wastewater Treatment
System West (Brushy Creek West) Wastewater Treatment Plant (WWTP). The draft permit
received on July 24, 2025 proposes a limit of 2 mg/L. The limit in the existing permit is 3 mg/L.
Included in this Scope of Work are descriptions of BASIC SERVICES and ADDITIONAL
SERVICES. BASIC SERVICES are those services known to be required for reviewing the
discharge model. A specific scope and budget for BASIC SERVICES is provided. BASIC
SERVICES include reviewing the discharge model and communicating results. ADDITIONAL
SERVICES are those services that are not included in the existing contact or this scope of work,
but may become necessary to further protest the change in permit limits. PLUMMER will not
conduct ADDITIONAL SERVICES unless requested by OWNER.
BASIC SERVICES
BASIC SERVICES for this contract include the following tasks:
Task 1. Water Quality Model Review
PLUMMER will request the updated and recalibrated water quality model from the TCEQ for
review and comparison to the previous model. Plummer will review model input assumptions
and evaluate the impact of the CITY's discharge and other existing discharges within the
watershed. PLUMMER will document findings, summarize model results, and identify discharge
limits necessary to protect aquatic life in Brushy Creek. Task 1 includes a virtual meeting
between CITY and PLUMMER to discuss results.
B-1
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App/2025 Amendment/EXHIBIT B-Engineering Service dock
ADDITIONAL SERVICES
ADDITIONAL SERVICES are those that are not currently anticipated to be a part of the project
to review the discharge model limits, but which could become necessary or desired to further
protest the limits. PLUMMER will perform ADDITIONAL SERVICES only as authorized to do so
by CITY. If CITY requests ADDITIONAL SERVICES, PLUMMER will prepare a specific scope
and budget for the services requested for review and approval of CITY prior to initiating the
services. Following is a list of some of the ADDITIONAL SERVICES that might be needed or
desired:
• Field reconnaissance by PLUMMER to collect data or information not otherwise
provided by CITY.
• Prepare application forms and documents required for application requesting changes
or amendments to the TPDES permits.
• Meetings with CITY, TCEQ, EPA, or other entities beyond those specified in BASIC
SERVICES.
• Meetings or telephone calls with potential or actual protestants, or the development of
public information or strategies to aid in avoiding protests.
• Prepare to serve or serve as an expert witness on behalf of CITY.
• Provide technical or procedural support if proposed permits are protested. Including
preparing for or participating in any public meeting or hearing.
• Paying for application fees required by the TCEQ.
• Publication costs of notices in local newspaper(s).
There may be other potential ADDITIONAL SERVICES. Should CITY desire PLUMMER to
perform ADDITIONAL SERVICES, this contract may be amended to accommodate the
additional scope of work and budget.
B-2
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App/2025 Amendment/EXHIBIT B-Engineering Serv,ce.docx
ADDENDUM TO EXHIBIT C
Work Schedule
CITY OF ROUND ROCK
BRUSHY CREEK REGIONAL WASTEWATER SYSTEM —WEST PLANT
TEXAS POLLUTANT DISCHARGE ELIMINATION SYSTEM
DISCHARGE PERMIT MODEL REVIEW
SCHEDULE
PLUMMER will initiate work on BASIC SERVICES upon written authorization to proceed from
the CITY. The following deliverables and schedule are anticipated:
• PLUMMER will request the modeling memo and model parameters from TCEQ upon
receiving authorization.
• PLUMMER will review the model inputs and results within three (3) days of receipt from
TCEQ. PLUMMER will communicate findings to CITY following review of results.
• PLUMMER and CITY will discuss results and next steps, then PLUMMER will
communicate CITY's request to TCEQ.
C-1
https://apaienv.sharepoint.com/sites/WQPermitting_Team/Shared Documents/General/Proposals and Scopes/0982-021-0-1887 City of Round Rock Brushy Creek West Permit
App/EXHIBIT C-Work Schedule.docx
ADDENDUM TO EXHIBIT D
Fee Schedule
Project Name: Brushy Creek Regional Wastewater System-West Plant TPDES Permit Discharge Model Review
Total Total Other
Task Labor Hours Loaded Labor Cost Direct Costs Subconsultants TOTALS
Task 1:TPDES Renewal Permit Application Preparation 13 $3,000.00 $0.00 $0.00 $3,000.00
GRAND TOTAL: 13 $3,000 $0.00 $0.00 $3,000.00
https://apaienv.sharepoint.com/sites/WQPermitting_Team/Shared Documents/General/Proposals and Scopes/0982-021-0-1887 City of Round Rock Brushy Creek West Permit App/2025 Amendment/Exhibit
D-Fee Schedule D-1