GM-20-03-20-086 :e7Z BRUSHY CREEK
REGIONAL UTII_ITYAUTHORITY
A Partnership of COO- Park. Lender. and hound Rock
SUPPLEMENTAL CONTRACT NO.4
TO CONTRACT FOR ENGINEERING SERVICES
FIRM:WALKER PARTNERS/FREESE AND NICHOLS JOINT VENTURE("Engineer")
ADDRESS: 804 Las Cimas Parkway,Suite 150,Austin,TX 78746
PROJECT: BCRUA Phase 2 Raw Water Delivery System
This Supplemental Contract No. 4 to Contract for Engineering Services is made by and between
the BRUSIIY CREEK REGIONAL UTILITY AUTHORITY, INC., hereinafter called
"BCRUA" and Walker Partners//Freese and Nichols Joint Venture, hereinafter called the
"Engineer".
WHEREAS, BCRUA and Engineer executed a Contract for Engineering Services, hereinafter
called the"Contract", on the 28th day of November, 2018 for the BCRUA Phase 2 Raw Water
Delivery System Project in the lump sum amount of$12,518,037.00 for Engineering Services
excluding Task 5.3.1—Geotechnical Investigation;and
WHEREAS, BCRUA and Engineer executed Supplemental Contract No. 1 on April 24,2019 to
amend the scope of services, specifically, Task 6.0, and to increase the compensation by
$75,496.00 to a total lump sum amount of $12,593,533.00 for a total project amount of
$13,697,291.00;and
WHEREAS,BCRUA and Engineer executed Supplemental Contract No. 2 on August 7,2019 to
amend the scope of services, specifically, Task 5.0 — Special Services, and to increase the
compensation by $42,348.00 to a total hunp sum amount of$12,635,881.00 for a total project
amount of$13,739,639.00;and
WHEREAS,BCRUA and Engineer executed Supplemental Contract No. 3 on March 5, 2020 to
amend the scope of services,specifically, Task 6.0—Agency and Stakeholder Coordination, and
to increase the compensation by $47,000.00 to a total hunp sum amount of$12,682,881.00 for a
total project amount of$13,786,639.00; and
WHEREAS, it has become necessary to amend the Contract to modify the provisions for the
scope of services, specifically, Task 6.0—Agency and Stakeholder Coordination,and to increase
the compensation by$18,155.00 to a total lump sum amount of$12,701,036.00 for a total project
amount of$13,804,794.00;
NOW THEREFORE, premises considered, BCRUA and the Engineer agree that said Contract
is amended as follows:
Supplemental Contract Rev.03/2011
0140.4634-47;00441484 215829
(J' Al, zv-03-2-D -CJ�
I.
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.
Il.
Article 4, Compensation (1) Lump Sum and Exhibit D, Fee Schedule shall be amended by
increasing by $18,155.00 the lump sum amount payable under the Contract for Engineering
Services, specifically, Task 6.0 — Agency and Stakeholder Coordination to a total lump sum
amount of $12,701,036.00 for a total Project amount of $13,804,794.00, as shown by the
attached Addendum to Exhibit D.
IN WITNESS WHEREOF, BCRUA and the Engineer have executed this Supplemental
Contract in duplicate.
WALKER PARTNERS&RE,ESE AND NICHOLS JOINT VENTURE
By:
Drew Hardin
$ March 20, 2020
Date
BRUSHY CREEK REGIONAL UTILITY AUTHORITY,INC.
By. a.e.,to
Karen Bondy, General Manager
03/20/2020
Date
APPROV D tS TO FO
By: Lt'd
.
Ste'MrGj. Sheets,BCRUA Attorney
2
ADDENDUM TO EXHIBIT B
ENGINEERING SERVICES
GENERAL
The purpose of Supplemental Amendment No. 41s to complete additional hydrologic modeling
requested by the Fort Worth District of the U.S.Army Corps of Engineers(USACE)at a meeting on
January 12, 2020. The evaluation will be documented in a report that will supplement information
previously submitted in the Tier 1 Hydrologic Modeling Guidelines report to the USACE. The analysis
will employ a spreadsheet model of Lake Travis using the following assumptions:
■ Historical hydrology(inflows and evaporation)from 2000 to 2016(includes drought-of-
record from 2010 to 2015)
■ Historical and adjusted demands for BCRUA and customers reflecting the following
conditions:
a. Historical demands, which ranged from 8,388 ac-ft/yr inf 2000 to 23,058 ac-ft/yr in
2016.
b. Historical demands with estimated demands during the period from September 2013
to September 2015 when the BCRUA intake was shut down. The estimated demands
assume that there was no shut down due to low lake levels. The estimated demands
will be interpolated based on historical trends from 2000 to 2018.
c. Expected demands just prior to construction of the Phase 2 intake. This is assumed to
be 46,521 ac-ft/yr with a peak diversion rate of 70.5 MGD(Section 1.B.1.1 of the HMG
Tier 1 Supplemental Report). The expected demands scenario will be run with(1)a full
or partial shutdown of BCRUA and customer city diversions around a Lake Travis
elevation of 623 feet and(2)no shut down for low lake levels.
d. Maximum theoretical demands from the existing intakes, which is assumed to be
76,469 ac-ft/yr(Section 1.B.1.1 of the HMG Tier Supplemental Report). This demand
scenario assumes a near constant diversion of 70.5 MGD.
e. Full expected demands with the proposed Phase 2 intake. This is expected to be 95,397
ac-ft/yr with a peak diversion rate of 144.7 MGD. Higher maximum diversion rates(up
to 150 MGD)or higher annual volumes(144.7 MGD maximum but with a lower
peaking factor)will be considered as well. !f there are no appreciable impacts, a higher
diversion amount may be suggested.
■ No changes in pumping capacity due to low lake levels. This is a conservative assumption
that will overestimate potential impacts during critical times. This will be stated in the final
memorandum.
■ Historical demands for all other users, including direct diversions from Lake Travis as well as
water released for downstream use(firm,interruptible and environmental flows)
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■ Flood releases may be adjusted to reflect changes in flood operation due to additional
empty storage
■ The analyses will use a calibrated Lake Travis model based on historical inflows,
evaporation, demands(lakeside and releases), and flood releases from previous
authorization.
BASIC SCOPE OF SERVICES
Task 6.0-Agency and Stakeholder Coordination
Insert Task 6.4.9 as follows:
6.4.9 Supplemental HMG Tier 1 Modeling for Section 404 authorization.
6.4.9.1 Run five scenarios to identify and quantify the impacts associated with
the Phase 2 intake based on the demand scenarios discussed in the
assumptions section.
6.4.9.1.1 Historical demands. Per USACE guidance,this scenario is the
baseline to which all other scenarios will be compared.
6.4.9.1.2 Adjusted historical demands assuming Owner was able to keep
diverting during low lake levels.This scenario will quantify the
portion of the impacts of the Phase 2 intake associated with the
increased reliability during low lake levels.
6.4.9.1.3 Adjusted Owner and customer demands to reflect expected
Owner operations just prior to construction of Phase 2, both with
and without loss of the Owner's floating intake during low lake
levels.This scenario will quantify the impacts based on conditions
with the expected level of demands that will be encountered
before initiating the project. Unlike the two prior scenarios,
Owner and customer demands will be assumed constant for every
year in the simulation period.
6.4.9.1.4 Adjusted Owner and customer demands to reflect maximum use
of existing floating intakes.This scenario reflects the theoretical
maximum use of the existing intakes as described in Section
1.13.1.1 of the HMG Tier 1 Supplemental Report.These demands
will be assumed constant for every year in the simulation period.
6.4.9.1.5 Adjusted Owner and customer demands to reflect full expected
use of the Phase 2 intake. This scenario reflects the ultimate
development of the Phase 2 project.The demands will be
assumed constant for every year In the simulation periods.This
scenario will consider potential increases in maximum diversion
rate or annual amount for inclusion in the final USACE submittal.
6.4.9.2 Analyze changes in diversions, reservoir outflows, and evaporation
associated with each scenario to quantify the source of water for the
new diversions associated with the Phase 2 intake.This will meet the
USACE requirement to identify how the new project changes the use of
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flows from current conditions. It will also quantify changes in reservoir
outflows.
6.4.9.3 Write a draft technical memorandum describing the analyses.The
memorandum will include model files and model documentation.
Provide to Owner and counsel for review.Address comments and
finalize.Technical memorandum to be provided in PDF file format for
both draft and final deliverables. Provide technical memorandum to the
USACE for review and comment.
6.4.9.4 Meet with USACE to discuss memorandum and next steps in the
permitting process.This task will only be performed if authorized by
Owner.
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ADDENDUM TO EXHIBIT C
WORK SCHEDULE
The draft technical memorandum will be submitted within two weeks of execution of this
supplemental amendment. The final technical memorandum will be submitted within two weeks
of receiving Owner comments.
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ADDENDUM TO EXHIBIT D
FEE SCHEDULE
Total compensation for services under Supplemental Amendment No. 4 is estimated to be $18,155.
Owner shall pay Engineer for services under Supplemental Amendment No. 4 on the basis of Lump
Sum as set forth in Exhibit D.
Total compensation for Task 6.0 — Agency and Stakeholder shall be increased by an amount of
$18,155 to$1,365,096.
Total compensation for the Project shall be adjusted to$13,804,794.
Task Description Fee
Task 6.4.9.1—6.4.9.3(Modeling and TM) $15,394
Tasl<6.4.9.4(USACE Meeting) $2,761
Total $18,155
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