Item 4JItem 4J
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M E M O R A N D U M
(August 6, 2019)
To: Shana Yelverton, City Manager
From: Rob Cohen, Director of Public Works
Subject: Approve an Engineering Services Agreement (ESA) with Halff
Associates, Inc. to provide engineering services for the
Kirkwood Branch Watershed Study project in an amount not to
exceed $163,800.
Action
Requested: Approve an Engineering Services Agreement (ESA) with Halff
Associates, Inc. to provide engineering services for the Kirkwood
Branch Watershed Study project in an amount not to exceed
$163,800.
Background
Information: In recent years, a number of significant drainage issues have been
observed within the Kirkwood Branch watershed which includes
portions of the City of Southlake, City of Keller, Town of Westlake
and the Town of Trophy Club. The most notable occurred in late
2018, when North White Chapel Boulevard was overtopped by
flood waters causing severe damage to the storm culverts as well
as the road surface. The road was closed for six months for repairs
causing major travel inconveniences, as well as safety concerns for
the 300+ households north of the crossing due to impacts to
emergency response times.
North White Chapel Boulevard will likely be overtopped again at
Kirkwood Branch due to its elevation relative to the allowable
flowage easement for Grapevine Lake. This study will provide new
detailed hydrologic and hydraulic modeling needed to make
recommendations for improvements to eliminate future flooding of
the roadway. Staff will work with the design team to evaluate
alternatives and bring proposal forward to Council for cons ideration
prior to entering into a contract for design, bid and construction
services.
The limits of this study will also include the tributaries of South
Kirkwood and Higgins Branches. Other deliverables include
conceptual alternative solutions that will reduce or eliminate
documented flooding problems along the North Peytonville and
Shady Oaks corridors based on fully developed conditions. Halff
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will provide estimates of probable cost for each alternative and will
assist staff in evaluating each. Staff will bring proposals forward to
Council for consideration for future projects and funding.
Financial
Considerations: Funding for the Kirkwood Branch Watershed Study is provided in
the Storm Water Utility System Fund from FY 2015 to FY 2019
Capital Improvement Program budgets. This agreement is within
the project budget.
Strategic Link: This item links to the City’s Strategy Map strategic focus areas of
Safety & Security, Mobility and Infrastructure. It specifically relates
to the City’s Corporate Objectives, C1: Achieve the Highest
Standards of Safety & Security, C2: Provide Travel Convenience
Within City & Region, and F2: Invest to Provide & Maintain High
Quality Public Assets. The Critical Business Outcomes are, CB02:
Enhance Mobility Through Aggressive Traffic Management
Initiatives and Capital Project Implementation and CB05: Improve
Quality of Life Through Progressive Implementation of Southlake’s
Comprehensive Plan Recommendations.
Citizen Input/
Board Review: None.
Legal
Review: The proposed agreement is a standard agreement that the City
Attorney has reviewed and approved.
Alternatives: The City Council may approve or deny the agreement.
Staff
Recommendation: Approve an Engineering Services Agreement (ESA) with Halff
Associates, Inc. to provide engineering services for the Kirkwood
Branch Watershed Study project in an amount not to exceed
$163,800.
Supporting
Documents: Attachment A: Engineering Services Agreement
Attachment B: Watershed Exhibit
Staff
Contact: Rob Cohen, Director of Public Works
Kyle D. Hogue, P.E., Deputy Director/City Engineer
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AGREEMENT FOR ENGINEERING SERVICES
THIS AGREEMENT is made this _____ day of ____________, 2019 by and
between the City of Southlake , Texas (hereinafter referred to as “CITY”), and Halff
Associates, Inc. (hereinafter referred to as “ENGINEER”).
WHEREAS, CITY contemplates the need to make possible future drainage
improvements within the Kirkwood Branch watershed. This project is to be known as
the Kirkwood Branch Watershed Study project and hereinafter referred to as the
“Project”.
WHEREAS , ENGINEER is qualified, able, and desirous of performing the
necessary engineering work upon which the Project is based and is willing and able to
work with CITY staff to organize and coordinate the professional services necessary to
complete the Project.
NOW, THEREFORE, CITY engages ENGINEER to perform, and ENGINEER
agrees to perform, the engineering work for the Project, as more fully described herein
below, and CITY agrees to pay as compensation, and ENGINEER agrees to accept as
compensation, the payments on the dates and in the amounts herein specified, all in
accordance with the terms more fully set out below and as provided in Proposal I which
is attached hereto and incorporated by reference as if fully set forth herein.
I. ARTICLE
ENGINEERING SERVICES
A. Scope of Work
ENGINEER will provide the supervision, direction, personnel and equipment to
perform the engineering Services outlined in Proposal I in accordance with the terms
set forth in this Agreement and in Proposal I.
B. Definitions
Services refer to the professional services performed by ENGINEER pursuant to
this Agreement.
C. Changes
CITY, without invalidating the Agreement, may order changes within the general
scope of the work required by the Agreement by altering, ad ding to and/or deducting
from the work to be performed. If any change causes an increase or decrease in
ENGINEER’s cost of, or the time required for, the performance of any part of the
Services under the Agreement, an equitable adjustment will be made by mutual
agreement and this Agreement shall be modified in writing accordingly.
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D. Coordination w ith Owner
The CITY shall make available to ENGINEER for use in performing Services
hereunder all existing plans, maps, field notes, statistics computations an d other data in
the CITY’s possession relative to existing facilities and to the Project.
E. Site and Local Conditions
ENGINEER has the right to examine the site in order to become acquainted with
local conditions and accepts conditions at the site un less otherwise noted in writing to
the CITY. Any coordination or scheduling of work by CITY shall not relieve ENGINEER
from its responsibilities specified hereunder. Necessary arrangement for access to any
site by ENGINEER’s employees will be made with CITY.
F. Assignment and Subcontractors/Third Party Rights
The rights and obligations covered herein are personal to each party hereto and
not to any third party and for this reason neither this Agreement nor any contract
hereunder shall be assigned by either party in whole or in part; nor shall ENGINEER
subcontract any of its obligations under this Agreement without the prior written consent
of CITY.
G. Independent Contractor
ENGINEER covenants and agrees that it will perform the work hereunder as an
independent contractor, and not as an officer, agent, servant, or employee of CITY; that
ENGINEER shall have exclusive control of and exclusive right to control the details o f
the work performed hereunder, and all persons performing same, and shall be sole ly
responsible for the acts and omissions of its officers, agents, employees, contractors,
subcontractors, and consultants; that the doctrine of respondent superior shall not apply
as between CITY and ENGINEER, its officers, agents, employees, contractors,
subcontractors, and consultants, and nothing herein shall be construed as creating a
partnership or joint enterprise between CITY and ENGINEER.
H. Disclosure
By signature of this contract, ENGINEER warrants to CITY that it has made full
disclosure in writing of any existing conflicts of interest or potential conflicts of interest,
including personal financial interests, direct or indirect, in property abutting the
proposed Project and business relations with abutting property owners. ENGINEER
further warrants that it will make disclosure in writing of any conflicts of interest that
develop subsequent to the signing of this contract and prior to final payment under the
contract. Finally, Engineer warrants that it has submitted to the City a completed
Conflicts of Interest Questionnaire as required by Chapter 176 of the Texas Local
Government Code.
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I. Approval by CITY
Approval by CITY of this Agreement shall not constitute or be deemed to be a
release of the responsibility and liability of ENGINEER, i ts officers, agents, employees,
and subcontractors for the accuracy and competency of the Services performed under
this Agreement, including but not limited to surveys, designs, working drawings and
specifications and other engineering documents.
Such approval shall not be deemed to be a waiver or an assumption of such
responsibility and liability by CITY for any negligent act, error, or omission in the
performance of ENGINEER’s professional services or in the conduct or preparation of
the subsurface investigations, surveys, designs, working drawings and specifications or
other engineering documents by ENGINEER, its officers, agents, employees and
subcontractors, it being the intent of the parties that approval by CITY signifies the
CITY’s approval of only the general design concept of the Improvements to be
constructed.
J. Indemnification
ENGINEER SHALL AND DOES HEREBY AGREE TO INDEMNIFY AND HOLD
HARMLESS CITY, ITS OFFICERS, AGENTS, AND EMPLOYEES FROM ANY AND
ALL DAMAGES, LOSS OR LIABILITY OF ANY KIND W HATSOEVER, BY REASON
OF DEATH OR INJURY TO PROPERTY OR PERSON CAUSED BY ANY OMISSION
OR NEGLIGENT ACT OF ENGINEER, ITS OFFICERS, AGENTS, EMPLOYEES,
INVITEES, OR OTHER PERSONS FOR WHOM IT IS LEGALLY LIABLE, WITH
REGARD TO THE PERFORMANCE OF THIS CONTRACT, A ND ENGINEER WILL,
AT ITS COST AND EXPENSE, DEFEND, PAY ON BEHALF OF, AND PROTECT CITY
AND ITS OFFICERS, AGENTS, AND EMPLOYEES AGAINST ANY AND ALL SUCH
CLAIMS AND DEMANDS. THE PROVISIONS OF THIS SECTION ARE SUBJECT TO
THE LIMITATIONS OF TEXAS LOCAL GOVERNMENT CODE SECTION 271.904
AND SHALL BE CONSTRUED TO THAT EFFECT.
K. No Third Party Beneficiary
For purposes of this Agreement, including its intended operation and effect, the
parties specifically agree and contract that: (1) this Agreement only affects
matters/disputes between the parties to this Agreement, and is in no way intended by
the parties to benefit or otherwise affect any third person or entity (except the
indemnitees identified or described in Article I, Section J., above), notwithstanding the
fact that such third person or entities may be in a contractual relationship with CITY and
ENGINEER, or both; and (2) the terms of this Agreement are not intended to release,
either by contract or operation of law, any third person or entity from obligati ons they
owe to either CITY or ENGINEER.
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L. Successors and Assigns
CITY and ENGINEER each bind themselves and their successors, executors,
administrators and assigns to the other party to this Agreement and to the successors,
executors, administrators and assigns of such other party with respect to all covenants
of this Agreement. Neither CITY nor ENGINEER shall assign or transfer its interest in
this Agreement without prior written consent of the other.
II. ARTICLE
CITY’S RESPONSIBILITIES
CITY will:
1. Provide full information as to CITY’s requirements for the Project;
2. Assist ENGINEER by placing at ENGINEER’s disposal all information in
CITY’s control or knowledge which is pertinent to the Project, including
executed right-of-way easements and final field survey data;
3. Examine all work presented by ENGINEER and respond within
reasonable time and in writing to the material submitted by ENGINEER;
4. Pay all costs incident to advertising for obtaining bids or proposals from
Contractors;
5. Give prompt written notice to ENGINEER whenever CITY observes or
otherwise becomes aware of any defect in ENGINEER’s work or in
Contractor’s work;
6. Designate in writing a person to act as its representative with respect to
this Agreement, such person having complete authority to transmit
instructions, receive information, and make or interpret the CITY’s
decisions;
7. Provide all information and criteria as to the CITY’s requirements,
objectives, and expectations for the Project including all numeri cal criteria
that are to be met and all standards of development, design, or
construction.
8. Provide to the ENGINEER all previous studies, plans, or other documents
pertaining to the Project and all new data reasonably necessary in the
ENGINEER’s opinion, such as site survey and engineering data,
environmental impact assessments or statements, zoning or other land
use regulations, etc., upon all of which the ENGINEER may rely; and
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9. Arrange for access to the site and other private or public property as
required for the ENGINEER to provide its services.
III. ARTICLE
COMPENSATION FOR ENGINEERING SERVICES
The CITY shall compensate ENGINEER for services rendered under this
Agreement, in accordance with the following:
For the completion of the work contemplated in Proposal I, the ENGINEER shall
be paid on a lump sum basis in the amount of $163,800 for Engineering Service as
billed monthly by ENGINEER.
IV. ARTICLE
TIMES OF BILLING AND PAYMENT
The ENGINEER shall bill CITY monthly for any services and expenses incurred
in accordance with the work performed subject to the limits set out in Article III.
Payment shall be due within thirty (30) days of receipt by CITY of a properly prepared
and correct invoice from ENGINEER. ENGINEER’s invoices shall be acco mpanied by
such records or other written proof as CITY deems necessary to verify the billings.
Invoices shall be made to City Finance Department’s office at 1400 Main Street,
Suite 440, Southlake, Texas 76092.
If CITY fails to make payment due ENGINEER within thirty (30) days of the day
when payment for services and expenses is due under the terms of this Agreement,
ENGINEER shall be entitled to interest on such unpaid sums at the rate provided in
Chapter 2251 of the Texas Government Code.
V. ARTICLE
AD DITIONAL ENGINEERING SERVICES
In addition to performing the engineering services set out in Article I, hereof,
ENGINEER agrees to perform additional services as requested by CITY from time to
time and CITY agrees to compensate ENGINEER for such services in accordance with
ENGINEER’s standard hourly fee and expenses (see Proposal I) for actual time
expended and actual out-of-pocket sums expended, such services to be one or more of
the following:
1. Make or prepare detailed description of sites, maps, or drawings related
thereto and outside the scope of the Project;
2. Appearances before courts or boards on matters of litigation or hearings
related to the Project;
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3. Preparation of environmental impact assessments or statements for any
governmental agency;
4. Miscellaneous engineering work for CITY not related to the Project;
5. To provide resident project construction inspection, unless such
inspection is not required, in writing, by the CITY;
6. Other services agreed to by the parties in writing and incorporated herein.
VI. ARTICLE
STANDARD OF CARE
In performing its professional services, the ENGINEER will use that degree of
care and skill ordinarily exercised, under similar circumstances, by reputable members
of its profession in the same locality at the time the services are provided and in
accordance with any applicable governmental laws, regulations and ordinances.
VII. ARTICLE
PERIOD OF SERVICE
This Agreement shall be effective upon execution by CITY and ENGINEER, and
shall remain in force until work is completed on the Project or until terminated under the
provisions hereinafter provided in Article VIII.
VIII. ARTICLE
TERMINATION
The CITY may terminate this Agreement at any time for convenience , with or
without cause by giving written notice to the ENGINEER. Such termination may be
made effective on such future date as agreed by the parties, but absent such
agreement shall be immediate. Upon receipt of such notice the ENGINEER shall
immediately discontinue all services and work and the pl acing of all orders or the
entering into contracts for supplies, assistance, facilities, and materials in connection
with the performance of this Agreement and shall proceed to cancel promptly all
existing contracts insofar as they are chargeable to this A greement.
The ENGINEER, upon termination, shall be paid for all services rendered
through the date of termination together with any additional reimbursable expense then
due.
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IX. ARTICLE
OWNERSHIP OF DOCUMENTS
1. All completed or partially completed reports prepared under this
Agreement, including the original drawings in both paper and electronic
formats, shall become the property of CITY if this Agreement is
terminated. Upon completion and payment of the contract, the final
design, drawings, specifications and documents in both paper and
electronic formats shall be owned by CITY.
2. Reuse, change or alteration by CITY or others acting by or on behalf of
CITY of such documents without the permission of ENGINEER shall be at
CITY’s sole risk.
X. ARTICLE
INSURANCE
ENGINEER shall carry and maintain at all times relevant hereto, at ENGINEER’s
expense, insurance of the type and of minimum coverage limits as follows:
1. Workers Compensation - Statutory Employer’s Liability - Limits as
required by the State of Texas.
2. Comprehensive General Liability, Bodily Injury and Property Damage
including contractual liability in a combined single limit - $500,000 per
occurrence.
3. Comprehensive Automotive Liability, Bodily Injury and Property Damage
in a combined single limit - $1,000,000 per accident.
Certificates of insurance for the above coverage in a form acceptable to CITY,
evidencing the coverage required above, shall be provided to CITY within ten (10)
business days after execution of this Agreement and prior to issuing Notice to Proceed.
Such certificates shall provide that the insurer will give CITY not less than ten (10) days
notice of any material changes in or cancellation of coverage. In the event any
subcontractor of ENGINEER, with or witho ut CITY’s consent, provides or renders
services under this Agreement, ENGINEER shall ensure that the subcontractor’s
services are covered by the same insurance limits as set forth above.
ENGINEER shall not commence work under this Agreement until it has obtained
Professional Liability (Errors and Omissions) Insurance as required hereunder and such
insurance coverage has been approved by CITY. Such insurance shall be in the
minimum amount of $1,000,000 and shall include coverage of Contractually Assumed
Liability. The insurance coverage prescribed herein shall be maintained until one (1)
year after CITY’s acceptance of the construction project and shall not be canceled
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without prior written notice to CITY. In this connection, upon the signing and return of
this Agreement by ENGINEER, a Certificate of Insurance shall be furnished to CITY as
evidence that the insurance coverage required herein has been obtained by
ENGINEER, and such certificate shall contain the provision that such insurance shall
not be cancelled or modified without thirty (30) days prior written notice to CITY.
ENGINEER shall notify CITY within ten (10) days of any modification or alteration in
such Professional Liability (Errors and Omissions) Insurance.
XI. ARTICLE
AUTHORIZATION, PROGRESS AND COMPLETION
CITY and ENGINEER agree that the Project is planned to be completed as
described in attached project schedule. ENGINEER shall employ manpower and other
resources, and use professional skill and diligence to meet the schedule; however,
ENGINEER shall not be responsible for schedule delays resulting from conditions
beyond its control. By mutual agreement, CITY and ENGINEER may modify the
Project schedule during the course of the Project and if such modifications affect
ENGINEER’s compensation, it shall be modified accordingly, subject to CITY’s
approval.
It is understood that this Agreement contemplates full and complete engineering
services for this Project, including any and all Services necessary to complete the work.
For additional Engineering Services, the authorization by CITY shall be in writing and
shall include the definition of the services to be provided, the schedule for commencing
and completing the services, and the basis for compensation as agreed upon by CITY
and ENGINEER.
XII. ARTICLE
NOTICE
Any notice required under this Agreement will be in writing and given either
personally, by registered or certified mail, return receipt requested, or by a nationally
recognized overnight courier service, addressed to the parties as follows:
If to CITY: Laura Hill
Mayor
City of Southlake
1400 Main Street, Suite 270
Southlake, Texas 76092
Phone: 817-748-8016
Fax: 817-748-8270
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If to ENGINEER: Scott A. Rushing, P.E.
Water Resources Team Leader
Halff Associates, Inc.
4000 Fossil Creek Blvd.
Fort Worth, Texas 76137
Phone: 817-847-1422
Fax: 817-232-9784
All notice shall be effective upon the date of receipt.
XIII. ARTICLE
SEVERABILITY
In the event that any provision of this Agreement shall be found to be void or
unenforceable, such finding shall not be construed to render any other provisions of this
Agreement either void or unenforceable. All provisions, which are void or
unenforceable, shall not substantially af fect the rights or obligations granted to or
undertaken by either party.
XIV. ARTICLE
VENUE-LAW
Venue of any suit or cause of action under this Agreement shall lie exclusively in
Tarrant County, Texas. This Agreement shall be construed in accordance with the laws
of the State of Texas.
IN WITNESS WHEREOF the parties have caused this Agreement to be
executed in two equal originals on the date and year first above mentioned.
CITY OF SOUTHLAKE:
By: _________________________________
Laura Hill, Mayor
ATTEST:
By: _________________________________
City Secretary
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ENGINEER: HALFF ASSOCIATES, INC.
By: ____________________________________
Brain Haynes, P.E., Vice President
THE STATE OF TEXAS §
COUNTY OF TARRANT §
Before me on this day personally appeared ______________ known to me [or
proved to me on the oath of _______________ or through ___________________
(description of identity card or other document)] to be the person whose name is
subscribed to the foregoing instrument and that he/she i s the duly authorized
______________________ of _____________________________, and acknowledged
to me that he/she executed the same for the purposes and consideration therein
expressed.
Given under my hand and seal of office this _____ day of __________,
A.D.______.
______________________________________
(SEAL) Notary Public, State of Texas
____________________________________
Notary’s Name Printed
Kirkwood Branch Watershed Study Page 1 of 7
July 10, 2019
P35692.001
Mr. Kyle Hogue, PE
City of Southlake
City Engineer/Deputy Director
1400 Main Street, Suite 320
Southlake, Texas 76092
RE: Kirkwood Branch Watershed Study Proposal
Dear Mr. Hogue,
The City of Southlake has requested Halff Associates, Inc. (Halff) to provide professional engineering
services for the Kirkwood Branch Watershed Study. This proposal includes the Project Overview,
Study Objectives, Scope of Work, Exclusions, Project Fees, Schedule and Exhibit. The following
attachments are included in the proposal:
Attachment A Project Schedule
Attachment B Project Exhibit
Project Overview
The City of Southlake has observed flood waters from Kirkwood Branch frequently overtop North
White Chapel Road over the past several years. The City has also observed flooding along Higgins
Branch, which is a tributary to Kirkwood Branch. The Kirkwood Branch watershed study will provide
new detailed hydrologic and hydraulic modeling to support of the objectives below. The watershed
study limits can be seen in Attachment B, which includes portions of the City of Southlake, City of
Keller, Town of West Lake, and the Town of Trophy Club.
Study Objectives
1. Assist City CIP Planning: Develop conceptual alternative bridge/culvert improvements for
North White Chapel Road along Kirkwood Branch and South Kirkwood Branch including
estimates of probable cost. The goal of the improvements will be 100-year level of service
with freeboard per City drainage criteria.
2. Identify Flood Risk: Prepare hydrologic and hydraulic information adequate to define and
quantify the flooding problems within the Higgins Branch watershed.
3. Evaluate Conceptual Drainage Improvements: Formulate and analyze conceptual
alternative solutions that will reduce or eliminate flooding problems within the Higgins
Branch watershed.
Kirkwood Branch Watershed Study Page 2 of 7
Scope of Work
Below is the detailed scope of work per task.
Task 1 – Data Collection
A. Data Collection
1. Utilize 2009 TNRIS LIDAR topography or more recent City LIDAR if available.
2. Obtain “as-built” plans for channel and bridge/culvert improvements as specified in Task
3 below.
3. Obtain GIS shapefiles from the City.
4. Obtain available zoning maps, land use maps, soils data and thoroughfare plans in the
project area from the City of Southlake, City of Keller, Town of West Lake, Town of
Trophy Club , NCTCOG, NRCS and others. Note: This scope assumes future land use or
zoning maps are available from the City of Southlake, City of Westlake, City of Keller,
and NCTCOG to be used as a base in preparing the hydrologic land use maps.
5. Collect applicable past studies and reports (including LOMRs), disaster files, complaint
files, rainfall records, records of street closures or rescues/deaths, and related flooding
data from the City.
6. Collect any technical data available from FEMA Region VI in regards to the current
effective hydraulic and hydrologic models.
7. Collect any technical data on proposed projects and/or roadway improvements along
streams in the project area.
B. Field Work
1. Conduct field reconnaissance to identify, map, and photograph the following: existing
channel and bridge/culvert conditions (North White Chapel Road along Kirkwood Branch
and South Kirkwood Branch and Plantation Drive, Dove Road, Peytonville Ave, Cross
Timbers Drive and Post Oak Trail along Higgins Branch), structures within the existing
100-year floodplain, and other physical features that could affect conveyance.
2. Field Surveys – To be performed to obtain existing information on physical features
within the study reaches.
a. Structure surveys will be performed for Plantation Drive and Dove Road along
Higgins Branch and North White Chapel Road along South Kirkwood Branch.
b. As-built plans will be utilized for the recently reconstructed North White Chapel
Road along Kirkwood Branch.
c. 10 Channel surveys will be performed along Higgins Branch to confirm and
supplement 2009 TNRIS topography. The 2009 TNRIS data should provide
sufficient elevation data for the project area which mainly consists of improved
channels and minimal vegetation. If the TNRIS topography is not sufficient, then
additional surveying services can be provided outside of this scope.
Kirkwood Branch Watershed Study Page 3 of 7
d. Shady Oaks detention within the Higgins Branch watershed, will be
photographed, surveyed and compared to as-built plans.
e. Key culvert crossings and bar ditches along Peytonville Ave, Cross Timbers Drive,
and Post Oak Trail will be photographed and surveyed in support of the 2D
analysis described under Task 4.
Task 2 – Hydrologic Analysis
Halff will prepare an ultimate conditions hydrologic model of the Kirkwood Branch
watershed using the latest version of the U.S. Army Corps of Engineers HEC-HMS software.
Ultimate conditions are recommended for this study to support conceptual alternative
improvement design of North White Chapel Road described under Task 4 and since the
Higgins Branch watershed is almost entirely developed.
A. Hydrologic Analysis
1. Utilize 2009 TNRIS LIDAR topographic maps to delineate watershed limits and sub-
basins. Sub-basin breaks will be limited to major roadways and confluences listed in the
FEMA FIS Summary of Discharges table within the Tarrant County FIS report along
Kirkwood Branch and South Kirkwood Branch.
2. Compare delineated watersheds with existing storm drain GIS shapefiles to verify sub-
basin alignments. Prepare hydrologic watershed map.
3. Develop a fully developed conditions hydrologic land use map based on build-out zoning
and land use data. Calculate fully developed conditions land use hydrologic parameters.
4. Prepare modified puls flood routing data from hydraulic models described under Task 3.
Compute ultimate conditions peak discharges for the 2-, 10-, 50-, 100-, and 500-year
storm events utilizing NOAA Atlas 14 rainfall data.
Task 3 – Hydraulic Analysis
This scope includes the tasks necessary to determine water surface elevations and limits of
flooding for the frequency storm events specified in Task 2. The hydraulic study limits are
defined below for each study stream and can be seen in Attachment B.
Study Limits:
• Kirkwood Branch: From approximately 2,000 feet downstream of North White
Chapel Road upstream to State Highway 114.
• South Fork Kirkwood Branch: From the confluence of Kirkwood Branch upstream to
State Highway 114.
• Higgins Branch: From confluence with Kirkwood Branch and extending 1.5 miles
upstream to the limits of the effective FEMA detailed mapping.
A. Existing Conditions Hydraulic Analysis with Ultimate Conditions Hydrology
1. Develop existing conditions hydraulic models for the study streams in HEC-RAS utilizing
2009 TNRIS LIDAR, supplemented with field survey cross-sections.
Kirkwood Branch Watershed Study Page 4 of 7
2. Incorporate bridge/culvert as-built plans and field surveyed data into hydraulic model.
All major roadway crossings along Kirkwood Branch and South Fork Kirkwood Branch
(other than North White Chapel Road) will be based on the effective FEMA model or
field measurements collected by Halff Associates if the major crossing is not within the
FEMA model.
3. Utilize normal depth boundary conditions along Kirkwood Branch. A known water
surface boundary condition will also be simulated for comparison based on 100-year still
water elevation from Grapevine Lake. A junction will be used at the confluence of South
Fork Kirkwood Branch with Kirkwood Branch. Normal depth boundary conditions will be
applied along Higgins Branch.
4. The FEMA effective model upstream of State Highway 114 for Kirkwood Branch and
South Fork Kirkwood Branch will be utilized as a routing model in support of the
Hydrologic Modeling described above. Modified Puls routing data along Higgins Branch
and downstream of State Highway 114 along Kirkwood Branch and South Fork Kirkwood
Branch will be based on the existing conditions hydraulic models developed as part of
this study.
5. Execute existing conditions flood profiles based on ultimate conditions hydrology for the
2-, 10-, 50-, 100-, and 500-year storm events.
6. Delineate ultimate conditions 100-year and 500-year floodplain mapping in GIS format
for Higgins Branch and ultimate conditions 100-year mapping for Kirkwood Branch and
South Fork Kirkwood branch based on the study limits described above.
Task 4 – 2D Study of complex overflow Shady Oaks Subdivision along Peytonville Ave to unnamed
Tributary of Higgins Brach (Post Oak Trail)
This scope includes the tasks necessary to determine Base Level Engineering (BLE) water
surface elevations and limits of flooding for the frequency storm events specified in Task 2.
The study reaches will include Unnamed Tributary (near Post Oak Trail) at the confluence
with Higgins Branch extending to Peytonville Ave.
Refer to Attachment B for a map showing the streams and the extents of the study reaches.
1. Develop existing conditions 2D hydraulic model utilizing InfoWorks ICM and 2009 TNRIS
LIDAR (or latest available LiDAR provided by the City), supplemented with field survey
described under Task 1.
2. Execute existing conditions flood profiles for the 2-, 10-, 50-, 100-, and 500-year storm
events.
3. Delineate the limits of the existing conditions hydraulic model for the 100-year and 500-
year floodplain in GIS format.
4. Compare existing conditions floodplain to existing City of Southlake drainage
easements.
Kirkwood Branch Watershed Study Page 5 of 7
Task 5 – Flooding Assessment
Flooding Assessment - Utilizing the floodplains and profiles, identify the locations of potential flood
damage and quantify the flooding problems along Higgins branch (i.e. number of structures in the
floodplain).
A. Identify the Flooding Problems
1. Based on the calculated flood elevations and delineated floodplains, determine the
structures inundated by each of the modeled storm events.
2. Based on the fully developed conditions analysis and citizen drainage complaints,
identify areas of needed improvements, including undersized bridge/culvert structures,
undersized improved channel sections, and flooded overbank areas
Task 6 – Conceptual Alternative Analysis
1. North White Chapel Road - Halff will prepare up to three (3) conceptual alternative
bridge/culvert improvements for North White Chapel Road along Kirkwood Branch and
South Fork Kirkwood Branch including any required mitigation. The goal of the
improvements will be 100-year level of service with freeboard per City drainage criteria.
5. Peytonville 2D Study Area – Halff will prepare up to three (3) conceptual alternative
solutions that will reduce or eliminate identified flooding problems within the 2D study
limits.
2. Higgins Branch – Halff will prepare up to three (3) conceptual alternative solutions that
will reduce or eliminate identified flooding problems along Higgins Branch.
3. Perform preliminary jurisdictional determination to identify and map the limits of
waters of the United States along North White Chapel Road. A field investigation will be
performed and a brief memorandum summarizing methodology and findings will be
produced for inclusion in the preliminary jurisdictional determination. A final
jurisdictional determination is not included in this scope or work but will need to be
performed once the permanent improvements at North White Chapel Road are
determined.
4. Coordinate with USACE to discuss conceptual alternatives through flowage easement at
North White Chapel Road.
5. Perform downstream assessment to check for adverse downstream or upstream
impacts from conceptual alternatives compared to the existing conditions hydraulic
analyses developed as part of this study.
6. Estimates of probable cost will be developed for each conceptual alternative.
7. Develop list of pros/cons for each alternative.
Task 7 – Project Management / Final Report
This scope includes the coordination and communication procedures to be implemented
between the City of Southlake and Halff Associates in completion of this project
A. Project Coordination and Management
Kirkwood Branch Watershed Study Page 6 of 7
1. Conduct one (1) project kickoff meeting with the City of Southlake.
2. Conduct up to three (3) project status meetings with the City of Southlake. Meetings
shall be to update the City on project milestones such as hydrology and hydraulic
results, mapping, etc.
3. Prepare monthly progress reports for City of Southlake identifying work accomplished,
work to be done, and outstanding issues that need attention.
B. Deliverables/Final Report
1. Prepare Drainage Report including procedures, results, and recommendations. The
report will include technical data utilized in preparation of the study in digital format,
including hydrologic and hydraulic models and shapefiles
2. Issue draft report for City staffs’ review
3. Incorporate staff comment revisions into Final Report.
4. Deliver two (2) copies of Final Report to the City of Southlake.
Exclusions
The following services are not included in the scope of work of this proposal. Halff Associates can
provide estimated fees for these services, if needed.
A. FEMA LOMR submittal
B. Elevations Certificates and Field Surveys beyond those listed in this scope
C. Evaluation of alternatives to alleviate flooding beyond those listed in this scope
D. SUE services to locate existing utilities along North White Chapel Road
E. Review of development submittals in the watershed
F. Final Jurisdictional Determination at North White Chapel Road
Kirkwood Branch Watershed Study Page 7 of 7
Fees:
The project will be a Lump Sum fee. Lump sum fee tasks will be billed monthly based on percentage
of work that has been completed. A summary of the professional services fees by task is listed in
the following table.
FEE SUMMARY
Task Description Total
1. Data Collection and Field Work $17,560
2. Hydrologic Analysis $18,500
3. Hydraulic Analysis $32,480
3. 2D Study $21,310
5. Flood Assessment $6,000
6. Conceptual Alternative Analysis $39,100
7. Project Management / Final Report $28,850
TOTAL $163,800
Direct Costs for expenses such as mileage, copies, scans, etc. are included in the lump sum fees.
We appreciate the opportunity to be of service to the City of Southlake. If you have any questions,
please do not hesitate to call me at (817) 764-7487.
Sincerely,
HALFF ASSOCIATES, INC.
Scott A Rushing, PE, CFM
Water Resources Team Leader
C: Levi Hein, PE, CFM
Brian Haynes, PE, CFM
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Kirkwood Branch
South ForkKirkwood Branch
Higgins Branch
Task 42D ModelStudy Area
Task 6North WhiteChapel Road
Southlake
Westlake
Keller
Trophy Club
Kirkwood BranchWatershed
Higgins BranchWatershed
South Fork Kirkwood BranchWatershed
Esri, HERE, Garmin, (c) OpenStreetMap contributors
ATTACHMENT BKIRKWOOD BRANCHWATERSHED STUDY
Legend
Stream Centerline
Hydraulic Study Extents
2D Study Area
Political Boundary
Watershed
Kirkwood Branch
South Fork Kirkwood Branch
Higgins Branch ³NTS