Dupont Wappoo Watershed Improvements Plan

City of Charleston
Dupont Wappoo Watershed Improvements Project
Request for Qualifications
(Design Services)
September 15, 2026
Statement of Qualifications must be received by 2:00 pm (local time) on October 9, 2026
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Table of Contents
SECTION A: NOTICE TO DESIGN TEAMS ........................................................................................................ 1
SECTION B: BACKGROUND DESCRIPTION AND CONCEPTUAL PLAN ............................................................... 2
SECTION C: QUALIFICATIONS, SCOPE OF SERVICES AND SCHEDULE .............................................................. 4
SECTION D: SUBMISSION INSTRUCTIONS .................................................................................................... 10
SECTION E: SELECTION PROCESS ................................................................................................................ 14
ATTACHMENTS
A. Project Location Map
B. 2019 Dupont Wappoo Watershed Master Plan
C. City of Charleston Small Business Enterprise (SBE) Forms and Affidavit

SECTION A: NOTICE TO DESIGN TEAMS
The City of Charleston is seeking an engineering firm to provide professional engineering services for the
Dupont Wappoo Watershed Improvements Project. The project aims to develop and evaluate flood
mitigation improvements within the Dupont Wappoo drainage basin, which encompasses approximately
1,600-acres in the West Ashley area of the City of Charleston. The basin primarily relies on a central
drainage channel to convey stormwater runoff to the Stono River; this channel is constrained by limited
maintenance access, undersized conveyance and storage capacity, and tidally influenced tailwater
conditions.
Through this project, the City of Charleston, in coordination with the U.S. Army Corps of Engineers
(USACE), is looking to evaluate improvements along this drainage channel and associated drainage
infrastructure. The project will assess existing conditions, identify major drainage constraints, develop
conceptual improvement alternatives, and evaluate the alternatives based on flood mitigation
performance, cost, feasibility, property and environmental impacts, and potential for phased or
standalone construction.
The City has identified potential improvement strategies that may be evaluated through this project to
help reduce flooding in the drainage basin, including:
* Improve existing drainage ditches and channels either through re-naturalized stream channels or
increased conveyance capacity;
* Replace and upsize existing undersized culverts and pipes; and
* Consider public access and pedestrian mobility components where appropriate.
The project design will be completed in two phases; this RFQ is for Phase One services only. Phase One
services are intended to develop a conceptual preliminary engineering and planning package for transfer
to USACE for use in future Phase Two services, which will include final design, permitting, and construction
documents. Phase One services will generally include the following:
1. Preliminary Site Assessment: Conduct a high-level existing conditions assessment necessary to
support preliminary project designs.
2. Preliminary Engineering: Develop a conceptual-level hydrologic and hydraulic model and evaluate
conceptual improvement alternatives.
3. Regulatory and Permitting Coordination: Review applicable regulatory and permitting
requirements and begin selected coordination with relevant agencies and utility providers where
necessary to inform the conceptual designs.
The Consultant will prepare a Phase One Design Package documenting the conceptual alternatives and
supporting analyses, modeling, conceptual opinions of cost, and other key implementation
considerations. The package will be provided to USACE and its selected design consultant to support
advancement of the recommended improvements into final design. The Phase One Consultant will
participate in a project handoff meeting with the CITY and USACE. With the exception of this limited hand-
off coordination, Phase Two services are not included in this scope of work.
Please contact the CITY Project Manager Jordyn Mallett at 843-579-6419 or mallettj@charleston-sc.gov
with any questions regarding the project. Please contact Ruth Jordan at 843-724-7434 or
jordanr@charleston-sc.gov with questions regarding Small Business Enterprise (SBE) requirements. The
Consultant should have the ability to meet Small Business Enterprise (SBE) goals established by the City
of Charleston.
Statements of Qualifications will be received at the City of Charleston Stormwater Management, 2 George
Street, Suite 2100, Charleston, SC 29401 until 2:00 pm (local time), October 9, 2026 for the drainage
design project for the Dupont Wappoo Watershed Improvements Project.
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SECTION B: BACKGROUND DESCRIPTION AND CONCEPTUAL PLAN
BACKGROUND
The proposed project area is shown on the attached project location map (see Attachment A).
The Dupont Wappoo drainage basin encompasses approximately 1,600 acres in West Ashley and includes a
mix of residential, commercial, and light industrial development within the City of Charleston and
unincorporated Charleston County. The watershed is generally bounded by Savage Road to the west, Paul
Cantrell Boulevard to the north, Ashley Hall Road to the east, and Savannah Highway to the south.
The basin relies on a network of culverts, pipes, ditches, and ponds to convey stormwater runoff to a central
drainage channel, which serves as the primary conveyance through the drainage basin. The channel begins
near the Palmilla Apartments, crosses Wappoo Drive, Sam Rittenberg Boulevard, under I-526, Savannah
Highway, and the West Ashley Greenway before ultimately discharging to the Stono River.
The City previously completed the 2019 DuPont Wappoo Watershed Master Plan (Attachment B), which
evaluated existing stormwater infrastructure and identified potential capital improvement opportunities
throughout the watershed; this plan as well as other relevant City data may be used as references for this
project.
PROJECT DESCRIPTION
The City of Charleston, in coordination with the U.S. Army Corps of Engineers (USACE), intends to identify
and evaluate flood mitigation improvements within the Dupont Wappoo watershed. The project will focus
on improvements to the central drainage channel and associated drainage infrastructure under varying
design storm and tidal conditions, without adverse impacts upstream or downstream and while considering
environmental impacts, property and easement requirements, constructability, and cost. The project may
also be evaluated for potential for phased construction, and the Consultant should identify components that
could be designed, permitted, funded, and constructed independently.
Project design funding is shared between the City of Charleston and USACE. The anticipated construction
cost limit for all components of the project is $20 million. The selected Consultant should consider this cost
limit throughout the development of conceptual alternatives.
The Consultant should be capable of providing professional engineering services necessary to develop a
conceptual engineering and planning package for subsequent use by USACE and its selected design
consultant. The Phase One work is intended to identify and evaluate potential project concepts and provide
sufficient information to support USACE's subsequent evaluation and advancement of selected
improvements info final design.
At a minimum, Phase One services will include the following:
* Preliminary existing site conditions assessment, including limited topographic survey and selected
field investigations at locations necessary to evaluate conceptual alternatives;
* Review of available studies, GIS data, stormwater inventories, existing models, survey information,
and other available information;
* Conceptual-level hydrologic and hydraulic modeling of existing and proposed conditions, based
primarily on publicly available LiDAR data and selected topographic survey along the primary drainage
corridor;
* Review of potential regulatory and permitting issues and selected coordination with applicable
utilities and regulatory agencies as necessary to inform evaluation of conceptual alternatives;
* Review of available property and easement information sufficient to identify potential real estate
considerations associated with conceptual alternatives;
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* Preliminary environmental review, including consideration of potential wetland and Critical Area
impacts;
* Development and evaluation of conceptual improvements, including layouts, exhibits, calculations,
cost estimates, and other supporting analyses;
* Public outreach and stakeholder coordination; and
* Recommendations for advancement into the Phase Two final design stage, including identification of
additional investigations, analyses, permitting, design, property/easement coordination, utility
coordination, potential project phasing and other activities that may be necessary to advance selected
improvements through final design and construction
Phase One deliverables will be prepared for use by USACE and its selected design consultant. The deliverables
are intended to communicate the conceptual project ideas, supporting analysis, anticipated benefits,
conceptual costs, and key considerations associated with the recommended improvements. Documentation
should identify significant assumptions, limitations, data sources, modeling methodologies, and outstanding
items that should be considered during subsequent final design.
All electronic files generated as part of the Phase One services, including H&H models, GIS/survey data, CAD
files, calculations, photographs, and other supporting project information will be provided to the City in
native formats, in addition to PDF deliverables.
PROJECT GOAL
The purpose of this Project is to identify and evaluate flood mitigation improvements within the Dupont
Wappoo watershed utilizing appropriate stormwater engineering practices without adverse impacts
upstream or downstream of the proposed project location.
Proposed flood mitigation improvements and designs should result in reducing flood depth and inundation
duration for the 10%, 4%, and 1% 24-hour Annual Exceedance Probability storms while accounting for tidal
influence and applicable future tailwater conditions. The H&H analysis shall use StormWise (formerly ICPR4)
and comply with the City of Charleston Stormwater Design Standards Manual
The selected Consultant will develop and evaluate alternatives based on the following objectives:
1. Significantly reduce flooding depth and inundation duration within key areas of the Dupont Wappoo
drainage basin, accounting for tidal influence and projected sea level rise tailwater conditions using
the City of Charleston Stormwater Design Standards Manual assumptions;
2. Evaluate opportunities to phase the recommended improvements and identify individual components
that could be advanced as standalone projects, where appropriate.
3. Prevent adverse impacts throughout the drainage basin as a result of the selected alternative
improvements and minimizing negative environmental impacts to existing wetlands and creeks; and
4. Consider property and easement requirements, environmental constraints, utility conflicts,
permitting considerations, constructability, maintenance, and other factors that may affect project
implementation.
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SECTION C: QUALIFICATIONS, SCOPE OF SERVICES AND SCHEDULE
Through this Request for Qualifications (RFQ), the CITY will select the most qualified Consultant to provide
engineering services per the Project Description above. A summary of the Consultant scope of services
and proposed schedule are as follows:
QUALIFICATIONS
Each Consultant who wishes to be considered for selection to perform this scope of services shall submit
to the CITY a concise description of:
1. Project Approach. The Consultant shall include a description of their management approach and
technical approach for the proposed scope of services.
2. Organization. Include a description of the Consultant including information regarding its primary
business, its background and history, its organizational structure, QA/QC program, and the number
of employees. This section should contain any additional information about the firm that the
Consultant feels will assist the CITY in better understanding the qualifications of the firm.
3. Personnel & References. All Statements of Qualifications will include and identify the top three key
team members to be assigned or employed to manage the Project by the Consultant with a resume
of each person (limit of 1 page, each). The proposal shall identify the person who will be the
primary day-to-day contact with CITY and the following two alternate personnel to be assigned to
the project. Key technical/environmental/permitting personnel shall be included with a resume
for each person (limit of 1/2 page each). The CITY requests that significant effort should focus on
highlighting the relevant qualifications and past experiences for the key team members and
technical/environmental/permitting personnel most likely comparable to work detailed in the
RFQ. Client references shall be provided on Project Resumes for key team members. The proposal
shall also identify all team members employed by SBE businesses registered with the CITY.
4. Ability to perform the Scope of Services. At a minimum, please demonstrate how your firm meets
the following qualifications.
a. A minimum of five (5) years of professional design experience related to flood reduction and
mitigation work demonstrated through at least five (5) project examples. Each project
reference should include a short description of the scope of work, the size of the project, the
engineering approach, the engineering and project budget amounts, the actual final project
cost, the timeframe required for completion, and any exceptional successes or challenges
encountered during the duration of the project.
b. Detailed knowledge and ability to competently conduct flood reduction design and hydrologic
and hydraulic analysis utilizing appropriate methodologies.
c. Experience with project requiring coordination with and obtaining required regulatory
permits from the United States Army Corps of Engineers (USACE), South Carolina Department
of Environmental Services (SCDES), SCDES Bureau of Coastal Management (BCM), South
Carolina Department of Transportation (SCDOT), Federal Emergency Management Agency
(FEMA), the City of Charleston (CITY), and other state, county, and local authorities having
jurisdiction.
d. Experience evaluating stormwater systems, flood storage, conveyance improvements,
and/or nature-based flood mitigation projects in coastal and/or tidally influenced
watersheds.
5. Capacity to Perform Work. Provide a description of the Consultant's capacity to perform work
requested by the CITY by describing the Consultant's current workload and the availability of the
staff to meet schedules. Please describe the methods utilized to track work progress, budgets, and
deadlines.
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6. Small Business Enterprise (SBE). The Consultant shall clearly demonstrate how it intends to follow
the City's SBE guidelines for this project. (See Attachment C.)
7. Licensures and Other Documentation. The Consultant shall provide professional licenses held by
the firm, certificate of current professional liability insurance, business licenses, and any
associations of which you are a member.
SCOPE OF SERVICES
The Consultant shall demonstrate ability to provide the professional engineering, conceptual design, H&H
modeling, regulatory review and selected coordination, public outreach, and other services required for
the project. Work may include, but shall not be limited to:
1. Perform Preliminary Engineering including, but not limited to:
a. Existing site conditions assessment within the Dupont Wappoo drainage basin and central
drainage channel, including limited topographical survey and select geotechnical or other
field investigations as needed to support design of the conceptual alternatives
b. Review of available studies, GIS data, stormwater inventories, existing models, survey
information, and other available information
c. Identification of primary drainage constraints, hydraulic deficiencies, structural deficiencies,
and areas of recurrent flooding
d. Evaluation of flood reduction benefits associated with the conceptual improvement
alternatives for various storm events, including improvements to maximum flood depth, flood
duration, and flood frequency
e. Review of potential regulatory and permitting issues associated with the conceptual
alternatives and selected coordination with applicable regulatory agencies, as necessary,
(including USACE, FEMA, SHPO, SCDOT, SCDES [BCM], City of Charleston, Charleston County,
Charleston Water System (CWS), County, City, etc.)
f. Conceptual opinions of probable construction cost for evaluated alternatives
g. Review of available property and easement information and identification of potential real
estate or easement considerations associated with conceptual alternatives
h. Preliminary environmental impact review, including consideration of potential wetland and
Critical Area impacts,
i. Evaluate opportunities to phase the recommended improvements and identify components
that may provide flood reduction benefits and be independently designed, permitted, funded,
and constructed without compromising the overall watershed improvement strategy
j. Identification of significant implementation considerations, including potential downstream
impacts, property or easement needs, utility conflicts, environmental constraints, permitting
considerations, or other factors that may affect future project development
k. Consideration and evaluation of alternate feasible solutions
2. Develop a conceptual-level Hydrologic and Hydraulic (H&H) model for the project basin using
StormWise (formerly ICPR4). The model should be developed primarily using publicly available
LiDAR data and selected topographic survey along the primary drainage corridor. Prepare a
technical memorandum documenting the model assumptions, data sources, methodology, results,
and limitations.
3. Prepare a Phase One Design Package based upon the work conducted in Items 1 and 2. The Phase
One Design Package is intended to provide USACE and its selected design consultant with a clear
conceptual understanding of the recommended project ideas and the supporting analyses and
considerations developed during Phase One. The package should include, as applicable:
a. Preliminary Engineering Report documenting existing conditions, identified deficiencies,
conceptual alternatives evaluated, evaluation criteria, recommended project components,
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design assumptions, limitations, and recommendations for advancement;
b. Hydrologic and Hydraulic Technical Memorandum documenting model assumptions and
limitations, boundary conditions, tidal and tailwater assumptions, and flood depth and
duration model results;
c. H&H model files and all associated input, output, GIS, boundary condition, and supporting
files necessary for USACE or its design consultant to review and utilize the model;
d. Conceptual project exhibits and layouts sufficient to communicate the recommended
improvements, including proposed general alignments, typical sections, drainage structures,
culvert and pipe improvements, nature-based solutions, and other major project
components, as applicable
e. Summary of potential property and easement considerations identified through available
information, including areas where future real estate or easement acquisition may warrant
additional investigation
f. Summary of environmental and regulatory considerations identified during Phase One,
including known wetlands, critical areas, environmental resources, potential impacts, and
permitting issues that may require additional evaluation during final design
g. Geotechnical and subsurface documentation developed during Phase One, including
recommendations for additional investigation required during final design, where
appropriate;
h. Utility coordination documentation and identification of known or anticipated utility conflicts;
i. Conceptual opinions of probable construction cost for the recommended improvements
and/or evaluated alternatives;
j. Conceptual phasing and implementation recommendations, including identification of
elements that may potentially be advanced independently; and
k. Identification of key assumptions, limitations, outstanding items, and potential next steps
requiring consideration by USACE and its design consultant during subsequent final design,
permitting, and implementation
4. The Consultant will participate in a formal Phase One Design Handoff meeting with the CITY,
USACE, and USACE's design consultant to facilitate transition of the Phase One work into
subsequent final design. The Consultant shall prepare its deliverables to minimize duplication of
effort and facilitate continuation of the project by a new design team.
5. Schedule and manage bi-weekly progress meetings with the CITY and/or their appointed
representatives. The Consultant shall prepare Status Reports for each meeting as well as produce
all meeting minutes. The Status Report shall include at a minimum:
a. Current scope of work completion status versus anticipated status;
b. Summary of budget status;
c. Project information and decision needs including the anticipated source, expected response;
d. Time and any issues or problems that could delay the expected response;
e. Anticipated tasks and accomplishments for the coming reporting period;
f. Questions, comments, problematic issues and suggestions;
g. Identification of out-of-scope task work; and
h. Invoicing issues and proposals to address such issues.
6. The Consultant will coordinate and lead public meetings, prepare all materials, project renderings,
presentations, and equipment for the public meetings. The Consultant will conduct public
meetings and perform other forms of outreach (letters to homeowners, HOA coordination, etc.) as
necessary for the project. The Consultant will also develop and maintain publicly available
information utilizing ArcGIS StoryMaps for use on the City's dedicated project website.
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SCHEDULE
Key Project planning schedule milestones are as follows; the schedule is tentative only and The City reserves
the right to adjust the schedule as the City deems necessary:
September 15, 2026 Request for Qualifications advertised by the CITY
September 28, 2026 Deadline for questions for Qualifications advertised by the CITY
October 9, 2026 Statements of Qualifications must be received by the CITY,
2 George Street, Suite 2100, Charleston, SC 29401 by 4:00 pm.
January 2027 Engineering design work commences.
June 2027 Phase One Design Package completed and submitted to CITY
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SECTION D: SUBMISSION INSTRUCTIONS
STATEMENT OF QUALIFICATIONS FORMAT
The CITY reserves the right to obtain financial data or other supplemental information concerning the
submitting entities, if relevant. Consultants should prepare their Statement of Qualifications simply and
economically, providing a straightforward and concise description of their abilities to provide the services
described at the expected quality level. The CITY reserves the right to accept the Statement of
Qualifications deemed most advantageous and in the best interest of the CITY.
Submission Details:
RESPONSE TO THIS REQUEST FOR QUALIFICATIONS MUST INCLUDE THE FOLLOWING:
Those Consultants interested in providing services must submit one (1) unbound original, five (5) bound
copies, and a digital copy (on flash drive) of proposals.
The base proposal is limited to 30 single-sided pages 8.5"x11" paper unless otherwise specified. Small
Business Enterprise (SBE) Compliance Provision Application and Affidavits (see Attachment C), liability
insurance certificate, and professional insurance certificate do NOT count toward the proposal page
limit.
The submission must include the items specifically enumerated in the "Submission Development". In
addition to the information required as described below, a Consultant may submit supplemental
information that it believes may be useful in evaluating its submission. This information may include
documents such as the Consultant's profile or brochure. Additional supplemental information is limited
to 20 single-sided pages separate from the proposal and clearly labeled "Supplemental Material".
A current resume including information on specific related project experience and the role of the person
on the project shall be submitted for key personnel. If sub-consultants are to be used as key personnel,
the resume requirement also applies.
A digital copy shall be provided in PDF format and all RFQ information should be submitted as a single
file. Any additional information supplemented to the RFQ should be submitted in PDF format in a
separate single file.
Submission Development:
All costs incurred by the Consultant associated with RFQ preparations and subsequent interviews and/or
negotiations, which may or may not lead to execution of the Contract, will be the responsibility entirely
and exclusively of the Consultant.
In responding to this RFQ, please submit a Statement of Qualifications addressing the following items:
1. Transmittal Letter with:
a. RFQ subject
b. Name of the Consultant responding, including mailing address, e-mail address, telephone
number, and name(s) of contact person(s).
c. The name of the person or person authorized to make representations on behalf of the
Consultant, binding the Consultant.
d. A Statement of Familiarity confirming key personnel have reviewed the proposal attachments
and are familiar with the project area, existing drainage conditions, terrain, and surrounding
areas.
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