HomeMy WebLinkAbout2004 - Retrofit AgreementEXHIBIT A
CITY OF SEBASTIAN
WORK AUTHORIZATION N0.4
MIDDLE STONECROP STORMWATER RETROFIT PROJECT
SCOPE OF SERVICES
PURPOSE
This is an attachment to the Engineering Services Agreement for the City of Sebastian
Continuing Services agreement dated Apri16, 2004, between the City of Sebastian (CITY) and
the firm of Camp Dresser & McKee Inc. (CDM) and made a part thereof. The purpose of this
Exhibit is to specify the required services of CDM to conduct the portions of Master stormwater
Management Plan (MSMP) Implementation requested by the CITY.
BACKGROUND
Recently, the CITY completed an updating of their MSMP. This revision of the MSMP included
hydraulic modeling of the primary canal system, water quality modeling of the portion of the
City tributary to the South Fork of the Sebastian River. The MSMP made recommendations to
reduce flooding due to a lack of storage and conveyance in the primary system. The MSMP also
made recommendations to reduce mass loading of nutrients and total suspended solids to the
South Prong of the Sebastian River.
The CITY and CDM met with the St. Johns River Water Management District (SJRWMD) in a
MSMP review meeting and discussed the potential rehabilitation and retrofit of the City's
stormwater system to improve water quality treatment and facilitate maintenance.
The proposed improvements discussed in this scope of services are the recommended
improvement known as Middle Stonecrop, or Majestic Ditch. The project area and select
features are shown on Figure 1.
Prior to being discharged into the South Prong of the Sebastian River, the runoff is routed
through a recently constructed retrofit stilling basin/wetland area. However, during the
modeling associated with the MSMP, several of the culverts within the alignment of Majestic
Ditch immediately upstream of this facility were indicated to flood in the 25-year/24-hour
design storm. Thus improvements to the stormwater management system were recommended.
During the review of the MSMP, St John River Water Management District (SJRWMD) staff
indicated that permitting this recommended improvement may prove to be challenging, due to
the recently constructed stormwater facility. Thus the first task in this scope consists of an
improvement feasibility study. The present scope and budget for Tasks 2 through 9 assumes
that the Middle Stonecrop Improvement will be permittable as recommended in the MSMP.
The project is broken into two phases: Phase 1 -Investigation, Design, Permitting, Bidding, and
Phase 2 -Construction Services. The project is described as follows:
Majestic Ditch is the end of the primary canal that drains approximately 545 acres of the City
area south of County Road 512 (CR512). The northern end of the canal is adjacent to CR512.
Currently there is a significant amount of vegetation evident within the canal right of way. The
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modeling associated with the MSMP indicated that several of the culverts along Majestic Ditch
were indicated to flood in the 25-year/ 24-hour design storm.
This portion of Majestic ditch is approximately 1800 feet long. The ditch has an approximate top
width of 25 feet. The proposed improvement along Collier Canal will include excavating the
channel, installing seawall and replacing culverts.
SCOPE OF SERVICES
The following tasks define the Scope of Services for the implementation of the stormwater
improvements recommended for the Phase 1 primary stormwater management systems
(PSMS). The tasks include the following services: survey, geotechnical, stormwater evaluation
and modeling, design, permitting, bidding services and public presentation to be completed by
CDM. Survey services will be provided by Masteller, Moler and Reed, Inc., geotechnical
services will be provided by Dunkelberger Engineering and Testing, Inc. and environmental
assessment will be provided by Ecosystem Research Corporation.
Phase 2 services for general and resident construction services will be determined at a later date.
CDM shall complete the following tasks under Phase 1:
TASK 1-PERMIT REVIEW AND CONCEPTUAL IMPROVEMENT
In order to ensure that the recommended alternative will be permittable, CDM will make a
preliminary assessment of the existing facility. This task is divided into three subtasks, as
follows:
Subtask 1.1 -Environmental Assessment
CDM will prepare a wetlands assessment report addressing wetlands and other environmental
impacts. It is possible that there may be limited wetland or other environmental impacts in the
Project area.
CDM will review potential wetland and T&E issues in both the alignment of Majestic Ditch
between Laconia and Stonecrop Streets and the Stonecrop stormwater treatment facility. The
ditch will be reviewed with the consideration that the recommended improvement is the
"hardscaping" of the side slopes i.e. seawalls. The treatment facility will be reviewed with
consideration of the result of the recommended improvement (e.g. higher peak flows). It is
noted that the treatment facility has been permitted as stormwater retrofit project.
A copy of the SJRWMD permit for the Stonecrop facility will be reviewed for environmental
and hydraulic concerns.
Subtask 1.2 -Meeting with SJRWMD
CDM will meet with SJRWMD staff onsite to discuss potential modifications to the existing
permit. CDM will draft a memorandum summarizing project permitability.
Subtask 1.3 -Review and Refinement of Alternative
Based upon the results of these investigations in Subtask 1.1 and 1.2, the improvement
recommended in the MSMP will be reviewed and modified as necessary to ensure
permitability. Contingent upon the level of modification made to the recommended
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improvement the scope and budget for the project will be modified and/or amended as
necessary.
TASK 2 -SURVEY SERVICES
CDM, as part of this scope, will collect the topographic information to design the proposed
improvements as listed in BACKGROUND above. A survey of the Majestic Ditch as well as a
limited survey of the tributary channel will be completed for hydraulic evaluation purposes.
The survey services will provide the necessary support to define the extent of the existing
drainage easements.
The survey will establish a State Plane Coordinate (NAD 83) baseline for horizontal and vertical
control, provide cross sections, flag wetlands, locate soil borings, potholes to locate utilities
conflicts (up to 10), determine invert/top elevations of utilities within the project area and
determine inverts and geometry of selected culverts. The survey services will also include
existing rights-of-way and easements. The survey services will be provided by a subcontracting
surveyor and are divided into three sub-tasks, as follows:
Subtask 2.1 -Overall Surveying Services
The following survey work is included in this sub-task:
^ Research: acquire horizontal and vertical control near the project, right of way map for the
Majestic Ditch and existing easements and right-of-ways.
^ Control: Establish State Plane Coordinate control (Horizontal NAD 83 and Vertical
NGVD29) as monuments at the project area for up to four (4) points.
^ Wetland jurisdictional location: Locate and map the wetland flagging placed by CDM. Up to
75 flags are estimated for budget purposes.
^ Locate all utilities within ditch ROW.
^ Project documents will be produced and submitted to the CITY in an electronic format
compatible and acceptable to the CITY (i.e., AutoCAD and Microsoft Word)
^ Survey work shall meet the requirements of Chapter 472, Florida Statutes, and Chapter
61G17-6, Florida Administrative Code. The surveys shall be signed and sealed by a
Surveyor and Mapper registered in the State of Florida. Survey information will be recorded
in a field book, which must be submitted upon request and/or at the end of the Contract.
When a data collector is used, the Surveyor shall submit a paper copy of the raw data files
bound in a book, together with the electronic copy on a disk. Design Survey computations
shall be documented in a Design Survey Computation Book, which shall be submitted to the
CITY with the Survey Field Notes upon request and/or at the end of the Contract.
Subtask 2.2 -Route Surveys
This work effort will be conducted on project area as described in Section II above, as follows:
^ There will be up to twenty (20) canal cross sections required. These cross sections include
nine (9) in Majestic Ditch beginning at Laconia Street and every 200 feet downstream, nine
(9) in tributary canal upstream of Laconia Street and one (1) in the channel downstream of
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Stonecrop Street (leading to stilling basin). The cross sections will include: both tops of bank
and interior points (maximum of 3 to 5) to describe the channel shape, and one elevation
point 20 feet landward from each top of bank.
^ Locate up to 16 soil boring sites along Majestic Ditch.
^ Baseline survey will be shown with sufficient geometry, monumented, and referenced in the
field.
^ Up to 75 spot elevations to define the topography of the wet detention/wetland treatment
area. The survey will be provided on the record drawing of this area in electronic format.
Subtask 2.3 -Right-of--Way and Topographic Survey Maps
This item of work involves preparing existing and proposed right-of-way maps for the Project
Area.
^ Existing right-of-way maps will show survey base line geometry tied to adjacent property
owners' lines and right-of-ways and easements existing over the project.
^ Right-of-Way maps and Topographic Survey will be delivered on 24 inch x 36 inch sheets at
1 inch = 20 feet scale as plan and profile showing property lines, drainage and utilities
easements, plotted line work, utility locations, topographic survey, baseline of survey and
monumentation.
^ Up to four construction and temporary easements descriptions.
TASK 3 - GEOTECHNICAL SERVICES
CDM will retain a qualified geotechnical investigation subcontractor to conduct test borings
and geotechnical laboratory testing. The geotechnical investigation will provide an overview of
conditions in the project area to help define the geotechnical limitations of the proposed
stormwater improvements. The sub-surface soil investigation shall include soil borings along
the edges of Majestic Ditch. Estimation of the seasonal high water table will also be provided as
part of the sub-surface soil investigation.
The geotechnical services that will be performed in the project area include conducting test
borings and geotechnical laboratory analyses, and providing geotechnical and design
recommendations to support the stormwater improvements and other elements of the project.
The results of the geotechnical analyses will be documented in a report containing the following
subtasks:
Subtask 3.1 -Data Collection
This task includes the collection of the geotechnical information to be used in subsequent
subtasks.
^ Soil borings and testing along both edges of Majestic Ditch (maximum of 16 sampling sites),
to provide geotechnical information to aid in the design of the proposed seawalls. The
testing will include: SPT, sieve analysis, organic content.
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Subtask 3.2 - Geotechnical Report
This task includes the reporting of the findings determined from the data collection and will
include:
^ Presentation of the field and laboratory test procedures used.
^ Description of subsurface conditions, including subsurface profiles, and estimated
geotechnical engineering properties to design seawalls, modification of existing channel
cross sections and spoils containment facility (with berms).
TASK 4 -HYDROLOGIC, HYDRAULIC, AND WATER QUALITY EVALUATION
CDM will use the ICPR (Version 3.02) hydrologic/hydraulic model developed for the City of
Sebastian s Master Stormwater Management Plan (CDM, 2004) and modify the model (based on
latest available survey) to develop the recommended alternative. The evaluation will consist of
the following subtasks by CDM:
Subtask 4.1 - Refinement of Hydrologic Representation
The area tributary to these two canals is approximately 545 acres and consists of 22 hydrologic
units in the existing stormwater model. In order to provide a more refined representation CDM
will subdivide up to five existing hydrologic units. In addition to the refinement of the
hydrologic units, the curve number and time of concentration will be recalculated.
Subtask 4.2 - Refinement of Hydraulic Representation
In the ICPR model, the existing representation of Majestic Ditch and the channel upstream of it
will be updated with the obtained survey. This will include up to 20 channel cross sections.
Subtask 4.3 -Simulation of Existing Conditions
CDM will simulate the mean annua1,10-year, 25-year and 100-year SjRWMD design storm
events of a 24-hour duration. CDM will also quantify the level of water quality treatment
currently being provided by the existing treatment system using the Watershed Management
Model (WMM) in terms of relative annual nonpoint source pollution load reduction in tabular
format. The evaluation will consider runoff volumes, peak stages, flows, and velocities within
the project.
Subtask 4.4 -Simulation of Proposed Conditions
CDM will use the modified existing conditions model to represent the proposed modifications
to Majestic Ditch and potentially the treatment area. These modifications will include: design
channel cross-sections, design culvert replacement and proposed modification to the treatment
area. CDM will also quantify the level of water quality treatment as equivalent volume of live
and permanent pool that will be provided by the proposed modifications in this portion of the
CITY. The modifications will be based upon the conceptual design as defined in Task 5 below.
Subtask 4.5 -Model Evaluation Report Section
CDM will document the results of the modification of the existing and proposed condition
models. This documentation will include discussion of curve number and time of concentration
calculations, refinement of hydrologic representation, refinement of hydraulic representation, a
tabular comparison of peak stages by nodes and flows at the outfall and a discussion of the
proposed conditions.
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This documentation will provide the basis of the permit application package to be submitted to
the SJRWMD as described in Task 6 below.
TASK 5 -ENGINEERING ANALYSIS AND DESIGN
CDM will prepare construction plans for the recommended improvement. CDM will prepare 24
inch by 36 inch plans (1 inch = 20 feet). The Canal and ditch work will be shown on plan and
profile drawings. The seawall will also be shown on the plan and profile drawings for the
Majestic Ditch. CDM will work with CITY staff to accommodate the proposed improvements
within the limited space to the extent possible without impacting adjacent properties and/or
identified utilities.
The proposed improvements, as outlined in BACKGROUND above, consist of modifying the
existing canal's cross section, adding seawalls and replacement of the existing culverts.
Subtask 5.1 -Conceptual Design
CDM will prepare a conceptual design (30 percent complete) for the project for review by the
CITY. The conceptual design will be developed in conjunction with the Hydraulic Evaluation in
Task 4. This will be done to determine the most cost effective design, which will meet the water
quality, water quantity, and permitting objectives of this project. The conceptual design will
consist of typical layouts, typical cross sections and typical details that will be used in the final
design. The conceptual design, will also include a conceptual cost estimate of the improvements
required for the entire system to allow planning of potential phasing of the capital
expenditures.
Subtask 5.2 -Contract Drawings
CDM will prepare plans for the construction of the proposed modifications for Majestic Ditch.
CDM will submit 30, 60 and 90 percent plans to the CITY for review. This task includes two (2)
review meetings with CITY staff at the 50 and 90 percent design milestones. Each design
milestone will include an opinion of the construction cost of the proposed improvements (Sub-
Task 5.4 below).
After the 30 percent design milestone has been reviewed and approved by the CITY, CDM will
incorporate comments and continue preparation of design documents for the project. At the 90
percent completion stage, CDM will provide a constructability review of proposed
improvements and update the hydraulic modeling as necessary.
The construction plans will consist of plan sheets listed in Table 1 below and include the
performance of specific work and preparation of details and documents as follows:
^ Plan and Profile drawings at 1 inch = 20 feet of improvements
^ Geotechnical Data
^ Access road details (if necessary)
^ Maintenance of Traffic
^ Stormwater structures
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^ Sheet pile layout and details
^ Culvert replacement and details (if necessary )
^ Foundation details
^ Typical Sections
^ Cross Sections
^ Utilities relocation (if necessary)
^ Erosion control
FDOT Roadway and Traffic Design Standards (2002) and Standards Specifications (2004) will be
used. These will be modified as recommended by CDM with CITY approval. Table 1 describes
an approximate sheet count for the construction plans:
TABLE 1
SHEET DESCRIPTION NUMBER OF SHEETS
Cover 1
Abbreviations, S mbols and General Notes 1
Index/Ke 1
Ditch T ical Sections 1
Plan and Profile -Majestic Ditch and Erosion
Control and Utilitiesl 3
Structural Details 2
Stormwater Structures 1
Details 3
Miscellaneous Structures 1
TOTAL 14
(1) Minor utility adjustments, if necessary.
CDM will submit 30, 60 and 90 percent plans to the CITY for review. This task includes two (2)
review meetings with CITY staff at the 50 and 90 percent design milestones. CDM will submit
three (3) copies of 11 inch x 17 inch (half sizes) FDOT format at each scheduled design milestone
for CITY review. The CITY's review comments will be incorporated into the final construction
documents (plans and specifications) as mutually agreed upon. CDM will furnish one
reproducible set of final construction documents to the CITY prior to bid advertisement. This
design does not include provisions for the permitting or design of a mitigation wetland
required for any wetland, which may be impacted.
Subtask 5.3 -Contract Specifications
CDM will provide contract specifications to the CITY for review. Edits agreed upon by CDM
and CITY will be incorporated. Sufficient specification will be provided for the construction of
the proposed improvement.
Subtask 5.4 -Probable Construction Cost Estimate
CDM will provide an engineer's opinion of the probable cost of construction for the project at
the 30, 60 and 90 percent completion milestones and prepare a final opinion of the probable
construction cost estimate at the completion of the design.
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Subtask 5.5 -Quality Assurance/Quality Control
CDM will hold a QA/ QC review of the proposed modifications to Majestic Ditch with the
CITY. This review will consider, at a minimum, constructability and regulatory considerations.
Subtask 5.6 - Project/Program Management
This task will consist of project management, coordination of project, invoicing, and the
generation of monthly project status reports.
TASK 6 -PERMIT ASSISTANCE
CDM shall prepare and submit permit packages to the St. Johns River Water Management
District (SJRWMD) and United States Army Corp of Engineers (USAGE) for their review and
approval.
CDM will provide permit assistance to the CITY. For this Scope of Services, it is anticipated that
a joint Environmental Resources Permit (ERP) will be required from the SJRWMD and USAGE.
Subtask 6.1 -Meetings with the SJRWMD and USAGE
CDM will meet with representatives of the SJRWMD and USAGE to discuss the objectives of the
overall project and to clarify the level of permitting needed for the proposed channel
improvements. A total of two meetings are estimated for budgeting purposes.
Subtask 6.2 - PermitApplication
CDM will prepare and submit an Environmental Resources Permit (ERP) package application to
the SJRWMD and USAGE and respond to up to two Requests for Additional Information (RAIs)
to clarify information in the permit application package. CITY will pay all applicable permit
fees. The following elements are typically required in the ERP application:
^ Brief report of project
^ Basin delineation
^ Peak flow quantities and analysis (25 year & 100 year-24 hour storms)
^ Construction sequence or phases (if applicable)
^ Proposed construction layout
^ Construction techniques
^ Stormwater treatment and control techniques
^ Wetland delineation and potential mitigation
^ Construction plans
TASK 7 -BIDDING SERVICES
CDM shall provide services to coordinate and facilitate the beginning of construction. CDM
shall assist the CITY in preparing bid documents. All construction specifications shall refer to
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FDOT specifications. CDM will prepare Special Provisions and Technical Specifications for
items not covered by FDOT specifications. CDM will attend the Pre-Bid Conference.
CDM will assist in answering questions of Bidders and in issuing addendums that are required.
Up to two addendums have been budgeted.
CDM will assist the CITY in reviewing the bidders and bids and in making a recommendation
for award to the CITY. As part of the recommendation, CDM will conduct an investigation of
the apparent low bidder and provide a written recommendation to the CITY regarding the
lowest responsive bidder.
TASK 8 -PUBLIC PRESENTATIONS
CDM will assist the CITY by attending up to two (2) public information meetings to be held at a
time and place to be determined by the CITY, CDM will make presentations relevant to the
design and affect of the improvements on the community and property owners. CDM will
answer questions from the public regarding the project as given by citizens or interested
groups. CDM will provide a written summary of the meeting minutes.
PHASE 2 (Not included in this Work Authorization
TASK 9 -GENERAL AND RESIDENT SERVICES DURING CONSTRUCTION
CDM will assist the CITY's engineering representative during the course of the construction
project. CDM will perform General Services during construction including correspondence with
the Contractor, shop drawing review, reviewing requests for clarification, performing site visits
and reviewing pay requests by the Contractor. CDM will also perform full or part time resident
inspection of the project during construction. The estimated length of time for construction of
this project is estimated to be 12 months.
This task has not been considered in the budget at this point in time. A separate scope of
services and budget for this task will be provided in the next phase of this project.
SERVICES NOT INCLUDED
The current scope and budget have not considered the following tasks:
^ General and Resident Inspection Services during Construction
^ Development of a mitigation plan for any potential wetland impacts
^ Development of detailed Threatened and Endangered Species (T&E) survey and mitigation
effort for potential T&E impacts
SCHEDULES AND TIME CONSTRAINTS
This project shall be commenced upon approval by City Council. CDM will endeavor to
complete this work in twelve (12) months from the date of the Notice to Proceed.
COMPENSATION
A project budget is attached. The budget outlines the levels of effort for each subtask by labor
category. CDM will invoice monthly based upon services provided.
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