2013-02 0 TETRA TECH
January 14, 2013
Ms Tamara Richardson, P E
Director of Engineering
City of Clermont
685 W Montrose Street
Clermont, Florida 34711
Re City of Clermont
Westside WTP Lower Florida Aquifer(LFA) ,
Water Quality Exploratory Well Testing
Change Order
Tt# 200-08310-11001
Dear Ms Richardson
Tetra Tech is pleased to furnish this change order proposal for professional services to provide
construction administration and construction observation services, for exploratory well construction
and testing to determine water quality at the Disston Avenue potable water supply well into the Lower
Floridan aquifer(LFA) A detailed scope of services, compensation summary, and project schedule are
included in Attachment A
Tetra Tech looks forward to continue serving the City of Clermont on this project If you should have
any questions,please do not hesitate to contact me at 407-839-3955
Very truly yours, APPROVED
Tetra` City of Clermont
.,.... ..\70
n D Fox, P E By
Vice President
Date /- Pl- /5
Attachments
JDF/slh/08310-I0002/bdinfo/p/Richardson-CO
C James Kinzler, City of Clermont
Miguel Garcia, PG, PMP, Tetra Tech
Sally Alfieri,Tetra Tech
Tetra Tech, Inc
201 E Pine Street Suite 1000 Orlando FL 32801
Tel 407 839 3955 Fax 407 839 3790 www tetratech corn
ATTACHMENT "A"
CHANGE ORDER PROPOSAL FOR PROFESSIONAL ENGINEERING SERVICES
WESTSIDE WTP LOWER FLORIDAN AQUIFER (LFA)
WATER QUALITY EXPLORATORY WELL TESTING
PROJECT OVERVIEW
The City of Clermont (City) has constructed a new potable water supply well to serve the
proposed Westside Water Treatment Plant (WTP) The well was constructed on a 2 76
acre parcel located north of Dairy Queen, bounded on the east by Disston Avenue and on
the north by E Highland Avenue The well was constructed into the Upper Floridan
aquifer (UFA) with a final casing diameter of 24-inches to a depth of 316 feet below land
surface (bls), and an open hole depth to 560 feet bls, with an estimated pumping capacity
of 2,500 gallons per minute (gpm) Water quality from the on-site Disston Well was
recently obtained during aquifer performance testing conducted after well completion
Original assumptions for the design of the WTP assumed total organic carbon (TOC) less
than 2 0 mg/I Water quality results indicate TOC levels greater than the assumption,
which can increase the potential formation of disinfection byproducts and result in higher
treatment and operation and maintenance costs
As an option to potentially reduce treatment costs at the WTP, Tetra Tech recommended
modifying the Disston UFA potable supply well into an exploratory test well, by
advancing the pilot hole into the Lower Floridan aquifer (LFA) to a total estimated depth
of up to 1,600 feet bls Water samples would be collected from the LFA to determine if
water quality in the LFA would require less treatment, and ultimately reduce the
treatment costs compared to water from the UFA at this well This proposal presents the
services required to provide construction administration and construction observation
services during the drilling into the LFA, analysis of the data generated, and preparation
of a memorandum summarizing the water quality in the LFA at the Disston well
This change order proposal is for additional professional engineering services associated
with construction administration and well construction observation services for the
project described above The services to be provided by Tetra Tech consist of the
following phases
A Construction Administration
B Well Construction Observation
These phases are discussed in detail in the following sections
II SCOPE OF SERVICES
A Construction Administration
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Upon approval of this change order, Tetra Tech will assist the City with
construction administration and shall complete the following tasks based on a
construction duration of 150 calendar days (to substantial completion)
Prepare a testing plan summarizing the testing sequence for submittal to
the drilling contractor
2 Review the Contractor's application for payment and the accompanying
data and schedules, determine the amounts owed to the Contractor, and
advise the City of the recommended payments to the Contractor
3 Conduct a substantial completion site visit and develop a punch list of
items to be corrected by the Contractor Conduct a final completion site
visit to determine if the punch list items have been completed in
accordance with the Contract Documents and if the Contractor's
obligations are fulfilled there under, and recommend final payment to the
Contractor
4 Prepare a memorandum summarizing the water quality testing results at
the Disston well from drill stem and packer testing, and include laboratory
results
H Well Construction Observation
1 Tetra Tech will provide a professional hydrogeologist or hydrogeologic
technician for observation of the well construction at all critical stages of
the testing This will provide the City with a greater degree of confidence
that the completed work will conform in general to the Contract
Documents and that the integrity of the design concept of the completed
construction as indicated in the Contract Documents has been
implemented and preserved by the Contractor
2 The hydrogeologist or hydrogeologic technician shall be present during
significant well drilling, drill stem water quality collection, geophysical
and video logging, and inflatable packer testing activities to observe the
work and log pertinent information The field construction hydrogeologist
or hydrogeologic technician will provide well construction observation
services for a total of up to 150 hours The number of hours is based upon
our partial observation experience with this well site and other similar
Floridan aquifer wells if the level of effort varies significantly from that
which we have assumed, we will notify the City in writing and request
direction before proceeding with additional or a higher level of service
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3 Water Quality Tetra Tech will coordinate collection of one sample
following completion of each (up to two) inflatable packer tests for
analysis of selected water quality parameters to determine treatment
requirements Groundwater samples will be submitted to Test America or
Flowers Chemical Laboratory for analysis The laboratory analytical costs
will be paid directly by the City and are not included in the compensation
summary below
111 COMPENSATION SUMMARY
The total lump sum compensation for the Scope of Services described in Section II is
summarized below
A Construction Administration $ 7,820 00
B Construction Observation *$ 15,814 00
Total Lump Sum Fee $23,634.00
*To be billed on a time and matenals basis
iV PROJECT SCHEDULE
The proposed project schedule for completion of the Scope of Services described in
Section ii is anticipated to be as follows
Calendar Days
from
Task CO Approval
A Construction 150
B Water Quality Memorandum 180
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