DR9802-PR 981012ll Halff Associates
ENGINEERS ' ARCHITECTS ° SCIENTISTS
PLANNERS * SURVEYORS
October 12, 1998
1010
Don Moulton, PE
NCH Corporation
2727 Chemsearch Boulevard
Irving, Texas 75062
8616 NORTHWEST PLAZA
DRIVE
DALLAS, TEXAS 75225
FAX (2~4) 739-0095
RE: Drainage Master Plan Study- NCH Site and Related Areas in Coppell, TX
Dear Mr. Mouiton:
Halff Associates is pleased to present this fee proposal for engineering services to prepare a
Master Drainage Plan for the NCH site and adjoining areas in Coppell, Texas. Generally, the
services will consist of conceptual drainage design, stream hydrology and hydraulics as
necessary to develop and document the Master Plan.
The entire engineering effort can be completed for a lump sum fee of $45,000. A detailed work
plan is attached as Exhibit A and a breakdown of the engineering fee is included as Exhibit B. A
suggested schedule is shown on Exhibit C.
Please call me at 214/346-6220 if you have any questions. We look forward to assisting you and
the City of Coppell with this important project. If this proposal meets with your approval, please
sign and return one copy to our office to indicate your authorization of the scope of work and fee
and our notice to proceed.
Sincerely,
HALFF ASSOCIATES, INC.
Walter E. Skipwith, PE
Vice President
APPROVED:
BY:
DATE:
TRANSPORTATION · WATER RESOURCES · LAND DEVELOPMENT * MUNICIPal. · ENVIRONMENTAL * STRUCTURAL
MECHANICAL * ELECTRICAL ° SURVEYING * GEOGRAPHIC INFORMATION SYSTEMS
ARCHITECTURE o LANDSCAPE ARCHITECTURE ° PLANNING
I I
Ill
· -- Halff Associates
lll
ENGINEERS · ARCHITECTS · SCIENTISTS
PLANNERS ° SURVEYORS
Don Moulton, PE
NCH Corporation
October 12, 1998
Page 2
EXHIBIT A
Scope of Work
Drainage Master Plan Study- NCH and Related Areas
in Coppell, TX
I. Data Acquisition/Basemap Preparation
A Kickoff meeting
B Obtain plans, current zoning, existing landuse l¥om City
C Obtain approved site topography and plans from NCH, adjacent sites and City
D Obtain and plot City topography
E Site visit, including photographs
F Merge site plans/topography and city topography to create basemap
G Create location map
II. Surveys
A
B
Miscellaneous surveys of drainage structures in the study area
Extend FEMA benchmark to study area
Ill. Drainage & Flood Plain Analysis
A Hydrology
1 Research effective fully developed (FD) landuse hydrologic model
2 Locate 'best' electronic files in archives, execute, plot
3 Compare 1 and 2
4 Revise model with added detail in upstream reaches
5 Debug, execute, plot results for 2- & 100-year flood discharges
6 Revise hydrology model for existing landuse
7 Debug, execute, plot results for 2- & 100-year flood discharges
8 Compare computed discharges with previous studies
Halff Associates
ENGINEERS · ARCHITECTS · SCIENTISTS
PLANNERS · SURVEYORS
Don Moulton, PE
NCH Corporation
October 12, 1998
Page 3
B Hydraulics
1 Identify effective stream hydraulics model from City
2 Locate 'best' electronic files, execute, plot
3 Compare 1 and 2
4 Extend existing conditions models per surveys and topographic map
5 Incorporate fully developed and existing landuse discharges
5 Execute, debug, plot revised model
6 Compare to existing models - tables of water surface elevations and velocity
C Mapping
1 Delineate 100-year flood plain based on fully developed landuses in the watershed
2 Delineate subdrainage areas and discharges
3 Add flood plain and baseline drainage information to basemap
D Meet with Owner(s) and City
IV. Drainage Master Plan
2
3
4
5
B
1
2
3
4
5
6
C
1
2
A
1
Formulate General Alternatives
Establish targets for detention alternative
a. Alternative 1- limit runoffrate from developed sites to predevelopment rates
b. Alternative 2- limit runoff rate from developed sites to that from a landuse less intense
that industrial (i.e. Single Family Residential)
Confirn~ conventional drainage criteria
Evaluate diversion possibilities ~ ~ ~
Evaluate pern~itting requirements
Meet with Owner and City
NCH and Adjoining Site
Conceptual design of conventional system
Conceptual design of detention alternatives
Conceptual design of combination systems
Exhibits
Cost estimates
Assess downstream impacts
Bethel Road Area
Conceptual design- conventional Bethel storm sewer
Conceptual design of Bethel storn~ sewer with detention in upstream basin
Ill
· -. Halff Associates
ENGINEERS ° ARCHITECTS - SCIENTISTS
PLANNERS ° SURVEYORS
Don Moulton, PE
NCH Corporation
October 12, 1998
Page 4
3
4
5
D
1
2
3
4
Exhibits
Cost estimates
Assess downstream impacts
Recommendations
Outline preliminary recommendations
Internal peer review meeting
Finalize recommendations
Meet with Owner(s) and City
IV. Study Report/Documentation
A
1
2
B
C
Report
Write report
Assemble and bind 10 copies
Compile electronic files of report and exhibits
Deliver reports and electronic files to Owner(s) and City
Ill
· ,, Halff Associates
llffi
ENGINEERS · ARCHITECTS · SCIENTISTS
PLANNERS ° SURVEYORS
Don Moulton, PE
NCH Corporation
October 12, 1998
Page 5
EXHIBIT B
Fee Breakdown
Drainage Master Plan Study- NCH and Related Areas
in Coppell, TX
Task
I. Data Acquisition/Base Map Preparation
II. Surveys
III. Drainage and Flood Plain Analysis
IV. Drainage Master Plan
V. Study Report/Documentation
Fee Breakdown
$ 3,486
$ 1,850
$ 16,145
$ 19,118
$ 4,401
Lump Sum Total $ 45,000
Halff Associates
ENGINEERS · ARCHITECTS · SCIENTISTS
PLANNERS · SURVEYORS '
Don Moulton, PE
NCH Corporation
October 12, 1998
Page 6
EXHIBIT C
Schedule
Drainage Master Plan Study- NCH and Related Areas
in Coppell, TX
Task
Notice to Proceed
Kickoff Meeting
Data Collection
Survey
Drainage and Flood Plain Analysis
Drainage Master Plan
Report
Completion Date
10/25/98
1 O/26/98
10/28/98
11/09/98
12/09/98
1/21/99
1/28/99