NC0024210_Staff Comments_19980525

V66ZI-IZ-1b
Division of Water Quality
May 25, 199 8
TO: Reggie Sutton
Bobby Blowe
Jason DoU
Ruth Swanek
Jay Sauber
Don Safrit
Dave Goodrich
Steve Mauney
Ron Linville
Corey Basinger
Larry Coble
FROM: Boyd DeVane
SUBJECT: High Point Discharge Bypass
In looking at the options to reduce the nutrient loading to the proposed Randleman
Reservoir, the possibility of relocating the discharge around the reservoir is by far the most
effective in reducing chlorophyll a violations predictions. However, the consulting firm
for the water authority put a fairly large cost estimate on that option. In fact, the cost was
approximately 5 times the cost estimated in 1980. 1 asked the consulting firm why the large
difference and they responded with the attached memo. We will be using this information
in the fiscal note and I wanted to send it to you folks to see if you see anything that may not
be accurate or appropriate in this estimate. Please look at it and get back to me in the next
week or two if you have any particular comment. If I don't hear from you, I win assume it
looks A to you.
Greg Thorpe
Coleen Sullins
Jimmie Overton
Steve Zoufaly
Dennis Ramsey
4�.

IWEN AND SAWYER
Environmental Engineers & Scientists
April28,1998
Mr. Boyd DeVane
Division of Water Quality
NC Department of Environment and Natural Resources
P 0 Box 29535
Raleigh, NC 27626-0535
Dear Boyd:
Hazen and Sawyer, R C.
4011 WestChase Blvd.
Raleigh, NC 27607
919 833-7152
Fax: [phone]
Re: Cost Estimate for High Point Eastside
Eff I u ent Bypass
H&S Job No.: 2901
The Piedmont Triad Water Authority has requested that we review a 1980 report
prepared by the W. M. Piatt Company concerning the cost for an effluent bypass for the
High Point Eastside wastewater treatment plant. The effluent bypass would provide a
means for moving the discharge from the High Point Eastside wastewater treatment
plant to a location below the proposed Randleman dam.
We have completed this review and this letter provides a summary of the major
differences in the Piatt estimate of the bypass cost and the Hazen and Sawyer estimate.
The H&S estimate is presented in the responses to DWQ comments for the PTWA
Nutrient Reduction Plan for Randleman Lake.
The table below presents some comparative data for the Piatt estimates and the
H&S estimate:
Parameter Piatt
Design Flow
(mgd) Average
16
Peak Hour
32
Design Pumping Rate (mgd)
16
Force main Size (inches)
36
Force main Length (feet)
57,000
Estimated Costs ($ million)
$5.4
(1980 dollars)
Engineering & contingencies
Not Included
Total Cost ($ million)
$5.4
H&S
26
78
78
66
729000
$23.0
(1998 Dollars)
$5.8
$28.8
New York. NY - ArmanK NY - Woodbury. NY - Upper Saddle River, NJ * Detroit, Ml - Raleigh. KC - Charlotte, NC - Fairfax. VA - Holy000d, Fl. - Boca Raton, Fl. - Fort Pierce, FL- Gainesville, FL - Samsota. Fl. - Mlarni, Fl.

RAZEN AND SAWYER
Mr. Boyd DeVane
April 28,1998
Page 2
The table above illustrates several major differences in design conditions and
cost information for each estimate. These items are discussed below:
1. Design Flow - The influence of this change is apparent. The flow
requirements at the Eastside plant have increased dramatically over the last
18 years. Consequently, all system components have increased in size and
cost.
2. Design Pumping -Rate - The original Piatt work assumed that a 3 mg
'laveraging pond" would be constructed to limit the required maximum
pumping rate by equalizing flows. There are several difficulties with this
assumption:
The hydraulic profile for the 26-mgd plant will not permit gravity flow
into the equalization pond prior to pumping. If this approach were
utilized, it would be necessary to pump both into and out of
equalization storage.
The required volume of the equalization pond would be much greater
due to the increase in total plant flow to 26-mgd. Given the daily
variations in plant flow, we believe that more than 3 mg of storage
would have been required at the 16-mgd design.
The current site plan for the plant would not accommodate the storage
reservoir. Land acquisition would be required to accommodate the
reservoir.
Given these difficulties, we remain of the opinion that the appropriate
design approach is too pump peak hourly flows. We believe this approach
to be both simpler and less expensive when all costs are considered.
3. Force Main Size - is a direct function of the design pumping rate. Higher
plant flows have almost doubled the required size of the pipeline.
4. Force Main - Piatt assumed across -country route that minimized the
pipeline length. H&S assumed that the pipeline would track along the
perimeter of the lake and be located within the 200-foot buffer already
controlled by the Authority. We believe our approach is more prudent given
expected property owner opposition to this type of utility crossing.
5. Estimated Costs - several of the factors noted above would increase the Piatt
estimate. Inflation based on the ENR cost indexes would almost double the
Piatt estimate (CCI ratio is 1.9). When the increased pipeline size is factored
in, the construction estimates would be very comparable.

I . I
RAZEN AND SAWYER
Mr. Boyd DeVane
Apri128,1998
Page 3
6. Enqineerinq and Contingencies - as noted in the Piatt report, engineering and
contingencies were not considered. These costs are assumed at 25 percent
of the construction cost, which is appropriate at this level of study.
We trust that this review adequately addresses your questions. Please feel free
to contact us if there is anything further that we can clarify for you.
Very truly yours,
HAZEN AND SAWYER, P.C.
r'l I P. E.
Donald L. ordeli. P.E.
Vice President
cc: Mr. John Kime, PTWA