DDW-2024-013401

MEMORANDUM

DATE: November 6, 2024
TO: Paul Wright
FROM: Riley Vane
PROJECT: Hildale City (Maple St.) Booster Station
PROJECT NO: 2305-003
RE: DDW Plan Review

Paul,

We’ve made the following revisions according to your comments.

Comment #1:
Cadence Hernandez with the DDW is the funding person in charge of this project. I was checking with
her on timelines for funding, but I wanted to get these comments to you. You will want to make sure you
work with her to get the bid package with all the correct information and sections and getting plan
approval will depend on funding being finalized.

Response #1:
The linked and revised bid package contains all the required DDW procurement documents.

Comment #2:
I noticed that the specifications didn't include any of the pipe material specifications nor anything with
regard to installation of the pipe, disinfection, pressure testing, etc. You mentioned something about
APWA, but I don't have access to those, and I know that currently APWA standards don't completely meet
all of the Division of Drinking Water rules. It would be better if you included those sections in the
technical specifications. I know you are waiting for funding, but I can't complete my review without some
of this information.

Response #2:
The linked and revised specifications have corrected and supplemented the APWA references.
Engineered specifications are included for all project components.

Comment #3:
The specifications also didn't list anything about the pumps, sizing, pump make and model or equal for
the pump station.

Response #3:
The linked and revised specifications include descriptions of the pump manufacturers, models
and other items for the booster components.
November 6, 2024
Page 2

Comment #4:
Even with a pump skid being bid out, I need to make sure that all of the proper pressure gauges are
included. Specifically, the suction side requires a compound gauge (measuring positive and negative
pressure) and the discharge side needs to have a standard gauge. If you could point out to me where
those are or if they are not, then they need to be shown in the drawings.

Response #4:
The appropriate pressure gauges have been called out on sheet A-102.

Comment #5:
Reading through the hydraulic report, I am concerned that the pump station may be undersized. Pump
stations need to have the ability to provide peak instantaneous or maximum flow demand, not just peak
day, which it seems that is what you have sized it for. I know the rule that your referenced said that, but
the rule was changed in June 2024 and now says:
i. Capacity and Minimum Distribution System Pressure. A pump used to provide
minimum distribution system pressure shall: (a) have the capacity to meet the
maximum demand of the specific portion of the distribution system served; and
(b) be capable of providing the minimum pressures required by Section R309-
105-9.
To get that maximum demand, you would typically use the information in R309-510-9 as shown below:
Peak Instantaneous Demand for Indoor Water Use.
(a) Large or complex water systems may determine peak instantaneous demand using
hydraulic modeling. The hydraulic model must either apply an instantaneous peaking factor to
account for peak instantaneous demand or use actual peak instantaneous water flow data.
(b) Alternatively, the peak instantaneous demand for a single pipeline shall be calculated
for indoor use using the following equation: Q = 10.8 x N^0.64
where N equals the total number of ERC's, and Q equals the total flow (gpm) delivered to the
total connections served by that pipeline.
Using the single pipeline formula, you would then get Q=10.8X 122 ^ 0.64 = 233 gpm.
You can also use a peaking factor applied to the 151 gpm peak day demand, which ever works. So it
seems that 200 gpm currently might be a little low.

Response #5:
The linked and revised modeling report has been updated to include PID demand. Please refer to
the pump curves in the report for verifying pump capacity.

Comment #6:
Because the Pump Facility rule did change recently, I have provided a link below of the new rule. You
should review it and make sure your design does meet all the requirements. Specifically, I want to make
sure your design accounts for things in R309-540-6 with regards to minimum intake pressures at your
booster pump station location and low pressure cutoff controls. (R039-540-6 (3))

Response #6:
The linked and revised specifications have the required pressure monitoring and automatic shut
off or low-pressure controller.