DDW-2025-008332

J. Paul Wright <[e-mail]>
Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File
#23768) - Additional Review Comments
Kelly Chappell <[e-mail]>Tue, Sep 2, 2025 at 1:27 PM
To: "J. Paul Wright" <[e-mail]>
Cc: Ben Hoffman <[e-mail]>, McLaws <[e-mail]>
Paul,
Thank you for your comments. Please see my comments below, as well as revised report. Please let me know if you
need anything further.
2025-08 Water Model Report_Hidden Canyon.pdf
2025-09-02_12293E_HIDDEN CANYON TANK.pdf
1) The Tank Set of plans still has the "For Review - Not For Construction" stamp on it, this should be removed, so that
plans are ready for construction. NOT FOR CONSTRUCTION Stamp has been removed.
2) The water system analysis report is using 50 gpd per room, based on locally collected data. Until this data has been
submitted to the Division of Drinking Water and verified for use as "System Specific Sizing", we need to use the numbers
from R309-510, especially for the new units that are considered hotel/motel units. This would be 150 gpd/day per unit
instead of 50 gpd/room or 100 gpd/unit. This will increase the peak day demand by a little over 2 gpm, so it is not really a
constraint for the design and source capacity, but I thought I would mention this since that is how it will be evaluated in
future inspections, until Zion Mtn Resort goes through the process of establishing their "system specific sizing". The local
data collection has been removed and instead R-309-510 used for system capacity (150gpd/unit)
3) Just an editorial note, I believe the second to last column (far right) should be titled Peak Day Demand, not Average
Day Demand. Good catch. This has been revised.
4) The Bilco Hatch, Detail 1, Sheet C-401 that is called out as the hatch to use for the modified spring box does not meet
the Division of Drinking Water design rules for access hatches. The handle that penetrates that surface of the hatch is not
allowed as per the rule below. You should use a hatch, similar to the Syracuse hatch called out for the tank (make sure
the tank hatch also does not have a handle or any other penetration through the surface of the hatch lid).
(2) Shoebox Lid.
The frame of any access opening shall be provided with a close-fitting, solid shoebox type
cover that extends down around the frame at least 2 inches and is furnished with a gasket(s)
between the lid and frame. The horizontal surface of the tank lid shallnot have any
openings, cracks, or penetrations, such as a lock, key hole, or bolted handle that would
allow contaminants to enter the tank. This detail has been revised to show a Syracuse style
hatch with a non-penetrating handle.
5) The overflow line that is shown on Detail 5, Sheet C-400 does not call out or show where the outfall line discharges. I
assume this might be Detail 7, Sheet C-400, so if it is, it should be referenced somewhere on Detail 5, to ensure that it is
constructed properly. A key note has been added to clarify the outfall line discharge to follow detail 7 C-400.
9/2/25, 11:02 PM State of Utah Mail - Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File #23768) - Additional Review C…
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Kelly Chappell | PE Principal
Main 435.896.2983 | Cell 385.315.8983
[e-mail] | ensigneng.com
CONFIDENTIALITY NOTICE: The content of this email is confidential, proprietary, and privileged. If you are not the intended recipient, please destroy it.
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J. Paul Wright <[e-mail]>
Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File
#23768)
Kelly Chappell <[e-mail]>Wed, Aug 20, 2025 at 8:12 AM
To: "J. Paul Wright" <[e-mail]>, Ben Hoffman <[e-mail]>
Cc: McLaws <[e-mail]>
Paul,
Thank you for your comments. Below are some initial responses to your questions. We will revise the plans andreport accordingly and resubmit shortly.
Distribution System
1) I just want to clarify that the pipeline portion of this project includes 1,920 LF of 12-inch DR11 HDPE and 7,900 LF
of 8-inch DR11 HDPE. Does this include the transmission lines that are included in the tanks plans as well? Yes this
includes the transmission lines that are in the tank set.
2) In the Project Notification Form, you said that this project adds 31 ERCs to the water system. From the hydraulic
modeling reports I saw that this includes 61 units (motel, hotel) , laundry, a 72 seat restaurant, and a meeting hall. Is
that correct? That is correct. 31 ERC's made up of the stated uses you described.
3) Multiple pressure zones were described in the modeling report, but there were no PRV station details in plans.
However, I did see that the tank plans included PRV station details. Will the plans be bid out together as one set toensure that the appropriate detail is included for the water lines? Yes the intent was to bid them at the same time, however, for clarity we will add the PRV to the distribution plans as well.
4) I noticed that the sewer collection system and septic tanks were in the plans. However, no treatment system in
plans which may be a drainfield for a Large Underground Wastewater Disposal system or it is being conveyed to
another treatment system further away. Please coordinate with Roberts Beers if LUWDS or Skyler if it is going to thenew sewer that is being planned. I have been in communication with Robert Beers for a LUWDS system. The ultimate
goal is to have this wastewater treated by the regional water reclamation facility that is currently in the works.
However, there may be a need to temporarily have an onsite system, to take care a some units before the waterreclamation facility comes on line.
5) With sewer on the plans, the design needs water/sewer separation details to ensure 10 feet horizontal separationand 18 inches vertical (when crossing) with water above the sewer or you can include that requirement in the
specifications. The current alignements facilitate this, but we will add a general note to the utility plans, so this is
clear.
6) It looks like the water source for this addition to Zion Mtn Resort is Big Spring. The source capacity analysis doesnot show existing Zion Mtn Resort demands. Need to evaluate safe yield of Big Spring and account for existingdemands as well. You mention East Zion SSD in your report, but Big Spring is a source specifically tied to Zion MtnResort (13055) and is a different water source, so it needs to be evaluated that way. I looked back at the sanitary
survey I did in 2019 and the source capacity was 40 gpm for Big Spring, so demands of existing resort (I showed about
8 gpm in 2019 but this may have changed), plus Hidden Canyon need to be accounted for and described) and isdefinitely not enough for future plans for Hidden Canyon, since you mentioned they were about 120 gpm. The
reference to EZSSD was made in error. I will revise the report showing the existing demands for Zion Mountain
Resorts and proposed demands for this phase. Future phases are far into the future, if they occur, and there isregional planning to get other water sources online. I will revise and resubmit the report.
500K Tank
7) The tank shows multiple inlet pipes. I am curious what they are all for? The utility plan, C-300 shows an inlet from
big springs (roughly the 12:30 position if the tank where a clock), an outlet to distribution is located at roughly 2:00
8/26/25, 5:24 PM State of Utah Mail - Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File #23768)
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position, a future transmission line is stubbed at roughly 4:00 (this is in the advent that another source is added to the
system, this would be the fill line to the tank from that source). At roughly 6:00 is the drain and overlfow location.
8) Related to my question above, are the water lines in the tank plans included in the 1,920 LF of 12-inch pipe from
distribution? Yes
9) There is a spring collection box (Detail 5, Sheet C-400) in the tank plans? Are improvements being made to the Big
Spring collection box? If so: The intent is to replace the existing spring collection box itself with a more modern hatchstyle collection manhole. We will update the drawings according to these comments below.
- the hatch detail says to refer to Detail 6, ME 401. That sheet does not exist. The hatch needs to meet all thesame requirements as a tank hatch. - the air vent does not show the size of pipe and a required #14 screen on downturn.- There needs to be an overflow (Detail 4 shows one, but no information on profile in Detail 5) and some sortof plan view showing where it will overflow with an appropriate 12 to 24-inch free fall and #4 screen on the end.
Kelly Chappell | PE Principal
Main 435.896.2983 | Cell 385.315.8983
[e-mail] | ensigneng.com
CONFIDENTIALITY NOTICE: The content of this email is confidential, proprietary, and privileged. If you are not the intended recipient, please destroy it.
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