DDW-2025-008331

J. Paul Wright <[e-mail]>
Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File #23768)
1 message
J. Paul Wright <[e-mail]>Tue, Aug 19, 2025 at 3:40 PM
To: Kelly Chappell <[e-mail]>, McLaws <[e-mail]>
Kelly and Kevin,
I have reviewed the plans for the Hidden Canyon 500K tank and water lines project. I have the following review comments:
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?
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?
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 to ensure that the appropriate detail is included for the water lines?
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 the new sewer that is being planned.
5) With sewer on the plans, the design needs water/sewer separation details to ensure 10 feet horizontal separation and 18 inches vertical (when crossing)
with water above the sewer or you can include that requirement in the specifications.
6) It looks like the water source for this addition to Zion Mtn Resort is Big Spring. The source capacity analysis does not show existing Zion Mtn Resort
demands. Need to evaluate safe yield of Big Spring and account for existing demands as well. You mention East Zion SSD in your report, but Big Spring is a
source specifically tied to Zion Mtn Resort (13055) and is a different water source, so it needs to be evaluated that way. I looked back at the sanitary survey Idid 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), plusHidden Canyon need to be accounted for and described) and is definitely not enough for future plans for Hidden Canyon, since you mentioned they wereabout 120 gpm.
500K Tank
7) The tank shows multiple inlet pipes. I am curious what they are all for?
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?
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 hatch detail says to refer to Detail 6, ME 401. That sheet does not exist. The hatch needs to meet all the same requirements as a tank hatch.
- the air vent does not show the size of pipe and a required #14 screen on downturn.
8/19/25, 3:40 PM State of Utah Mail - Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File #23768)
https://mail.google.com/mail/u/0/?ik=f3bcb897f8&view=pt&search=all&permthid=thread-a:r3341147082413822016&simpl=msg-a:r-7759541971835863231 1/2
- There needs to be an overflow (Detail 4 shows one, but no information on profile in Detail 5) and some sort of plan view showing where it will
overflow with an appropriate 12 to 24-inch free fall and #4 screen on the end.
Let me know if you have any questions.
Paul
--
J. Paul Wright, P.E. | District Engineer | Southwest Utah District
435.986.2590 (office) | 435.680.0163 (cell) | 435.986.2595 (fax)
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8/19/25, 3:40 PM State of Utah Mail - Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File #23768)
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J. Paul Wright <[e-mail]>
Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File
#23768) - Additional Review Comments
J. Paul Wright <[e-mail]>Thu, Aug 28, 2025 at 12:09 PM
To: Kelly Chappell <[e-mail]>
Cc: Ben Hoffman <[e-mail]>, McLaws <[e-mail]>
Kelly,
I have a few more comments that need to be addressed before a plan approval letter can be issued. These are based on
the revised plans and comment responses that were submitted for this project on August 25.
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.
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".
3) Just an editorial note, I believe the second to last column (far right) should be titled Peak Day Demand, not Average
Day Demand.
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.
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.
Let me know if you have any questions.
Paul
On Mon, Aug 25, 2025 at 4:24 PM Kelly Chappell <[e-mail]> wrote:
Paul,
See revised Tank Planset, Distribution Planset, and Hydraulic report revised per your comments.
Please reach out if you have any questions.
2025-08 Water Model Report_Hidden Canyon.pdf
8/28/25, 12:10 PM State of Utah Mail - Zion Mtn Resort (13055) Hidden Canyon 500K tank and Water lines (Project File #23768) - Additional Review …
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