DDW-2024-007083

154 EAST 14075 SOUTH DRAPER, UTAH 84020
TEL: [phone] FAX: [phone]

April 30, 2022
Mr. Nathan Lundstad
Utah Division of Drinking Water
P.O. Box 144830
Salt Lake City, Utah 84114-4830
Subject: Slot Canyons Inn Well No. 1, PWS# 09103 - Request for Exception on Grout Sealing
Requirements
Dear Mr. Lundstad:
This exception request is prepared and submitted on behalf of Adam Rex, owner of Slot Canyons Inn. The
purpose of this letter is to request an exception to the grout seal rule requirements for existing Slot Canyons
Inn Well No. 1. The rule exception is requested under rule R309-600-6 (6)(i) and related rule R309-515-6
(5)(iii) for the certification process. This exception request is to allow a grout seal to a depth of 30 feet in
lieu of 100 feet due to site specific hydrogeologic conditions as described below.
Slot Canyons Inn is a newly designated Public Water System (PWS). Slot Canyons Inn Well No. 1 was
constructed prior to the PWS designation, and the Well is not constructed to DDW standards because it
does not have a 100-foot-deep grout seal. This is due to the limited depth of the aquifer at the Well site and
not due to inadequate well construction. Slot Canyons Inn has developed a Preliminary Evaluation Report
(PER) for Well No. 1 that delineates DWSP Zones for the Well. As part of the PER effort,existing geologic
and hydrogeologic reports and well drillers logs were gathered and evaluated. The primary reference for
the geologic information summarized below is Doelling & Willis, 2018 (Interim Geologic Map of the
Escalante Quadrangle). Please refer to the PER submittal for additional data.
The only known aquifer at the Well site is the Lower Member of the Straight Cliffs Formation. On Slot
Canyons Inn property the bottom of the Straight Cliffs Formation is only 50 to 80 feet below ground surface
with only 30 to 50 feet of water saturated interval above the bottom of the Formation. The Straight Cliffs
Formation sandstone aquifer on the property and at the Well site is therefore very limited in depth and
saturated thickness at the Site. It is not possible to construct a well in the Straight Cliffs aquifer with a 100-
foot grout seal. The existing Well seal is constructed to Utah water well standards with a grout seal to a
depth of 30 feet.
Underlying the Straight Cliffs Formation sandstone is the Tropic Shale, a gray thinly laminated marine
shale. The Tropic Shale is considered a low permeability aquitard in the area. It is expected to have poor
water quality. The thickness of the Tropic Shale is estimated at 600 to 900 feet in the area. There are no
known water wells drilled through the Tropic Shale in the area near Slot Canyons Inn. Doelling & Willis
(2018) speculate that formations normally underlying the Tropic Shale are not present in this area, and the
Navajo Formation sandstone underlies the Tropic Shale. Therefore, the next aquifer that could be targeted
for a water well at the site is possibly up to 950 feet below ground surface, and a completed well might
Mr. Nathan Lundstad
April 30, 2022
Page 2

possibly need to extend to at least 1,100 feet. Cost estimates from drillers for such a deep well are several
hundred thousand dollars.
In summary, the Straight Cliff Formation aquifer is the only known aquifer at the Slot Canyons Property.
There are no existing wells within five (5) miles that have been drilled to the Navajo Formation. There is a
lack of any deep wells in the area that would define the depth to the next deeper aquifer. There are
unknowns in the underlying geology and significant risks and high costs to drilling a 1,000 foot plus deep
well. A PER has been completed that delineates the DWSP Zones for the Well and will be the basis for
future protection of the Well. We request an exception to allow the use of the existing Well No. 1 with a
30-foot-deep grout seal.
Thank you for your consideration of this exception request. Feel free to contact me or Adam Rex if you
would like to discuss our exception request.
Sincerely,
Chris D. Mikell, P.G.
Hydrogeologist