Attachment 3: GLCA 6914 Predesign Material-GeologicMemo

GEOLOGIC MEMORANDUM

391 Front Street, Suite D
Grover Beach, CA 93433
(805) 481-9590
www.yeh-eng.com

Date:
April 7, 2025
Project No. 223-430
To:
Aaron Swafford, PE, Apurva Sawant, PE - Jacobs
From:
Luke Salemme, EIT, Tom Whitman, PG, CEG (CA), Judd King, PE, GE (CA) - Yeh Reviewed by: Brett Arpin, PE (UT) – Yeh
Subject:

Glen Canyon National Recreation Area - Hite Boat Launch Ramp, Hite, Utah 4/7/2025

Yeh and Associates (Yeh) is providing site reconnaissance and geologic services for the Glen Canyon National Recreation Area (GLCA) Launch Ramp project in Hite, Utah. Our services are being provided per our Task Order No. 148054979 with Jacobs effective April 29, 2024, in association with Jacob’s agreement for professional services with the National Parks Service (NPS). NPS predicts that in the near future Lake Powell will have a limited number of operable boat launch ramps due to historically low water levels. The existing boat launch ramp at Hite is currently closed and no longer provides boat access
to the Colorado River. NPS
proposes to advertise a designbuild contract to construct a new boat ramp at the Hite location to
accommodate future access needs
for Lake Powel. The location of the
proposed boat launch ramp and the
project limits are shown in Figure 1.
Yeh staff visited the proposed Hite
boat launch ramp on May 15 and
16, 2024. During the site
reconnaissance, staff walked the
proposed alignment, performed
surface geologic mapping, noted
site-specific hazards along the
proposed alignment, and obtained
rock mass structural geologic data
that could impact the proposed
alignment. Yeh collected
photographs and videos from the
ground level and from the air
utilizing a drone to supplement the

Figure 1: Vicinity Map

GLCA Hite Boat Launch Ramp
Geologic Memorandum

Project No. 223-430
April 7, 2025

observations. This memorandum summarizes the existing conditions at the site, the results of the site reconnaissance and geologic mapping, as well as preliminary geologic recommendations for the construction of the Hite boat launch ramp.

1. EXISTING SITE CONDITIONS

The project site is located along the south side of the Colorado River, just west of the Hite Crossing Bridge on State Route 95 and east of the confluence of the Colorado and Dirty Devil rivers in Hite, Utah. The location of the project site is shown in Figure 1 and the approximate ramp alignment from the site map is shown in Figure 2. The site consists of the main canyon incised by the Colorado River