Attachment 9: GRCA GISR

Geologic Interpretive Summary Report

GRCA 318719: Rehabilitate North Rim
Utility Infrastructure
Waterline Construction from the North Rim Ballfield Site to Roaring Springs Pump House
Grand Canyon North Rim, Arizona
Submitted to:
HDR Engineering, Inc.
419 Canyon Avenue
Fort Collins, CO 80521
Submitted by:
GEI Consultants, Inc.
350 Indiana Street, Suite 750
Golden, CO 80401
303.625.9502
March 31, 2026
Project No. 2305987

Nate C. Soule, P.E., P.G.
Principal Engineer

Matt P. Olson, P.E.
Project Manager

March 31, 2026
Project No. 2305987
VIA EMAIL: [email protected]
Matt Gough, P.E.
HDR Engineering, Inc.
419 Canyon Avenue
Fort Collins, CO 80521
Re:

Geologic Interpretive Summary Report
Waterline Construction from the North Rim Ballfield Site to Roaring Springs Pump House GRCA 318719: Rehabilitate North Rim Utility Infrastructure Grand Canyon North Rim, Arizona

Mr. Gough:
Submitted herewith is the Geologic Interpretive Summary Report for the Waterline Construction from the North Rim Ballfield Site to the Roaring Springs Pump House, a component of the GRCA 318719 Rehabilitate North Rim Utility Infrastructure project. This report was prepared in general accordance with the Agreement between GEI Consultants, Inc. and HDR Engineering, Inc. The Geologic Interpretive Summary Report includes discussions of the geological conditions, geotechnical data, and interpretations for the subsurface conditions that are anticipated to be encountered during the proposed construction, and construction considerations in support of the subject project. If you have any questions regarding the contents of this report, please contact the undersigned. Sincerely,
GEI Consultants, Inc.

Rob D. Johanson, P.E.
Project Engineer

Matt. P. Olson, P.E.
Project Manager
www.geiconsultants.com

Nate C. Soule, P.E., P.G.
Principal Engineer
GEI Consultants, Inc.
350 Indiana Street, Suite 750
Golden, CO 80401
303.625.9502

Geologic Interpretive Summary Report
GRCA 318719: Rehabilitate North Rim Utility Infrastructure Grand Canyon North Rim, Arizona
March 31, 2026

Report Organization

iv

1.

Introduction

1.1.
1.2.

Project Description
Description and Purpose of the GISR

2.

Project Background

2.1.

Project Overview

2.1.1. Existing System

2.1.2. Proposed Improvements

Subsurface Investigations

2.2.1. North Rim Investigation

2.2.2. Inner Canyon Investigation

2.2.3. Geophysical Investigation

Literature Review
Historic Projects