Harrison Lake Dike: Documented Engineering Evidence

Overview

Multiple engineering and geotechnical reports confirm that the Village of Harrison Hot Springs is planning upgrades to the Harrison Lake Dike and that detailed subsurface investigations were required to assess soil stability, groundwater conditions, and seismic risk.

This page summarizes verifiable facts from released engineering documents and links to source material.

Documented Engineering Findings

Planned Dike Upgrades

A factual geotechnical report prepared by Thurber Engineering Ltd. for Northwest Hydraulic Consultants states that the Village plans upgrades to the Harrison Lake Dike and access road infrastructure.
Source: Thurber Engineering Ltd., Harrison Lake Dike Factual Geotechnical Report, Oct 21, 2025, p. 1.

Extensive Geotechnical Investigation

The investigation included:

  • 18 test holes

  • 3 seismic cone penetration tests (SCPT)

  • Groundwater measurements in test holes

Source: Thurber Engineering Ltd., Factual Geotechnical Report, pp. 1–2.

This level of testing is typical for major flood-protection infrastructure design.

Soil and Groundwater Conditions

Soil samples were collected and tested for:

  • Soil classification

  • Moisture content

  • Atterberg limits (soil plasticity and strength)

Groundwater seepage was observed during drilling.
Source: Thurber Engineering Ltd., Factual Geotechnical Report, pp. 1–3, Appendix B.

Fill and Mixed Soil Materials in the Dike

Test hole logs identify layers of sand, silt, gravel, peat, and other fill materials within the dike structure.
Source: Thurber Engineering Ltd., Factual Geotechnical Report, Appendix B (Test Hole Logs).

Fill materials can behave differently from engineered core materials used in certified flood dikes and require careful engineering design.

Seismic and Liquefaction Assessment

Seismic cone penetration testing was conducted to evaluate:

  • Liquefaction potential

  • Seismic deformation risk

Source: Thurber Engineering Ltd., Factual Geotechnical Report, Section 2.3.

This indicates engineers considered earthquake-related failure risks.

FOI Engineering Records

Freedom of Information (FOI) records confirm the Village contracted engineering consultants for waterfront flood mitigation design, including raising dike elevation and potential flood wall construction.
Source: Village of Harrison Hot Springs FOI Response, Jan 12, 2026.

Why This Matters

These documents confirm:

  • The Village considers the dike a critical flood-protection structure

  • Engineering upgrades are planned

  • Soil stability, groundwater seepage, and seismic risks were evaluated

  • Major infrastructure decisions and costs are involved

This raises important public policy questions about flood risk, infrastructure priorities, and long-term community safety.

Source Documents

Engineering Reports

  • Thurber Engineering Ltd. – Harrison Lake Dike Factual Geotechnical Report, Oct 21, 2025

  • Northwest Hydraulic Consultants – Flood Mitigation Design Documents

Freedom of Information Records

  • Village of Harrison Hot Springs – FOI Response (Geotechnical Investigation Records), Jan 12, 2026

(PDFs available upon request)

Disclaimer

This page summarizes publicly released engineering and FOI documents. It does not constitute engineering, legal, or professional advice. Readers are encouraged to review the original source documents.