Humboldt Bay Municipal Water District Submits Drilling Program Plan for R.W. Matthews Dam

The Humboldt Bay Municipal Water District has submitted a Drilling Program Plan (DPP) to the Federal Energy Regulatory Commission to investigate the condition of the R.W. Matthews Dam embankment, which is a critical structure that plays a vital role in the water supply and flood control of the region. The district has engaged GEI Consultants, Inc. to perform a geotechnical investigation, including borings, cone penetration testing, and field and laboratory testing, to assess the subsurface data needed to address safety concerns outlined in the 2021 Ninth Part 12 Safety Inspection. The investigation is supported by a FEMA grant and has significant schedule constraints and milestones that must be met.

Key Takeaways:

• The Humboldt Bay Municipal Water District has submitted a Drilling Program Plan to the Federal Energy Regulatory Commission to investigate the condition of the R.W. Matthews Dam embankment.
• The investigation includes borings, cone penetration testing, and field and laboratory testing to assess the subsurface data needed to address safety concerns outlined in the 2021 Ninth Part 12 Safety Inspection.
• The investigation is supported by a FEMA grant and has significant schedule constraints and milestones that must be met by the terms and conditions of the grant.
• The district has engaged GEI Consultants, Inc. to perform the geotechnical investigation, which will provide the necessary subsurface data to inform Probable Failure Modes and address Recommendations R-5 and R-6.
• The Drilling Program Plan was prepared by GEI Consultants, Inc. and dated July 7, 2025, and was submitted to the Federal Energy Regulatory Commission on July 14, 2025.
• The investigation is critical to ensuring the safety and reliability of the R.W. Matthews Dam and the water supply and flood control of the region.
• Timely review of the Drilling Program Plan is essential to avoid potential delays or funding impacts, particularly during the limited work season due to the dam typically spilling into early summer, and winter rains starting in the early fall.

Statistics:

• The R.W. Matthews Dam is a critical structure that plays a vital role in the water supply and flood control of the region.
• The dam is subject to a FEMA grant, which has specific schedule constraints and milestones that must be met.
• The Drilling Program Plan includes borings, cone penetration testing, and field and laboratory testing.
• The investigation is supported by a FEMA grant.
• The district has engaged GEI Consultants, Inc. to perform the geotechnical investigation.

Sources:

• "HUMBOLDT BAY MUNICIPAL WATER DISTRICT 828 Seventh Street * Eureka, California 95501-1114 PO Box 95 * Eureka, California 95502-0095 Office 707-443-5018 * Fax 707-443-5731 Essex 707-822-2918 * Fax 707-822-8245 Email: Office@hbmwd.com Website: www.hbmwd.com"
• "Federal Energy Regulatory Commission 100 First St. Suite 2300 San Francisco, CA 94105"
• "Drilling Program Plan - R.W. Matthews Dam Embankment, prepared by GEI Consultants, Inc., dated July 7, 2025."