HDD Subsurface Mapping Standards Upgraded for WA

The Washington State Department of Transportation (WSDOT) has upgraded its compliance requirements for directional boring beneath state road systems. Ground-penetrating radar scanning is now mandatory for all HDD crossings within 50 feet of active highways, and bore logs must be submitted in real-time. The new standards aim to prevent roadbed subsidence and utility strikes in state rights-of-way.

Under the updated guidelines, contractors must provide a comprehensive 3D subsurface profile of the bore path before execution. This includes mapping all intersecting utilities with dual-frequency GPR scans and physical potholing where clearances are less than 24 inches. The logging requirements mandate the tracking of pitch, roll, depth, and drilling fluid pressure at 10-foot intervals throughout the boring process. Additionally, a minimum vertical clearance of 3 to 5 feet under highway structures and 2 feet under active drainage pipelines must be maintained.

Merra's steering systems log drill telemetry instantly, meeting these updated guidelines. Our advanced walkover locators and wireline steering tools sync directly with our database, providing WSDOT inspectors with real-time documentation. This immediate access to bore logs ensures fast approvals, avoids project delays, and guarantees strict compliance with Washington state engineering standards.