Rockfall Mitigation
GRW mitigates rock and debris hazards on steep slopes and cliffs.
We remove unstable loose rocks and install protection systems so communities and critical infrastructure stays safe, protected and in service.
Understanding Rockfall Mitigation
What is rockfall mitigation?
Rockfall mitigation combines hazard assessment, slope scaling, reinforcement, and catchment or barrier systems to reduce rockfall risk to an acceptable level
What it solves
It is used when loose blocks, ravelling faces, or debris flows create a rockfall risk that no longer meets geotechnical risk criteria and must be brought under control
Where it applies
Areas requiring control include above highway and rail cuts, dams and powerhouses, mine highwalls, steep pipeline and transmission corridors, and bluff or canyon slopes above developed property
Rockfall Mitigation Techniques
What Scaling Is: Scaling is the controlled removal of loose and unstable rock from steep faces by experienced high scalers working on rope access systems.
Why We Do It: It is often the first step on new cuts or existing slopes where blasting, weathering, or prior instability has created loose blocks or ravelling zones above critical assets.
How We Do It: GRW scalers use scaling bars, airbags, mechanical tools, to bring down unstable rock in a controlled manner, coordinated with traffic control, exclusion zones, and safety requirements
What A Mesh System Is: Mesh systems use high-strength steel mesh to prevent or control rockfall.
Why We Do It: Pinned mesh is fixed tight to the rock face with distributed anchors.
How We Do It: Draped mesh is hung from the crest and allowed to run freely down the slope into a catchment. Elevated mesh is suspended off the face or above the ground on posts or cables to guide rock and debris behind the mesh while keeping clearance at the toe
What Are Rock Bolts: Rock bolts are drilled and grouted steel bars used to reinforce rock masses by tying potentially unstable blocks and slabs back into competent rock.
Why We Do It: We use rock bolts where engineering assessment identifies larger structures or discontinuities that need reinforcement to achieve the required factor of safety while retaining the rock in place.
How We Do It: GRW installs resined or fully grouted and partially bonded bolts with bar types, lengths, inclinations, and bond lengths matched to design, supported by pull testing, grout testing, and detailed installation records
What Are Rock Dowels: Rock dowels are untensioned, fully grouted steel bars used as passive reinforcement to stitch smaller blocks and fractured zones back into the rock mass.
Why We Do It: We use dowels where there are smaller-scale instabilities that benefit from additional interlock and restraint but do not require tension.
How We Do It: GRW drills and installs dowels in patterns matched to face conditions and design guidance.
What Are Rockfall Barriers: Dynamic rockfall barriers are placed downslope where they stop falling rocks, while rockfall attenuators are installed higher on the slope to deflect rocks so they travel behind the net and come to rest in ditches below
Why We Do It: Designed to withstand the volumes and impacts of debris flows and rockfall events, these specialized barriers provide reliable protection for construction sites, highways, hydroelectric facilities, pipelines, and bridges
How We Do It: GRW has installed some of the largest rockfall and debris barriers in North America
What Are Debris Flow Barriers: Debris flow barriers are engineered flexible net systems positioned in gullies to intercept fast-moving mixtures of water, soil, rock, and woody debris before they impact assets downstream
Why We Do It: We use debris flow barriers in confined flow paths above roads, pipelines, power facilities, and communities where intense rainfall, snowmelt, or wildfire-affected slopes can trigger debris flows or shallow landslides and conventional basins or check structures are not practical
How We Do It: GRW installs debris flow barrier systems with engineered foundations, anchors, posts, nets, and energy-dissipating components sized for project-specific events and debris characteristics, working in narrow steep channels and coordinating access, spoil removal, and environmental controls with the project team
Why work with us
Experience: GRW is a construction contractor at heart—our crews scale slopes, drill holes, hang mesh, stand posts, and build barriers every season GRW has been operating for 20 years on projects ranging from $10,000 to $20,000,000 across diverse industries, geographies and climates.
Rope Access: We are North America’s first SPRAT certified geohazard contractor, with 100% of field technicians certified to work on steep slopes, cliffs, and canyons.
Safety: Our extensive safety program is 3rd party audited and recognized as best in class. Safety is in our DNA and extends throughout the organization as our leading priority.
Equipment: GRW utilizes track-mounted drills, spider excavators, telehandlers, heli-portable and custom equipment so we can reach and stabilize slopes that conventional equipment cannot.
Project Management: Our teams include PMP-certified project managers who use structured planning, risk registers, and an internal ERP, supported by tools like MS Project and Safety Evolution, to ensure we stay on top of our projects.
Collaboration: We build relationships and communicate early with our clients, subcontractors and vendors to ensure joint succes. We are prequalifed and preferred with many agencies, utilities and GC’s.
Emergency Response: GRW can respond immediately for emergency landslides and rockfall often caused from storms, floods, earthquakes or gravity
Frequently Asked Questions
A near miss with rockfall just occurred, what do I do?
First secure the area and keep people and traffic from the impact zone. Assess if additional debris can come down and notify your geotechnical engineer.
Contact a rockfall contractor to complete a rapid site assessment and temporary risk control measures as a permanent mitigation plan is put into place..
How early should we involve GRW in project planning
As early as possible once rockfall hazards are identified or new cuts are being considered.
We add the most value when we can advise on access, staging, and practical mitigation options before designs are finalized and traffic or outage plans are locked in
How does GRW handle differing ground conditions
We expect ground conditions to vary on steep slopes and rock faces, and understand subsurface samples may not always be economical to provide.
When we encounter conditions that differ from assumptions, we document them, raise them quickly through RFIs or change notices, recommend means and methods modifications, and work with the owner and engineer to agree on scope and pricing adjustments
Can GRW respond to emergencies
Yes, we can!
We frequently mobilize quickly after rockfall or slope failures to secure the area, remove immediate hazards, and reopen access, then work with owners and engineers to transition into permanent engineered rockfall mitigation systems.
How does GRW work with our internal or contracted engineer of record
We typically build to the engineer of record’s design, asking questions early about access, staging, and constructibility.
On many projects we also support design-assist, providing field feedback and options so the final design can be built safely and efficiently in the terrain you actually have.
Does GRW offer design-build solutions?
Yes. When fitting we deliver design-build in partnership with trusted geotechnical engineers so owners get a single, coordinated team for investigation, design, and construction This approach works well on time-sensitive or complex projects where access, staging, and differing ground conditions need to be resolved quickly and turned into constructible, defensible engineered solutions.