Cooling Water Intake Structure Construction JHA (Job Hazard Analysis / Activity Hazard Analysis)
Updated 2026-06-23
A Cooling Water Intake Structure Construction JHA (Job Hazard Analysis / Activity Hazard Analysis) is the plan that keeps the crew building a cooling water intake structure from drowning in the adjacent water body, being caught in a cofferdam or excavation failure, or injured during the in-water and marine work. Cooling water intake structure construction builds the intake that draws cooling water from a river, lake, or ocean for the power plant — combining the water and drowning hazards of working at the water body, the deep excavation and cofferdam work, and the marine/in-water construction. This guide walks through building a Cooling Water Intake Structure Construction JHA that names the water/drowning, excavation, and cofferdam hazards and assigns the water-safety, excavation, and cofferdam controls that hold up in the field.
Why cooling water intake structure construction needs its own JHA
Cooling water intake structure construction builds the intake — the structure that draws cooling water from an adjacent water body (river, lake, ocean, or cooling pond) and screens it for the plant's cooling system — including the intake structure itself, the screens and pumps, and the connection to the water body, typically requiring work at and in the water with cofferdams, deep excavation, and often piling. The hazards combine the water and drowning (working at and over the water body — a drowning hazard, the defining hazard of water-adjacent work), the deep excavation and cofferdam (the intake is built below water level, requiring cofferdams to hold back the water and deep excavation — cofferdam and excavation-failure hazards, with flooding), the marine/in-water work (in-water construction, diving, and marine equipment), and the piling and heavy construction. The water/drowning and the cofferdam/excavation hazards justify a dedicated JHA.
Breaking cooling water intake structure construction into steps
The steps for a Cooling Water Intake Structure Construction JHA follow the structure:
- Establish the cofferdam to hold back the water
- Dewater and excavate within the cofferdam
- Manage the water and drowning hazards throughout
- Construct the intake structure below water level
- Install the screens, pumps, and equipment
- Perform any in-water/marine work
- Remove the cofferdam and connect to the water body
- Verify and commission
Each step carries a hazard, and the water/drowning, the cofferdam/excavation, and the in-water work are where the most serious risks concentrate.
The hazards step by step
Water and drowning
Working at and over the water body is a drowning hazard — the defining hazard of water-adjacent construction, with falls into the water, work over water, and the water body's currents and conditions. The controls are the water-safety program: personal flotation devices (PFDs/life jackets) for work over or near water, guardrails and fall protection at the water edge, rescue provisions (rescue boat/skiff, ring buoys, throwable devices, a trained water-rescue capability), the buddy system, and managing the water conditions. The drowning hazard requires the full water-safety program. (These follow the work-over-water fundamentals.)
Deep excavation and cofferdam
The intake is built below water level, requiring cofferdams to hold back the water and deep excavation — with cofferdam-failure and flooding hazards (a cofferdam failure floods the excavation with the crew in it — a catastrophic drowning and inundation hazard), and the deep-excavation hazards. The controls are an engineered cofferdam (designed for the water loads, monitored for integrity and seepage), the dewatering system, excavation protective systems, monitoring the cofferdam and water levels, an emergency evacuation plan for cofferdam/flooding, and the excavation controls. The cofferdam failure/flooding is a catastrophic hazard. (These follow the excavation and cofferdam fundamentals.)
Marine and in-water work
The in-water construction, any diving, and the marine equipment (barges, marine cranes) carry marine and in-water hazards. The controls are the marine-work controls, dive-safety controls where diving is involved, safe marine-equipment operation, and coordinating the in-water work. (These follow the marine-construction fundamentals.)
Piling and heavy construction
The piling (for the intake foundations) and the heavy construction carry the piling and construction hazards. The controls are the pile-driving controls, and the heavy-construction controls.
A simple Cooling Water Intake Structure Construction JHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Establish cofferdam | Cofferdam failure / flood | Engineered cofferdam, monitor integrity/seepage, evacuation plan | OSHA 1926.652 |
| Dewater/excavate | Excavation / flooding | Dewatering, protective systems, monitor water levels | OSHA 1926.651 |
| Work near water | Drowning | PFDs, edge protection, rescue provisions, buddy system | OSHA 1926.106 |
| In-water/marine work | Marine / drowning | Marine controls, dive safety, safe marine equipment | OSHA 1926.605 |
| Drive piles | Struck-by / caught-in | Pile-driving controls, spotters, clear of hammer | OSHA 1926.603 |
| Remove cofferdam | Flooding / drowning | Controlled removal, water-safety controls | OSHA 1926.106 |
Water-safety, the cofferdam, and drowning prevention
A Cooling Water Intake Structure Construction JHA centers on water-safety and the cofferdam, because the defining hazard is water and drowning. The water-safety addresses working at and over the water body — controlled by PFDs, edge protection, rescue provisions (rescue boat, ring buoys, trained rescue), and the buddy system. The cofferdam addresses building below water level — the cofferdam holds back the water, and a cofferdam failure floods the excavation catastrophically — controlled by an engineered cofferdam monitored for integrity and seepage, the dewatering system, water-level monitoring, and an emergency evacuation plan for flooding. A JHA built on water-safety, the engineered cofferdam, and drowning prevention, with marine and excavation controls, addresses the hazards that define cooling water intake structure construction.
From the field: what actually goes wrong
In fourteen years across federal, heavy civil, and industrial projects, cooling water intake construction is defined by the water — the whole point is to build a structure at a river, lake, or ocean to draw cooling water, so the crew works at and over the water body, and drowning is the defining hazard. The controls are the full water-safety program: personal flotation devices for work over or near the water, edge protection and fall protection at the water's edge, rescue provisions (a rescue boat or skiff, ring buoys and throwable devices, and a trained water-rescue capability), and the buddy system. Water-adjacent work demands water rescue be ready, because a person in the water needs help immediately.
The cofferdam and the excadation are the other defining hazards, and the cofferdam failure is the catastrophic one. The intake is built below water level, so a cofferdam holds back the water while the crew excavates and builds in the dry — and if the cofferdam fails, the excavation floods with the crew in it, a catastrophic drowning and inundation hazard. The controls are an engineered cofferdam designed for the water loads and monitored for integrity and seepage, the dewatering system, monitoring the cofferdam and water levels, and an emergency evacuation plan for a cofferdam or flooding event. On the projects I have run, the in-water and marine work (barges, marine cranes, any diving) brings marine hazards, and the piling brings its own. The JHA built on water-safety, the engineered cofferdam, and drowning prevention is the one that protects the intake crew.
The bottom line
A Cooling Water Intake Structure Construction JHA names the water/drowning, the excavation, and the cofferdam hazards with specific controls — the full water-safety program (PFDs, edge protection, rescue provisions) for the drowning hazard, an engineered cofferdam monitored for integrity with a flooding evacuation plan, and the excavation and marine controls. The water/drowning and the cofferdam/flooding are the defining hazards. The JHA that manages them is the one that protects the crew.
Frequently asked questions
Why is drowning the defining hazard?
The intake is built at and over a water body (river, lake, ocean), so the crew works near and over water, with falls into the water and the water's currents and conditions creating a drowning hazard. Controls are the water-safety program: PFDs for work over or near water, edge protection and fall protection at the water edge, rescue provisions (rescue boat, ring buoys, trained water-rescue), the buddy system, and managing the water conditions.
Why is a cofferdam failure catastrophic?
The intake is built below water level, so a cofferdam holds back the water while the crew excavates and builds in the dry — and a cofferdam failure floods the excavation with the crew in it, a catastrophic drowning and inundation hazard. Controls are an engineered cofferdam designed for the water loads and monitored for integrity and seepage, the dewatering system, monitoring the cofferdam and water levels, and an emergency evacuation plan for cofferdam/flooding.
What marine hazards does intake construction involve?
The in-water construction, any diving, and the marine equipment (barges, marine cranes) carry marine and in-water hazards. Controls are the marine-work controls, dive-safety controls where diving is involved, safe marine-equipment operation, and coordinating the in-water work with the water-safety program.
Is piling involved in intake construction?
Often yes — the intake foundations frequently require piling (driven piles in the water body or bank), bringing the pile-driving hazards (struck-by from the hammer and pile, caught-in, noise). Controls are the pile-driving controls (keeping clear of the hammer and pile, spotters, hearing protection) combined with the water-safety controls for piling at the water.
Related JHAs
- Cooling Water Piping Installation JHA — the cooling water piping from the intake
- Excavation and Trenching JHA — the deep excavation
- Pile Driving Operations JHA — the intake foundation piles
- Condenser Installation JHA — the condenser the cooling water serves
Written by Mustafa Tok, CSP, ASP, CHST — OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.