Phoenix Has More Marine Contractors Than You Would Guess
By Ray Whitfield, ADCI-certified commercial dive supervisor. Reviewed by Amanda McCallister, editor.
Potable Water Tank Inspection & Cleaning | Wastewater & Sewer Diving July 8, 2004. The water in the Central Arizona Project's 100th Street pump station forebay was 92 degrees, green, and thick enough to taste. I was in a wet suit, wearing a full-face mask, and using a jetting hose to clean a trash rack. My buddy on deck was a sounding kid from Globe with a radio. I found a pair of bolt cutters and a chunk of rebar the length of my arm. That was Phoenix. Not a postcard, but a working canal. So don't tell me there are no marine contractors in Phoenix. There are. There are more than you'd guess. I've been doing this for 28 years, and I can name six types of diving work that happen within the city limits and the surrounding valley on any given week. Here's the list.
1. Dam and Reservoir Inspection Divers
Every five years, federal safety rules require a dive inspection of the gates, valves, and seat seals of certain dams. The Salt River Project owns a chain of dams on the Salt and Verde rivers—Roosevelt, Horse Mesa, Mormon Flat, Stewart Mountain, and the others—plus the CAP has its famous dams. A lot of the critical components are underwater. You don't drain them; you send a diver. I've spent days on a single gate, using a six-inch ruler to check for gaps in a seal. It hurts your neck, and it's boring until you find a chunk missing.
2. Canal and Aqueduct Underwater Construction
The CAP aqueduct runs 336 miles, and SRP's canal system adds 131 miles. These are open channels carrying drinking water and irrigation water. When a concrete panel cracks or a joint leaks, you can't just empty the canal. You drop a portable cofferdam around the work area and build a dry space, or you send a diver down to patch a hole in the lining. I've done both. In 2013, I spent four days underwater in a canal near Chandler, placing rubber membrane patches over a joint that had opened up. We used a shutter and a pump to hold the water away from the patch. The water was 95 degrees on the surface, and we had to shade the site with tarps to make it safe.
3. Potable Water Tank and Intake Cleaners
Every municipal water utility in the valley has storage tanks. They range from 100,000 to five million gallons. Over time, sediment settles on the tank floor, and the interior wall needs inspection. We clean those tanks without draining them, using underwater vacuum and brushing equipment. We float on pontoons, and we follow strict hygiene protocols from the American Water Works Association. It's not glamorous work, and it's not a place for a drug test refusal. You are inside the tank that feeds your neighbor's kitchen sink. The reason there's a crew for this in Phoenix is simple: there are hundreds of tanks, and they don't clean themselves.
4. Urban Lake Recovery and Law Enforcement Support
Phoenix has a collection of urban lakes scattered across the metro area, and more than a few have a car in them. Police call us to search for evidence, and sometimes for people. I remember a call to a lake in north Scottsdale about a stolen ring and a purse. We did a search pattern with lights, and I found the purse on the bottom in six feet of water, still zipped. It's not always dark and dangerous; sometimes it's just a Saturday afternoon with a sunburn. But the reason this work exists is that Phoenix is built around lakes that people use in the summer, and things go wrong.
5. Underwater Welding and Cutting
For buried or submerged pipes, you sometimes have to modify a live system. That's where the wet welders come in. We rig a shielded metal arc welding setup inside a dam or a pump intake. The water might be flowing at several feet per second, so you set up a habitat around the joint to keep the arc out of the water. I've done hot taps on a 12-inch steel pipe in a water plant in Glendale, and another in a cooling water line at a power plant. It's the most dangerous work in the trade. The reason Phoenix has this work is that the metro area is one huge network of pressurized pipes, and lifting a section out is rarely an option.
6. Bridge and Culvert Foundation Divers
There are hundreds of bridges in Maricopa County, and every one of them sits on piers that go down into either dry wash or the riverbed. Monsoon flood events can scour out the sand around a pier, leaving the foundation exposed. That's a problem you can't see from the surface. So divers go down, feel around the pier, and place armor rock or pump grout. I did a job on a Gila River bridge near the Casa Blanca district in 2016. The dive was 15 feet deep with zero visibility, but the client needed to know if the scour had reached the base of the footing. It hadn't.
Frequently Asked Questions
Do I need a special license to dive in a canal or lake? Commercial diving is different from a hobby. You need an ADCI-certified supervisor and a three-person team, plus a properly configured surface-supplied system. In Phoenix, you also need permission from the canal operator—SRP or the CAP—and you have to follow their regulations. For a city water tank, you need to meet AWWA standards and show a clean drug test. Is it true that underwater welding is dangerous? Yes. You have an electric arc in water, and the current can be fatal if the equipment isn't perfect. We use custom insulated gear and a dedicated tender, and we never work alone. The wet-welding codes are strict, and a good dive company will walk away from a job that isn't set up safely. Why would a city need to send a diver into a drinking-water tank? Isn't it spotless? Not at all. Sediment and silt settle out despite filtration. It doesn't necessarily cause a problem, but it can clog outlet valves and make measurements off. Inspections are also needed to check the interior coating. We use vacuums to bring the tank back to design condition.