Hydro excavators help save time and money

Nate Thomas, left, and James Sauls use a hydro excavator to clear soil and debris from their work area.

New hydro excavator technology has improved the ability of City Light crews to clear soil and debris in preparation for construction – resulting in increased efficiency, lower costs and fewer errors.

Instead of using a metal augur, hydro excavators use high-pressure water jets and suction hoses to clear the area around poles and underground vaults, where water often gathers. The use of a water jet instead of a metal drill and shovels greatly reduces the risk of damaging other equipment that may be underground, such as gas, water, electric, sewer, or communications lines.

“We used to encounter unmarked utilities on a fairly regular basis,” explains Richard Moralez, Manager of Electrical Services and Construction at the City Light South Service Center. “The use of hydro excavators has helped us to avoid a lot of damage.”

Underground utility equipment is often decades old and unmarked, meaning crews frequently aren’t able to see it until it is too late. The result – in the past – was typically equipment damage that had to be repaired by City Light or other utilities.

Using a hydro excavator means any damage is minimal to nonexistent when crews encounter unforeseen underground equipment. The most common damage is only minor nicks from the suction tube. This vast improvement in technology saves the utility money and reduces construction times – meaning lower costs for our customer-owners.

There are several additional benefits to using hydro excavators. Water and debris are vacuumed up into a large capacity tank on the work truck, which can then easily be disposed of at City Light’s new decant facility. The decant facility pretreats the water and solids using a carbon filtration system, allowing for cost-effective disposal while complying with all federal, state and local environmental regulations.

If crews encounter contaminated soil on the job, they are able to localize and dispose of it at the South Service Center decant facility or other certified facilities. Samples of the material can be collected and identified, allowing the information to be shared with the rest of the city’s utilities, increasing safety and reducing costs.

Another important benefit is reduced wear and tear for crew members. Crews no longer need to clean and shovel dirt off of metal augurs and then hand-shovel dirt back into the area post-construction. Instead, they can use the much gentler and more effective hydro excavator to clear the work space, and then refill the area with clean backfill material from a separate dump truck. This has the added benefit of leaving the construction space with the best possible appearance when they leave the job, so that when a restoration crew comes in, there isn’t much left to clean up. Instead of needing three or four trucks in a fleet, crews may need only one truck to get the job done.

“The utility first started using hydro excavators periodically within the last 10 years, but has greatly increased its usage recently as we’ve found it to result in much lower incidences of damage,” said Moralez.

Although City Light is not liable for damage to unmarked utilities, it’s still an inconvenience to the customer who may go without cable, telephone, or water service during repairs.

“The real success story is the improved service to the customer,” Moralez said.

New Decant Facility Helps Nation’s Greenest Utility Protect Environment, Reduce Costs

A vactor truck delivers water pumped from underground vaults to City Light’s new decant facility.

A new facility in South Seattle is helping Seattle City Light protect the environment, streamline operations and reduce costs for our customer-owners.

City Light recently completed construction of a $1.5 million carbon filtration decant facility at our South Service Center on 4th Avenue S. The facility pretreats storm water and solids that utility crews collect from electrical vaults and slurry from pole excavation activities so it can be disposed of in a cost-effective manner while meeting all federal, state, and local environmental regulations.

“We’ve been having to haul liquids and solids from vaults all the way to Fife,” General Manager and CEO Jorge Carrasco said during a ribbon-cutting ceremony May 15. “It’s very expensive to do that,” he said. “Just as important, we’ve always wanted to do the right thing environmentally.”

Some of this water comes from underground vaults that crews must empty before they can perform maintenance work. City Light also collects the water we use when crews dig holes with hydro excavators for many utility poles. Instead of a metal augur, hydro excavators use high-pressure water jets and suction hoses to remove soil, reducing the risk of damaging other underground equipment like gas, water, communications and sewer lines that might be in the area.

Before the new decant facility opened, a treatment plant in Fife was the closest option for City Light to properly dispose of the water we collected. Operating our own facility will save the utility at least $125,000 per year in operating costs and reduce the amount of time employees spend hauling large quantities of storm water to Fife. It also will cut down on the amount of greenhouse gas emissions created by our trucks, which helps us remain carbon neutral because we’ll have less to offset.

Those efficiencies will help City Light continue to provide some of the lowest cost electricity in the nation to our customers in an environmentally responsible manner. That’s one more reason we call ourselves the nation’s greenest utility.

The facility now operates at the southwest corner of the South Service Center grounds. It was designed by Gray & Osborne and built by McClure and Sons Construction.