A Three-Generation Family Company Perfects Barge Service for Hard-to-Reach Waterfront Projects

Canada’s Coulson Brothers Scow Service specializes in complex onsite systems for island homes in the upscale Muskoka Lakes region

A Three-Generation Family Company Perfects Barge Service for Hard-to-Reach Waterfront Projects

 A Coulson Bros. Scow Service barge loaded with equipment is pushed to a commercial landing to work on an onsite system project. (Photos by Bruce Bell)

Interested in Systems/ATUs?

Get Systems/ATUs articles, news and videos right in your inbox! Sign up now.

Systems/ATUs + Get Alerts

A wealthy gentleman about to close on the purchase of an island in a Canadian lake wanted to be sure there was room for a 4,000-square-foot house and a septic system. 

The real estate agent called Arnie Coulson and asked him to go to the island and investigate. About 20 minutes later, to the buyer’s amazement, Coulson called back with an answer.

“It just happened that I was in between tasks and it was a beautiful sunny day,” says Coulson, co-owner of Coulson Bros. Scow Service in Milford Bay, Ontario. “It was a two-minute drive down to the dock to get in my float plane. The flight took about four minutes. I did a bunch of measuring, and 15 minutes later I called the real estate agent and said, ‘Yes, we’re good.’

“The gentleman had a hard time believing I was on the island because the drive up there would have taken an hour, and then you would have to find a boat. He said, ‘You’re going to be doing all my work from now on.’” 

The man bought the island, and Coulson Bro. installed a 7,500 liter-per-day (2,000 gpd) onsite system with a Waterloo Biofilter treatment unit, along with steel docks and all landscaping on the property. It’s the kind of customer service that has made this third-generation, family-owned company a fixture in its territory for more than 50 years.


Coulson Bros. specializes in systems for island homes in lakes Muskoka, Joseph and Rosseau, a combined roughly 100 square miles of water about two-and-a-half hours north of Toronto. The area, known as Muskoka Lakes, has become a worldwide visitor destination. 

Around the turn of the 20th century, industrial titans from Pittsburgh built summer homes there. “Then they started putting up massive hotels,” says Coulson. “It became a tourist area, and everyone wanted their little piece of Muskoka. People call these places cottages, but they are borderline estates. It’s not uncommon to see a 7,000- to 8,000-square-foot cottage.” 

Installing onsite systems for these homes is a logistical challenge few contractors face. All equipment and materials have to cross the lakes in barges pushed by tugboats. Coulson and his brother Keith custom-built most of those conveyances. There are 10 barges, on average 25 by 75 feet, fabricated from 5/16-inch steel plate.

The eight tugboats average 33 feet long with a 10-foot beam, and draft about 40 inches of water. They are powered by 300 hp Caterpillar or Cummins diesel engines. 

“We started the first tugboat in 1989 and finished it in 1992,” Coulson says. “It was patterned after an old steam tug that plied the lakes way back at the turn of the century. We didn’t just build boxes; we tried to add some flair. Each of them has some personality. They all have names with some significance to us personally.” 


Ken Coulson, Arnie’s father, started the business in 1969 after serving in the Royal Canadian Navy and living for a few years in Hamilton, Ontario. “He moved back, bought a barge, and the rest is history,” says Coulson. “He figured out what he was going to do, and the timing was good. This area became more and more desirable. With proximity to Toronto and its financial sector, it became the go-to place to have a cottage.”

The elder Coulson was among the first to install what is known as a Whitby Class 4 filter bed on an island, working under Ministry of Environment supervision. The system is similar to the Wisconsin mound; it’s built with a grade of sand found near Whitby, Ontario, that passes a sieve test for fines. “You basically dig a hole or create a pocket and add 30 inches of Whitby sand,” Coulson says. “You layer it in and level it. Then then you put a 12-inch layer of free-draining stone on top and suspend the pipe in it. That is followed by filter cloth, sand, and a topsoil cover.” 

Arnie and Keith began working for the company during summers while in high school, then joined full-time. In 1992, their father retired and they took ownership; they worked in the field while their sister, Donna Robinson (not active with the company but still part owner), ran the office. 

“When we took it over, our dad had two barges, and we had four employees,” Coulson recalls. “My brother and I ran with it. We started taking on larger projects. We bought our first tracked excavator around 1993. Until then it had been just backhoes. From that point, we kept building.” The company now has more than 40 employees; a steel dock division keeps the team members busy during the winters. 


The company’s tugs and barges travel throughout the three lakes. Lakes Rosseau and Joseph are connected by a canal. Lake Muskoka is connected to the other two by a large lock and a small lock; the barges are sized to go through the large lock. 

Coulson Bros. has its own commercial landings on Lake Joseph and on Lake Muskoka and can use various public landings. Each barge has two 4-foot-by-20-foot independently hydraulically operated ramps at the front for loading and unloading. 

Alternative systems are more the rule than the exception on the islands. “It’s a unique area,” Coulson says. “We have a lot of pine trees and a lot of bedrock. Soil conditions aren’t necessarily the greatest. It has always been a challenge developing these properties, and the complexity of the systems has increased over the years. Everything is dictated by flow rates, which are determined by the sizing of the cottages and the number of fixture units.” 

A typical system requires more than one barge load. “If we’re doing a little two-bedroom system,” says Coulson, “we can just about get it all on one barge. But if we’re into clay soils or the site is mostly bedrock, and we have to import a lot of sand fill, that’s different.” The largest barge can carry as much as eight 20-ton loads of sand, delivered on Western Star tri-axle trucks from another company subsidiary, Muskoka Disposal. 

The barges also carry a wide variety of machinery, including excavators as heavy as 45 tons.

Onsite systems mainly use plastic septic tanks supplied by Roth Global; drainfield media is stone; piping is PVC. Where conditions call for advanced treatment units, the Coulsons prefer Waterloo Biofilter units; they also install Ecoflo (Premier Tech Water and Environment) peat and Aqua-Aerobic Systems products depending on site conditions. Coulson sees and welcomes a trend toward more systems with treatment units. 

Waterloo Biofilter modular flatbed systems are built with lightweight fiberglass shells that contain the filter media. The Coulsons typically install systems no smaller than 800 gpd, up to 2,641 gpd. Any system larger requires engineering and permitting through the Ministry of Environment.


Coulson Bros. enjoys close relationships with regulators in the various jurisdictions. The Ontario Building Code dictates the minimum septic system design standards, but townships have their own requirements as well. 

In a typical case, Coulson drills test holes to evaluate the soils, calculates the system flow and the soil percolation rate, creates the design and sends a permit application to the township. Next comes a meeting at the site where he and the local regulator review soil conditions and discuss the design. Assuming all is agreeable, the permit is issued and the project is placed on the work schedule.

Setbacks from the water can pose challenges on some sites. The Ontario Building Code specifies a 50-foot setback, but several townships in the Muskoka region increased that to 100 feet at the request of the lake association and out of environmental concern. Where site conditions make it impossible to meet the setbacks, property owners can appeal to the town council.  

Townships also seek to minimize phosphorus discharges to the lake; that generally means limiting impervious surfaces to help prevent runoff. “If we’re landscaping with flagstone rock, we leave the joints between the flagstones open, so that when rain comes it percolates down and dissipates into the soil,” Coulson says.

To no surprise, these island septic systems are costly; prices generally range from $25,000 to $85,000 (Canadian dollars). The work also requires creativity: “We’ve tried to be very progressive. Because we’re in such a unique field of work, we’ve had cases where the equipment we needed wasn’t available, and we made our own.

“We converted a fleet of John Deere log-skidders by adding boxes to them, so they are like miniature off-road articulated dump trucks. We have six of them with 5-cubic-yard boxes. We dump all the soil on the barge, we go to the island and we have a John Deere skid-steer on the barge that loads the skidders. On the job site, we scoop the material out with an excavator. 

“It’s not like the equipment drove the development of the business. The development drove the equipment,” Coulson explains. “We’ve had to scale our barges up a little bit to keep up with the equipment needs of these projects.” 

The equipment fleet includes:

  • 23 excavators, 1.5 to 23 tons, mainly John Deere, Caterpillar and Kobelco
  • 12 John Deere skid-steers on tracks and wheels
  • 6 John Deere skid trucks
  • 6 tracked dumpers (Yanmar and Canycom)
  • 2 Western Star tri-axle roll-off trucks
  • Freightliner truck


Coulson’s float plane, which he flies mainly for pleasure, plays no small part in the equipment fleet. It’s a fully restored 1964 single-engine Cessna 180 Coulson has owned for 10 years. It helps him save time, especially when there’s a need to respond to a customer, or help a work crew that has experienced an equipment breakdown or some other problem on a site.

In one case, an architect, a homeowner and a building contractor were meeting on a site; they called to ask a question. “I said it would be better if I was there,” Coulson recalls. “They said, ‘OK, we’re going to be here for a couple of hours figuring this out.’ 

“I jumped in the airplane, and I was there in seven minutes. I landed, and the owner came down and said, ‘I have never in my life experienced this type of customer service.’ 

“It’s not that the plane gets used for work a lot, but when your whole business revolves around water-access properties, it’s a great convenience.” 

And it’s a convenience for customers to have a company like Coulson Bros. to provide wastewater treatment for their island getaways. 


Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.