Rocky Mountain Report — Watch the Plow and Heavy Machinery During Tricky Springtime Installations

Working on mountain grades and surrounded by snowdrifts is nothing new for Colorado’s Nick’s Dirt Works

Rocky Mountain Report — Watch the Plow and Heavy Machinery During Tricky Springtime Installations

 Nick Waldow used a Case excavator and a Mustang skid-steer loader to remove the thick blanket of snow. It took about a day to clear the sloping, heavily wooded lot. While the snow initially was a hindrance, it also helped by insulating the ground, which prevented it from freezing. The lot contains heavy clay at a depth of 14 inches, which made it a good candidate for a GSF system. (Photos courtesy of Nick’s Dirt Works)

Installing a septic system in the middle of winter with roughly 4 feet of snow on the ground may sound implausible to installers in warmer climates, but it was just another day at the office for Nick Waldow, the co-owner of Nick’s Dirt Works, based in Fraser, Colorado.

Waldow installed an Eljen Geotextile Sand Filter system in March 2019 because the property owners ­didn’t want to wait until early summer to move into a newly built, four-bedroom home, located outside of Granby, a small mountain town about 85 miles northwest of Denver.

“If the homeowners would’ve waited, the snow melt would’ve turned the site into a mud pit,” says Waldow, who co-owns the company with his wife, Caroline. “Then they probably would’ve had to wait until June to move in.”

The thick layer of snow actually worked in Waldow’s favor because it insulated the ground and kept it from freezing. Nonetheless, it still required some skill and finesse to clear all that snow off portions of the 2-acre, heavily wooded and sloping lot, he says.

“We had to be very careful to not damage any trees or ruin any landscaping,” says Waldow, who owns a Case CX160B excavator and a skid-steer loader manufactured by Mustang (a brand owned by the Manitou Group). “You just have to watch the bucket and take your time.

“We put the snow wherever there was room to pile it,” he adds. “It took a day to remove the snow. We’re actually used to working in winter, so it wasn’t as bad as it sounds.”

Fortunately, temperatures during the roughly two-week-long project hovered in the mid-40s. The downside? The warmer temperatures made local roads softer, so deliveries of sand and other materials had to be scheduled during mornings to minimize road damage from dump trucks.

“We tried to get them in as early as possible while the roads were still cold,” Waldow explains.

Restricted access

Hundreds of small trees on the lot limited access to the drainfield, located on the south side of the lot at the bottom of a slope with about a 5-degree grade. The easiest path to the site happened to pass over the planned location of the septic tank.

So to avoid potentially damaging an installed septic tank with heavy excavation equipment, Waldow instead installed the nearly 1,500-square-foot drainfield first. That required digging a roughly 14-inch-deep trench about 12 feet wide and 130 feet long.

“We cleared off all the snow where needed, then shot the elevations to be sure the laterals would be at the correct grade,” he says.

Accurate grade measurement was critical so effluent would drain properly and not freeze inside the pipes during winter. Furthermore, piping from the 1,250-gallon, three-chamber concrete tank to the drainfield had to be covered by a minimum of 1 foot of soil.

Soil on the lot contains heavy clay at a depth of about 14 inches, which made a pretreatment system a good solution for the site.

While digging the drainfield trench, excavator operators had to be careful not to smear the damp clay with the bucket. That would reduce the absorption rate of the ground below the GSF units, Waldow says. “Instead of using the bottom of the bucket to smooth it up, you have to just scratch it with the bucket to loosen up the clay,” he explains.

Install proceeds quickly

After that, the crew laid about a 12-inch layer of washed concrete sand, then installed the GSF units, which measure roughly 4 feet long by 3 feet wide by 7 inches tall. 

“We used a walk-behind skid-steer loader (Bobcat) to run the sand to the drainfield so we wouldn’t damage any trees,” Waldow says.

The crew laid 62 units — 32 in two rows on one half of the curving, boomerang-shaped trench and 30 in two rows on the other half of the trench. They left approximately 3 feet of space between the two rows and about one foot between the trench walls and the GSF units, he says. “The GSF units are really light and easy to install,” Waldow says. “You just snug them up against each other.”

The next step: Use U-shaped clips to attach four roughly 60–foot-long sections of 4-inch-diameter, perforated PVC SDR 35 pipe atop the four rows of GSF units. After that, the crew placed anti-siltation geotextile filter fabric over the pipes and the GSF units to keep sand from clogging the units, then put sand on top to keep the fabric in place.

Bring in the tank

With the drainfield installed, workers moved on to installing the septic tank, which was set with a crane owned by the company that delivered the tank. The tank includes a pump chamber to discharge effluent to the drainfield. The system, designed for 525 gpd, also features a two-way cleanout between the house and the tank.

“After that, we dug a trench from the house to the tank and hooked up the house to the tank,” Waldow says. “Then we connected the tank to the 

D box, then the D-box to the perforated pipes on top of the GSF units.”

Workers then filled the drainfield trench with enough sand to cover the GSF units and the filter fabric. In the final step, they backfilled the rest of the trench with the original soil and compacted it, he says.

Waldow had never installed this kind of Eljen system before.

“I’d say it’s a pretty good application for this particular situation,” he says, referring to the limited space for a drainfield, not to mention the high clay content, which makes pretreatment a preferred option. “It keeps the size of the drainfield down, which minimized disruption to the lot. Once you figure it out, it’s pretty easy to install.” 


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