How Incline Village sewage ends up in Carson Valley
You could say Harvey Johnson, a chemist schooled at the University of Wisconsin, knows how to make a silk purse out of a sow’s ear.
Johnson, plant superintendent for the Incline Village General Improvement District, oversees the processing of sewage produced in Incline Village at the north end of Lake Tahoe through two stages of treatment and 22 miles of pipeline, to flow into the flourishing wetlands at the north end of Carson Valley.
Why so far and why the Carson Valley?
“It actually started in 1984,” Johnson said. “Before that, we used to dump the effluent (treated sewage) into the Carson River, but at one point the EPA said we couldn’t release secondary treated wastewater into the Carson River – only tertiary water – so we had to find an alternative.”
For years, from April to November, the effluent (one step away from being drinkable) had been used for crop irrigation on the Snyder Ranch in north Jacks Valley, Johnson said. Then, from November to April, the Incline water was released into the Carson River not far from what is now the Incline Village General Improvement District Wetlands Enhancement Facility.
The 900-acre site is located in north Douglas County, just north and west of the Johnson Lane housing development, off Vicky Lane. The land, formerly part of the Dangberg estate, was purchased in the 1970s, Johnson said, by the IVGID, and not put to use until the mid-1980s.
Considering several alternatives – building a reservoir to hold water for summer irrigation, treating the effluent to a tertiary level or sending it to the Carson Valley for evapotranspiration – IVGID decided the most cost-effective, best choice, was the latter, and because the pipes were already close to the site, a minimum pipeline extension would be necessary.
There were already natural wetlands at the 900-acre plot, fed by water from nearby hot springs and occasional flood water from the Carson River. Construction of additional evaporating ponds, necessary for the effluent’s final treatment, only created more habitat for the birds that already flocked to the area.
– Ultimate benefactors. The wetlands provide a wonderful habitat for an informal inventory of 58 species of birds and mammals seen at the site.
Without trying too hard, more than 20 species of birds can be seen in a few minutes on an April morning at the wetlands – American avocet, black-necked stilt, yellow-headed blackbird, red-winged blackbird, Brewer’s blackbird, killdeer, shoveler, mallard, Canada geese, ruddy duck, cinnamon teal, American coot, pintail, marsh hawk, American kestrel, red-tailed hawk, white-faced ibis, ring-billed gull, common egret, cliff swallow, barn swallow and more.
During hunting season, usually from October through January, the Wetlands Hunting Club, made up of waterfowl hunters from Incline Village and the Carson Valley, comes to duck blinds and hunts on foot for waterfowl.
In 1998-99, 815 ducks and 18 geese were taken from the site. Johnson said 135 acres at the north end of the wetland remain as a refuge for the birds and is off limits to hunters.
By mid-July, the ponds will be dried up, Johnson said, except for the natural hot springs-fed water bodies.
– How it works. After wastewater leaves an Incline Village home or business, Johnson said, it goes to one of 18 sewer lift stations and then on to the treatment plant behind the Ponderosa Ranch. There, it gets a secondary active sludge treatment, which is an aerobic (requiring air) biological process using microorganisms that are grown on site, fed and re-seeded, like a sourdough culture.
The liquid then goes through a clarifier gravity drum, where the “good” water rises and floats off the top and bio-solids sink to the bottom. This top water is then disinfected with a strong solution of chlorine bleach and it starts the 22- mile pipeline journey, tumbling through the pipes, reaching a half million-gallon tank across from Sand Harbor and dropping 3,000 feet in altitude from the Spooner area to the Carson Valley, where it is released into the wetlands. The whole process only takes a few days, Johnson said.
After reaching the eight constructed wetland cells, or ponds, the evapotranspiration takes place – evaporation into the air and transpiration into the pond’s plants, where the nutrients are removed. Percolation into the soil also processes the water, as it flows from cell 1 to cell 2 and on to cell 8.
At this point, the water isn’t technically potable, but doesn’t negatively affect the wetland’s wildlife. It is only one step away from being drinking water, Johnson said, and through time in the ponds, the third step – removing the nitrogen and phosphorous -occurs naturally through plant action.
– Who uses the water? The Sunridge Golf Club, located west of the wetlands in Sunridge, used some of the water to fill ponds, Johnson said. Recently, IVGID signed a 25-year contract with Bently Agrowdynamics to provide irrigation water for their nearby agricultural fields. Next year, Johnson said, Bently will use IVGID’s bio-solids as a soil conditioner and compost agent.
“Pretty soon, they will be taking 99 percent of what we produce,” Johnson said.
– Better access soon. Because of problems with trespassers and poachers, Johnson said a full-time residence is planned for the wetland, starting this summer.
“It’s a liability thing as much as it is a safety issue,” Johnson said. “Someone could get hurt here and lie there for a week until they were discovered. And, when we have someone here full-time, we’ll be able to offer more education programs to the community.”
Spring at the wetland is a lively place, with the skies and waters alive with huge a variety of courting and nesting birds. Johnson said any teachers who want to take their classes to the wetlands for a field trip should call him at (775) 832-1289.