City mulls ideas for leaking reused water reservoir

Carson City sewer users may foot most of the $30 million bill in the next several years for fixing a leaky reservoir and expanding the sewer's wastewater system.

The public will get its first look at a draft plan today, outlining different ideas on what the future system should look like.

One possible controversial idea might be to dig massive infiltration basins near residents living above the Mexican Dam area. The pools would allow treated wastewater to filter into groundwater supplies in the area.

"Some residents out there are concerned about that concept," said City Utilities Manager Tom Hoffert.

Most imminently, the city plans to install a lining in Brunswick Reservoir, a $2.8 million project. The basin leaks 2,000 acre-feet of treated effluent each year. Last year, the state Department of Environmental Protection directed the city to adopt an official plan by Sept. 30.

The Draft Reuse Master Plan also lists four alternatives for reusing the water. After gathering public comment tonight, the city will present the plan to the Board of Supervisors to pick a preferred alternative.

"We have to submit basically our action plan and timeline for sealing the reservoir," said Hoffert. "It's very important for the city to get the public comment on the (plan) alternatives report as decisions and a timeline need to be made in time to meet a deadline requirement placed on us."

The city reclaims about 5,800 acre-feet of wastewater that can be reused for irrigation each year. Currently, the city treats about 5 million gallons each day. That amount is expected to nearly double in 20 years.

Once the reservoir is lined, the city will need extra customers to use the leftover water. It already serves ball fields, recreation areas, golf courses and the Nevada state Prison farm and dairy.

One option is to build another 1,000 acre-foot reservoir near the rifle range behind the city landfill. Then, the city would need to find properties totaling 2,600 acres to provide with treated wastewater, either by signing up new customers or using it on public lands within city limits.

The city would then install two "rapid infiltration basins" above the Mexican Dam where treated water would be pumped. The water - treated to drinking water standards with nitrates less than 10 milligrams per liter - would pool in the basins and filter through the earth to eventually integrate again with groundwater. Monitoring wells would be installed around the basins to insure quality, Hoffert said.

Plan No. 2 would be to build larger infiltration basins and not seek 2,600 acres to provide with wastewater in the city.

With the third plan, the city would not install the infiltration basins or build another reservoir. Instead, an additional 2,100 acres of property would be found to supply with wastewater in Carson City and the city would ship 2,000 acre-feet of the water to Bently Agrodynamics in Douglas County during the winter to be stored for summer use.

The fourth option would require the city to upgrade its wastewater treatment plant and process effluent to a higher level of purity, then discharge it into the Carson River.

Right now, the state doesn't allow the scenario and laws would need to be changed.

"That's a big unknown, but that is an option," Hoffert said. "It's probably the least likely of the four."

Overall, the plan would take the city to 2025. Not all changes would occur immediately. If everything goes smoothly, the city expects to fix Brunswick Reservoir with a lining sometime between 2008 and 2010.

Sewer ratepayers would bear the cost, but the city is searching for outside funds, Hoffert said.

"We're actively searching and trying to find federal assistance, so our existing ratepayers may not have to bear the full cost of this over time," he said.

If you go

What: Public Hearing on Draft Reuse Master Plan

When: 6:30 p.m. tonight

Where: Sierra Room, Carson City Community Center, 851 E. William St.

Glossary

An acre-foot is about 326,000 gallons, or enough water to meet the needs of an average family of five for a year.

Contact Jill Lufrano at jlufrano@nevadaappeal.com or 881-1217.