Sewer plan prepares for the worst

A study to show how to bring sewer to the Rathdrum Prairie recently hit a major milestone – predicting how much sewage the growing prairie population might produce in the next 100 years and beyond.

The Rathdrum Prairie Wastewater Planning Committee, which includes city planners and engineers from Post Falls, Rathdrum, Hayden and Kootenai County, this month agreed to use the “worst-case scenario” of possible future growth on the prairie.

The consultants are using the projection of 12 people per acre to calculate the maximum future flow of wastewater that the cities and county could generate if the prairie were covered by homes and businesses.

The current density on the prairie is about one person per acre.

Yet officials are quick to say this density projection is only for calculating potential sewage flow and is not a vision for how much development the entities will allow on the prairie or where the building should go.

“That will sound scary to people,” said Project Manager Paul Klatt of JUB Engineers about the incredibly high density that more closely resembles an urban center than development on former bluegrass fields.

All Klatt cares about is figuring out how much wastewater might be generated on the prairie in the future. To do that, the prairie cities and county had to agree to a projected density.

“When it comes to infrastructure you want to plan for the worst-case scenarios because you never want to dig up pipes,” said Hayden Planning Director Lisa Key, adding that the density number is of no use to anyone but the engineers and planners cranking out the sewage flow prediction.

That prediction is crucial because it will dictate the size of sewer pipes, their location on the prairie and the placement of lift stations and treatment plants.

And that’s the whole focus of the $250,000 sewer master plan study, a concept that was born in 2004 and got started in 2005 when the cities and county contracted with JUB Engineers. By year’s end, the committee expects to have a draft ready for public comment.

The study also will help protect the aquifer, which is below the Rathdrum Prairie and is the sole source of drinking water for more than 500,000 people.

Currently the Panhandle Health District only allows one septic system on every 5 acres above the aquifer in the county. The master plan will eventually eliminate septic tanks from the prairie.

The study results are needed as soon as possible because development on the prairie isn’t waiting.

“We are getting just inundated with requests,” Kootenai County Commissioner Todd Tondee said.

Developers are asking to put large subdivisions on county land in the middle of the prairie. There are many requests for large projects in the areas where the prairie cities plan to grow.

Just this week, Post Falls Mayor Clay Larkin asked the county commission to hold off making a decision on whether to allow Real Life Ministries to build a new church campus on 116 acres of grass fields until the sewer master plan is complete. The commission is expected to make a final decision Thursday.

Hayden and Rathdrum have made similar requests.

Real Life Ministries’ senior pastor, Jim Putman, said the church is willing to hook to sewer as soon as it becomes available and that septic tanks could sustain the facilities until the sewer plan is complete.

Key said it’s not that simple.

“People are getting way ahead of themselves,” she said. “They think that once we have a plan for piping, life is good.”

Key said the pipes still have to reach the property, and then there is a need for lift stations and ensuring they can handle the flow.

In March, the commission denied another high-profile development because of worries that the 700-home project could harm the aquifer.

Copper Basin Construction’s plans included a sewage treatment system that would have stored treated effluent in lagoons for use in irrigating about 80 acres of open space.

Post Falls officials said they had no intention of annexing the 290 acres along state Highway 53 or taking over the sewer system. The county commission said it was uncomfortable putting such a lagoon system over the aquifer and approving a development that is essentially the size of the county’s fifth-largest city but with no services.

Post Falls also recently rejected annexing 280 acres east of state Highway 41 for the Foxtail housing development, citing sewer capacity and traffic concerns.

Now the development company is asking Kootenai County to change the zoning to allow the development to go forward.

Post Falls City Engineer Bill Melvin, the chairman of the sewer study committee, said the committee is staying out of the “philosophical and political” debate.

“Our committee is really trying to focus more on the technical aspects,” Melvin said.