New Development Concerns Shawnee Residents Neighbors Fear Flooding Will Increase When Houses Replace Absorbent Natural Vegetation

Denise Arnold remembers when her street in the Indian Trail neighborhood ended at a pine-covered slope. Even then, when rains mixed with snow melt from January through March, a swift stream spilled down the hill, often pouring onto Shawnee Drive and washing past her home.

So when developers started clearing trees off the slope to make room for houses and streets, Arnold began to worry about the impact the new development might have.

“My first thought was, ‘You don’t put a tent in the middle of a stream path,”’ she said. “How can you put a development on top of a river?”

Arnold and other Shawnee neighbors want some answers before the wet weather begins. Shawnee Canyon Estates will be built on county land upstream from houses sitting on city property. Residents fear a heavy rain will wash them into a cross current between the city and county, with neither entity taking responsibility for cleanup and maintenance.

Hundreds of acres of Five Mile Prairie drain down Shawnee Canyon. With roofs, streets and other non-porous materials taking the place of absorbent natural vegetation, Arnold fears more flooding than in years past.

But she and other concerned neighbors are not against development.

“We just want the city and county to be accountable for the regulations placed on drainage in the area,” she said.

After pleading with members of City Hall to re-examine drainage requirements for Shawnee Canyon Estates, neighbors succeeded in alerting city and county officials to the special needs of the area. Their efforts delayed a street vacation hearing until last Monday.

“We got them to look at the big picture,” Arnold said. “They were ready to grant the street vacation, but realized they needed to look at the area more closely.”

Developer Bob Frisch of Tomlinson-Black has a certificate of exemption from the county for six lots that allows him to bypass the plat process. He has also applied for 11 additional plats - for which he will go through a preliminary plat hearing - to develop the 25 acres at the east end of Shawnee Drive.

Frisch said the area is designed well and that development will not increase flooding.

“Dry wells and retention ponds will actually retard it,” he said. “The area has only flooded when people have dumped grass clippings and garden waste into the drains. It’s never flooded when the drains have been clean.”

Eldon Brown, principal engineer for the city of Spokane, agrees plugged culverts have caused most of the flooding at the base of the hill. Residents wonder whose job it is to keep the drains debris-free.

“That’s something that has to be resolved,” Brown said. “Our street maintenance people have been doing the cleaning, but it’s never been established who should be responsible.”

Such questions were raised as city and county representatives met with residents to hear their concerns and explain the process of preparing a reliable drainage plan. Their primary aim is to prevent water flow from increasing.

“We’re trying to control the water that would run off impervious surfaces,” said Brown. “The developer is responsible for handling runoff on site. The goal is to allow the natural water to flow and not add to it.”

“We want to make sure that whatever goes in there does not have a negative impact,” added Katherine Miller, project engineer for the county’s division of utilities.

She listed four major concerns the city and county are working together to address: handling water with frozen ground conditions, evaporation ponds, having open channels instead of drainage pipes and homeowners assuming drainage maintenance responsibilities.

Now a road winds up the hill past one nearly completed house. It crosses over the natural stream bed that has been rerouted at a sharp angle to flow through rock-lined ditches.

As it appears now, the course designed for runoff and rainwater starts wide and funnels downhill, flowing under the new street, through a pipe 3 feet in diameter, into a holding pond and through a pipe 1 foot in diameter before passing into the city’s drainage system.

“It’s not feasible,” said Trish Howe, who lives two houses away from the new development and now plans to buy flood insurance. “The water will have to take some 90-degree turns.”

“You just can’t control water like that,” Arnold added. “It’s going to go wherever it wants.”

But Brown said there is nothing wrong with how the stream path has been routed. Holding ponds provide temporary storage for excess water and help establish a controlled flow, he said.

“They’ve made a good attempt to mitigate the potential for erosion,” he said of the developers.

Currently, the pipes have no grates covering their openings - a serious concern with so many children in the area, just a few blocks from Woodridge Elementary School.

But Miller said the drainage plan is still in a conceptual stage and future plans call for the removal of the pipes.

With a public preliminary plat hearing still to come, Shawnee neighbors will undoubtedly bring their concerns to the table. They plan to question the county about the safety of creating an open drainage ditch and to press the city on how runoff water will be accounted for once it hits the main drainage system.

Arnold points to a holding pond at Sylvia Court, a few streets down from the new development. Though it was built to store excess water, she has seen it stay empty while the streets flood.

“We were told it would work here and it didn’t,” Arnold said. “Now we’re skeptical.”