Coeur d’Alene Parks Director Doug Eastwood was surprised recently to find a 25-foot hole where a city park is planned to serve residents of a new housing development off Atlas Road.
The discovery has sparked discussion about how developers should move dirt so it doesn’t cause drainage problem, lack of vegetation and potential harm to the Spokane Valley/Rathdrum Prairie Aquifer, which is the sole source of drinking water for more than 400,000 people.
The hole was created when Prairie Falls LLC, the developers of the 362-lot Sunshine Meadows, removed the soil and gravels from the 2.6-acre future park site and trucked it to Blackwell Island. Local businessman Duane Hagadone used the material, which engineers consider to be suitable building soil, to elevate about five acres of land that sometimes floods. Hagadone eventually plans to build on the site as part of a planned expansion for his Marina Yacht Club.
When Eastwood discovered the hole, which is considered a surface mine and an illegal activity within Coeur d’Alene’s city limits, he stopped the developers from using topsoil to fill the pit. Using topsoil could cause drainage problems, which Eastwood said has already happened in other Coeur d’Alene parks.
Because the first layers of soil are so fine, it’s difficult for water to drain when the dirt is compacted. That means the area turns into a mud pit. Or, if the soil isn’t compacted, water can drain too rapidly through the ground, making it difficult for grass and other plants to grow. When that happens, it forces the city to use extra water. That’s a threat to the aquifer because nobody knows how much water is left in it.
Eastwood said the city needs to prevent getting chunks of land for public parks that have inadequate soil because it costs the city money and heartache.
“Mother Nature did a good job creating a soil profile,” Eastwood said. “I would have preferred to have seen that left alone.”
The developers agreed to donate the 2.6-acre park when Coeur d’Alene included the 108-acre property in the city limits in June 2003. Eastwood said the city won’t convert the land into a park for about five years.
Eastwood routinely takes soil samples of Coeur d’Alene’s parks, sending them to the University of Idaho for scrutiny. He always wondered why the results were so varied. Now he suspects it’s because developers aren’t doing a good job of replacing native soils.
The worst example is the area surrounding the Interstate 90 and Northwest Boulevard intersection. Eastwood said the city can’t get anything to grow there and the shrubs that have survived are anemic. That’s because crews covered the areas with sand, instead of topsoil that contained organic materials and nutrients needed for plant life. Each year the city adds about a quarter-inch of organics to the ground in hopes grass eventually will grow.
Sunshine Meadows developers are currently working with the city to find a way to fill the hole at the property east of Atlas Road and south of Prairie Avenue. Prairie Falls LLC hired a geotechnical engineer to come up with a plan and Coeur d’Alene called Idaho Department of Lands for help.
Neither the city nor the Department of Lands is pursuing the surface mining violation because they just want to find a solution.
Jim Brady, who oversees surface mining for the Department of Lands, sees the use of topsoil as fill as a much larger problem than area cities and counties realize. Another issue is that developers often remove all the topsoil from a site, so no vegetation can grow unless the new homeowners buy topsoil. He said that people often skimp and don’t buy enough topsoil to get healthy plant growth so they end up wasting water because they need to irrigate constantly.
That’s why he recently talked to the Coeur d’Alene Parks Committee and will give a presentation Monday to the city’s General Services Committee, which includes three City Council members.
“We have a very important resource below us – the aquifer,” Brady said. “We need to be more proactive.”
Neither Brady nor Eastwood are totally pleased with the way Prairie Falls is proposing filling the hole and would like to see it filled with an equal mixture of topsoil and gravel. Yet the developer’s plan still is to fill it with topsoil and then dome the top so water runs off and soaks into the areas that weren’t dug up.
Eastwood requested that the developers put a layer of sand and gravels on top to help the area drain in addition to about a three feet of topsoil so the city can get grass, shrubs and trees to grow. Initially the developers proposed putting less than a foot of topsoil on the surface.
“That seems to be the core of the problem,” Eastwood said. “We need it filled so there is sustainable plant life.”
Most people agree there is no easy solution. Developers need to remove the topsoil because it’s not suitable to build on. Often they stockpile it on site or sell it.
Bill Radobenko of ACI Construction, who did the excavating work both at Sunshine Meadows and Blackwell Island, said he was shocked the city had a problem with the dirt moving. He said it’s common for developers to transfer dirt from one project to anther.
“They’re making a mountain out of a hole,” Radobenko said about the city’s concerns.
Yet if city officials decide to develop more specific rules for the use of topsoil, Radobenko said he would be happy to help them hash out a plan.
Eastwood said it’s unknown what will happen next.
“I think now there’s an awareness,” Eastwood said. “Probably there is something that can be done, we just don’t have all the information.”