The U.S. Army Corps of Engineers has given local businessman Duane Hagadone a 60-day extension to provide additional soil tests to show whether dredging the Blackwell Island Channel would release heavy metals into the Spokane River and the aquifer.
In July, the corps threatened to withdraw Marina Yacht Club’s permit application if the company didn’t provide additional tests.
The corps wants to know how much dirt contaminated with heavy metals the company plans to haul to an undetermined disposal site. It also wants specific plans about how the disposal process would work, in addition to information on whether the dredging would cause heavy metals to seep into the Rathdrum Prairie Aquifer.
“They’ve just been poring over the specifics of our letter and trying to make it clear in their minds what we are asking for,” said Gregg Rayner of the corps’ Coeur d’Alene office.
Hagadone representatives met with corps officials at the Walla Walla district office Aug. 21. Officials from Idaho Department of Environmental Quality and the U.S. Environmental Protection Agency also were present.
Jim Coleman, Hagadone’s engineer, said he believes they have supplied the state and federal agencies with ample tests but that the corps and EPA want to satisfy the protocol for dredging in open water. Coleman said the marina company already revised its plans and that all proposed excavation would take place in the dry, meaning workers would use dams to keep out the water and decrease the chance of releasing heavy metals into the water.
“They probably will not come to any different conclusion, but they still wanted to have us do some additional testing,” Coleman said.
Hagadone wants to upgrade the marina at the mouth of the Spokane River, allowing for larger boats. He reconfigured the location of the proposed boat slips to avoid dredging in open water at the mouth of the channel, near Cedars Restaurant. Hagadone wants to dredge dirt from the channel to make it about 50 percent wider and at least 8 feet deep to allow for bigger boats. The manmade island is bisected by U.S. Highway 95 as it crosses the river.
The new tests also will determine whether the company must cap the channel with a clay liner to prevent leaks which could potentially send contaminated water into the aquifer.
Coleman said previous studies showed that a large amount of water from the channel already leaks into the aquifer, and the dredging would cause only a small increase.
Hagadone decided to transport the contaminated soils off-site after the corps ruled last year that about 2 to 4 feet of surface material isn’t suitable for disposal where it could leach into the lake or river.
Coleman said they are looking at five locations but won’t make a final decision until the corps issues the permit.