How do you restore an old riverside gravel quarry, protect native species, reduce erosion and stabilize a wildly vacillating river? That's the challenge faced by Metro's natural areas program as it starts looking at restoring River Island.
River Island is 240 acres of wetlands, oak savanna, upland and riparian forests located near Barton in Clackamas County. The river is home to native salmon, steelhead, lamprey and western painted turtles, all of which are considered critical to the river's ecology.
More than 20 years of gravel mining, combined with a major flood in 1996 changed the course of the river and the ecology of the site, causing massive ramifications that remain to this day.
From 1963 to 1999, this area was mined by the River Island Sand and Gravel Company. The company initially mined gravel in the middle of the river, but eventually mined in the nearby floodplain. A 2006 report by P.J. Wampler estimates at least 2.7 million cubic meters of gravel in total was removed from River Island. That's roughly enough gravel to cover a square mile with a foot of gravel.
The floods of 1996 breached the dikes constructed by the gravel company and flooded the gravel pit. Within two days of flooding, more than 135,000 square meters of land and gravel had eroded and changed the course of the river.
Brian Vaughn, a natural resource scientist at Metro, said floods are a natural way that rivers change course and riparian forests help stabilize the river changes.
"High water events in rivers are natural and they help form the natural habitats that are known on rivers - side channels, islands, log jams all those types of features," Vaughn said.
But when the Clackamas River flooded the gravel pit, it didn't have these forested areas to mitigate the flow. Riverbanks now erode, the river itself has sped up, and the large gravel pits have become giant holes that take in sediment that would normally flow farther down the river.
"The whole channel within a couple miles of River Island is out of balance," Vaughn said.
Riz Bradshaw lives on the Clackamas River upstream from River Island. He has noticed the river becoming wide and fast. He also notices fewer salmon.
"The old holes where we typically salmon fish are gone - the river has flattened out," Bradshaw said, adding that fish need deep, cool spots in the river in summertime.
Charlie Christensen, a neighbor on the border of the River Island site, says the river is changing its course every year, which he attributes to the mining operations.
"The river is wildly changing its course every winter. Before the gravel pit degraded the property, the river behaved in way you expected it to," Christensen said. "The river changed so much it now flows through our property when it once bordered it."
Christensen also says that the mining operations changed the quality of the soil near his property and affected the groundwater, making the soil impermeable.
Vaughn said there are many challenges to restoring the area, due to all of the material that has been removed from the site. In addition to gravel that had been removed, the mining operation dumped concrete and asphalt as fill material.
Metro is holding an open house at 6 p.m. on June 26 at Barton County Park. The meeting will help prioritize the needs of the project. Vaughn said Metro is presenting the technical design draft and wants public input to refine it.
The specifics about the restoration of River Island are still up in the air, but there is consensus on two key ideas – the restoration needs to remove the infrastructure left by the mining operation, and Metro won't try to reroute the river back to the original channel.
Vaughn said moving the river is not feasible because it has deepened in its current channel. Instead, Metro will focus on improving the river where it currently flows.
"There's no going back. What we are trying to do is to just basically get the river functioning more naturally," Vaughn said.
Metro Councilor Carlotta Collette said Metro isn't fighting against nature – it's partnering with it.
"The river is going to do what the river wants to do," Collette said. "You want to take your time and watch what's happening … and then base what you do on that. So you are more as a partner to nature than trying to alter nature's intention."