Delta restoration could start this summer
SANDPOINT — A massive project to restore the fading Clark Fork River Delta is slated to start this year if environmental clearances are secured.
An Environmental Assessment being prepared by the Bonneville Power Administration is forecasted to be complete by early May, which will give way to pre-condition monitoring, according to Kathy Cousins, an Idaho Department of Fish & Game wildlife biologist.
Construction staging could start in July and work will proceed through the winter, when Lake Pend Oreille is drawn down to a lower winter pool of 2,051 feet above sea level.
The initial phase of work will focus on fortifying the land mass between the two main channels of the river that flow into Lake Pend Oreille.
“It’s the largest of the areas and has the greatest erosion rates and so it needs to be protected first,” Cousins told Idaho’s Lakes Commission on Wednesday.
Temporary roads will be established to bring materials in or serve as a toe for a vegetated rock breakwater. Some barrow material to build up areas may also be barged in.
Fish & Game will be using lessons learned in restoring the Pack River Delta to fine-tune restoration of the Clark Fork Delta. Log vanes, for instance, were used in the Pack, but the department is opting for bendway weirs — rock sills built at an angle in the river channel to control water velocity and current direction — in the Clark Fork.
Cousins said log vanes were not strong or high enough to handle the forces of the river.
“But these (weirs) are perfect,” she said. “They’re easy to construct and pretty cheap compared to the log vanes, which were very technical and took a lot of man hours to put in place.”
Funding for the entire restoration project — which is estimated to be $10-11 million — is still something of a moving target. Avista and BPA have so far only pledged $3 million apiece as mitigation for delta erosion caused mostly by the Albeni Falls Dam and to a lesser extent the Cabinet Gorge Dam, according to Cousins.
It’s estimated that the delta is eroding at a rate at least 15 acres per year. The delta is approximately 5,000 acres and the restoration will address 1,200 acres of trouble spots and opportunities to counteract dam effects.
The project also calls for 78,000 willow plantings and 10 acres of herbaceous bench plantings.
Cousins conceded that environmental clearances under the federal National Environmental Policy Act are behind schedule. However, BPA expects an EA finding that a more rigorous Environmental Impact Statement will not be necessary.
“I don’t anticipate us needing to go through an EIS for this project,” said Jenna Peterson, BPA’s environmental lead for the restoration project.
Cousins said a comprehensive website and social media presence is under development to apprise the community of the work that’s being done and provide a way for people to volunteer their time or make donations.