| Dam News 2010 River Restoration Q and A |
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Excerpted from the Dam News 2010 Why restore it?
Why restore it? The Clark Fork River may not be dammed any more, but it's temporarily straight-jacketed within the bypass channel. After removal of all the reservoir sediment, there's no longer any channel for the Clark Fork, so rather than simply turning the river loose across the construction site, the State of Montana will create a natural channel and floodplain.
What are the goals of Milltown restoration?
How will it be done? An entirely new channel and floodplain will be created from scratch in the former reservoir area (CFR 2). Then, just upstream from this (CFR 3A), a wedge of sediment will be excavated and removed in order to create a consistent channel and floodplain slope from upstream to downstream as the river flows into the former reservoir area. Further upstream (CFR 3B), additional channel work will temporarily stabilize the Clark Fork so that it feeds smoothly into the newly constructed floodplain downstream. All in all, restoration work extends more than a mile above the reservoir area.
Will native plants come back? What about wildlife? Native plants are a key element in the restoration effort, and they are in fact what will hold much of the project together. Some natural re-growth is already occurring. In the former reservoir area, where the stumps of old trees that date back to the early 1800s were uncovered, an interesting and somewhat unusual assemblage of native vegetation has sprouted. Botanists think that some of these plants may be growing from native seed that's been buried for 100 years under the reservoir sediment. Since these areas are already doing well, they've been fenced off and allowed to recover on their own. Most of the site, however, will be revegetated according to a carefully designed plan.
The revegetation plan calls for a wide variety of native plants, located appropriately for each of the site's land-forms. For example, upland species such as Ponderosa pine will be planted on the terraces, while sedges and cattails will find homes in the wetland swales, and willows will sprout from the river's banks. Some of the plants used for this effort have been salvaged from on-site construction areas, some are being grown in a nursery, and some will be grown from seed. In 2009, more than 5,000 plants and 25,000 willow cuttings were planted throughout the restoration area. To help ensure success of the native plantings, an aggressive weed control program has already begun and will continue after project construction completion.
Once native vegetation is established, it shouldn't be long before wildlife returns to the newly created habitat. Deer are already attracted to the new vegetation, beavers are busy in nearby side channels, and birds are starting to reclaim their old territory. And, of course, trout have been moving up the Clark Fork River since dam removal in 2008.
How long will the project take? Channel and floodplain construction along the Clark Fork River should be completed by 2011. Sometime in early or mid-2011 the Clark Fork will be routed out of the bypass channel and into its new channel through the former reservoir area. After that, the bypass channel will be demolished and backfilled. Native vegetation will be planted and weed control will continue throughout this period. Most project work should be finished by 2012, although weed control and monitoring will extend beyond that.
Who's paying for it? The work is funded by the Natural Resource Damage Program (NRDP) through the proceeds of a lawsuit that the State of Montana filed against the Atlantic Richfield Company (ARCO) in 1983. From these funds, $11.5 million dollars have been set aside for restoration, along with an additional $2.8 million from a grant for extra sediment removal.
Who's doing the work? The restoration is planned and managed by the State's Natural Resource Damage Program. NRDP has contracted with three Montana firms to design the project. River Design Group of Whitefish and WestWater Consultants of Corvallis have collaborated on the channel design while Geum Environmental Consulting of Hamilton has produced the revegetation plan. Envirocon, which has just finished the remediation work, won the construction contract to carry out the channel and floodplain construction in CFR 3B. The NRDP will bid out at least three more contracts to complete the restoration of the Clark Fork River channel and floodplain.
How will we know if it's successful? River restoration is an emerging science, and figuring out whether a project is successful requires well-defined goals, performance criteria, and a comprehensive monitoring program. The Milltown project incorporates all of these. The monitoring program will include measurements of water quality, river channel form, sediment transport, fish habitat features, number of trout, and the diversity and number of birds and fur-bearing mammals. Monitoring will also keep track of the functional wetland area, wetland vegetation, and depth to groundwater. Vegetation will be surveyed by measuring floodplain cover types, canopy cover, and the ecological succession of plant communities as vegetation matures. The restoration designers will evaluate the monitoring data each year to see if changes should be made as time goes on in order to achieve both the short and long-term goals of the project. For example, if the constructed wood and rock structures in the river channel were preventing the river from migrating naturally after floodplain vegetation is well-established, the restoration designers may elect to remove or demolish them.
What's next? Overlapping the restoration work is a redevelopment plan focused on turning the Superfund site into a state park. Those efforts are well underway and will be highlighted in the next, and final, edition of the Dam News in 2010. Read more in the Dam News 2010.
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