ATC to begin soil boring in Yahara Wetlands
Environmentally friendly process will help determine pole placement
MADISON, Wis. – Although the actual construction won’t begin until 2011, American Transmission Co. is starting preliminary field work this week for a new 32-mile, 345,000-volt electric transmission line through Dane County between the towns of Middleton and Christiana. The power line route along the Beltline Highway that was approved last summer by the Public Service Commission of Wisconsin includes the placement of several transmission structures in the wetlands adjacent to the Yahara River.
Determining the exact placement, depth and design of structures requires an analysis of the conditions for supporting a 120-foot, steel transmission pole. This analysis, which is accomplished through soil borings, helps determine whether the structures will be placed in soil, rocks or moisture and what provisions will be required to ensure the concrete pole foundations are adequate to secure and stabilize the weight of the poles.
“Conducting soil boring is a fairly routine task on any power line construction project,” says Brian Fischer, ATC project manager. “But marshy wetland areas present additional challenges to ensure that we are minimizing disturbances to an environmentally sensitive area.”
For this reason, ATC’s contractors are conducting the work during the winter months using a specialized vehicle called a Marsh Buggy to access these wetlands where at least ten structures may be located. “This vehicle is designed to navigate marshy areas while minimizing impacts, and has been used successfully on similar projects in other areas of the country where environmental impacts had to be managed,” says Fischer.
The Marsh Buggy, which will be visible from the Beltline Highway, will carry the soil boring equipment and will remain on site for about two to four weeks beginning this week. The vehicle measures about 25 feet long and 14 feet wide, and may be frequently visible from the Beltline. “While visually the Marsh Buggy may appear intrusive, it’s the best piece of equipment available for the job and it’s the best time of year to perform this type of work in this particular area,” says Amy Lee, ATC environmental project manager. “In addition, ATC will have environmental staff on site monitoring this two-to-four week operation, which will also require the removal of some vegetation to allow crews to safely maneuver the vehicle and operate the soil boring equipment.”
In addition to the Marsh Buggy, a second smaller vehicle similar to an ATV, called an ARGO, will be used to transport crews and supplies to and from the Marsh Buggy.
Elsewhere on the 32-mile route, crews will be conducting soil borings in the coming months using standard vehicles and also performing environmental surveying, along with other activities in advance of the start of construction in 2011. Construction is expected to be completed in 2013.