Thursday, August 01, 2013
Brian Johnson, an expert witness for SWEPCO in its application to the Arkansas Public Service Commission for authority to build a new high voltage transmission line in Northwest Arkansas, recently filed testimony rebutting many of the concerns raised by expert witnesses for interveners opposing the project.
“Various individuals have raised concerns about the right-of-way (ROW) clearing including loss of habitat, erosion, landslides and impact to waterways,” said Johnson, a Tulsa-based employee of SWEPCO who is project manager in the Transmission Engineering & Project Services department of AEP, the parent company of SWEPCO. “All of these issues are recognized and mitigated by SWEPCO in the design, construction, operation and maintenance of its transmission lines.”
SWEPCO’s preferred Route 33 would run 48 miles, and some opponents have taken that to mean that 48 miles of forest would be removed if that route were chosen. But Johnson points out that route 33 and the other five routes under consideration contain a mix of lands that includes land already cleared for crops and pasture, in addition to forested areas.
“In areas that are already cleared, very little or no clearing would be required. In forested areas, clearing of the right-of-way would be necessary in most areas,” Johnson said. “In clearing, trees and other woody vegetation would be removed within the right-of-way. Following installation of appropriate erosion controls along the ROW, woody vegetation from the ROW and adjacent large trees which could pose a danger to the line may also need to be trimmed or removed. SWEPCO would work with individual landowners to address specific issues related to marketable timber, firewood, pecan and other production trees, and large shade trees associated with residences that may be within or adjacent to the required ROW.”
Another big concern has been about removal of trees and other vegetation in extremely steep areas, which some fear could led to erosion and water contamination from faster runoff after rainfalls. But Johnson said in areas where the line spans across deep ravines, clearing at the floor level may not be required where safe clearances can be maintained to trees below the line.
“SWEPCO always seeks ways to minimize the impact of ROW clearing,” Johnson said. “Where possible, mechanized clearing equipment will be used. Tracked, rubber-tired and low pressure rubber-tired equipment are used as site conditions warrant. Felled trees and roots may be removed, shredded, chipped, cut to firewood or burned when permitted in accordance with local burning ordinances and after appropriate consultation with local authorities. In sensitive areas such as wetlands and at stream banks, hand clearing is employed in accordance with established best management practices (BMPs) and care is taken not to disturb the root structure of vegetation in these areas. Minimal root disturbance is also employed in highly erodible areas such as steep slopes.”
Following completion of line construction, SWEPCO ROW restoration would be undertaken with any remaining construction debris removed and disturbed areas graded back to preexisting contours. Johnson said soil stabilization will be completed, disturbed non-crop areas re-vegetated with native grasses and forbs, and finally the temporary erosion controls will be removed after regrowth is established in compliance with the Storm Water Pollution Prevention Plan (SWPPP) or other permit conditions.
Landowners traversed by one or more of the proposed routes, Dr. James Helwig, Fritz Goodnow, Tom Oppenheim and Rick Clark, have commented on possible landslides or erosion due to loss of vegetation along hillsides during clear-cutting operations. Hydrogeologist Thomas Aley has testified about concerns that sediment runoff would degrade groundwater.
Johnson said SWEPCO appreciates their concerns, but it is important to note that SWEPCO and AEP have successfully installed and maintained rights-of-way for many hundreds of miles of transmission lines in mountainous and/or hilly terrain for several decades, including other existing transmission lines within the study area of this proposed project.
“Clearing has the potential to disturb surface soils,” he said. “Therefore, SWEPCO will develop and implement an appropriate Arkansas Dept. of Environmental Quality-approved SWPPP prior to commencing clearing in a particular area. Implementing a SWPPP for project construction is standard practice for SWEPCO. Clearing activities would begin once the BMPs for erosion sediment control are in place in accordance with the SWPPP. Removal of trees within the easement area is undertaken with care and an understanding of the impact to the existing environment. In sensitive areas, clearing operations are modified to minimize disturbance to the existing root structure.
“The SWPPP requires SWEPCO to continuously monitor, maintain and manage erosion controls to ensure ongoing effectiveness throughout construction and the post-construction restoration period.”
After line construction is complete, SWEPCO plans to reseed the ROW with native grasses and forbs to provide long-term soil stabilization.
Johnson also responded to widespread concerns raised about how spraying herbicides on the ROW for maintenance could impact both surface and groundwater in the karst region where chemicals sprayed on the ground can enter into drinking water supplies. Concerns have also been raised about pesticide drifts that can kill gardens, yard vegetation and expensive grape vineyards, and how it would affect organic farming certifications for properties on or near a route.
Johnson said SWEPCO utilizes both mechanized and manual clearing and herbicide applications to maintain rights-of-way. “Herbicide applications for ROW maintenance are applied only where and when necessary to control the root systems of woody stemmed vegetation,” he said. “Manual and mechanical clearing without follow-up herbicide applications does not control the root systems of trees and woody-stemmed vegetation that can threaten reliability. Converting the vegetative cover types in a transmission ROW to low growing grass-forbs-herb covers inhibits the germination, establishment and growth of most tree species.”
Johnson testified that more than 50 years of research has shown that selective herbicide applications are the most effective means to bring about this conversion. He said that same research has also shown that herbicide applications are more beneficial to wildlife than clearing operations for ROW maintenance.
“In all cases, SWEPCO uses herbicides that are registered by the U.S. Environmental Protection Agency and the appropriate state regulatory agency,” Johnson said. “The herbicides are applied by licensed application businesses that employ trained applicators. Buffer zones are maintained around streams, ponds, springs, wetlands, wells and similar features in accordance and compliance with herbicide label directions.”
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