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Power lines trump trees by The Commons Mall
Along South 324th Street, by The Commons Mall, stumps are the only things left of a row of pine and deciduous trees that stood for years.
Approximately 30 trees lined the mall side of the street and had grown to heights tall enough to provide patches of shade and shelter. It’s unclear when the trees were planted or what kind they were. Cynthia Stanley-Lee, general manager of the mall, said the trees may have been planted when the mall was built in the mid-1970s.
The trees were cut down between March 14 and 16 by the Bonneville Power Administration, which owns the land where the trees stood. Vegetation was also cut down along the perimeter of the BPA Trail.
Bonneville Power Administration operates three-fourths of the Pacific Northwest region’s power transmission lines. The system includes more than 15,000 miles of line. The trees that were cut posed a threat to the high-voltage lines above, said BPA spokesman Doug Johnson. The lines are among the highest voltage the company operates, he said.
“500KV lines are kind of the main grid of our transmission system,” he said. “It’s important to protect them.”
Removing trees has become a more common practice by the Bonneville Power Administration (BPA) in the past decade, Johnson said. The company’s vegetation management program underwent some changes after two massive, widespread power outages — one in 1996 and another in 2003 in the Northeast United States. The outages left millions of people without electricity for days. The blackouts were both caused when tree branches came in contact with high-voltage power transmission lines. BPA’s power lines carry between 69,000 and 500,000 volts of electricity.
The company takes extra precaution to avoid power blackouts. Precautions include preventive maintenance. This undertaking is a national requirement initiated by the two massive power outages, and calls for strictly managing vegetation located near power lines. Utility companies that do not abide by the requirements face fines of up to $1 million a day, according to BPA policy information provided by Johnson.
Due to the federal regulations, BPA’s vegetation maintenance policy calls for a minimum of 25 feet between high-voltage power lines and landscaping. The 25-foot rule takes into consideration how tall a given tree or plant may grow and how low the power lines may sag under periods of high use, according to BPA’s policy. Vegetation is rarely left to grow tall enough where it could interfere with the lines. According to the policy, tree removal is sought:
• If a tree has grown to a point at which it poses a threat to the 25-foot safety zone
• If a tree is in danger of toppling onto the power lines
• If maintenance crews know the tree, at its maturity, will grow to a height at which it will violate the 25-foot clearance
“We just have to cut instead of trim now,” Johnson said.
BPA has maintenance cycles that range from three to 15 years. The line near the mall is on a three-year schedule. Employees that perform the vegetation maintenance have forestry degrees and know how tall trees will grow, Johnson said.
Shrubs and low-growing plants will replace the trees at the mall, said Cynthia Stanley-Lee, general manager at The Commons Mall. The mall will plant the landscaping, she said. Johnson said BPA generally does not replace the vegetation it cuts unless it has an agreement with the adjacent landowner to do so.
Residences and businesses in Federal Way and near other BPA power lines can expect to see similar vegetation management in years to come, Johnson said.
Take a look
To see what the tree-lined street used to look like, view a Google Earth photo of South 324th Street near The Commons Mall in Federal Way by clicking here.