Vegetation Managment Practices
When managing distribution rights-of-way, no single approach can be taken. The objective of this plan is to provide basic information regarding Coast Electric's vegetation management practices.
Coast Electric's vegetation management practices include:
- Removing trees and underbrush located beneath overhead distribution lines.
- Removing vegetation that interferes with the routine maintenance of overhead and underground facilities.
- Removing dead or hazardous trees that could fall and damage Coast Electric facilities.
- Pruning trees growing close to overhead conductors.
- Applying herbicides at low-volume rates.
Vegetation Management Objectives
Coast Electric's mission statement sets several high standards.
We exist to provide our member-owners superior service and dependable electricity at the lowest possible price, and to improve the economy and quality of life in our community.
A successful Vegetation Management Plan (VMP) is an essential element needed for Coast Electric to accomplish our mission. Three important objectives of our VMP are safety, reliability and cost.
Safety
All electric utilities have an obligation to provide safe clearances between trees and energized conductors. As a result, right-of-way (ROW) maintenance must be scheduled frequently enough to ensure minimal contact between vegetation and electric facilities throughout the entire length of the planned cycle. Coast Electric's ROW maintenance schedule is currently every three to four years. The amount pruned and/or cut during ROW maintenance cycles is based on the characteristics of the tree species, and the type and location of conductors. In some cases, a tree or trees may have to be removed to provide access to Coast Electric's equipment and safe clearances between vegetation and conductors. Tree removal may also be necessary to protect the public and provide a safe working environment for Coast Electric employees. Training is provided to help ROW personnel to identify trees in need of removal.
Reliability
We understand the importance of offering dependable electric service to our member-owners. Like most electric providers, a large number of Coast Electric's power interruptions are related to trees and/or vegetation. In 2007, the leading cause of Coast Electric's reported outages were vegetation and/or tree related. However, since 2007, the number of vegetation related outages occurring within the widths of Coast Electric's rights-of-way have dropped by over 60 percent. Furthermore, the number of outages caused by hazard trees located outside the widths of our rights-of-way has dropped by more than 95 percent since 2007.
Currently, healthy trees and/or tree limbs that fall during inclement weather contribute to a large percentage of our tree related outages. While much progress has been made, Coast Electric continues to seek cost-effective ways to reduce the amount of outages caused by vegetation and/or trees.
An effective VMP is more than just a commitment to reduce the number of reported outages. When outages occur, for whatever reason, clear rights-of-way allow restoration crews to locate and repair problems faster. Restoration times are greatly reduced when problems are quickly identified and repaired. Reduced power interruptions and faster restoration times are better for our members.
Costs
Along with promoting safety and reliability, Coast Electric’s VMP allows your cooperative to operate more efficiently. While a VMP can be costly, power outages and restorations can also be expensive. In addition, damages to Coast Electric facilities can occur when vegetation comes into contact with energized conductors. Consequently, power outages, restoration efforts, repairing damaged equipment and line loss negatively impact our annual operating expenses. Coast Electric's VMP helps us provide safe and reliable electric service at the lowest possible price.
Since 2010, right-of-way maintenance costs have dropped by 10 percent, mostly due to tree removals and selective herbicide applications. The ability for Coast Electric to reduce overall costs without affecting system reliability is a tribute to an integrated VMP.
Vegetation Management Guidelines
Coast Electric adheres to Rural Utilities Services (RUS) and the National Electrical Safety Code (NESC) when managing rights-of-way.
RUS Guidelines
The right-of-way shall be prepared by removing trees, clearing underbrush, and trimming trees so that the right of way is cleared close to the ground and to the width specified. However, low growing shrubs, which will not interfere with the operation or maintenance of the line, shall be left undisturbed if so directed by the owner. Slash may be chipped and blown on the right of way if so specified.
The landowner’s written permission shall be received prior to cutting trees outside of the right of way. Trees fronting each side of the right of way shall be trimmed symmetrically unless otherwise specified. Dead trees beyond the right of way which would strike the line in falling shall be removed. Leaning trees beyond the right of way which would strike the line in falling and which would require topping if not re-moved, except that shade, fruit or ornamental trees shall be trimmed and not removed, unless otherwise authorized.
RUS Part 1730.22 (c), Facilities must comply, be maintained, and be inspected according to the National Electrical Safety Code.
NESC Guidelines
Section 218 - Vegetation Management
- General:
- Vegetation that may damage un-grounded supply conductors should be pruned or removed. Vegetation Management should be performed as experience has shown necessary.
Note 1: Factors to consider in determining the extent of vegetation management required include, but are not limited to: line voltage class, species’ growth rates and failure characteristic, right-of-way limitations, the vegetation’s location in relation to the conductors, the potential combined movement of vegetation and conductors during routine winds, and sagging of conductors due to elevated temperatures or icing.
Note 2: It is not practical to prevent all tree-conductor contacts on overhead lines.
- Where pruning or removal is not practical, the conductor should be separated from the tree with suitable materials or devices to avoid conductor damage by abrasion and grounding of the circuit through the tree.
- At line crossings, railroad crossings, limited-access highway crossings, or navigable waterways requiring permits:
The crossing span and the adjoining span on each side of the crossing should be kept free from overhanging or decayed trees or limbs that otherwise might fall into the line.
RUS & NESC Guideline Exceptions
It may be necessary to remove trees if excessive trimming is required for Coast Electric to comply with RUS and NESC specifications. When trees are located beneath overhead conductors, removal is often necessary to provide safe clearances. Most tree species in the southern United States have mature heights between 60 and 100 feet. Consequently, it is Coast Electric's practice to remove such trees to maintain the vertical and horizontal clearances mandated by the NESC.
During power restoration, the applicability of RUS and NESC standards may vary. For example, trees that are considered a potential hazard to the public and/or Coast Electric facilities are removed as quickly as possible without notifying the landowner.
Overhead Maintenance
Coast Electric's overhead maintenance practices include, but are not limited to:
- Accomplishing specified minimum clearances around all primary and secondary conductors, including de-energized lines.
- Multi-phase lines - 30 feet.
- Single-phase lines - 20 feet
- Open-wire secondary lines - 10 feet
- Triplex or duplex secondary lines - 6 feet
- Pruning over-hang clearance 30 feet or greater (measured from the highest phase conductor or shield wire).
- Pruning trees to the most applicable standard between RUS Guidelines, NESC and/or ANSI A300.
- When applicable, mechanically trimming trees as close to the tree-base as possible.
- Clearing every pole structure and guy wire from trees, underbrush and/or vines (a minimum of 10 feet in width).
- Cutting vegetation growing in and around fence-lines just above the top of the fence with the sides neatly trimmed.
- Cutting stumps less than 6” in diameter 2” above ground level or less. Larger stumps will be allowed to exceed 2” in height at the discretion of Coast Electric's ROW Coordinator. No stumps shall be left in a condition that may result in injury or harm. Coast Electric is not responsible for grinding or removing stumps.
- Cutting or topping hazard trees that may threaten the reliability of overhead facilities. Hazard trees may be dead, dying, diseased, damaged, leaning or otherwise structurally unsound.
Underground Maintenance
Coast Electric's underground maintenance practices include, but are not limited to:
- Cutting and/or mowing trees and/or vegetation from over buried conductors (10 feet minimum, 5 feet from each side of the conductor).
- Clearing trees and/or vegetation from around electric facilities (10 feet in front and 5 feet from the back and sides).
- Removing trees and vegetation that prevents access to and/or maintenance of underground facilities.
- Coast Electric is not responsible for grinding or removing stumps cut away from electric facilities.
- Decals listing planting zones shall be placed on electric facilities.
General
Coast Electric utilizes low-volume herbicide applications to control the vegetation growing within the association’s ROW. The key objective of Coast Electric's herbicide program is to eliminate tall-growing tree species from within the cooperative's ROW while encouraging the growth of low-growing grasses, flowers and plants. Coast Electric only utilizes herbicides that have been approved by the Environmental Protection Agency and the Mississippi Department of Agriculture. The herbicides used are environmentally friendly and pose no danger to people, pets, wildlife or livestock.
Coast Electric's herbicide applications generally occur six to 12 months following ROW maintenance and are considered sufficient when 98 percent of the targeted vegetation is controlled. Herbicide crews do not harm and/or treat any fruit, shade or ornamental trees, shrubs or bushes growing within maintained yards. Coast Electric's maintenance personnel have a working knowledge of the herbicides being used and have all federal, state and local licenses, certificates and/or permits required by law. We also require the presence of a licensed commercial pesticide applicator on every herbicide maintenance project.
Herbicide Specifications
Coast Electric's herbicide maintenance practices include, but are not limited to:
- Mixing and applying herbicide formulations according to label directions and/or to manufacturers’ recommendations.
- Using herbicides that are labeled specifically for use on utility rights-of-way.
- The proper disposal of all chemicals and/or containers.
- Locating sensitive and/or restricted non-vegetative rights-of-way locations where herbicides, as specified on the manufacturer’s label, should not be applied.
- Transporting all necessary herbicides and herbicide agents safely from one job location to another.
- Keeping all equipment in a condition that prevents leaks and/or spills.
- Providing detailed records that include the:
- location and date of herbicide applications.
- name and amount of herbicides being applied.
- applicators name and license number.