Budget Cut, Backlog, and Two Problem Feeders
You manage vegetation for a municipal electric utility with 620 miles of overhead distribution, a 5-year trim cycle, and a $1.9 million annual vegetation budget. The GIS backlog shows 1,840 open trim work orders; 410 are more than 12 months overdue. Two feeders account for 38% of vegetation-caused outages (SAIDI 212 minutes versus 96 systemwide). Feeder 12 runs through a floodplain with cottonwood and silver maple; Feeder 7 serves a hospital and a water treatment plant and has 14 spans with less than 4 ft clearance to 12.47 kV conductors. The utility just absorbed a 9% budget cut, and contractor workforce is 30% below plan because of a regional labor shortage. The regulator wants a plan within 30 days. You have outage data, species inventory for 60% of the system, and four in-house crews plus three contract crews. A storm last month generated 260 emergency tickets.
1. Using only the data in the setup, propose a 12-month risk-based prioritization method and show how you would allocate the available crews. Explain why backlog age alone is not adequate.
Read the worked answer
A defensible method scores each work unit on risk, not age. One practical 100-point model:
- Reliability impact (35): feeder vegetation-caused SAIDI/SAIFI, repeat outages, customer count.
- Safety/clearance (25): spans below 4 ft, conductor conflict, school/hospital/high-traffic areas.
- Critical customers (15): hospital, water treatment, emergency services.
- Growth and species (10): cottonwood/silver maple versus slow-growing species; use the 60% inventory and field-verify gaps.
- Access and landowner difficulty (10): refusals, permits, floodplain access.
- Regulatory/documentation (5): known compliance exposure.
Crew allocation for 12 months: about 20% to emergency tickets, 25% to Feeder 7 critical spans, 30% to the two high-outage feeders, and 25% to the remaining backlog selected by risk score. Backlog age alone fails because an old ticket on a slow-growing, low-customer lateral may be lower risk than a new ticket on a hospital feeder. Age also rewards queuing, not risk reduction. State the method, publish the scoring, and document overrides.
2. The hospital and water treatment plant on Feeder 7 have 14 spans under 4 ft clearance. The contractor workforce is short. What do you do first, and what do you defer?
Read the worked answer
Treat the 14 spans as immediate work, not cycle work. Under 4 ft to 12.47 kV conductors is a clearance and reliability problem at a critical facility. Use in-house crews first because they are available and can be moved quickly; do not wait for contract crews to backfill. Notify the hospital and water treatment plant, schedule the work with them, and document the clearance before and after.
Defer low-risk cycle trimming on feeders without outage history, and defer old tickets in slow-growing areas where field review confirms adequate clearance. Do not defer Feeder 12 entirely: cottonwood and silver maple in a floodplain grow fast. Schedule Feeder 12 before the next growing season, prioritizing spans with the least clearance. The reasoning is that critical-customer safety and reliability outrank backlog age, but fast-growing species still create a time-limited risk.
3. The regulator asks for measurable outcomes. Identify four metrics and explain how you would adjust the plan after a major storm.
Read the worked answer
Four useful metrics: (1) percentage of critical spans cleared to target, (2) average post-work clearance at maximum conductor sag, (3) vegetation-caused SAIDI/SAIFI on the two target feeders, and (4) risk-weighted backlog completed, not simple ticket count. Add cost per mile and percentage of tickets over 12 months old as supporting measures.
After a major storm, separate storm tickets from planned work so storm response does not silently consume the entire plan. Re-run the risk score on new emergency tickets, protect the Feeder 7 and Feeder 12 commitments, and report the tradeoff explicitly. If storm work forces deferral, document which lower-risk work slipped and when it will be recovered. The regulator should see that the plan changed for a defined reason, not that the backlog was re-aged.