Date: 202010
Local time of day: 1801-2400
Location: ZZZ.Tower, US
Aircraft: Small Aircraft
Flight plan: VFR
Flight phase: Landing
Airspace: Class D ZZZ
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Confusion; Distraction; Fatigue; Situational Awareness; Time Pressure
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Environment - Non Weather Related; Human Factors; Staffing
Primary problem: Staffing

Narrative: Runway XXR was NOTAMed closed for 2 hours due to a crane on the departure end of the runway. Runway XXL was in use. Aircraft inbound from the west was given a right downwind entry for Runway XXL. The aircraft was sequenced to follow multiple aircraft ahead. On short final; I noticed that he appeared to be lined up for the closed runway (Runway XXR). I instructed the pilot to go-around and re-enter right traffic Runway XXL and emphasized to the pilot that Runway XXR is closed. When I cleared him to land Runway XXL; he again appeared to be lined up for XXR. I verified if he was lined up for the correct runway and on very short final; he appeared to maneuver for the correct runway.Background: all controllers at ZZZ have been on 6 day work week for the last few months due to a shortage in staffing. Our facility has also been experiencing roughly a 20% increase in traffic volume compared to last year. In September; our traffic count index has reached the numbers for us to qualify for a level 8 upgrade. If we sustain our traffic numbers for the next couple of months; level 8 at ZZZ will become a reality once it gets approved by the National Validation Team.We are all fatigued from the increase in traffic and the amount of overtime we have all been working. This is no doubt affecting our performance on position. Morale is down and controllers are becoming more and more impatient with pilots as a result of being over-worked. I worry that this will impact safety by increasing the possibility of human error.I felt noticeably fatigued towards the end of my work week. If I had not been as fatigued; I may have been able to recognize the aircraft lined up for the incorrect runway sooner. Thankfully; I recognized it at the last second; but it was very close.Yesterday; I was working CIC combined with GC. Traffic was busy. A Controller who was finishing an overlap in the back of the cab was on the phone with someone and relayed information to me. I was in the middle of working a lot of traffic on ground and what I thought I heard was to have the pilot of an Aircraft X with an XXXXX tail number call the airport manager when he lands. It turned out that the airport manager wanted us to call him when the aircraft landed.  Had we had more staffing and CIC was de-combined; this information would have been properly relayed to me. I would have been able to figure out that we had to call the airport manager and not have the pilot call. Again; my lapse in judgement may have also been due to fatigue from prolonged 6 day work weeks.For the safe of safety; the agency needs to take our staffing situation seriously. In the midst of the pandemic; our tower hours have changed to XC:00am to XO:00pm. Even though we have a staffing issue; due to the compressed tour hours; there is a good amount of overlap between controllers so we can keep LC split into 2 positions. In a little over a week; we will be going back to our normal hours which are XA:00am until XQ:00pm. This means the staffing will be spread out and during peak work hours; we may be forced to combine the LC position. As busy as it has been; it is very unsafe to work the volume of traffic we have been working with a combined LC position. This will result in 2 hour holdovers for many of us on top of the 6 day work weeks we have already been working.We have been begging for better staffing for years. There has been word that the higher ups in our region are finally taking the situation seriously. I hope this is true and we get more staffing numbers to alleviate this serious issue.




Synopsis: ATC Controller reported fatigue and safety concerns due to 6 day a week shifts and short staffing related to the COVID-19 pandemic.