You entered a contest for "Calendar Photos". These have certain expectations in regards to composition, subject matter and other variables. You have good subject matter. The issues I see are:
- The trees obscuring the top of the bridge.
- Placement of key point of interest-the bridge and its reflection-is too close to the center line.
- Trees on the left side of the frame are distracting.
- It looks a bit dark.
If there were any way you could have found an angle to get this capture without the top of the bridge obscured by trees, and place the bridge and its reflection in the "sweet spot" rule of thirds intersection a bit to the left of where they are now, it would have been a much stronger photo.
On the other hand, I think some of the winners don't qualify as being any better. But, the person putting together the calendar (and any other judges) probably did what most people do when judging photos. They went with their initial "Oh, that's pretty!" response and didn't go much deeper than that.
Some people operate cameras. Others use them to create images. There is a difference.