Do It Yourself of course.
Why is it not a good job to hire out?
Finicky detailing to get good patches and reinforcing properly placed, along with scattered locations.
Preping the holes takes hours, leaving preped holes open exposes them to erosion and redigging or extensive covering.
If you order a truck load of concrete, you need a bunch of workers to get it nto the ground fast.
The pond is as old as the house, probably older.
This is on the path of least resistance to one of the 3 local year round springs. Lost in history is when it was decided to make a little dam, dig a little hole and start this pond. When gramps bought the place, he added some concrete curbing, and every fall he and pops would hook up a 2 foot diameter iron bucket dredge and chain to the WWII surplus jeep and drag the bottom most of a day, making the pond deeper and the lawn flatter.
In the 60's we wanted more of a swimming pond than a mud bottomed frog pond, and an over his head conctractor took it on along with some other civil engineering in the valley. Well, he didn't do so good, but, most of it was still there, and if I hadn't skimmed on maint. over 20 years, in favor of working, it'd be ok. As it is, 20 yrs back maint. in a single year, ekkk.