In my previous house, they were doing a major teardown/remodel of the house behind us. During excavation of the new foundation, they uncovered and cracked an unplatted drainage pipe. During an ensuing storm, it poured into the excavation. We informed the village and the builder. The city informed us that it was not uncommon to have unplatted drainage. Since it wasn’t on our property, we didn’t ask what they would do about it. The builder was extremely unscrupulous, and simply backfilled the excavation. Result was that for the couple of years that the site stood vacant (the prospective buyers understandably backed out), the supposed million$ + home had a stagnant cement pond in the sub-basement!
Actually, our property was improved. It used to be that the back of our lot would pool water in heavy storms. After this, our lot no longer pooled - apparently it was all going into the neighboring basement.
Bottomline, I do not expect this to be a situation with a simple solution from a book. It is going to require communication, negotiation, and possibly litigation. The OP is going to have to decide what they wish to do and how best to get there. I’d be shocked if he were going to be able to get the pipe moved - especially if the city is involved either through owning the golf course or installing/maintaining the pipe. So instead, you’re looking at who you can sue for how much in damages. Messy, and whatever you get is not likely to make up for not being able to use your property as you wished. Might at least want the golf course or prior owner to pay for an accurate survey, to assist you in planning any improvements.
Also, now that you know of it, you will have to disclose it should you wish to sell.
Were you planning on building a garage? Installing a pool? Planting trees? Or are you just listing things than can’t be done with the pipe? Also, why do you consider the easement to be 20’ wide? In the towns I’ve lived, I haven’t thought planting/construction had to be 10’ away from gas/water/sewer. One of my concerns would be the places where the pipe is only a couple of inches deep. That sounds awfully hinky. But otherwise, you could possibly site the garage somewhere other than right on the pipe, and have the driveway installed in some way that allows access wiith minimal hassle.
In any event, I would be trying to get some definite word from the city and the golf course as to what they understand the situation to be, and how it impacts me. I’d suspect you’re looking at a few hundred $ off the top for a layer to write some letters.
Hey Lightnin’ - just out of curiosity - willing to offer up the name of your burg and the golf course in question?