I need to build a jetty for our dam the jetty needes to get over the mud which is three meters any help

Get really big muscles!! How do you plan on lifting rocks weighing at least 1/2 ton? Most jetties are built from the water side with a barge and crane.

I built a jetty 6 meters long on our lake. I started with 2 200mm dia. Treated poles with one end pointed with a chain saw. Then got a digger in and chained the poles to the bucket which pushed them down into the lake bed until they were firm.( I was in a dingy steadying them) Then bolted a bearer to each pole and fixed them to the shore then nailed the decking across. This was 10 years ago and it has never moved. Hope this helps.Cheers.