How much beach can you own?

Answer 1

It depends very much on the particular country you are in, and possibly even on your state or province.

For example, in my state there is a 20 metre easement along any permanent waterway (or the coast) giving a public right of access. (There must be some sort of modification of this for wharves, marinas, etc. -- I am no expert on the law). In the neighbouring state, one can own and fence a property right to the water's edge. The Murray River forms the border. Mildura is a regional town in Victoria, situated on/near the Murray. On the Victorian Southern bank of the river, there is no development along the river's edge. On the Northern bank, across a bridge from the main town, there is a row of luxury mansions, with fenced yards right to the water's edge, and private jetties and moorings.