It sometimes depends on where you live. My HOA does not allow parallel fences. Usually people here build tile walls on the bottom and put the fence on top of the tile wall. The tile wall would require a building permit if it is a retaining wall and would require weep holes. You have to make sure the water is not directed at your neighbors property unless you have a fluid easement and you have to make sure the wall does not trap water in your yard. Pooling after rain is a problem with yards that build fortresses around here. They usually destroy the swales building the walls then fail to address drainage and have flooded back yards when it rains hard.
Happy gardening in Hawaii. Gardens are where people grow.