Like tide water marinas, the inland facilities must cope with varying water levels. From inches on a daily basis to 50 feet at flood stage as is the case in Paducah, Kentucky.
The infrastructure required is considerable. Starting with a break wall which must stand up to seven or more knots of current. The docks, fuel docks, buildings and any amenities onsite such as a swimming pool must be built on floating pods. Power and water supply to each slip must also be able to accommodate quick changes in water level. In one historic Mississippi River flood, the water rose 14 feet within a 24 hour period.
The pilings must be robust enough to stand up to the current plus strikes by debris carried in the flood water. The debris includes whole trees, branches, tyres, docks, appliances and anything else picked up by the raising water.
Here are some photos from Alton Marina in Illinois as an example.
The marina can run 12 months a year with boats in their slips. A covered slip for Moon Dance at 39 feet would be $4,050 for the year. No haul out, not much winterizing
Moon Dance IV 