you have to elaborate. how large a house?

The most important study for you will be the tide levels study & the type of soil that is present on the site. Steel will be the last option if you have no budget constraints but it have to be treated well to survive the water corrosion. You should go for concrete stilts or stone masonry piers but designed in such a manner that the water flow is not obstructed(minimum obstruction) so that the structure you build faces minimum obstruction from the natural habitat(water flow) around. Do keep in mind that such structure can be highly vulnerable for water flooding so be intelligent with the design criteria.

The house has to be constructed on raised stilts, allowing the water to flow without any obstruction. Various materials are available for construction of stilts, it depends on the scale of the cottage. The cottages can be built with G.I framing and Cement fibre boards, or similar materials. Above is an example in a different setting, Even here we had to allow the water to flow down. But in Sandy area Materials will be different.