Inspect your feedline you plan to use (sounds like it is Heliax) and make sure the jacket is undamaged. If it is okay, you can bury it or just lay it on the ground and it won't matter if water covers it. Of more concern is keeping the junction where the feedline divides dry.
If you use enough radials, you won't have to worry about the feedline shield becoming a radial. It will be one, but the RF on it will be minimal because it will be one among many radials. But you have to have a lot of radials. I am taking your description of the field being under water for only a couple of weeks a year into account. If you are concerned about animals chewing on the line, burying it or elevating it may be needed. I've had something chew on my 1/2 inch line but I guess rodents realize the jacket isn't the same as wood so they don't go very far. The line is fine due to the solid copper shield. This is one of the reasons why Heliax is superior to braided shield line and a worthwhile investment. 73 Rob K5UJ _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
