PLP, I have a pond in Thailand that averages 5 acres in size depending on the season. I did the same thing with my pond and left app. one acre that I term the "swamp". Most of the pond was dug to a sloping depth of 10 feet (from the plain) however the swamp was only dug out to 3 feet. At the height of the rain season it gets to about 7 feet deep then has been dropping to 1 1/2 foot at the end of dry season. I planted tall grasses and lotus plants in this area. The tall grasses are doing well so far and are somewhat controlled as they are stunted every year by the flood, the lotus have not been successful as I have a fish called Pacu that has destroyed them.

My pond is only a little over two years old so I don't have much background on whether building a swamp was a good idea yet or not, so far it is working well and does provide habitat for the forage fish. I don't have many birds that frequent the area as in Thailand, Thais hunt and eat any winged creature. Several folks on this site have had problems with Herons and Cumarants in their ponds, being on the east coast and major migratory routes you may have problems in this regard also. Another concern that may or may not come about will be siltation over the years and whether or not the area will eventually fill in.

Glad you asked the question and happy to share my limited results thus far with my experiment. Hopefully we both we get more postings and enlightenment from all the expertise/experiences on this site.

Don