welcome to PB osymandius.

ryan's comment to call the county is a good one. find out if yer legal.

then the usual advice is first check out some of the pond boss books available. do some homework on pond construction.

a few follow on suggestions:

based on some up front planning (lay of land, extent and depth of desired pond) i would get a backhoe, make a nice access, and dig test pits in pond area to determine what the pond site is composed of. determine the soil profile, evaluate those soils w/ regard to holding water, are they sand, silt, or clay soils? is bedrock present, shallow or deep? what kind of bedrock? is groundwater present, shallow or deep? the test pits would answer if a spring or natural water table is present.....these critical factors will determine how and if you can construct a good fish worthy pond (assuming you want fish).

come on back here after the test pits are dug and lets discuss the results.

my 2c

GSF are people too!