OK now I live in PA, and here, building a pond, is a royal paperwork deal,
have to build a plan, have it approved by the state, and then get a list of permits, and then, have it built in a said time frame, and then you have to have a plan in effect for any ruptures, permits to add fish and so on
last summer had a pond at the farm rupture from a sink hole, and WOW what a can of worms that opened
DEP , Fish commision, Soil conservation, and a few other depts all got involved, and its still going on, month later now
and all that was done was a few truck loads of stones were added to fix the hole that opened up

so I strongly suggest before you build one, find out the legal matters, as fines with water can be in the six digits range and add up fast!