How big of a pond are you putting in? Is it a preformed or are you using a liner? The best way to deal with leaves is to use a
skimmer. It's kind of like an overflow point and a basket catches the leaves before they sink to the bottom. If you want any plants in your pond it will need sun for 3-4 hours a day (early morning is best). My sister's pond is shaded by an ash tree. Mine is shaded by an apple tree part of the morning, then by our house the rest of the afternoon. We have pecan trees too and those leaves always end up in my pond. as well as the leaves from just about all of our neighbors trees. My sister puts a piece of netting over her pond every fall to keep the leaves from falling in.