I'm in the wrap up stage of a new pond I decided to build myself. Pond is built in a ravine so the slopes are fairly steep and water will get deep quick making me think there will be little vegetation growth around the banks. I'm wondering what percent of the pond should be shallow enough for growth and if I should cut in some shallower flat areas for this?

My question is why you want the vegetation. For aesthetics? That's OK.

I have 3 ponds with no vegetation other than a small willow tree that I control and have never had a problem.

Only based on a handbook I read stating that some vegetation was required for a balanced ecosystem.

Vegetation becomes more important as competition to algae, help with plant - nutrient - productivity balance, and some habitat for fish. Goals for the pond are important for helping to determine the amount of beneficial vegetation. Since your pond is in a valley it will get lots of leaf and outside organic inputs into the dammed up water flow. Annual flushing and short turnover time will help some with reducing overall nutrient accumulation. Organics will tend to settle and accumulate in the pond basin. Generally IMO all plant problems occur in shallow water so the less shallow water the fewer the plant problems that will occur especially long term.

Nature will introduce naturalized plants; some good,,, some not so good. Do some reading and home work in this link. Steep sides will help minimize submerged vegetation that usually promotes clearer water as submerged vegetation competes with plankton and submerged algae. If it were mine I would introduce some of the beneficial plants discussed in the link.

https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=440475#Post440475

Some thing to consider with ponds that have steep banks. Fish have a hard time spawning on the side of a slope..........

Thank you for the replies and the link. I appreciate it.