I would give it a complete overhaul.

The springs that are coming into the pond, are they entering from the top level of the pond? Do you know if any are coming in from under the water level? One reason to know this is for equipment needed to rework the pond: can something get into it, or does it all have to be done from the shoreline. Have you had anyone out for bids and seeking their thoughts?

For a pond that small, the leaves are going to kill you. I think some equipment could get around them for cleanup, but what's your thoughts on removing them?