Those trees will need attention for sure....looks like you have large ones on the dam - is that a young shagbark hickory in the first picture? Good smoking wood if so
What fills the pond? Looks like a gutter run off pipe on the house side bank - or is that a septic drain?
The road running along the topside of the pond, does runoff backup above road? Is the road blocking off your pond fill run off source? Has the pond ever held water year round? Look it up on google earth and use the historical aerial slider to view past data
You can calculate the evaporation rate per surface area here
https://www.engineeringtoolbox.com/evaporation-water-surface-d_690.htmlThat will give you the baseline of how much water you "could" lose to evaporation so you can get an idea of water you lose due to leaking
