It sounds like a lovely feature. Finding another source for water is the answer I recommend.
- I would suggest installing a rainwater barrel collection system on your home that collects the water from your gutters and feeds it to the pond via gravity.
- Then install a small, economical solar water pump to create a fountain or to filter/maintain the pond.
You can also consider installing a graywater collection system to gather water from showers, sinks, dishwashers, etc., and filter it for use in the pond.
For more information:
Read "Is it feasible to reuse greywater as irrigation water?" a Q&A answered by Randy Potter.