Do you have any artesian springs at elevations above your pond? Building a spring box and running some piping would be much cheaper and lower maintenance than a solar pumping system.

Do you have another draw/ravine on your property that is adjacent to your pond? If so, you might consider building a second pond (or lined pit) there. You could use it as a grow out pond during normal conditions, and then during a drought seine it and pump the water to your main pond to supplement your more important pond.

Do you have rural electricity on one of your property lines? If so, they may be able to set a small transformer and charge you a small monthly fee for electricity. You could put your groundwater well near that location, and then pump the water to the pond. In general, water piping is much cheaper than electrical line these days. Also, the frictional pressure losses in the water line are much less than the electrical losses in a long run of wiring.

If you have a contiguous and highly permeable groundwater aquifer on your property, then the water level should be roughly equal across the property. In that case, do you have a low spot of ground near the pond? If so, that might be a good location for your well and solar pump. If the land surface is close enough to the groundwater level, you can make your own large diameter well. Also, a much shallower well makes your work installing and maintaining the pump that much easier.

Good luck on your supplemental water project!