http://www.youtube.com/watch?v=_qZq4xZtcPM
From YouTube:
Yes you can add another pump to your existing well and make it solar. We added a centrifugal solar pump alongside an existing pump. The well was a 6.25″ id casing. We expect to get about 3000-5000 gallons per day! This will take care of the orchard, gardens, and stay ahead of this site’s pond evaporation.
Go to www.practicalpreppers.com if you would like us to design your off grid water system.