Solar Powered watering system

I am new to this.  I am wanting to build a solar powered water system that pumps from a small pond and goes about a half a mile over some hills and I want it to water about 25 trees.  I don't want it to run all the time and for only about 2 hours a day for awhile and then only a few hours a day the rest of the week once the trees have set in.  I am wondering what I need to accomplish this any information will help. The area where this will be at get lots of suns it is in west Texas near El Paso.  The lake I feel needs to be a surface pump.  I am not around this area a lot so it needs to be asself maintaining as possible.  The water is murky so I am sure a filter system is needed.