A salutatorian is a graduate who finished with the second highest rank in his or her class. Only the valedictorian did better. Being the salutatorian of your graduating class is a great honor. Traditionally, the salutatorian gives the opening remarks at the graduation ceremony. So, just as a salutation is a greeting, a salutatorian is responsible for offering a formal greeting at the event. Having been a salutatorian looks great on a resume, as long as you spell it correctly.
Rainwater can be collected from rivers or roofs, and in many places the water collected is redirected to a deep pit (well, shaft, or borehole), a reservoir with percolation, or collected from dew or fog with nets or other tools.
Purified water is a general term that usually means the water is filtered in some way. Water filtration can be accomplished via reverse osmosis or activated carbon and ceramic filters, although the common goal is to remove harmful substances from the water.