Hire an illustrator to make game boards for keeping track of books read. The game board should include water animals and swimmers. Add a title such as "Make a Splash with Reading" and include the required number of game spaces for the number of books expected to be completed.
Choose water-related prizes for every five or so books read. Prizes could include sand buckets, water toys, rubber ducks or even water-related sponsor gift certificates such as a free ticket to a local aquarium.
Plan library events that center around the water theme. You could invite a lifeguard to give a talk about water safety, an author to come read a children's story relating to water or an oceanographer or park ranger to come talk about aquatic life.
Plan reading events with water-related books. Some examples could be, "Curious George Goes to the Beach", "One Fish Two Fish", "Clifford and the Big Storm" and "Froggy Learns to Swim."
Select water-related movies for the kids to view if your library does summer movies. For little kids, you could use movies such as "Dora The Explorer- Summer Explorer" and "Sesame Street: Elmo's World- Summer Vacation." For older kids some examples include, "Magic in the Water," "Disney Nature Earth," "IMAX: Under the Sea," and "Soul Surfer."