Idea from a former high school principal:
This might work well for other sports too, such as bowling.
The I-League model might be able to be replicated in other sports beyond swimming. At its core, the I-League helps students at schools without swim teams get a swimming experience. Perhaps the same benefit could be true for other sports, such as bowling.
Kids at schools without a bowling team might be able to get a high-school bowling experience with the help of an I-League established for bowling.
The I-League's original proposal is to grow participation in aquatics: Swimming, Diving, Water Polo, Triathlon, Swim Lessons and SKWIM. However, if the cooperative nature of the I-League works among schools for one sport, let's consider an expansion into other sports too.
Many schools don't offer sports teams in every sport.