Finally their unattractive appearance creates a hostile barrier between the school and the nearby community. The retention pond, while requiring more room, has many advantages. Designed to hold water even during the dry season, they can be used to form a physical barrier or moat to prevent trespassing to certain parts of the school. They can help segregate play and pedestrian areas from areas of heavy vehicular traffic. The water in a retention pond allows it to support indigenous water plants that are effective in filtering heavy metal pollution washed from school parking areas by rainwater.
Plants absorb excess nitrogen from fertilizer runoff.
Shade trees planted along the banks of the pond help regulate a cool water temperature allowing the native flora and fauna to flourish. In this way it is possible to have a natural self regulating system that lowers maintenance costs. An attractive landscaped retention pond can become an asset that serves to link the school and the local community. An alternative to utilitarian fencing can include landscaped low walls and wrought iron fencing. This facilitates the need for a protective barrier while permitting clear views to the pond.