There are several things that can be done to repel cats from various environments like ponds or gardens. IMustGarden.com suggests that planting plastic forks or Popsicle sticks about 7 inches apart in a garden bed can repel cats and keep the animals from digging in the garden.
If you are trying to keep a cat away from a body of water, IMustGarden recommends covering the surface of the water with netting. For gardens, spraying the garden with a solution, like I Must Garden Dog and Cat Repellent, can keep cats away from the garden as well. The spray contains botanical oils, and cats don't care for the scent of the oils.
Planting flowers like rue can also repel cats. Rue is a woody perennial plant that grows to be about 3 inches high and wide. The plants can grow in poor soil and will prevent cats from ruining the other plants in the garden. Leaves of the rue can also be sprinkled around the garden bed to keep cats away.