The theme of this manhole cover is seasons and nature. Canada is a four seasons country. Vancouver, also known as one of the greenest city in the world. Our tree grows every year, season by season, year by year, they change every seasons.
The tree represents the nature, by saving water, we save trees, and they can grow accordingly to its seasons.
The rabbit around spring trees means that by saving trees, not only us, but we save animals around the trees. Animals need plants to grow and reproduce.
Their life, their existence, and their habitat are all depend on us. That's why it's written: "THE WORLD DEPENDS ON US".