In the "slow lane" water flows into a dish and then ripples down a gentler slope. Both lanes of water - which will be shallow enough for children to paddle in - converge in a dished hollow. By night the moat, which will be planted with grasses and trees, can be lit up. Ms Gustafson said the moat is a symbol of the Princess "reaching out, letting in". She added that her design is "historic and formal, contemporary and relaxed".