Bluewater was a planet whose surface was covered by 98% water. As this water was full of minerals, the UNSC set up various reservoirs on the planet, the water of which was supplied to UNSC forces on the frontline at Harvest and, earlier, to the SPARTAN-IIs in training. In 2531 the Covenant located the planet, and attacked the ships guarding it and those collecting water there. A series of Counter-ops took place by ground forces to protect the resovoirs, but proved fruitless, as the Covenant destroyed them. -Admiral Cole.