The City Council unanimously approved the sale of a conservation easement on land near the Northwest River to the Navy. The sale price was $1.55 million.Development is now prohibited on 640 acres of land near the river, which the city purchased in June for $3.3 million.For the Navy, keeping the land clear of development reduces the possibility of electromagnetic interference with a military surveillance system in the Naval Support Activity Northwest Annex facility.The system, called ROTHR, or relocatable over-the-horizon radar, provides wide-area surveillance to military and law enforcement agencies.Learn more from The Virginia-Pilot.