Control lines - Control lines are identified around the perimeter of the burn unit to ensure the fire is contained within the pre-determined area. Such lines may be pre-existing such as asphalt or dirt roadways or may need to be constructed by removing much of the existing fuel. In the Hill Country, control lines generally consist of wide mowed lines. Water is applied to these mowed areas with fire equipment during the fire operation and this improves their ability to contain the fire. These type of control lines are called wetlines.