It has several advantages over other methods of thawing frozen culverts in that it needs no outside power source and is very simple to operate. It is more compact as all of the invention is within the culvert and would be cheaper to operate and maintain than other methods of thawing frozen culverts.
 Prior to this invention there have been two patented inventions that have tried to solve the problem of road culverts blocked with ice and snow. The first is patent number “CA 2213904” invented by Robert Laurel Sterling and Rudiger Schmidt. It uses a heat cable inside the culvert to thaw a path for the melt water to flow. This idea works but it has some inherent problems with it. The costs associated with a heat cable are much higher for both initial and maintenance. The other invention is “CA 1244663” invented by Lars-uno Olsson of Sweden. This invention is a spongy cord running though the culvert. When the culvert gets plugged with ice and snow the cord can be stretched to allow melt water to flow around the cord The problem with this and the first mentioned invention is that both have to have apparatus outside the culvert, which could be hit by a grader or other road maintenance vehicle. With my apparatus there is nothing outside the culvert.
 The invention is a tube running inside the length of the culvert and is fastened to the culvert by a series of bolts and clamps. The bolts and clamps are set at differing lengths so that the water inside the tube can be drained out after being used The ends of the tube are blocked off with watertight plugs when the tube is not in use. When the watertight plugs are taken out of the ends of the tube water will flow though the tube. As the water flows though the tube it raises the temperature of the tube to the temperature of the water flowing, which is above freezing thus melting the ice and snow around the out side of the tube and inside the culvert creating a channel. After a while of this activity water will begin to flow around the tube, inside the culvert through this channel. At this time the inlet side of the tube can be blocked off and the tube drained of all water. Then the discharge end of the tube can be blocked off so it will be ready for the next use.
 Figures one.
 A—is the tube that is mounted inside and running trough the axis of the culvert.
 B—is the mounting bolt and clamp assembly that fastens tube A to the inside of the culvert D. One mounting bolt and clamp assembly should be used every two to three feet to provide rigidity to tube A. The mounting bolts and clamps should hold the tube A at an acute angle traveling from the culvert D inlet being closest to the top of culvert D to a few inches below the top of culvert D at the outlet.
 C—water tight end cap for tube A
 D—any steel or plastic road culvert or aqua duct.
 E—shim block
 H—road with culvert installed
 I—melted snow and ice
 J—snow and ice blocking culvert (D)
 A—a corrugated tube
 Detailed Description
 In the top of a road culvert that is either in use in a road or new. Several holes would be drilled or punched along its length and bolt (B