A fill is an artificial ridge or dam of earth or gravel. It is constructing to support a prepared right-of-way such as a railroad or highway across a valley or depression. Cooling tower is an evaporative cooler. It is used for cooling water or other working medium to near the ambient wet-bulb air temperature. It uses evaporation of water to reject heat from processes such as cooling the circulating water used in oil refineries, chemical plants, power plants and building cooling.