Water temperature usually 6.5 C or more above mean air temperature. If head is 10 m for two points 100 m apart, hydraulic gradient is 0.1 or 10 percent. When head and distance of flow are same, hydraulic gradient is 100 percent. There are many hydrocarbons. The simples, methane , is chief component of natural gas .
Petroleum is a complex mixture of hydrocarbons.
This method supplies about 4 percent of world's electrical energy . Frequently contains, and deposits in economically workable concentrations, minor elements that, because of incommensurate ionic radii or electronic charges, have not been able to fit into atomic structures of common minerals of igneous rocks . All Rights Reserved Worldwide.