A low-head impulse jet waterwheel for power generation at irrigation canal drop structures and navigation dam spillways achieves renewable electric power generation that has been lost until now due to lack of suitable equipment to convert such energy at competitive cost. Conventional practice has limited use of impulse turbines to heads of more than 50 meters or about 150 feet. However, there is now no need for such a limitation. Kinetic energy of a low-pressure jet is employed in a way that enables numerous locations to generate electricity conveniently near points of use, from a renewable source at minimum cost. The equipment can be pre-assembled for minimum installation cost at sites with no existing impoundment and can be automatically raised clear of flood levels with built-in lifting equipment. Existing multi-span bridges offer convenient access for installation and maintenance. Raising the equipment also provides clear passage for fish migration.