headraces

Headrace, or head race, is a term used in two distinct domains: hydropower engineering and competitive rowing. In hydropower, a headrace denotes the water conveyance channel that carries water from the intake to the turbine, forming part of the plant’s hydraulic system. In rowing, a head race is a long-distance time-trial race where crews start at intervals and race against the clock rather than directly against other boats.

In hydroelectric installations, the headrace begins at the intake structure and may include screens, desanding facilities, and gates. Water travels through channels, tunnels, or pipelines to the turbine inlet, often via a penstock. The system operates under hydraulic head, a function of reservoir elevation and losses due to friction and fittings. Design goals include minimizing losses, controlling flow, and protecting aquatic life through features such as fish passes. The headrace is typically complemented by surge tanks and control equipment to manage transient flows and keep turbine operation stable.

In rowing, head races are characterized by staggered starts and elapsed-time results over a long course, usually several kilometers. They contrast with sprint regattas, where boats race side by side over short distances. Head races are commonly held in autumn or winter and are governed by river conditions and traffic considerations. Prominent examples include the Head of the Charles in the United States and the Head of the River Race in the United Kingdom. Courses may vary in length and layout, but the objective is to achieve the fastest time over the designated course.

The term headrace is sometimes written as two words or as head race, depending on context.