This paper uses detailed hydrometeorological data to evaluate the inยฏuence of channel bed processes on the river energy budget at an experimental site on the regulated River Blithe, Staordshire, UK. Results from a pilot study are presented for eight days during July, September, October and November 1994.
Total energy gains were dominated by net short-wave radiation (97 . 60%) with signiยฎcant contributions from sensible heat exchange and friction (1 . 17 and 1 . 06%, respectively) and minor additions from condensation and bed conduction (0 . 16 and 0 . 01%, respectively). Net long-wave radiation, evaporation, conduction into the river bed, sensible heat transfer and the energy advected during evaporation accounted for 53 . 98, 23 . 56, 16 . 27, 5 . 25 and 0 . 94% of the total heat losses. On average, over 82% of the total energy transfers occurred at the airยฑ water interface. Approximately 15% of the total energy exchanges occurred at the channel bed, but maximum daily heat exchanges accounted for up to 24% of the daily total energy transfer. The amount of short-wave radiation attenuated in the water column, and values measured at the channel bed varied considerably from those calculated using a standard coecient. Values of bed conduction varied in response to dierent vertical thermal proยฎles in the channel bed, reยฏecting the variable inยฏuence of sedimentology and groundwater ยฏux. Fluctuations in levels of periphyton and macrophyte cover were also shown to have a signiยฎcant eect on energy ยฏuxes at the channel bed.