BLANKET BOG IN NEWFOUNDLAND .2. HYDROLOGICAL PROCESSES

The water balance was calculated for a 9.4 ha blanket bog basin between 5 and 28 July 1989, and between 16 May and 24 June 1990. Rainfall for these periods was 174 mm and 231 mm, respectively, and fog deposition added 31 mm and 23 mm of water to the inputs, respectively. Runoff was the largest loss, accounting for 70% and 63% of inputs in 1989 and 1990, respectively, compared with 24% and 28% for evaporation, and 6% for groundwater seepage. Fog simultaneously enhances the inputs and reduces the evaporative loss. Evaporation occurs at the potential rate for a very short period following fog, but decreases quickly as the surface dries, making it difficult to predict. Pipe-flow and high near-stream gradients, coupled with the high transmissivity of the elevated water table, produce a flashy hydrograph. The maritime climate maintains a high water table, despite relatively steep gradients, which is essential to the development of blanket bog systems in Newfoundland.