Abstract/Summary

The paper demonstrates the use of the C. S. B. Grimmond et al. (this issue) water balance model. It is used to calculate the daily, monthly, and annual water balance components for a suburban catchment in Vancouver, British Columbia. The budget results for one complete year are presented and where possible are compared with those from other cities. The balance is also compared with that for a rural area in the region, thereby illustrating the effects of suburban development. In interpreting the results special consideration is directed toward elucidating the role of irrigation (mainly garden sprinkling) in the suburban water balance. The temporal pattern of external water use is related to prevailing weather conditions. In particular, it is shown to be closely related to evapotranspiration. The relationship is a complex feedback system involving human as well as biophysical controls. The model is run both with, and without, an irrigation input to gauge its impact on the water budget. Together the results provide both quantitative and qualitative support for the idea that irrigation is the source of water supporting the relatively large rates of suburban evapotranspiration reported in energy balance studies.