Long term water budget in a grassland catchment in Ireland

This paper describes some of the results of a one year hydrometeorological field experiment of a grassland Catchment near Cork, Ireland (from November 1996 to November 1997). The objective of the experiment was to compare actual evapotranspiration from the annual water balance of a small Catchment with Penman-Monteith reference evapotranspiration. In addition, Class A pan measurements are compared over a shorter period of 4 months with daily resolution. Actual evapotranspiration is 98% of Penman-Monteith reference evpotranspiration. In the investigated period (July to October 1997) Penman- Monteith reference evapotranspiration is 73% of Class A pan evaporation. The annual actual evapotranspiration from the water balance is 29.27 % of precipitation from the grassland. This suggests that for the humid Irish climate Penman-Monteith is a good estimate of actual evapotranspiration (for grasslands).