environmental impact statement kilmainhamwood compost facility ...

5361- Kilmainhamwood Compost Facility Extension- EIS
At the composting facility area, approximately 56% of the total annual rainfall is recorded during the
winter period (October – March). This amount of precipitation (including snow) will normally be
associated with more prolonged Atlantic frontal weather depressions passing over the region compared
to the summer.
9.4.2.4 Evapotranspiration and Effective Rainfall
The nearest meteorological station with evapotranspiration measuring equipment is located at the
Clones Synoptic Station. Evapotranspiration is the return of water vapour to the atmosphere by
evaporation from land and by the transpiration of plants, generally measured from a short-grass
covered surface (such as a permanent pasture) adequately supplied with water. Evaporation is the
return of water vapour to the atmosphere by evaporation from a free water surface such as a pan of
water, known as a “Class A Pan”, fitted with a depth measuring gauge. The evapotranspiration figures
for the Clones Synoptic Station are detailed in Table 9.10.
It can be noted that evapotranspiration is very low during winter months, when plant growth is minimal.
The vast majority of evapotranspiration during winter months is attributable to direct evaporation from
ground surfaces. During summer months the rate of evapotranspiration increases and often exceeds
the monthly rainfall. This is due to increased free evaporation from the surface and from transpiration
from leaves and plants.
Using the rainfall data calculated for the site in Table 9.9 and the potential evapotranspiration data for
the nearest synoptic station, i.e. Clones Synoptic Station, the effective rainfall for the subject site can be
calculated. Table 9.10 also shows the effective rainfall to the site. Any rain falling on the site will
infiltrate to the ground, evaporate from the surface or become surface water runoff.
Table 9.10 Hydrological Data for the Development Site
Month Rainfall (mm)
For inspection purposes only.
Consent of copyright owner required for any other use.
Potential Evapo-
transpiration (mm)
Actual Evapo-
transpiration (mm)
(PE x 0.92)
Effective Rainfall
(mm)
January 108 2.4 2.2 105.8
February 74 14.6 13.4 60.9
March 78 29.9 27.5 50.9
April 65 51.7 47.6 17.6
May 70 72.1 66.3 3.9
June 67 79.8 73.4 -6.2
July 64 74.1 68.2 -4.0
August 86 58.5 53.8 31.7
September 89 35.9 33.0 55.6
October 99 16.8 15.5 83.3
November 90 3 2.8 86.9
December 102 -0.5 -0.5 102.3
Total 1032 438.3 403.2 588.8
147
EPA Export 01-06-2010:03:55:59