Page 54 - Haryana Water Resources Atlas 2025

Potential Evapotranspiration (PET)

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Scale
otential Evapotranspiration (PET) refers to the water loss from a
Kms
uniformly covered large area with actively growing short green 0 12.5 25 50 75 100
Pcrops when water availability is not a limiting factor. It represents
the upper limit of evapotranspiration during a specific time period and
cannot exceed the evaporation from the surface of free water under the
same weather conditions. This concept is applicable in humid conditions
and is determined by factors such as temperature, relative humidity, wind
velocity, and radiation while being unaffected by soil and plant
characteristics. PET is also known as reference ET.
Figure 20 illustrates the PET values for the year 2023 in Haryana, ranging
from 1600 to 2400 mm per year, derived and modified from satellite-based
products. Areas with evapotranspiration below 1600 mm are observed in
the built-up regions of all districts. Slight variations up to 1800 mm are
predominantly observed in Yamunanagar and Palwal districts, with
smaller patches in Faridabad, Mewat, Gurugram, Jhajjar, Sonipat,
Panipat, and Kaithal. The common range of PET values, ranging from
1800 to 2000 mm, covers major districts including Yamunanagar,
Fatehabad, Jind, Panipat, Sonipat, Rohtak, Jhajjar, and parts of Palwal,
Mewat, Gurugram, Charkhi Dadri, Hisar, Fatehabad, Sirsa, Kaithal,
Ambala, and Karnal. The Western and Southern parts of Haryana,
including Sirsa, Hisar, Bhiwani, Charkhi Dadri, Mahendragarh, Rewari,
Kurukshetra, Kaithal, and Karnal, fall within the range of 1800 to 2000
mm. Finally, a significant but small range exceeding 2000 mm per year is
observed in Hisar and Bhiwani.
The variability in PET across districts can be attributed to variations in
precipitation, temperature, and other meteorological conditions
throughout the state. Factors such as light and moisture play a direct role
in PET in arid areas. PET is closely linked to surface water and energy
balance, which largely explains its variability across different climatic and
ecological regions in the state. Accurate estimation of evapotranspiration
rate is essential for determining water requirements, soil water
availability, soil water chemistry and Ground Water recharge forming the
basis for effective water management strategies.

Figure 20. Potential Evapotranspiration Data Source-HARSAC

Haryana Water Resources Atlas 36|