Page 113 - AJWEP-v22i2

Assessing drought impacts for adaptive response

Table 3 shows that wheat and pea crops are more
sensitive to decreased rainfall and increased temperature,
as they need more irrigation water compared to other
crops under the first drought scenario. Overall, reduced
rainfall and higher temperatures increased the need for
irrigation water for crops in the basin. 12,35 The results
also indicate that the highest reduction in yield and
the greatest increase in irrigation water needs were
observed for wheat crops due to the decrease in rainfall
and the rise in temperature in the Kowsar Dam basin. Figure 7. Unmet water demand for the agricultural
This reinforces the fact that wheat crops are more units in Bashet under the second drought scenario
dependent on rainfall and temperature than other
crops. Furthermore, the simulation results suggest that
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the percentage changes in irrigation water requirements
were not significantly different between the two drought
scenarios, except for rice crops. Therefore, reducing the
amount of available water did not have a significant
negative impact on irrigation water needs for most
crops, except for rice. Similarly, it can be concluded that
the reduction in available water has a greater negative
impact on crop yield compared to the decrease in the
amount of rainfall. Nevertheless, the impact on irrigation
water requirements was noticeably different. Moreover, Figure 8. Unmet water demand for the agricultural
the decrease in rainfall and the increase in temperature units in Gachsaran under the second drought
showed a more significant negative impact on irrigation scenario
water needs for the crops in the basin compared to the
decrease in the amount of available water.

3.3. Hydrological impacts of drought scenario
After describing the impacts of reduced rainfall, higher
temperatures, and limited water availability on crop
yields and water needs, the effects of drought on the
water situation of the basin were analyzed. The unmet
water demand, defined as the difference between water
demand and water supply, serves as an indicator of the
basin’s water situation. The greater the disparity between
water demand and the amount of water supplied, the Figure 9. Unmet water demand for the agricultural
higher the unmet demand; and vice versa. The unmet units in Choram under the second drought scenario
water demand in different regions of the basin during
the 2011 – 2030 period was studied under both normal the agricultural areas of the Bashet region, making it
conditions and drought conditions (reduced rainfall, more difficult to meet their water needs in the future.
higher temperatures, and reduced water availability). The results further suggest that by the end of 2030,
The unmet water demand for the Bashet, Gachsaran, the unmet water demand for agricultural areas in this
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and Choram regions was simulated under the second region will surpass 92 million m . In 2030, about 38%
drought scenario, as depicted in Figures 7-9. of the water demand of agricultural areas will remain
Figure 7 shows that the unmet water demand is unmet under drought conditions, which constitutes
higher under the drought scenario than under normal a significant shortfall. Thus, it can be concluded that,
conditions. Under normal conditions, the unmet during a drought, the areas in this region will face
water demand exceeded 60 million m , while under substantial problems in meeting their water demands.
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drought conditions, it fluctuated around 85 million m . Figure 8 illustrates that the average unmet water
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This indicates that drought will significantly affect demand during drought conditions in the Gachsaran

Volume 22 Issue 2 (2025) 107 doi: 10.36922/ajwep.8381