Investigating Impacts of Climate Change on Irrigation Water Demands and Its Resulting Consequences on Groundwater Using CMIP5 Models

Abstract

In this study, the impacts of climate change on crop water requirements and irrigation water requirements on the regional cropping pattern were evaluated using two climate change scenarios and combinations of 20 GCM models. Different models including CROPWAT, MODFLOW, and statistical models were used to evaluate the climate change impacts. The results showed that in the future period (2017 to 2046) the temperature in all months of the year will increase at all stations. The average annual precipitation decline in Isfahan, Tiran, Flavarjan, and Lenj stations for RCP 4.5 and RCP 8.5 scenarios are 18.6 and 27.6%, 15.2 and 18%, 22.5 and 31.5%, and 10.5 and 12.1%, respectively. The average increase in the evapotranspiration for RCP 4.5 and RCP 8.5 scenarios are about 2.5 and 4.1%, respectively. The irrigation water demands increases considerably and for some crops, on average 18%. Among the existing crops in the cropping pattern, barley, cumin, onion, wheat, and forage crops are more sensitive and their water demand will increase significantly. Results indicate that climate change could have a significant impact on water resources consumption. By considering irrigation efficiency in the region, climate change impacts will result in about 35 to 50 million m /year, over-extraction from the aquifer. This additional exploitation causes an extra drop of 0.4 to 0.8 m in groundwater table per year in the aquifer. Therefore, with regard to the critical condition of the aquifer, management and preventive measures to deal with climate change in the future is absolutely necessary.

Responses of Soybean Water Supply and Requirement to Future Climate Conditions in Heilongjiang Province

“…In this study, the annual average ET c for the soybean growing season under RCP4.5 and RCP8.5 for 2021-2080 was higher than that of soybean in Heilongjiang Province for 1966-2015 reported by Li et al [30]. The higher ET c indicated soybean in this study area may suggest the need for more water due to the increase in evapotranspiration derived from future climate conditions [50].…”

“…In the Jayakwadi command area, India, the ET c of major crops and P e increased during the growth period, resulting in less I r under climate change [29]. In the Najafabad plain in Iran, ET c increased and P e decreased during the growth period of major crops; therefore, more water needed to be irrigated [30].…”

Reducing Groundwater Pumping Cost Using Alternate Pulsed Pumping

“…Many countries designated as "water scarce" have substantial groundwater reserves (MacDonald et al 2012). Under the scope of climate change groundwater's strategic role for global water and food security will probably intensify (Taylor et al 2013;Goodarzi et al 2019). In general, poor groundwater resources management, spurred by population growth, has resulted in a worldwide predicament.…”

Climate change impact on the estimation of reference evapotranspiration, water requirement, and irrigation requirement in irrigated areas (a case study: Bardsir plain)

“…Goodarzi et al investigated the climate change effects on the irrigation water requirement and related complications on groundwater levels in the 2017-2046 period using a combination of 20 different GCMs with RCP8.5 and RCP4.5 scenarios. According to their findings, there would be, respectively, a 4.1 and 2.5% increase in mean evapotranspiration of all months of the year under RCP8.5 and RCP4.5 scenarios, and an 18% rise in the mean irrigation water requirement of some plants, which mean climate change would significantly influence water consumption (Goodarzi et al 2018). Gondim et al examined the climate change effects on the water requirement in the Jaguaribe region in northeastern Brazil in the 2025-2055 period using CMIP5 5 under two RCP scenarios.…”