Ahmedabad, Gujarat’s largest city, is grappling with a concerning decline in dew formation, revealed by a recent study focusing on water resources in the state. The study, titled ‘Evolution of Dew and Rainwater Resources in Gujarat (India) between 2005 and 2021’, conducted by researchers from the National Remote Sensing Centre (Isro) and DAIICT Gandhinagar, underscores Ahmedabad’s stark contrast in dew yield compared to coastal counterparts like Jamnagar and Porbandar.
According to the findings, while coastal areas like Jamnagar and Porbandar experience dew-to-rain ratios of 37.2% and 32.8% respectively, Ahmedabad and Surat lag significantly with only 4.6% and 8.5% respectively. This disparity is attributed to factors such as high night-time temperatures and urban pollution, which inhibit the condensation process necessary for dew formation in urban environments. The study’s lead researcher, Mr. Roy, emphasized the historical significance of dew harvesting projects in Gujarat, citing a pioneering initiative at Kothara in Kutch led by late Prof. Girja Sharan. This project demonstrated the potential of dew harvesting as a supplementary water resource, capable of yielding up to 500 litres per day through specially designed panels. Analyzing weather data from multiple sites across Gujarat, including Ahmedabad, Rajkot, Junagadh, and Jamnagar, the study identifies a positive trend in both rainfall and dew formation. It notes an increase in dew yield from an average of 3.4mm per month (2005-2013) to 5.8mm per month (2014-2021), correlated with a rise in relative humidity (RH) from 83.6% to 84.4% during the same periods.
However, urban areas like Ahmedabad face unique challenges in dew collection due to prevalent high temperatures that hinder condensation and accelerate dew evaporation. Pollution further exacerbates these conditions, limiting the city’s potential to harness ambient water through dew harvesting technologies. Looking forward, the study forecasts potential implications of climate change on dew formation and water resources in Gujarat. It underscores the need for continued research and strategic urban planning to mitigate the impact of rising temperatures and ensure sustainable water management practices. Funded by the state government’s climate change department, the study aims to provide a comprehensive understanding of dew formation dynamics and inform future strategies for water conservation and management amidst evolving climate patterns.
