Introduction
This study attempts to understand the ecological changes and agrarian transformations brought about by the irrigation methods used in Uttar Pradesh from 1850 to 2000. Without considering ecological and agrarian concerns, new systems of irrigation based on the scientific revolution were introduced during the colonial period and further expanded during the post-colonial period.

Methodology:

The present study uses an integrated historical and environmental analytical approach to trace relations between irrigation means and their ecological effects. It depends on a variety of primary and secondary sources. It draws data from archival sources such as revenue settlement reports, irrigation records, newspapers, administrative records, and policy documents related to the colonial and post-colonial periods. It also includes critical analysis from secondary literature research articles and books.

Results :
The main argument of this study is that while irrigation brought initial economic gains by encouraging water-intensive crops and chemical use, it disrupted traditional water systems, altered cropping patterns, and contributed to environmental problems which have been profound and often irreversible. It also posed long-term challenges such as soil degradation, soil salinization, waterlogging and groundwater depletion, and agrarian distress. Traditional water systems were undermined, and disparities in agrarian society were widened.

Discussion:
This study concludes that irrigation must be understood not merely as a developmental intervention, but as an ecological force with enduring consequences. Recognizing the historical roots of environmental degradation is essential for formulating sustainable agrarian and irrigation policies today. This study suggests a need to rethink irrigation policy with consideration for environmental concerns.