Reducing Carbon Emission, Groundwater Over-Exploitation and Energy Consumption on Agricultural Lands by Off-Farm Water Management Practices: Modernization of Surface Water Distribution Systems

Abstract

A wide range of endeavors has been made to propose various approaches to reduce Greenhouse gas emissions in the agricultural sector. The present study investigates the impacts of Surface Water Distribution Systems (SWDS) modernization in reducing groundwater overexploitation, energy consumption, and carbon emission in the agriculture sector. Four modernization alternatives, including an improved manual-based system (A1, A2), off-line, and real-time automatic control systems (A3, A4), are developed and tested on a real test case in Central Iran, which is confronted with severe water shortages. The results reveal that SWDS’s operating system modernization improves 4 ~ 21% surface water distribution through the alternatives A1 ~ A4. This surface water distribution enhancement led to groundwater over-extraction reduction. Spatial analysis reveals that 0.075, 0.100, 0.281, and 0.470 of the irrigation district’s cultivated area was thoroughly fulfilled by the delivered surface water and no need for groundwater extraction due to alternatives A1 ~ A4, respectively. Closure of several active tubewells up to 1,668 semi-deep and 497 deep tube-well were verified. SWDS’ modernization led to 5, 7, 20, and 30% of energy consumption and consequently 1,864.90, 2,714.33, 8,427.19, and 12,674.32 tC ha-1 carbon emission reduction in alternatives A1 ~ A4, respectively. This study’s results show that modernization of off-farm operating systems - responsible for surface water conveyance and distribution from a dam reservoir to farms - resulted in significant environmental benefits through improving the reliability of systems supplied by surface water and reducing the tendency of the farmers to groundwater resources.