Use of alternative water sources in irrigation: potential scales, costs, and environmental impacts in California

Abstract

Under the risk of drought, unreliable water supplies, and growing water demand, there is a growing need worldwide to explore alternative water sources to meet the demand for irrigation in agriculture and other outdoor activities. This paper estimates stocks, production capacities, economic costs, energy implications, and greenhouse gas (GHG) emissions associated with recycled water, desalinated brackish and seawater, and stormwater in California, the largest US state and the most significant fresh and processed food producer. The combined recycled water and stormwater supply could increase the share of alternative water use in urban land irrigation (parks and golf courses) from the current rate of 4.6% to 48% and in agriculture from 0.82% to 5.4% while increasing annual water costs by $900 million (1.8% of California's annual agricultural revenue) and energy use by 710 GWh (0.28% of California's annual electricity consumption). The annual supply of alternative water greatly exceeds the amount of water currently used in the food processing industry. In case studies of high-value agricultural produce, conventional water use was found to contribute approximately 17%, 12%, 4.1%, and 1.7% to the total GHG emissions of avocados, lemons, celery, and strawberries, respectively. However, materials (mostly packaging) contribute 46%, 26%, 47%, and 66%, and diesel use on farms 18%, 28%, and 14% for lemons, celery, and strawberries, respectively (data for avocados were not available). Switching to recycled water or stormwater would increase the total GHG emissions of one serving size of packaged strawberries, celery, lemons, and avocados by 3.0%, 7.8%, 11%, and 27%, respectively, desalinated brackish water by 23%, 58%, 150%, and 210%, and desalinated seawater by 35%, 88%, 230%, and 320%. Though switching to alternative water will increase costs, energy demand, and GHG emissions, they could be offset by turning to less environmentally damaging materials in agricultural production and sales (especially packaging). BackgroundThe use of alternative water sources (other than surface or groundwater), such as recycled water, brackish water, seawater, and stormwater, has been practiced in many regions of the world and for many types of irrigation such as agricultural crops, golf courses, forests, and open-space landscapes [1][2][3][4][5][6]. Under the changing precipitation patters due to climate change, pressure of growing populations, and risk of drought, a well-articulated need is forming in parts of the world to explore additional and more reliable water sources to meet the future demand of water in agriculture and other outdoor irrigation. Many cities have formed near traditional agricultural areas and are located close to salt water. These proximities provide an opportunity for the use of alternative sources of water.Agriculture accounts for a large share of water consumption. As the largest agricultural producer in the United States by value, California is a great case study of opportunities, challenges, and past and current p...

Germination, physio-anatomical behavior, and productivity of wheat plants irrigated with magnetically treated seawater

“…Furthermore, alternative water sources, such as recycled water, brackish water, seawater, and storm water, have been used for irrigation in various parts of the world and for a variety of purposes, including irrigating agricultural crops. Such examples from the current and previous studies showed the challenges associated with higher salinity water irrigation in general, and those which negatively affect wheat crops in particular ( Qin and Horvath, 2020 ; Dolan et al, 2021 ).…”

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Integrated Water Management at the Peri-Urban Interface: A Case Study of Monterey, California

“…With layered uncertainty characterizing future water supply and demand on the Monterey Peninsula, more information is needed before the region can confidently plan a permanent water solution. Alternative water supplies require greater cost, energy, and emissions compared to conventional surface and groundwater sources [87], so planning efforts must consider the best balance between conventional and alternative supplies, in addition to the right portfolio of alternative supplies [88]. Uncertainty surrounding Monterey's water demand stems partly from the recent decline in water demand within CalAm's service area, which fell from 16.3 million m 3 /y (13,200 AFY) in 2009 [36] to 11.4 million m 3 /y (9200 AFY) in 2019 [89].…”