The Impact of Location on Decentralized Water Use in Urban Agriculture

Urban Agriculture is becoming more prevalent across the world because of its ability to provide healthy and nutritious food for urban populations and contribute to urban ecosystem services. Generally, potable water is the main source of irrigation for urban agriculture, and in many regions, this negatively impacts ecosystem services because of the energy required to transport and treat potable water. Rainwater harvesting is a decentralized water strategy and urban agriculture is a decentralized food production method. This chapter reviews the literature on rainwater harvesting for urban agriculture, two decentralized strategies promoting urban sustainability. Four case studies in the Unites States (two are in wet regions and two are in semi-arid regions) are used to analyze rainwater harvesting’s ability to irrigate urban agriculture, save energy, and reduce greenhouse gas emissions. Study results show that location does matter because rainfall directly affects the ability for cities in semi-arid regions to harvest rainfall for irrigation. A significant difference is apparent in rainwater availability between arid and wet regions of the US because of the significantly lower amount of precipitation in arid regions, as well as the number of days in arid regions where there is insufficient rainfall to produce runoff.

Results also demonstrate that, even in arid regions, rainwater harvesting has the potential to lower potable water use, save energy, and reduce greenhouse gas emissions.