The Water-Energy-Food Nexus model is used to describe the interconnected issues related to water, energy, and food sustainability, deeming each one interdependent on the other. It is estimated that by 2030, global water demand will increase by more than 50%, with agriculture alone requiring more than want can be sustained to feed the world, when even more domestic and industrial needs are considered.
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Colleen L. Boodleman
an AgWater Science consultant with the {http://www.sfuaa.org/|San Francisco Urban Agriculture Alliance}.
This blog is a repost and has been reposted with kind permission by the author. It is part of an ongoing series of {http://www.farmingfirst.org/ypard-august|Farming First} with the {http://www.ypard.net/2014-august-29/reshaping-water-food-energy-conundrum-address-urban-agriculture|Young Professionals for Agricultural Development network (YPARD)}.
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These figures are shocking, but rarely is the Water-Energy-Food Nexus considered in the context of meeting challenges at a local level. When most of the world's food is produced at a small-scale, an overly complex model that addresses these issues at a global scale can be confusing. In fact, many urban water and food projects have demonstrated that urban agriculture can play a key role in solving implications related to interconnected water, energy, and food sectors.
Food security is not just a concern for the developing world. In California the prevalence of food insecurity is at 15.6% as compared to the national average estimated at 14.6%. Within San Francisco approximately 805,000 people experience food insecurity on a daily basis. To address poverty, hunger, and malnutrition in city environments — a number of community food plots have begun to emerge to nourish marginalized low-income populations, and to provide food access to individuals suffering from hunger, poverty and homelessness.
Producing food at a local scale is one of the ways urban agriculture is involved in sustainably reshaping the interconnections between local water, energy, and food sectors in San Francisco. Here's how:
Green spaces to redirect energy and soak up city storms
The arrival of climate change in California has brought with it warmer temperatures and heavy rainfall. These are two aspects of global change that pose long-term risks to city communities experiencing extreme temperatures and flooding from storm surges. Concrete cities aren't equipped to absorb this deluge of water or intense warming, but with the creation of green spaces by start-ups like Nomad Gardens, water and soil erosion within the city can be reduced by providing portable community garden sites that absorb the runoff connected to extreme rainfall events. Other urban agriculture projects have been designed to capture and manage city storm water and moderate high temperatures with sidewalk gardens.
These gardens along with rainwater harvesting proposals are encouraged by San Francisco city agencies as a means to reduce the burden of storm water on sewer systems while also improving water quality by reducing pollutant contributions to the surrounding Bay. Green infrastructure can be described as "city microclimates" because some types provide a place for natural energies in the form of rainfall, solar radiation, or wind pressures to be captured, stored, and released. These spaces also help capture and store greenhouse gases, a process referred to as carbon sequestration.
Reducing water and energy footprints through technological innovations
Access to adequate food in urban areas requires access to energy resources for transporting and maintaining food support services. Urban agriculture connects people to food sources within their own immediate areas, therefore reducing this burden. Energy-efficient technologies can help redistribute food resources to neighbourhoods and places in the city that may not be a part of major transportation lines.
The technology sector is a key player in elevating urban agriculture benefits to the public. Online crowd sourcing and open source platforms like Local Grow can directly connect people to the food being grown in their local area. But more importantly, it can be used to inform growers of available space for growing food. Space for growing food is a limited resource in San Francisco, and as a result urban agriculture zoning databases and geospatial information systems provided by county agencies can improve resource use efficiency, by putting information in the hands of growers. Open source information is also providing growers with sites and tools where they can learn to manage water efficiently by tracking evapotranspiration rates for garden plants and learning about plant ecophysiology via software and applications downloaded to their personal mobile devices.
Urban agriculture uses less water than you might think
Water meters have been installed in urban agriculture gardens, in collaboration with city utility agencies, in an effort to better measure grey water sources and separate them from total water consumption. In the Nexus approach, water is viewed as a critical limiting resource for food production, however within San Francisco, urban agriculture explains a small fraction of the total urban water budget. However, it is often grouped within total urban water consumption data. As a result, urban agriculture water use can easily be misrepresented as a "Nexus type competitor" with rural agricultural industries and energy development projects associated with urban growth. One way this is being addressed is with water efficiency ordinances which have been created to set upper limits of how much freshwater can be applied to a landscape. This helps to minimize the negative trade-offs and maximize the helpful synergies between the food and water sectors in public and private enterprise planning.
Urban agriculture is a localized approach that is encouraged in cities because it has the potential to solve interconnected water, energy, and food sector issues. By reframing the Nexus approach to include more interventions at a localized scale — cross-sectoral interactions and goals related to water, energy and food issues will be more feasible and lead to greater collaborations among sectors working on complex challenges.
