Irrigation is a necessary part of agricultural systems. Urban farmers mostly rely on municipal water, which can be expensive. Rainwater harvesting presents a beneficial alternative for both farmers and the urban farming ecosystem. Catchment can take many different forms and some cities have infrastructure and systems in place to support these efforts, this sheet breaks down some of the benefits associated with rainwater harvesting as well as provides information on individual strategies of collection.
Irrigation for Urban Farms
While municipal water is the most common water source, it can be very expensive. Irrigation systems oftentimes take the form of hand-watering with hoses and watering cans, overhead watering using sprinklers, drip irrigation, or recirculating water in aquaponic systems. Hand-watering is the least cost prohibitive initially but takes a large amount of time in the long run. Over-head sprinklers can be useful for cooling crops and mimicking rainfall but can increase disease pressure. Drip irrigation is considered the most efficient but requires an investment in plastic tubing, as well as routine maintenance.
Irrigation water testing can provide important information about minerals, pH, and salinity which is especially important for growers. CCE has a list of water testing drop off sites around the state.
Depending on the location of the urban farm or garden, access to water may act as a large barrier. Rainwater harvesting can be a potential solution. There is some level of contamination if surfaces exposed to birds or rodents are used for rainwater collection.
Benefits of Rainwater Harvesting
Rainwater harvesting in urban environments not only saves money on the water bill for urban farmers, but also has a positive environmental impact. Many US cities have a Combined Sewage Overflow system, which means that rainwater and sewage water use the same pipes. When there is a significant rainstorm the pipes can get overloaded with rainwater, and can lead to rainwater and sewage overflowing into waterways. Rainwater harvesting helps to keep stormwater out of the sewage system and in turn can help maintain the cleanliness of local water bodies. Note that rainwater should only be used for the purposes of irrigation or for cleaning equipment, but is not safe for washing produce.
Rainwater Catchment Systems
Building a rainwater catchment system can be relatively simple such as digging swales or constructing a rain barrel catchment watering system. For those interested in building their own rainwater catchment system in New York State, good places to start include:
- GrowNYC in New York City provides a how-to manual and video for building your own rainwater catchment system, as well as a map, descriptions, and photos of existing catchment systems.
- New York City’s Water Resources Group is a coalition of greening and community groups that installs rainwater catchment systems across the city, and maintains a blog and listserv featuring news and updates about rainwater harvesting.
Before building a rainwater catchment system, check your city’s building, construction and plumbing codes pertaining to water recycling systems. For example, the New York City Construction Code (2008) reads:
- PC C101: Water recycling systems shall receive storm water captured from roofs and balconies, condensate reclamation systems, gray water discharge only of lavatories from public restrooms in commercial office buildings, and the treated effluent from an approved black water treatment system as regulated by Department of Mental Health and Hygiene. Recycled water shall be utilized only for flushing water closets and urinals, cooling tower makeup and irrigation systems that are located in the same lot as the water recycling system. Recycled water shall be considered potable. Such systems shall comply with sections C101.2 and C101.12.
Some towns and city departments promote rainwater collection by providing free or very affordable rain barrels. In Washington DC, DC Greenworks has partnered with the DC Department of Environment to provide training and installation of rain barrels. In Monroe County, NY the Soil and Water Department provides rainwater kits for private homes. Rain Check, in Buffalo, NY, is a citywide effort to manage water where it falls and protect water quality and quantity. Individuals can submit applications for rain barrels.
Other Resources
The Save the Rain program in Onondaga County, NY is a comprehensive stormwater management plan that provides information about and funding to the development of green infrastructure and stormwater mitigation techniques.
