Estimated Water Savings Potential of Florida-Friendly Landscaping Activities
Introduction
The Florida-Friendly Landscaping™ (FFL) program promotes a number of environmentally friendly landscaping practices intended to protect natural resources. These practices implement the nine basic principles of FFL that, taken individually or collectively, reduce landscape maintenance and resource requirements. These nine principles are
- right plant, right place;
- water efficiently;
- fertilize appropriately;
- mulch;
- attract wildlife;
- manage yard pests responsibly;
- recycle;
- reduce stormwater runoff; and
- protect the waterfront (UF/IFAS 2009).
The FFL program for residential landscapes—Florida Yards and Neighborhoods (FYN)—educates homeowners on how to design, install, and maintain low-impact landscapes. Homes can be recognized as an FFL by passing an evaluation performed by an FYN Extension Agent or a Master Gardener Yard Advisor; however, any homeowner can independently adopt the practices as long as they are consistent with homeowner association requirements or restrictive covenants. Homeowners can gradually adopt FFL practices or focus on one, such as the second principle, "water efficiently." Watering efficiently can reduce water bills and can help conserve Florida's limited water resources.
The FFL evaluation is based on a checklist of landscape practices. The checklist consists of required practices and optional practices. Optional practices are assigned point values. In order to be recognized as an FFL, a homeowner must follow all applicable mandatory practices and collect a certain number of points from the optional practices. The listed practices for watering efficiently are given below. The first two practices are required, and the remaining practices are optional. Many of the practices apply only to landscapes that use irrigation systems.
Required
- A functioning automatic rainfall shutoff device is maintained on in-ground systems, and a rain gauge is used to track rainfall amounts.
- Spray and rotor heads are installed on separate zones.
Optional
- For a landscape that does not use an irrigation system, the landscape is designed and maintained to exist on rainfall and minimal hand watering once plants are established.
- Not more than 50 percent of the irrigation system (by area) is high-volume. (High-volume irrigation has a flow rate of 0.5 gallons per minute or higher. In most cases, spray sprinklers, rotor sprinklers, and bubblers are considered high-volume [SJRWMD 2015].)
- Turfgrass and landscape plants are irrigated only as needed (in compliance with any existing watering restrictions).
- A smart controller (evapotranspiration, soil moisture sensor, or similar) is installed and operational. (Evapotranspiration controllers use weather data to schedule when and for how long irrigation should occur, and soil moisture sensors bypass scheduled irrigation events when the soil has enough stored water. Both types of smart controllers are used with in-ground automatic irrigation systems. Additional information on smart controllers can be found in EDIS document AE442, Smart Irrigation Controllers: What Makes an Irrigation Controller Smart? [Dukes 2015].)
- Separate irrigation zones for turf and landscape plants are maintained.
- Low-flow irrigation is installed and maintained in plant and flower beds.
- The irrigation system is calibrated to apply 1/2–3/4 inches of water per application and is maintained regularly to repair clogs and leaks.
Water Savings Potential
To help homeowners predict the impact of implementing some of the water conservation measures listed on FFL checklist as well as other conservation measures, a table of estimated water savings has been developed (Table 1). Homeowners can select from Table 1 which FFL activities are the best fit for their landscape and can also use the table to see which FFL activities have the most conservation potential. The water savings is compared to a baseline case of typical irrigation behavior. Savings are in units of gallons per 1,000 square feet of irrigated landscape per year (gal/1,000 sq ft/yr). Typical suburban residential homes in Florida may have a total lot size of about 10,000 sq ft (about 0.2 acres) and landscaped area of about 5,000 sq ft (about 0.1 acres). The water savings given in Table 1 are usually not additive (i.e., cumulative). For example, calibrating the sprinkler to deliver ½" of water and calibrating the sprinkler system to replace 60% of evapotranspiration (FFL activities 2 and 3 in Table 1) are both ways to adjust the sprinkler system, and the savings are not additive. Reducing irrigation in the summers and winters (FFL activities 10 and 11 in Table 1) would be cumulative because the activities are independent.
Baseline case: A homeowner irrigates their turfgrass according to UF/IFAS recommendations (Table 5 in Dukes and Haman 2002) twice per week with 100% evapotranspiration (ET) replacement and an irrigation rate of 1.0 in/hr. Annual baseline irrigation is 31,787 gal/1,000 sq ft of turfgrass.
Rationale: Based on Table 5 in Dukes and Haman (2002), average monthly irrigation is 29.4 min/event in central Florida. With a rate of 1 in/hr and 2 events/wk, irrigation depth is 51.0 in/yr, or 31,767 gal/1,000 sq ft/yr.
Note: The baseline may be higher or lower than what some homeowners typically use. In southwest Florida, Haley and Dukes (2012) observed that the control group of homes irrigated 2.5 in/month (18,849 gal/1,000 sq ft/yr). In central Florida, Haley et al. (2007) observed that the control group of homes irrigated 5.9 in/month (43,882 gal/1,000 sq ft/yr). Therefore, a homeowner who does not follow the UF/IFAS recommended irrigation schedule may be irrigating significantly more or less than 31,767 gal per 1,000 sq ft. Additionally, geographic location may influence irrigation use. Using the same IFAS recommendations (Table 5 in Dukes and Haman 2002), baseline irrigation is 23,015 gal/1,000 sq ft in north Florida (28% lower than in central Florida) and 35,765 gal/1,000 sq ft/yr in south Florida (13% higher than in central Florida).
References
Cárdenas-Lailhacar, B., M. D. Dukes, and G. L. Miller. 2010. Sensor-based automation of irrigation on bermudagrass during dry weather conditions. Journal of Irrigation and Drainage Engineering 136(3): 161–223.
Cárdenas-Lailhacar, B., M. D. Dukes, and G. L. Miller. 2008a. Sensor-based automation of irrigation on bermudagrass during wet weather conditions. Journal of Irrigation and Drainage Engineering 134(2): 120–128.
Cárdenas-Lailhacar, B., and M. D. Dukes. 2008b. Expanding disk rain sensor performance and potential irrigation savings. Journal of Irrigation and Drainage Engineering 134(1):67–73.
Davis, S. L., M. D. Dukes, and G. L. Miller. 2009. Landscape irrigation by evapotranspiration-based irrigation controllers under dry conditions in Southwest Florida. Agricultural Water Management 96(12): 1828–1836.
Dukes, M. D. 2015. Smart Irrigation Controllers: What Makes an Irrigation Controller Smart? Gainesville: University of Florida Institute of Food and Agricultural Sciences. https://edis.ifas.ufl.edu/ae442.
Dukes, M. D. 2014. Summary of IFAS Turf and Landscape Irrigation Recommendations. Gainesville: University of Florida Institute of Food and Agricultural Sciences. https://edis.ifas.ufl.edu/ae436.
Dukes, M. D., and D. Z. Haman. 2015. Operation of Residential Irrigation Controllers. Gainesville: University of Florida Institute of Food and Agricultural Sciences. https://edis.ifas.ufl.edu/ae220.
Haley, M. B., M. D. Dukes, and G. L. Miller. 2007. Residential irrigation water use in Central Florida. Journal of Irrigation and Drainage Engineering 133(5): 427–434.
Haley, M. B., M. D. Dukes. 2012. Validation of landscape irrigation reduction with soil moisture sensor irrigation controllers. Journal of Irrigation and Drainage Engineering 138(2): 135–144.
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Saint Johns Rivers Water Management District (SJRWMD). 2015. Florida Water Star Technical Manual: Irrigation system criteria. http://floridawaterstar.com/technicalmanual/irrigation/highvolumeirrigation.html.
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