Irrigating with Reclaimed Water
Irrigation of landscapes with reclaimed water in El Paso is conserving millions of gallons of potable water each year for domestic uses. Reclaimed water is non-potable and contains higher levels of salts and nutrients than potable water. There are some suggested best management practices users should be aware. Reclaimed water has a higher content of salts than potable water and these salts can accumulate in the soil with time if not managed properly.
El Paso Water Utilities’ commitment with its customers has enable the continued sponsorship of research projects aimed to assist reclaimed water users, water conservation, and soil salinization prevention among others. Through the dedicated cooperation of Texas A&M University – Agriculture Research Center (TAMU), several brochures have been produced identifying plant responses to salinity, and best management practices (BMP) for turf management, and irrigation. EPWU and TAMU, with cooperation of the US Bureau of Reclamation produced a video that explains in detail the response of soil and vegetation to the salinity from Reclaimed Water and suggested practices to manage it. The video is available to reclaimed water customers upon request.
Planning and Managing a Reclaimed-Water Irrigated Landscape
The basics for having a successful landscape is to know the type and quality of the soil to be landscaped. Proper Soil Identification is important since this will determine if the existing soils will have the capability to sustain a landscape or if soil amendments are needed. Good drainage is required for reclaimed water irrigated sites to allow for leaching of excess salts. Clay and caliche soils are less desirable since these prevent or reduce drainage. Removal or amendment of clay and caliche soils is highly recommended to improve the quality of the soil. Soil aeration must also be considered in preparing and managing a landscape.
Choose salt tolerant species to incorporate into an existing or new landscape. A list of trees, shrubs, and grasses that have been studied by TAMU for response to water of higher salinity. Some plants may be salt-sensitive at the root system while other may be salt-sensitive at The foliage (leaves). Not all drought-resistant plants are tolerant to water with higher salinity. Plan ahead by listing all the existing plants that will stay and those that need to be replaced and compare these against the existing or new irrigation system.
An adequate irrigation system must also be considered to deliver the right amount of water needed for the plant’s optimal growth. Modify existing irrigation systems to accommodate the landscape’s response to added salinity. Avoid spraying foliage of plants that are leaf salt-sensitive by replacing sprinkler-heads with low-angle nozzles or converting to bubbler or drip irrigation systems as needed. Consider replacing highly salt-sensitive plants with salt resistant species.
State Regulations as well as Public Service Board Regulation No. 12 require compliance with PURPLE color coding - specific to reclaimed water. Modifications to the irrigation system may also be required to comply with State Regulations. All irrigation system pipeline used for reclaimed water must be color PURPLE. Above-ground water faucets and quick-couplers must be enclosed in a lockable device. All irrigation valves must be in a purple locking box. Consult with your irrigation system supplier for availability of reclaimed water (purple) fittings such as rotor and sprinkler head caps, emitter tips, pipe, quick-coupler caps, valve box covers, etc.
All sites using reclaimed water (residential, commercial, parks, schools, cemeteries, etc.) must have reclaimed water warning-signs posted within the premise, as required by the State and PSB’s Regulations. Warning signs must be on purple-color background with white or yellow lettering in English and Spanish. The size must be adequate to provide easy visibility to visitors but no less than 12x24 inches. Residential customers may install smaller signs but these may not be smaller than 8x8 inches.
The number of signs needed in an establishment is based on the size of the property, the number of access points (entrances) and how many people access the site.
Landscape Management Program
The Texas A&M University – Agricultural Research Center in El Paso has been an active member of the Reclaimed Water Program. Through continued research, TAMU has produced several reports on effective uses of reclaimed water and landscape management. EPWU and other agencies continuously support TAMU research initiatives. Through a close partnership we have produced a Landscape Management Program. EPWU will provide with technical assistance prior, during and after conversion to reclaimed water. Water use audits, soil sampling and testing, landscape performance assessments, workshops, and other activities are available upon request. Customers, landscape and irrigation professionals are encouraged to take advantage of these activities. Literature on specific landscape management topics are available from the Water Reclamation Staff and TAMU Agriculture Research Center.