An irrigation scheduling protocol for TREATED INDUSTRIAL EFFLUENT in the Chihuahuan Desert

Abstract

As the population of southwestern New Mexico expands, land application of industrial and municipal wastewater is increasingly seen as a cost‐effective and environmentally safe water management technique. Yet virtually no management guidelines exist for scheduling land application of wastewater in semi‐arid climates of the United States. This article describes a web‐based methodology for scheduling wastewater irrigation in the Chihuahuan Desert. It also details how to input data that are specific to the region and climate into a spreadsheet program to schedule wastewater irrigation at rates that avoid adverse effects to the application site. A website helps utility managers outside of New Mexico use the methodology. An irrigation schedule created by this technique was tested over three years in Las Cruces, N.M. The land application was designed to maximize vegetative cover to increase the capacity of a site to serve as a sink for wastewater contaminants, minimize salt accumulation in the root zone, and avoid nitrate leaching into the groundwater. The step‐by‐step instructions provided here help utilities eliminate the guesswork of how much and when to apply water in a land application process.

The Response of Ornamental Plants to Saline Irrigation Water

“…Alternative water sources might be recycled water, treated municipal effluent and brackish groundwater, all of which generally have higher levels of salts compared with potable waters (Niu et al, 2007b). Treated effluent may also contain nutrients essential for plant growth; if water quality is good (not too saline), treated effluent can improve plant growth and reduce fertilizer requirements (Gori et al, 2000;Quist et al, 1999); application of industrial and municipal wastewater to land can be an environmentally safe water management strategy (Rodriguez, 2005;Ruiz et al, 2006). The potential physical, chemical or biological problems that are associated with effluent water applied to edible crops (Kirkam, 1986) are of lesser concern for landscape plant production (Gori et al, 2000).…”

Land Application of Treated Industrial Wastewater on a Chihuahuan Desert Shrubland: Impacts on the Natural Vegetation

“…We used two adjacent 0.4-ha plots (24 m wide and 150 m long), one non-irrigated and one irrigated of sufficient size for characterizing Chihuahuan Desert vegetation biomass (Huenneke et al, 2001). Irrigation was scheduled by the methods of Ruiz et al (2006), and during the 4-yr study, a total of 143 cm of effluent was applied to the irrigated plot, while 79 cm of rain fell on both plots (Picchioni et al, 2012).…”

Land Application of Treated Industrial Wastewater on a Chihuahuan Desert Shrubland: Implications for Water Quality and Mineral Deposition

“…The ET-crop coefficient (K c ) method for irrigated crops was used to schedule irrigation, based on the average shrub ET under non-limiting water conditions (Ruiz et al, 2006;Babcock et al, 2009). We acknowledge that this procedure may have overestimated actual ET on the sparsely-vegetated site (Mata-González et al, 2005;Zhang et al, 2012), especially due to insufficient effluent to meet 100% of theoretical shrub ET (Babcock et al, 2009).…”

“…In the present study, wastewater application was not arbitrary but rather based on average ET of the native shrubs, L. tridentata and P. glandulosa (Ruiz et al, 2006). However, as soil reactions with waste contaminants are critical to sustainable land application systems (Bastian, 2005), the impact of wastewater application on soil properties must be addressed.…”