AWWA JAW62636

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. Includes 29 references, tables, figures.