Water Hogs

 Although winter and spring rainfall has been plentiful this year water continues to be a limited resource in New Mexico.  While conservation efforts continue to improve water use, many people do not realize that weeds are another source of water loss as many use a tremendous amount of water.  These weeds are known to be “water wasters or water hogs”.  Many of these are woody exotic trees like saltcedar.  This species has been shown to use large quantities of water (36,820 gal water/acre in a southern Colorado site; 200 gallons per day per tree in Texas).  This is why saltcedar has been targeted for control along the Rio Grande and Pecos Rivers for the last two years by state of New Mexico. 

While much or our rivers are lined with these woody exotics, few are present along canals and ditchbanks.  In these areas the most common plants are weedy annuals like kochia and Russian thistle.  Although these weeds are annuals, they can also be “water hogs” as they have been shown to be able to use large amounts of water.  For example studies have shown that kochia and Russian thistle can use 22 and 29 gallons of water per plant respectively.  When this information is scaled up to densities that are seen under natural conditions in New Mexico, water used annually can exceed 20,000 gallons for kochia and 75,000 gallons for Russian thistle.  Below is a table that estimates water loss at varying infestations levels.  Remember these plants are some of the most common weeds found along canals and other disturbed areas throughout the state, so much of this water is lost!