New well to serve southeast Mesa, help meet peak demands

Drilling, casing and test pumping have been completed at Desert Well 17 (DW 17), the first well to be completed since the new arsenic rule took effect in January 2006. Initial testing at this site revealed high levels of arsenic in the water at certain depths. However, by selectively screening those layers (i.e., not perforating the casing at those depths), DW 17 will meet the new arsenic standard without treatment.

The water from the well can now be pumped directly into the distribution system or used as a blending source for a well with a higher arsenic level. This is also the first well Mesa has equipped with stainless steel casing instead of the standard slotted steel pipe, which should increase the well’s useful life from about 40 years to 60 to 80 years.

The well is expected to produce approximately two million gallons per day or 1,300 gallons per minute (gpm) and will serve as a back-up source for the CAP plant in the summer and during canal dry-up. DW17 is slated to come online later in 2007, after pumping equipment is installed.