A few monsoonal clouds helped only slightly with 105 degree temperatures

They don’t make a big public fuss about it and they don’t usually refer to it as such but for Las Vegans, Indirect Potable Reuse (IPR) plays a big role in helping to cope with difficult water supply issues. After drawing most of its water from Lake Mead, Las Vegas produces an average of 193 million gallons (mgd) of wastewater per day. The wastewater is treated to an advanced purification and disinfection process and is returned to Lake Mead via the Las Vegas Wash. The water is then reused by the city (and by downstream users like San Diego).

The returned water gets credited to Las Vegas as part of the calculation specifying how much water the city can draw from Lake Mead, so IPR is integral to keeping those showers and faucets running. Because of that allowance, the IPR operation in Las Vegas is commonly referred to as “Return-Flow Credits.”

Since San Diego is only now preparing to undertake a study of a small-scale IPR operation for itself while Las Vegas is already doing it full-scale, I decided to see if I could visit the Las Vegas facilities and get a feel for how IPR has worked out for them. Not only were they willing to allow me to visit, the Southern Nevada Water Authority graciously scheduled a whole series of tours for me over a three-day period. That was a special treat after a disappointment I had when I asked to visit the Alvarado Water Treatment Plant a short distance from my home in San Diego and the reply was “The Federal government made us stop the tours following 9/11 and they haven’t allowed us to start them again.”

My visit last week included visits to the two existing water pumping and transmission facilities at Lake Mead as well as the third intake under construction, the Alfred Merritt Smith Water Treatment Plant, the River Mountains Water Treatment Plant, the Water Quality Laboratory and Applied Research & Development Center, the Clark County Water Reclamation District, the Las Vegas Wash, and Lake Mead & Hoover Dam.

I’ll need to digest everything I learned and intend to write about it in the future, but for now I’d like to share some photos from the visit. You can click them for enlargements.

Read the rest of this entry »