Monday, February 13, 2023

In Oro Valley, Water Is A Challenge But There Is Plenty For Which To Hope

Some hope for an increase Colorado River water
As you know, demand for Colorado River Water exceeds supply. One reason is that Colorado River Water is oversubscribed. There are seven states, Mexico, and various tribes that draw from it. That is a total of 40 million people and 5.5 million acres of farmland that rely on it. 

The second reason is a 23-year drought, some of which has been alleviated with the extensive precipitation this winter. "Colorado's current snowpack is at 128%. Some parts of Utah have reported over 200% of their snow-water equivalent compared to average. When the snow melts, it will eventually flow into the Colorado River and help alleviate reservoir stress." (source)

Keeping the power working is the main focus of efforts regarding CAP Water
This is good news but it will take many more years of extensive precipitation to make Colorado River Water a long-term reliably supply. Thus, the need for continued effort to ensure that the water levels of Lake Meade and Lake Powell stay high enough to allow continued electric generation. 

The seven states have been given a deadline by the US Bureau of Land Management (BLM) to develop guidelines to do just that. This effort is called "reclamation."  Six of the seven states have submitted a plan. California, the big dog in the Colorado River water take, has not yet agreed to anything. Essentially, the plan reduces the water take of each state when the water levels of the two lakes reach specific levels.  Arizona continues to take big hits even under this plan.

Purified reclaimed water is a potential source of drinking water...Scottsdale is an example
During a discussion with Council last June, Oro Valley Water Director Peter Abraham mused at the possibility of purifying reclaimed water and putting it back in the drinking water supply. That is what Scottsdale does with some of its reclaimed water.  They call it "indirect potable water use." (Not “toilet to tap”)

The Scottsdale Advanced Water Treatment Plant ".. takes tertiary effluent from the city’s conventional water reclamation plant and further treats it through ozonation, membrane ultrafiltration, reverse osmosis and ultraviolet photolysis."  Scottsdale built the plant in 1998. The plant created 1.7 billion gallons of purified water last year. It comes from treating reclaimed water. (Source) That water is recharged into the aquifer. It is not directly put into the water system, though a 2018 Arizona statute allows them to do so. The drinking water treatment plant is part of the Scottsdale Water Campus.

Desalinated water is also on the horizon
Oro Valley Council Member Mo Greene discussed desalinated water at February 1 council meeting. "All of us have been following water pretty closely." Referring to the map at left: "If you follow the blue track, It goes down to Rocky Point (Puerto Penasco), where they are beginning to look at a desalinization plant, which could be brought by pipe up to Phoenix...this is something you may want to keep an eye on." According the Greene, speaking at this past Friday’s Council strategy session: “Desalinated water is in our future whether you like it or not.”

The "they" to which Greene referred is the State of Arizona. "Arizona officials voted to advance a $5.5-billion plan to build a water desalination plant in Mexico, as well as a 200-mile pipeline and associated infrastructure as part of a state effort to address its drought-driven water uncertainty" The State will finance this through a new organization called the Water Infrastructure Finance Authority (WIFA).  Desalinated water can be made available by 2027.

The plan is to pipe water to two new reservoirs west of Phoenix. From there, the water would enter the CAP canal, flowing to Phoenix, Pinal County and Tucson. Some of the desalinated water would go though a separate pipeline to Hermosillo. The plant, constructed and operated by IDE Technologies, would provide 300,000 acre feet annually at a cost of about $2,500 per acre foot. That's less than a penny a gallon. The cost is about two times the cost of non desalinated water.

...but what to do is fraught with politics and environmental "concens" and cost concerns....
The problem with all this is that it is fraught with politics. The Puerto Penasco plan is merely an idea at this point. There is no commitment to do anything.There is only a commitment to study it.  There are other alternatives, like using the water to swap with Mexico's Colorado river take. And the water is costly. And there are environmental impacts. And the desalinization process uses lots of electricity. Here's a CNBC report on why desalinization is a "bad idea".

Still, it's a start at resolving a long term water issue that will plagues our desert communities. 
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