The $247 million Wichita ASR water project operates at just a fraction of its design capacity.
An important part of Wichita’s water supply infrastructure is the Aquifer Storage and Recovery program, or ASR. This is a program whereby water is taken from the Little Arkansas River, treated, and injected in the Equus Beds aquifer. That water is then available in the future as is other Equus Beds water.
With a cost so far of $247 million, the city believes that ASR is a proven technology that will provide water and drought protection for many years. Last year the city recommended that voters approve $250 million for its expansion, to be paid for by a sales tax. Voters rejected the tax.
According to city documents, the original capacity of the ASR phase II project to process water and pump it into the ground (the “recharge” process) was given as “Expected volume: 30 MGD for 120 days.” That translates to 3,600,000,000 (3.6 billion or 3,600 million) gallons per year. ASR phase II was completed in 2011.
The ASR project is able to draw from the Little Arkansas River when the flow is above 30 cubic feet per second. It doesn’t flow at that rate every day of the year. That’s why the expected production volume is calculated based on 120 days of operation per year.
What has been the experience of the ASR project? I’ve gathered data from the U.S. Geological Survey on the flow of the Little Arkansas River at the relevant measuring station. USGS also has production figures. I’ve presented these previously in articles like Wichita water statistics update.
The nearby charts give an idea of the efficiency of operation of the ASR project. (Click charts for larger versions.) For each month, I counted how many days had a river flow above 30 cfs at every measurement for the day. (The flow is measured several dozen times a day.) If a day had all measurements above 30 cfs, I counted that as a day of adequate river flow. I then calculated the number of days of work actually accomplished using the water produced each month, the number of days of adequate river flow for the month, and the ASR design capacity.
As can be seen in the charts, the ASR project is operating far below its design goal. So far the city has not been able to provide an explanation as to why this project is not meeting its goals.