Hickory Aquifer Update
The 30-inch transmission pipeline from the Hickory Aquifer and the booster pump stations were substantially completed last month. Meanwhile, construction on a groundwater treatment facility has begun as the contractor excavates for the building foundations.
Substantial completion of the 62-mile-long pipeline and the booster pump station, which will help pump the water from McCulloch County to Eden, where it will flow into San Angelo via gravity, means the infrastructures are operational, but that minor details must be addressed before the contract is closed.
Once the Hickory Aquifer project is complete, the improvements will be capable of delivering 9 million gallons per day to San Angelo, supplementing the City’s surface water supply on an as-needed basis.
The pipeline was deemed substantially complete Oct. 25. The booster pump station phase of the project included equipping nine existing wells and construction of two ground storage tanks, booster pumps, electrical transmission lines and a communication tower. The well field piping that will deliver water from the nine wells to the 30-inch transmission main is also complete.
A notice to proceed on the project’s groundwater treatment plant and a new disinfection facility was issued to PCL Construction of Irving on Sept. 9. The treatment facility at Avenue K and Metcalfe Street, adjacent to the current water treatment plant, will remove the naturally occurring radium from the Hickory’s water. That phase of the project is scheduled for completion on Nov. 8, 2014.
Earlier this month, Alsay Inc. of Houston began drilling six additional wells above the Hickory Aquifer. Currently, one drilling rig is operational and a second rig is being assembled on site. Those wells are scheduled to be completed by Dec. 16, 2014.
A second phase of the well field expansion will be advertised for bids Nov. 20. That project will include equipping the six new wells with pumps, installing piping from the wells to the existing distribution system, and constructing a booster pump and roads to the new wells. A notice to proceed is scheduled to be issued to the contractor on March 1, 2014, with completion slated for Jan. 1, 2015.
The project is being funded by a $120 million low-interest loan from the Texas Water Development Board. The loan can only be used on the Hickory project.
The project was initially designed to bring 6 million gallons per day to San Angelo. Originally, the City planned to increase production to 9 million gallons per day in 2026. (Daily water usage in San Angelo is approximately 9 MGD during the winter, when few people water lawns.) Because of extended drought conditions, the City Council previously decided to expand the capacity to 9 MGD as soon as possible. This became financially possible because of savings from earlier phases of the project.
The initially planned production rate of 6 million gallons per day would enable the City to take full advantage of its annual allocation of water from the aquifer and the amount of water that has been “banked” since those allocations were established.
The expansion will provide the City with another option to respond to future or continued droughts, although utilization of the 9 MGD production rate would cause the “banked” water to be used more quickly and would impact the City's future production abilities from the Hickory until annual allocations increase in 2026. The additional 3 MGD would be used only to supplement the City's water supply if no other sources are available to meet daily needs.
In a worst-case scenario, the City could produce 9 MGD on a continual basis for five years before all the banked water would be used. Afterward, San Angelo would still be able to use its annual water allocation, which is currently 2,750 acre-feet per year. This amount increases to 5,000 acre-feet per year in 2021, to 10,000 acre-feet per year in 2026 and to 12,000 acre-feet per year in 2036.
San Angelo relies upon O.H. Ivie, Twin Buttes and O.C. Fisher reservoirs, and Lake Nasworthy as its water sources, and currently has a 16-month supply of water, assuming the worst-case scenario of no rainfall or runoff. As of Nov. 13, Ivie was at 15 percent capacity, Twin Buttes was at 2 percent, Fisher at 3 percent and Nasworthy 77 percent.
San Angelo has received 18.06 inches of rainfall to date this year. Normally, San Angelo averages 19.89 inches through Nov. 13.