The Positive Impact of Alcoa’s Water Quality Investments: Water Leaving Yadkin Project Hits Mark 100% of the Time

Water leaving the Yadkin Project meets state standards for water quality 100% of the time, according to a report on dissolved oxygen that was submitted to the NC Division of Water Resources in March.

Dissolved oxygen levels are a key indicator of water quality and are often used by state agencies as a benchmark. Alcoa Power Generating (APGI) has been closely monitoring dissolved oxygen levels at the Yadkin Project since 2007 and provides an annual report to the state. The Yadkin Project is not currently subjected to state standards for dissolved oxygen, but it will be once a new federal license is issued.

The report shows that turbine upgrades and other enhancements made several years ago have continued to improve water quality at the Yadkin Project.

“The investments we’ve made at Narrows Dam continue to enhance water quality,” said Ray Barham, APGI’s Yadkin Relicensing Manager. “We’ve spent more than $5 million in new technology at the Narrows Dam and it has been very effective at improving downstream water quality.”

Quality Improves As Water Flows Through the Yadkin Project
Water enters the Yadkin Project at High Rock Lake with relatively low concentrations of dissolved oxygen. After traveling 38 miles down the Yadkin River and passing through four dams operated by APGI, the water quality improves significantly before it is discharged at the Falls Dam.

In 2013, water discharged from High Rock Dam met the state standard for dissolved oxygen 78% of the time (based on daily average measurements). It met those same standards 100% when discharged from Narrows Dam and Falls Dam.

$80 Million in Additional Investments Planned by Alcoa
APGI has committed to investing up to $80 million to continue improving water quality at the Yadkin Project, beginning with a $40 million investment at High Rock Lake. APGI will install three “through-the-blade” aerating turbines at High Rock once the Federal Energy Regulatory Commission (FERC) issues a new license for the Yadkin Project. The engineering, planning, and model testing of the new turbines has already been completed.

“We will begin work at High Rock Dam as soon as we receive a new license,” Barham said.

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Summary of 2013 Dissolved Oxygen Report Findings
The state measures dissolved oxygen concentrations in two different ways: through instantaneous measurements recorded every 15 minutes, and with a daily average of all measurements in a given day. Here is how the four Yadkin dams performed in 2013 versus a state standard that will take effect when a new federal license is issued:

High Rock Dam (Water enters the Yadkin Project at High Rock)
77.8% compliance with new standard - Daily Average Measurement (Up 39% over 2012)
93.4% compliance with new standard - Instantaneous Measurement (Up 34.2% over 2012)

Tuckertown Dam   
70.1% compliance with new standard - Daily Average Measurement (Up 36.9% over 2012)
87.4% compliance with new standard - Instantaneous Measurement (Up 36.6% over 2012)

Narrows Dam (New technology installed in 2001 and 2007)
100% compliance with new standard - Daily Average Measurement (Up 0.5% over 2012)
99.9% compliance with new standard - Instantaneous Measurement (Same as 2012)

Falls Dam (Water exits the Yadkin Project at Falls) 
100% compliance with new standard - Daily Average Measurement (Up 13.7% over 2012)
100% compliance with new standard - Instantaneous Measurement (Up 3.4% over 2012)

Additional Notes
1. The state standards for dissolved oxygen do not currently apply to the Yadkin Project, but the rule will be applicable under a new federal license.
2. Differences in hydrologic, meteorological and/or other natural conditions or tailwater aquatic vegetation can effect dissolved oxygen levels from one year to the next.

Alcoa Investments Improving Water Quality at Yadkin Project

Water quality at the Yadkin Project has improved dramatically since we invested more than $5 million in turbine upgrades and other enhancements specifically designed to increase the amount of oxygen in the water.

That's the finding of a report on water quality that APGI released this week. It shows that water discharged from the Narrows Dam contains the highest concentration of dissolved oxygen — a key indicator of water quality — since we began monitoring water quality in 2007. This demonstrates that the Yadkin Project’s water quality is consistently improving, as measured by state standards for dissolved oxygen that will take effect when we receive a new federal license.

Why is this important? It's further evidence that the Yadkin Project deserves the state water quality certificate it was issued in 2009. A water quality certificate is a requirement for receiving a new FERC license.

We have installed new technology at three turbines at Narrows Dam, and water discharged from Narrows would have met the new state standard 100 percent of the time in 2011 — a 115 percent improvement since the majority of the work at Narrows was completed in 2007. We were confident that this technology would significantly improve dissolved oxygen conditions and it has.

In addition, APGI has committed to invest up to $80 million more to continue improving water quality at the Yadkin Project, beginning with a $40 million investment at High Rock Lake. Once we complete those upgrades, the Yadkin Project will fully comply with state water quality standards.

Click here to read the press release.
Click here to view the complete report.

APGI releases additional information on 401 appeal

On Friday, January 28, Alcoa Power Generating Inc. (APGI) appealed the North Carolina Division of Water Quality's (DWQ) revocation of APGI's water quality certification (401).

Today, we are releasing documentation showing that DWQ was well informed about the equipment in question and its functionality in increasing levels of dissolved oxygen (DO) in the water and that APGI did not withhold important information. 

Please visit our website at www.alcoa.com/yadkin/en/info_page/401_appeal_summary.asp for more information.

Dissolved Oxygen Report Shows Continued Improvement at Alcoa Power Generating’s Yadkin Project

Water Leaving Yadkin Project Meets State Instantaneous Dissolved Oxygen Standard 99.9 Percent of the Time

Water leaving Alcoa Power Generating’s (APGI) Yadkin Project met a state standard for dissolved oxygen levels 99.9 percent of the time in 2010, according to a report submitted last week by APGI to the North Carolina Division of Water Quality (DWQ).

APGI’s Yadkin Project operates four dams along the Yadkin River. Water enters the project area at High Rock Dam, then flows through Tuckertown Dam, to Narrows Dam and exits the project at Falls Dam. The report demonstrates that water coming into the project at High Rock has relatively low levels of dissolved oxygen (DO). But there is a substantial improvement in DO at the Narrows Dam, where APGI installed new technology in 2008 and 2009 to enhance DO levels, and that improvement is maintained until the water exits the Yadkin Project at Falls dam.

The report on dissolved oxygen levels in the Yadkin Project tailwaters shows that discharges from the Falls Dam met the state instantaneous dissolved oxygen standard 99.9 percent of the time and daily average dissolved oxygen standard 97.4 percent of the time. Water coming into the project at High Rock, where a $40 million project to install DO enhancement technology awaits approval of APGI’s operating license by the Federal Energy Regulatory Commission (FERC), met the state instantaneous dissolved oxygen standard 65.1 percent of the time and daily average dissolved oxygen standard 43.1 percent of the time.

“This report shows continued improvement of dissolved oxygen levels in water below the Narrows Dam and demonstrates that new technology installed at Narrows is successfully increasing dissolved oxygen levels in downstream waters. This is true under the full range of unit operation, including ramp up, ramp down and other periods of relatively low operation,” said Kevin Anton, Chief Sustainability Officer for Alcoa. “These results provide reassurance that additional technology enhancements at Narrows and High Rock planned under a new federal license will further increase dissolved oxygen levels as part of our commitment to meet state DO standards.”

An adequate amount of oxygen in the water is necessary to support healthy aquatic life, and many states monitor DO levels as one way to help measure water quality in lakes and rivers.

Under state standards applicable to the Yadkin Project under a new federal license, DO concentrations must meet or exceed 4.0 mg/L when measured instantaneously, and DO concentrations must meet or exceed 5.0 mg/L when measured on a daily average basis.

APGI has developed a comprehensive plan for improving DO levels throughout the Yadkin Project that will cost up to $80 million, depending upon the final requirements. As part of its plan, APGI has been monitoring DO levels since 2007.

The DO report submitted to the Division of Water Quality summarizes the levels of dissolved oxygen measured in the Yadkin Project tailwaters since 2007. Data is recorded every 15 minutes, 7 days a week in the tailwaters of each dam between May 1 and November 30. The measurements are taken during this time period, when DO levels are typically at their lowest, at the state’s request.  Tailwaters are those waters immediately below the dams where dissolved oxygen levels would be influenced by water released through the dams. DO monitors are located in well-mixed areas that are representative of temperature and dissolved oxygen conditions throughout the tailwaters.  Normandeau Associates, a national firm specializing in environmental management and consulting, is responsible for quality assurance/quality control, calibration, maintenance and collection of data from the DO monitors. 

The report shows significant improvements since DO technology was installed at Narrows:

• For the third consecutive year, Falls tailwaters substantially met the state instantaneous DO standard: 99.9 percent in 2010, 99.7 percent in 2009, and 99.5 percent in 2008.

• Narrows tailwaters met the state instantaneous DO standard 93.4 percent of the time in 2010 — a 34 percent increase over 2007 levels (69.6 percent). Since 2007, APGI installed two draft tube air valves on Narrows Units 1 and 2 to improve DO levels. The same technology was installed on Unit 4 in 2001 and will be installed on Unit 3 once a new FERC license is issued.

• Dissolved oxygen levels are enhanced at Narrows even when generating units are operating as low as one megawatt, due to aeration from vacuum breaker valves. The vacuum breaker air valves open when the units are operating at lower settings and introduce air into the water.

• The High Rock and Tuckertown tailwaters met the state DO standard less frequently in 2010. High Rock met the state instantaneous DO standard 65.1 percent of the time, and Tuckertown met the state instantaneous DO standard 56.3 percent of the time.  This could be due annual variability in hydrologic and meteorological conditions or changes in the quality of the water entering High Rock.

The Yadkin Project’s Relicensing Settlement Agreement (RSA) outlines a schedule for installing “through-the-blade" aerating turbines for all three generating units at High Rock once a new FERC license is issued. The engineering, planning, and model testing of the new turbines has been completed and long lead-time items have been ordered. APGI has committed to install additional DO enhancement technology at Tuckertown and Falls if necessary to meet state DO standards.

“We have made great progress and have every reason to believe the technology enhancements will continue to increase dissolved oxygen levels and allow the Yadkin Project to meet the state DO standard,” Anton said. “Our commitment to reaching that goal has never been in question.”

Click here to read the full report.