Water Resources
Water management in our fossil fuel plants
Our coal-fired and gas-fired plants draw water directly from lakes and rivers, such as the St. Clair River in Ontario, the Skookumchuck River in Washington, and Wabamun Lake and the North Saskatchewan River in Alberta. As well, some gas-fired plants draw water from deep wells and municipal water systems.
Our plants process water in different ways. In our coal-fired plants, purified water is either returned to its source under regulated temperatures (Wabamun) or recirculated through cooling ponds (Keephills and Sundance). In our gas-fired plants, most of the water is recirculated in operations, keeping discharge volumes low. Wherever possible, we look for opportunities to minimize our water consumption through advanced plant design.
Our statistics for water consumption show the difference between our water intake and discharge. In 2004, our coal and gas plants used about 92.4 million cubic metres (3,263 million cubic feet) of water, compared with 99.2 million cubic metres
(3,503 million cubic feet) in 2003. This decrease was due mainly to the shutdown of our Wabamun unit 3 at the end of 2002. Similarly, our water consumption intensity (cubic metres of water consumed per megawatt hour) improved nearly 11 per cent over the previous year.
Managing water discharge
In our coal and gas plants, we discharge primarily cooling water. At our Wabamun coal plant, we also use some water to transport ash through a series of settling ponds as part of an ash treatment system. Once the ash settles out, the water is returned to the lake. Before discharge, the water is monitored to ensure it meets environmental standards.
Water treatment plant exceeds requirements
TransAlta’s operations are one of many factors that affect the water level of Wabamun Lake. Warm water from the Wabamun plant causes some evaporation, the Highvale mine diverts surface water as part of its operations and the Sundance plant uses water for boiler makeup and domestic purposes. Our company’s average impact on the lake level is about 11.5 million cubic metres or 11.4 centimetres (4.5 inches) each year. Other impacts to the lake include precipitation, surface run-off, ground water flows and natural evaporation.
In 1997, we built the Wabamun Lake water treatment plant to mitigate our operations’ past and ongoing impacts on lake levels. In response to requests from our neighbours, we expanded our output of water with the construction of an additional plant, which began operating in May 2002. The facility treats water from the Sundance plant’s cooling pond and pumps high purity water to the lake. Water taken from the cooling pond is replaced by water from the North Saskatchewan River. Water released into the lake is designed to meet stringent government guidelines to protect the ecology of the lake.
TransAlta plans to repay 20 million cubic metres per year from 2004 to 2006 and another 8 million in 2007. In 2004, we continued to make progress against our annual commitment to repay our historic debt to the lake. At year-end, the water treatment plant returned over 21 million cubic metres of water to the lake, exceeding our commitment for the second year in a row.
At the end of 2004, the Wabamun Lake water treatment plant’s cumulative water production was 44.3 million cubic metres, about 10 per cent better than the license requirement.
Ken Omotani,
senior environmental engineer at TransAlta
Case study
Long-term plan for water treatment plant
Our company plans to continue to operate the Wabamun water treatment plant after we have repaid our historic debt requirements at Wabumun Lake, Alberta. We have developed an operational plan detailing how the facility will operate after that milestone is reached.
“We’re making good progress against the water debt and are on target to repay it by July 2007,” says Ken Omotani, senior environmental engineer at TransAlta. “With this in mind, we’ve now begun to look closely at what makes the most sense in terms of offsetting our annual operating impact on the lake.”
In 2004, Omotani worked with a TransAlta team and an engineering consultant to develop four different operating scenarios, which will enable our company to offset its annual impacts and meet regulatory requirements. These were discussed with Alberta Environment, Wabamun Watch and other community groups.
Omotani says, based on the consultation, TransAlta is now focusing on a proposed option that will result in an annual pumping rate, calculated each year based on the previous five years’ operational impacts.
“Our stakeholders thought this particular option was reasonable and made the most sense, because it puts the most water back into the lake, and the constant pumping rate tends to mimic the natural ebb and flow of the lake more closely than the other options. Plus, it’s the easiest one to manage, because we know exactly how much water we need to pump back into the lake each year and can plan maintenance in advance.”
After further consultation with stakeholders on the proposed option, TransAlta will submit the final long-term operational plan for the water treatment plant to Alberta Environment for approval later in 2005. Omotani says the company will recommend that the operational plan be reviewed every five years.
Scientific review of Wabamun Lake released
TransAlta continued to work with government and local stakeholders to evaluate potential environmental and health impacts from our Wabamun power plant and other local activities on the watershed. These studies have been under way since 2001 when complaints were first raised about murky water in Wabamun Lake near our Wabamun plant’s ash lagoon.
In early 2004, we completed a detailed risk assessment report to determine the contributions of the power plant to trace metal concentrations and the risk to people and the lake’s ecosystem. Our findings show no additional health risks to people, wildlife or aquatic life.
In 2004, a task force of Alberta scientists, under the direction of Dr. David Schindler, a University of Alberta ecology professor, reviewed all available information on water quality in Wabamun Lake, including TransAlta’s report, to find out if further studies were needed. Their review covered various impacts to the health of the lake, including TransAlta’s operations.
In early 2005, the scientific team concluded that the lake is in “moderately good condition,” despite recreational activity and industrial use. Their study also confirmed that TransAlta employees have applied good environmental management practices for many years. Alberta Environment will study their report before deciding on the recommendations.
Fish management system at Wabamun
During spawning seasons, fish sometimes come into contact and are injured by our intake screens at the Wabamun coal plant. Fish species at greatest risk are pike during the spring and whitefish during the fall.
We have put in place a comprehensive fish management system to minimize the risk of fish injuries at the site. Our program consists of specially designed screens, fish return systems, acoustical and strobe lighting deterrents and staffing the plant screen house 24 hours a day, seven days a week, during high risk periods, with employees trained by fisheries biologists. Wherever possible, we plan plant outages to coincide with spawning times, thereby reducing water flow near the screens and lowering risks to fish.
Since installing the system in 2002, we have significantly lowered the number of fish entering our intake screens and now report very few fish mortalities.
Essential fish habitat evaluations
Whenever we develop growth plans for our plant and mine operations, we conduct extensive assessments to understand the potential effects of our proposed activities to water bodies and sensitive environmental areas. Essential fish habitat evaluations are required of many projects that affect streams and wetlands.
In 2004, as part of our revised mining and land reclamation plan for our Centralia mine, we carried out essential fish habitat evaluations. These identified the temporary loss of some streams and wetlands as a result of our proposed plans to expand the mine. To offset these impacts, we developed plans for fish alcoves (backwater areas) along a creek on our property to create new fish rearing areas for coho salmon. We also are developing plans to restore a section of the Big Hanaford Creek, long ago drained by agricultural activities, to its natural stream channels, thereby enhancing wetlands and habitat for coho salmon.
