If current weather trends continue, Lakes Graham and Eddleman could be unusable as public water sources as soon as May of 2015 unless action is taken by the city to re-engineer the way water is removed from the conjoined lakes for treatment, according to a report commissioned by the City of Graham.
“At the present rate of elevation decline, the lake level will reach the level of the city’s intake structure by November, 2015,” concludes the report. “A lake floor ridge that could present an obstruction to the flow of water to the intake structure was identified recently at 1,058 feet and could be reached by May, 2015.”
The city is currently working on plans to re-engineer the removal of water from the lake to allow for continued use below that elevation, said city manager David Casteel.
“At the next meeting, I’ll have some engineers come in and give us some options on how to get the water out,” said Casteel.
The city commissioned Scott Swanson of LaCosta Environmental to determine how fast the water in Lakes Graham and Eddleman will disappear under various climate circumstances and what would be required to recharge, or refill, the lakes. He reported his findings to the council at its May 22 meeting.
This report was the first of four city-commissioned studies aimed at determining contingency plans for Graham’s water supply as the severe drought in the southwest United States continues.
“It did rain the last time I was here. I tell people when I go and talk that I like to bring a little rain with me,” joked Swanson to begin his presentation. “I’ll take credit for anything you guys get in the next three days.”
Swanson’s report considers five possible weather scenarios moving forward: Minimum, dry, normal, wet and maximum. Each category represents possible rainfall totals for the area with the minimum being 11.23 inches a year, the same as 2011. Normal constitutes the average local rainfall total for a year at 27.8 inches, and the maximum is set at 40.78 inches a year.
Over the previous 27 months this area has been following the “dry” trend of at or below 24.01 inches of rain yearly, the report states, causing the lake to drop 12 feet in elevation.
“Under continued dry rainfall conditions, the lake could fall below 20 percent capacity by January, 2016,” Swanson’s report said.
Not all of the lake can be used for drinking water.
“When you get down to 20 percent getting it out is very difficult,” explained Casteel.
Read the entire story in Wednesday's Graham Leader.