More than 40 million gallons of water a year will be saved from aquifers beneath Woodbury in a highway project that will pipe stormwater ­runoff to two golf courses.

The $9.9 million makeover of County Road 19, known locally as Woodbury Drive, includes installation of piping and irrigation ditches that planners say will improve water quality in nearby Colby and Bailey lakes.

“It seems we have to start looking at ways to conserve and this might be one of them,” said Steve Kernik, environmental planner for Woodbury. “We’ve got to be smart with the way we use our water. Even though we’re in the land of 10,000 lakes, it’s not an inexhaustible resource.”

The project involves rebuilding a 1.75-mile stretch of County Road 19 into modern times. The crumbling two-lane highway, built when Woodbury was a much smaller city, now sees substantial traffic.

Stormwater runoff from the ­highway has been draining into nearby lakes, causing algae growth because of the high phosphorous content. As a result, the Minnesota Pollution Control Agency (MPCA) has added Colby Lake to its impaired waters list.

Reconstruction of the highway will include the new water plan — diverting stormwater to holding ponds at nearby Eagle Valley and Prestwick courses where it will irrigate grass.

Traditional stormwater ponds were scratched off the construction list when it became apparent they wouldn’t fit into the busy neighborhood, said Cory Slagle, transportation construction engineer for Washington County.

“There are houses built up and down the corridor and there is not a lot of other space,” he said. “We needed a place to put our water and also to treat our water.”

Because of the stormwater diversion plan, golf courses will reduce their pumping from wells by about 40 ­million gallons a year, Eckles said, which has benefits for a city of about 65,000 residents that’s been frugal with its water ­supply.

“The water that was going to grow algae in the lakes now will grow grass,” said Klayton Eckles, Woodbury’s city engineer. “I think long-term the implication is we don’t want to run out of groundwater. This is another one of our efforts to reduce the overall water footprint, or draw, on the aquifer.”

Woodbury and other east-metro cities are painfully aware of recent theories that municipal wells surrounding White Bear Lake are tapping aquifers to the point that they’re slurping water from the lake. Water demands in suburbia, coupled with years of successive drought, have led to new conservation ­measures.

Eckles said he wants to make sure that some agencies charged with monitoring stormwater don’t pull the plug on creative uses like the County Road 19 plan because of concern over possible health problems. Golf courses have sprinkled surface water for 100 years, he said, and owners of lake homes do it, too.

“It’s happening all around us,” he said. “My interest is making sure that we don’t ­regulate it to the point of making it infeasible.”

The County Road 19 project is managed by Washington County, Woodbury and the South Washington Watershed District. Eckles and Kernik hope the water plan will become a model for other projects.

“It’s an elegant little ­system,” Kernik said. “We’ll keep our fingers crossed and hope it works.”