Kayakers on the Beaverdam Reservoir in Loudoun County. (Jim Barnes/For The Washington Post)

Last Sunday morning, dozens of water enthusiasts arrived at a cramped parking lot, traveling solo or in small groups. They unloaded brightly colored kayaks, paddle boards and canoes from their vehicles and pushed off from a small incline into a shimmering, 600-acre body of water.

A fisherman cast his line from the shore nearby, while another dropped his line from a boat a few hundred yards away. A great blue heron flew back and forth, close to the surface, scanning for food and occasionally landing on the shore to take in the scene.

The tranquility at Beaverdam Reservoir was striking, in part because it is such a short distance from the traffic and bustle of Ashburn. Because the reservoir supplies drinking water for thousands of Loudoun residents, the scene was undisturbed by the sounds of gas-powered watercraft, which are prohibited to protect the water quality.

The park is open daily from dawn to dusk — but not for long, said Susan Crosby, a spokeswoman for Loudoun Water, the utility that owns the reservoir. On Nov. 1, the park will close for two years for repairs that will bring the dam and spillway up to state standards. It will reopen permanently in 2019, she said.

The 1,000-acre public park includes the reservoir and adjacent land, much of which is wooded. Beaverdam is accessible from Mount Hope Road, just west of Belmont Ridge Road, near Ashburn.

Despite getting little publicity, the reservoir is a popular spot for outdoor recreational activities, park manager Dale Riggs said.

“On a busy weekend day, we’re doing 300 or more [visitors] at Mount Hope parking area,” Riggs said.

The most popular water activities are kayaking and paddle boarding, Riggs said, adding that four high school crew teams also practice there. There is a two-mile unpaved hiking trail along the east side of the reservoir, and another trail is planned for the west side, he said.

“We can’t make it a loop [around the reservoir], because the dam is off-limits,” Riggs said.

Before Loudoun Water purchased the reservoir from the city of Fairfax in January 2014, recreational use of the property was not supervised, Loudoun Water spokeswoman Crosby said. In spring 2015, Loudoun Water closed the reservoir for a few months.

“When we bought it, we weren’t really sure what all was there,” Crosby said. “We had to do some exploration on the bottom of the reservoir, look at the dam and spillway . . . and we had to lower the water level. It was kind of an unknown at that point.”

The utility’s primary objective has been to protect the water supply, she said.

“Obviously, we’re concerned with the fact that it is a drinking water reservoir, which is why it’s more of a passive recreation park,” she said.

After completing an assessment of the property, Loudoun Water determined that it was safe to use the reservoir for public recreation, and it partnered with Nova Parks, the Northern Virginia Regional Park Authority, to reopen it last summer.

Loudoun Water and Nova Parks had a community meeting in October to gather input on how the park might be used. About 200 area residents attended, Crosby said, providing comments on topics such as environmental stewardship and education, nature appreciation, hiking, fishing, paddling, rowing and picnicking.

While the park is closed, Loudoun Water will work with Nova Parks to create a land-use plan for the property, drawing on feedback from the community input session, Crosby said.

Crosby said she expects to schedule another community meeting in the next year “to share some preliminary plans of what the park is going to look like when it does reopen.”

“We’re really excited about what this is going to be when we’ve done the repair of the dam, and we can focus on the park,” Crosby said. “It’s such a special place. There’s really nothing else like it in Loudoun County.”